Stuff

README.md

@@ -6,16 +6,14 @@ A TUI IDE.
 
 # TODO
 
-- [ ] Add folding support at tree-sitter level (basic folding is done).
 - [ ] Add feature where doing enter uses tree-sitter to add newline with indentation.
     - it should also put stuff like `}` on the next line.
-- [ ] Add this thing where selection double click on a bracket selects whole block.
-    - (only on the first time) and sets mode to WORD.
 - [ ] Add the highlight of block edges when cursor is on a bracket (or in).
-- [ ] Add support for brackets/quotes to auto-close. (also for backspace)
+- [ ] Add this thing where selection double click on a bracket selects whole block.
+    - (only on the first time) and sets mode to `WORD`.
 - [ ] Add support for virtual cursor where edits apply at all the places.
-- [ ] Add search / replace along with search / virtual cursors are searched pos.
 - [ ] Add alt + click to set multiple cursors.
+- [ ] Add search / replace along with search / virtual cursors are searched pos.
 - [ ] Add support for undo/redo.
 - [ ] Add `.scm` files for all the supported languages. (2/14) Done.
 - [ ] Add splash screen / minigame jumping.
@@ -24,3 +22,5 @@ A TUI IDE.
 - [ ] Normalize / validate unicode on file open.
 - [ ] Add git stuff.
 - [ ] Fix bug where alt+up at eof adds extra line.
+- [ ] Think about how i would keep fold states sensical if i added code prettying.
+- [ ] Redo folding system and its relation to move_line_* functions.

grammar/bash.scm

@@ -1,13 +1,3 @@
-[
-  (function_definition)
-  (if_statement)
-  (case_statement)
-  (for_statement)
-  (while_statement)
-  (c_style_for_statement)
-  (heredoc_redirect)
-] @fold
-
 ;; #bd9ae6 #000000 0 0 0 1
 [
   "("

grammar/ruby.scm

@@ -1,19 +1,3 @@
-[
-  (method)
-  (singleton_method)
-  (class)
-  (module)
-  (if)
-  (else)
-  (case)
-  (when)
-  (in)
-  (do_block)
-  (singleton_class)
-  (heredoc_content)
-  (lambda)
-] @fold
-
 ;; #ffffff #000000 0 0 0 1
 [
   (identifier)

include/editor.h

@@ -10,12 +10,13 @@
 #include <map>
 #include <shared_mutex>
 #include <unordered_map>
+#include <vector>
 
 #define CHAR 0
 #define WORD 1
 #define LINE 2
 
-#define EXTRA_META 3
+#define EXTRA_META 4
 
 struct Highlight {
   uint32_t fg;
@@ -39,6 +40,14 @@ struct Spans {
   std::shared_mutex mtx;
 };
 
+struct Fold {
+  uint32_t start;
+  uint32_t end;
+
+  bool contains(uint32_t line) const { return line >= start && line <= end; }
+  bool operator<(const Fold &other) const { return start < other.start; }
+};
+
 struct SpanCursor {
   Spans &spans;
   size_t index = 0;
@@ -105,14 +114,66 @@ struct Editor {
   const TSLanguage *language;
   Queue<TSInputEdit> edit_queue;
   std::vector<Highlight> query_map;
-  std::vector<int8_t> folded;
+  std::vector<Fold> folds;
   Spans spans;
   Spans def_spans;
-  std::map<uint32_t, bool> folded_node;
   uint32_t hooks[94];
   bool jumper_set;
 };
 
+inline const Fold *fold_for_line(const std::vector<Fold> &folds,
+                                 uint32_t line) {
+  auto it = std::lower_bound(
+      folds.begin(), folds.end(), line,
+      [](const Fold &fold, uint32_t value) { return fold.start < value; });
+  if (it != folds.end() && it->start == line)
+    return &(*it);
+  if (it != folds.begin()) {
+    --it;
+    if (it->contains(line))
+      return &(*it);
+  }
+  return nullptr;
+}
+
+inline Fold *fold_for_line(std::vector<Fold> &folds, uint32_t line) {
+  const auto *fold =
+      fold_for_line(static_cast<const std::vector<Fold> &>(folds), line);
+  return const_cast<Fold *>(fold);
+}
+
+inline bool line_is_fold_start(const std::vector<Fold> &folds, uint32_t line) {
+  const Fold *fold = fold_for_line(folds, line);
+  return fold && fold->start == line;
+}
+
+inline bool line_is_folded(const std::vector<Fold> &folds, uint32_t line) {
+  return fold_for_line(folds, line) != nullptr;
+}
+
+inline uint32_t next_unfolded_row(const Editor *editor, uint32_t row) {
+  uint32_t limit = editor && editor->root ? editor->root->line_count : 0;
+  while (row < limit) {
+    const Fold *fold = fold_for_line(editor->folds, row);
+    if (!fold)
+      return row;
+    row = fold->end + 1;
+  }
+  return limit;
+}
+
+inline uint32_t prev_unfolded_row(const Editor *editor, uint32_t row) {
+  while (row > 0) {
+    const Fold *fold = fold_for_line(editor->folds, row);
+    if (!fold)
+      return row;
+    if (fold->start == 0)
+      return 0;
+    row = fold->start - 1;
+  }
+  return 0;
+}
+
 void apply_edit(std::vector<Span> &spans, uint32_t x, int64_t y);
 Editor *new_editor(const char *filename, Coord position, Coord size);
 void free_editor(Editor *editor);
@@ -124,7 +185,7 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number);
 Coord move_right(Editor *editor, Coord cursor, uint32_t number);
 void cursor_left(Editor *editor, uint32_t number);
 void cursor_right(Editor *editor, uint32_t number);
-void scroll_up(Editor *editor, uint32_t number);
+void scroll_up(Editor *editor, int32_t number);
 void scroll_down(Editor *editor, uint32_t number);
 void ensure_cursor(Editor *editor);
 void ensure_scroll(Editor *editor);
@@ -141,5 +202,11 @@ void word_boundaries(Editor *editor, Coord coord, uint32_t *prev_col,
                      uint32_t *next_clusters);
 void word_boundaries_exclusive(Editor *editor, Coord coord, uint32_t *prev_col,
                                uint32_t *next_col);
+std::vector<Fold>::iterator find_fold_iter(Editor *editor, uint32_t line);
+bool add_fold(Editor *editor, uint32_t start, uint32_t end);
+bool remove_fold(Editor *editor, uint32_t line);
+void apply_line_insertion(Editor *editor, uint32_t line, uint32_t rows);
+void apply_line_deletion(Editor *editor, uint32_t removal_start,
+                         uint32_t removal_end);
 
 #endif

include/knot.h

@@ -117,6 +117,14 @@ LineIterator *begin_l_iter(Knot *root, uint32_t start_line);
 // freed by the caller
 char *next_line(LineIterator *it, uint32_t *out_len);
 
+// Returns the previous line as a null terminated string
+// `it` is the iterator returned from begin_l_iter
+// it can be used to iterate backwards
+// and can be used along with next_line
+// doing prev_line then next_line or vice versa will return the same line
+// `out_len` is set to the length of the returned string
+char *prev_line(LineIterator *it, uint32_t *out_len);
+
 // Used to start an iterator over leaf data
 // root is the root of the rope
 // the caller must free the iterator after use

src/editor.cc

@@ -23,7 +23,6 @@ Editor *new_editor(const char *filename, Coord position, Coord size) {
   editor->cursor_preffered = UINT32_MAX;
   editor->root = load(str, len, optimal_chunk_size(len));
   free(str);
-  editor->folded.resize(editor->root->line_count + 2);
   if (len <= (1024 * 128)) {
     editor->parser = ts_parser_new();
     Language language = language_for_file(filename);
@@ -45,24 +44,6 @@ void free_editor(Editor *editor) {
   delete editor;
 }
 
-void fold(Editor *editor, uint32_t start_line, uint32_t end_line) {
-  if (!editor)
-    return;
-  for (uint32_t i = start_line; i <= end_line && i < editor->size.row; i++)
-    editor->folded[i] = 1;
-  editor->folded[start_line] = 2;
-}
-
-void update_render_fold_marker(uint32_t row, uint32_t cols) {
-  const char *marker = "... folded ...";
-  uint32_t len = strlen(marker);
-  uint32_t i = 0;
-  for (; i < len && i < cols; i++)
-    update(row, i, (char[2]){marker[i], 0}, 0xc6c6c6, 0, 0);
-  for (; i < cols; i++)
-    update(row, i, " ", 0xc6c6c6, 0, 0);
-}
-
 void render_editor(Editor *editor) {
   uint32_t sel_start = 0, sel_end = 0;
   uint32_t numlen =
@@ -74,6 +55,7 @@ void render_editor(Editor *editor) {
     if (editor->hooks[i] != 0)
       v.push_back({editor->hooks[i], '!' + i});
   std::sort(v.begin(), v.end());
+  auto hook_it = v.begin();
   std::shared_lock knot_lock(editor->knot_mtx);
   if (editor->selection_active) {
     Coord start, end;
@@ -135,12 +117,29 @@ void render_editor(Editor *editor) {
   span_cursor.sync(global_byte_offset);
   def_span_cursor.sync(global_byte_offset);
   while (rendered_rows < editor->size.row) {
-    if (editor->folded[line_index]) {
+    const Fold *fold = fold_for_line(editor->folds, line_index);
-      if (editor->folded[line_index] == 2) {
+    if (fold) {
-        update_render_fold_marker(rendered_rows, render_width);
+      update(editor->position.row + rendered_rows, editor->position.col, "",
+             0xAAAAAA, 0, 0);
+      char buf[16];
+      int len = snprintf(buf, sizeof(buf), "%*u", numlen - 3, fold->start + 1);
+      uint32_t num_color =
+          editor->cursor.row == fold->start ? 0xFFFFFF : 0x555555;
+      for (int i = 0; i < len; i++)
+        update(editor->position.row + rendered_rows,
+               editor->position.col + i + 2, (char[2]){buf[i], 0}, num_color, 0,
+               0);
+      const char marker[15] = "... folded ...";
+      uint32_t i = 0;
+      for (; i < 14 && i < render_width; i++)
+        update(rendered_rows, i + render_x, (char[2]){marker[i], 0}, 0xc6c6c6,
+               0, 0);
+      for (; i < render_width; i++)
+        update(rendered_rows, i + render_x, " ", 0xc6c6c6, 0, 0);
       rendered_rows++;
-      }
+
-      do {
+      uint32_t skip_until = fold->end;
+      while (line_index <= skip_until) {
         uint32_t line_len;
         char *line = next_line(it, &line_len);
         if (!line)
@@ -151,8 +150,7 @@ void render_editor(Editor *editor) {
         global_byte_offset++;
         free(line);
         line_index++;
-      } while (line_index < editor->size.row &&
+      }
-               editor->folded[line_index] == 1);
       continue;
     }
     uint32_t line_len;
@@ -167,21 +165,27 @@ void render_editor(Editor *editor) {
     while (current_byte_offset < line_len && rendered_rows < editor->size.row) {
       uint32_t color = editor->cursor.row == line_index ? 0x222222 : 0;
       if (current_byte_offset == 0 || rendered_rows == 0) {
-        char buf[EXTRA_META + 16];
+        const char *hook = nullptr;
-        char hook = ' ';
+        char h[2] = {0, 0};
-        for (auto &p : v) {
+        auto it2 = hook_it;
-          if (p.first == line_index + 1) {
+        for (; it2 != v.end(); ++it2) {
-            hook = p.second;
+          if (it2->first == line_index + 1) {
+            h[0] = it2->second;
+            hook = h;
+            hook_it = it2;
             break;
           }
         }
-        int len = snprintf(buf, sizeof(buf), "%c%*u", hook, numlen - 2,
+        update(editor->position.row + rendered_rows, editor->position.col, hook,
-                           line_index + 1);
+               0xAAAAAA, 0, 0);
+        char buf[16];
+        int len = snprintf(buf, sizeof(buf), "%*u", numlen - 3, line_index + 1);
         uint32_t num_color =
             editor->cursor.row == line_index ? 0xFFFFFF : 0x555555;
         for (int i = 0; i < len; i++)
-          update(editor->position.row + rendered_rows, editor->position.col + i,
+          update(editor->position.row + rendered_rows,
-                 std::string(1, buf[i]).c_str(), num_color, 0, 0);
+                 editor->position.col + i + 2, (char[2]){buf[i], 0}, num_color,
+                 0, 0);
       } else {
         for (uint32_t i = 0; i < numlen; i++)
           update(editor->position.row + rendered_rows, editor->position.col + i,
@@ -252,21 +256,27 @@ void render_editor(Editor *editor) {
     if (line_len == 0 ||
         (current_byte_offset >= line_len && rendered_rows == 0)) {
       uint32_t color = editor->cursor.row == line_index ? 0x222222 : 0;
-      char buf[EXTRA_META + 16];
+      const char *hook = nullptr;
-      char hook = ' ';
+      char h[2] = {0, 0};
-      for (auto &p : v) {
+      auto it2 = hook_it;
-        if (p.first == line_index + 1) {
+      for (; it2 != v.end(); ++it2) {
-          hook = p.second;
+        if (it2->first == line_index + 1) {
+          h[0] = it2->second;
+          hook = h;
+          hook_it = it2;
           break;
         }
       }
-      int len =
+      update(editor->position.row + rendered_rows, editor->position.col, hook,
-          snprintf(buf, sizeof(buf), "%c%*u", hook, numlen - 2, line_index + 1);
+             0xAAAAAA, 0, 0);
+      char buf[16];
+      int len = snprintf(buf, sizeof(buf), "%*u", numlen - 3, line_index + 1);
       uint32_t num_color =
           editor->cursor.row == line_index ? 0xFFFFFF : 0x555555;
       for (int i = 0; i < len; i++)
-        update(editor->position.row + rendered_rows, editor->position.col + i,
+        update(editor->position.row + rendered_rows,
-               std::string(1, buf[i]).c_str(), num_color, 0, 0);
+               editor->position.col + i + 2, (char[2]){buf[i], 0}, num_color, 0,
+               0);
       if (editor->cursor.row == line_index) {
         cursor.row = editor->position.row + rendered_rows;
         cursor.col = render_x;

src/editor_ctrl.cc

@@ -1,450 +1,11 @@
-#include <cstdint>
 extern "C" {
 #include "../libs/libgrapheme/grapheme.h"
 }
 #include "../include/editor.h"
 #include "../include/main.h"
-#include "../include/ts.h"
 #include "../include/utils.h"
 #include <cmath>
 
-static Highlight HL_UNDERLINE = {0, 0, 1 << 2, 100};
-
-void handle_editor_event(Editor *editor, KeyEvent event) {
-  static std::chrono::steady_clock::time_point last_click_time =
-      std::chrono::steady_clock::now();
-  static uint32_t click_count = 0;
-  static Coord last_click_pos = {UINT32_MAX, UINT32_MAX};
-  if (event.key_type == KEY_MOUSE) {
-    auto now = std::chrono::steady_clock::now();
-    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(
-                        now - last_click_time)
-                        .count();
-    switch (event.mouse_state) {
-    case SCROLL:
-      switch (event.mouse_direction) {
-      case SCROLL_UP:
-        scroll_up(editor, 10);
-        ensure_cursor(editor);
-        break;
-      case SCROLL_DOWN:
-        scroll_down(editor, 10);
-        ensure_cursor(editor);
-        break;
-      case SCROLL_LEFT:
-        cursor_left(editor, 10);
-        break;
-      case SCROLL_RIGHT:
-        cursor_right(editor, 10);
-        break;
-      }
-      break;
-    case PRESS:
-      if (event.mouse_button == LEFT_BTN) {
-        Coord cur_pos = {event.mouse_x, event.mouse_y};
-        if (duration < 250 && last_click_pos == cur_pos)
-          click_count++;
-        else
-          click_count = 1;
-        last_click_time = now;
-        last_click_pos = cur_pos;
-        Coord p = editor_hit_test(editor, event.mouse_x, event.mouse_y);
-        editor->cursor_preffered = UINT32_MAX;
-        if (click_count == 1) {
-          editor->cursor = p;
-          editor->selection = p;
-          if (mode == SELECT) {
-            mode = NORMAL;
-            editor->selection_active = false;
-          }
-        } else if (click_count == 2) {
-          uint32_t prev_col, next_col;
-          word_boundaries(editor, editor->cursor, &prev_col, &next_col, nullptr,
-                          nullptr);
-          if (editor->cursor < editor->selection)
-            editor->cursor = {editor->cursor.row, prev_col};
-          else
-            editor->cursor = {editor->cursor.row, next_col};
-          editor->cursor_preffered = UINT32_MAX;
-          editor->selection_type = WORD;
-          mode = SELECT;
-          editor->selection_active = true;
-        } else if (click_count >= 3) {
-          if (editor->cursor < editor->selection) {
-            editor->cursor = {p.row, 0};
-          } else {
-            uint32_t line_len;
-            LineIterator *it = begin_l_iter(editor->root, p.row);
-            char *line = next_line(it, &line_len);
-            free(it);
-            if (!line)
-              return;
-            if (line_len > 0 && line[line_len - 1] == '\n')
-              line_len--;
-            free(line);
-            editor->cursor = {p.row, line_len};
-          }
-          editor->cursor_preffered = UINT32_MAX;
-          editor->selection_type = LINE;
-          mode = SELECT;
-          editor->selection_active = true;
-          click_count = 3;
-        }
-      }
-      break;
-    case DRAG:
-      if (event.mouse_button == LEFT_BTN) {
-        Coord p = editor_hit_test(editor, event.mouse_x, event.mouse_y);
-        editor->cursor_preffered = UINT32_MAX;
-        mode = SELECT;
-        if (!editor->selection_active) {
-          editor->selection_active = true;
-          editor->selection_type = CHAR;
-        }
-        uint32_t prev_col, next_col, line_len;
-        switch (editor->selection_type) {
-        case CHAR:
-          editor->cursor = p;
-          break;
-        case WORD:
-          word_boundaries(editor, p, &prev_col, &next_col, nullptr, nullptr);
-          if (editor->cursor < editor->selection)
-            editor->cursor = {p.row, prev_col};
-          else
-            editor->cursor = {p.row, next_col};
-          break;
-        case LINE:
-          if (editor->cursor < editor->selection) {
-            editor->cursor = {p.row, 0};
-          } else {
-            LineIterator *it = begin_l_iter(editor->root, p.row);
-            char *line = next_line(it, &line_len);
-            free(it);
-            if (!line)
-              return;
-            if (line_len > 0 && line[line_len - 1] == '\n')
-              line_len--;
-            free(line);
-            editor->cursor = {p.row, line_len};
-          }
-          break;
-        }
-      }
-      break;
-    case RELEASE:
-      if (event.mouse_button == LEFT_BTN)
-        if (editor->cursor.row == editor->selection.row &&
-            editor->cursor.col == editor->selection.col) {
-          mode = NORMAL;
-          editor->selection_active = false;
-        }
-      break;
-    }
-  }
-  if (event.key_type == KEY_SPECIAL) {
-    switch (event.special_modifier) {
-    case 0:
-      switch (event.special_key) {
-      case KEY_DOWN:
-        cursor_down(editor, 1);
-        break;
-      case KEY_UP:
-        cursor_up(editor, 1);
-        break;
-      case KEY_LEFT:
-        cursor_left(editor, 1);
-        break;
-      case KEY_RIGHT:
-        cursor_right(editor, 1);
-        break;
-      }
-      break;
-    case CNTRL:
-      uint32_t prev_col, next_col;
-      word_boundaries(editor, editor->cursor, &prev_col, &next_col, nullptr,
-                      nullptr);
-      switch (event.special_key) {
-      case KEY_DOWN:
-        cursor_down(editor, 5);
-        break;
-      case KEY_UP:
-        cursor_up(editor, 5);
-        break;
-      case KEY_LEFT:
-        editor->cursor_preffered = UINT32_MAX;
-        if (prev_col == editor->cursor.col)
-          cursor_left(editor, 1);
-        else
-          editor->cursor = {editor->cursor.row, prev_col};
-        break;
-      case KEY_RIGHT:
-        editor->cursor_preffered = UINT32_MAX;
-        if (next_col == editor->cursor.col)
-          cursor_right(editor, 1);
-        else
-          editor->cursor = {editor->cursor.row, next_col};
-        break;
-      }
-      break;
-    case ALT:
-      switch (event.special_key) {
-      case KEY_DOWN:
-        move_line_down(editor);
-        break;
-      case KEY_UP:
-        move_line_up(editor);
-        break;
-      case KEY_LEFT:
-        cursor_left(editor, 8);
-        break;
-      case KEY_RIGHT:
-        cursor_right(editor, 8);
-        break;
-      }
-      break;
-    }
-  }
-  switch (mode) {
-  case NORMAL:
-    if (event.key_type == KEY_CHAR && event.len == 1) {
-      switch (event.c[0]) {
-      case 'a':
-        mode = INSERT;
-        cursor_right(editor, 1);
-        break;
-      case 'i':
-        mode = INSERT;
-        break;
-      case 'n':
-        mode = JUMPER;
-        editor->jumper_set = true;
-        break;
-      case 'm':
-        mode = JUMPER;
-        editor->jumper_set = false;
-        break;
-      case 'N':
-        for (uint8_t i = 0; i < 94; i++)
-          if (editor->hooks[i] == editor->cursor.row + 1) {
-            editor->hooks[i] = 0;
-            break;
-          }
-        break;
-      case 's':
-      case 'v':
-        mode = SELECT;
-        editor->selection_active = true;
-        editor->selection = editor->cursor;
-        break;
-      case ';':
-      case ':':
-        mode = RUNNER;
-        break;
-      case 0x7F:
-        cursor_left(editor, 1);
-        break;
-      case ' ':
-        cursor_right(editor, 1);
-        break;
-      case '\r':
-      case '\n':
-        cursor_down(editor, 1);
-        break;
-      case '\\':
-      case '|':
-        cursor_up(editor, 1);
-        break;
-      case CTRL('d'):
-        scroll_down(editor, 1);
-        ensure_cursor(editor);
-        break;
-      case CTRL('u'):
-        scroll_up(editor, 1);
-        ensure_cursor(editor);
-        break;
-      case 'p':
-        uint32_t len;
-        char *text = get_from_clipboard(&len);
-        if (text) {
-          edit_insert(editor, editor->cursor, text, len);
-          uint32_t grapheme_len = count_clusters(text, len, 0, len);
-          cursor_right(editor, grapheme_len);
-          free(text);
-        }
-        break;
-      }
-    }
-    break;
-  case INSERT:
-    if (event.key_type == KEY_CHAR) {
-      if (event.len == 1) {
-        if (event.c[0] == '\t') {
-          edit_insert(editor, editor->cursor, (char *)"  ", 1);
-          cursor_right(editor, 2);
-        } else if (event.c[0] == '\n' || event.c[0] == '\r') {
-          edit_insert(editor, editor->cursor, (char *)"\n", 1);
-          cursor_right(editor, 1);
-        } else if (event.c[0] == 0x7F) {
-          edit_erase(editor, editor->cursor, -1);
-        } else if (event.c[0] == CTRL('W')) {
-          uint32_t prev_col_byte, prev_col_cluster;
-          word_boundaries(editor, editor->cursor, &prev_col_byte, nullptr,
-                          &prev_col_cluster, nullptr);
-          if (prev_col_byte == editor->cursor.col)
-            edit_erase(editor, editor->cursor, -1);
-          else
-            edit_erase(editor, editor->cursor, -(int64_t)prev_col_cluster);
-        } else if (isprint((unsigned char)(event.c[0]))) {
-          edit_insert(editor, editor->cursor, event.c, 1);
-          cursor_right(editor, 1);
-        } else if (event.c[0] == 0x1B) {
-          mode = NORMAL;
-          cursor_left(editor, 1);
-        }
-      } else if (event.len > 1) {
-        edit_insert(editor, editor->cursor, event.c, event.len);
-        cursor_right(editor, 1);
-      }
-    } else if (event.key_type == KEY_SPECIAL &&
-               event.special_key == KEY_DELETE) {
-      switch (event.special_modifier) {
-      case 0:
-        edit_erase(editor, editor->cursor, 1);
-        break;
-      case CNTRL:
-        uint32_t next_col_byte, next_col_cluster;
-        word_boundaries(editor, editor->cursor, nullptr, &next_col_byte,
-                        nullptr, &next_col_cluster);
-        if (next_col_byte == editor->cursor.col)
-          edit_erase(editor, editor->cursor, 1);
-        else
-          edit_erase(editor, editor->cursor, next_col_cluster);
-        break;
-      }
-    }
-    break;
-  case SELECT:
-    if (event.key_type == KEY_CHAR && event.len == 1) {
-      uint32_t len;
-      char *text;
-      switch (event.c[0]) {
-      case 0x1B:
-      case 's':
-      case 'v':
-        editor->selection_active = false;
-        mode = NORMAL;
-        break;
-      case 'y':
-        text = get_selection(editor, &len);
-        copy_to_clipboard(text, len);
-        free(text);
-        editor->selection_active = false;
-        mode = NORMAL;
-        break;
-      case 'x':
-        text = get_selection(editor, &len);
-        copy_to_clipboard(text, len);
-        edit_erase(editor, MIN(editor->cursor, editor->selection), len);
-        free(text);
-        editor->selection_active = false;
-        mode = NORMAL;
-        break;
-      case 'p':
-        text = get_from_clipboard(&len);
-        if (text) {
-          Coord start, end;
-          if (editor->cursor >= editor->selection) {
-            start = editor->selection;
-            end = move_right(editor, editor->cursor, 1);
-          } else {
-            start = editor->cursor;
-            end = move_right(editor, editor->selection, 1);
-          }
-          uint32_t start_byte =
-              line_to_byte(editor->root, start.row, nullptr) + start.col;
-          uint32_t end_byte =
-              line_to_byte(editor->root, end.row, nullptr) + end.col;
-          edit_erase(editor, start, end_byte - start_byte);
-          edit_insert(editor, editor->cursor, text, len);
-          free(text);
-        }
-        editor->selection_active = false;
-        mode = NORMAL;
-        break;
-      }
-    }
-    break;
-  case JUMPER:
-    if (event.key_type == KEY_CHAR && event.len == 1 &&
-        (event.c[0] > '!' && event.c[0] < '~')) {
-      if (editor->jumper_set) {
-        for (uint8_t i = 0; i < 94; i++)
-          if (editor->hooks[i] == editor->cursor.row + 1) {
-            editor->hooks[i] = 0;
-            break;
-          }
-        editor->hooks[event.c[0] - '!'] = editor->cursor.row + 1;
-      } else {
-        uint32_t line = editor->hooks[event.c[0] - '!'];
-        if (line > 0) {
-          editor->cursor = {line - 1, 0};
-          editor->cursor_preffered = UINT32_MAX;
-        }
-      }
-    }
-    mode = NORMAL;
-    break;
-  case RUNNER:
-    if (event.key_type == KEY_CHAR && event.len == 1) {
-      switch (event.c[0]) {
-      case 0x1B:
-        mode = NORMAL;
-        break;
-      }
-    }
-    break;
-  }
-  ensure_scroll(editor);
-  if (event.key_type == KEY_CHAR && event.c)
-    free(event.c);
-}
-
-void editor_worker(Editor *editor) {
-  if (!editor || !editor->root)
-    return;
-  if (editor->parser && editor->query)
-    ts_collect_spans(editor);
-  uint32_t prev_col, next_col;
-  word_boundaries_exclusive(editor, editor->cursor, &prev_col, &next_col);
-  if (next_col - prev_col > 0 && next_col - prev_col < 256 - 4) {
-    std::shared_lock lock(editor->knot_mtx);
-    uint32_t offset = line_to_byte(editor->root, editor->cursor.row, nullptr);
-    char *word = read(editor->root, offset + prev_col, next_col - prev_col);
-    if (word) {
-      char buf[256];
-      snprintf(buf, sizeof(buf), "\\b%s\\b", word);
-      std::vector<std::pair<size_t, size_t>> results =
-          search_rope(editor->root, buf);
-      std::unique_lock lock(editor->def_spans.mtx);
-      editor->def_spans.spans.clear();
-      for (const auto &match : results) {
-        Span s;
-        s.start = match.first;
-        s.end = match.first + match.second;
-        s.hl = &HL_UNDERLINE;
-        editor->def_spans.spans.push_back(s);
-      }
-      std::sort(editor->def_spans.spans.begin(), editor->def_spans.spans.end());
-      lock.unlock();
-      free(word);
-    }
-  } else {
-    std::unique_lock lock(editor->def_spans.mtx);
-    editor->def_spans.spans.clear();
-    lock.unlock();
-  }
-}
-
 uint32_t scan_left(const char *line, uint32_t len, uint32_t off) {
   if (off > len)
     off = len;
@@ -564,6 +125,7 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
     x++;
   uint32_t numlen =
       EXTRA_META + static_cast<int>(std::log10(editor->root->line_count + 1));
+  bool is_gutter_click = (x < numlen);
   uint32_t render_width = editor->size.col - numlen;
   x = MAX(x, numlen) - numlen;
   uint32_t target_visual_row = y;
@@ -575,21 +137,24 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
   if (!it)
     return editor->scroll;
   while (visual_row <= target_visual_row) {
-    if (editor->folded[line_index]) {
+    const Fold *fold = fold_for_line(editor->folds, line_index);
-      if (editor->folded[line_index] == 2) {
+    if (fold) {
       if (visual_row == target_visual_row) {
         free(it);
-          return {line_index, 0};
+        if (is_gutter_click) {
+          remove_fold(editor, fold->start);
+          return {UINT32_MAX, UINT32_MAX};
+        }
+        return {fold->start > 0 ? fold->start - 1 : 0, 0};
       }
       visual_row++;
-      }
+      while (line_index <= fold->end) {
-      do {
         char *l = next_line(it, nullptr);
         if (!l)
           break;
         free(l);
         line_index++;
-      } while (editor->folded[line_index] == 1);
+      }
       continue;
     }
     uint32_t line_len;
@@ -642,7 +207,7 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
   return editor->scroll;
 }
 
-Coord move_right(Editor *editor, Coord cursor, uint32_t number) {
+Coord move_right_pure(Editor *editor, Coord cursor, uint32_t number) {
   Coord result = cursor;
   if (!editor || !editor->root || number == 0)
     return result;
@@ -661,9 +226,108 @@ Coord move_right(Editor *editor, Coord cursor, uint32_t number) {
       free(line);
       line = nullptr;
       uint32_t next_row = row + 1;
-      while (next_row < editor->root->line_count &&
+      if (next_row >= editor->root->line_count) {
-             editor->folded[next_row] != 0)
+        col = line_len;
-        next_row++;
+        break;
+      }
+      row = next_row;
+      col = 0;
+      it = begin_l_iter(editor->root, row);
+      line = next_line(it, &line_len);
+      free(it);
+      if (!line)
+        break;
+      if (line_len > 0 && line[line_len - 1] == '\n')
+        --line_len;
+    } else {
+      uint32_t inc =
+          grapheme_next_character_break_utf8(line + col, line_len - col);
+      if (inc == 0)
+        break;
+      col += inc;
+    }
+    number--;
+  }
+  if (line)
+    free(line);
+  result.row = row;
+  result.col = col;
+  return result;
+}
+
+Coord move_left_pure(Editor *editor, Coord cursor, uint32_t number) {
+  Coord result = cursor;
+  if (!editor || !editor->root || number == 0)
+    return result;
+  uint32_t row = result.row;
+  uint32_t col = result.col;
+  uint32_t len = 0;
+  LineIterator *it = begin_l_iter(editor->root, row);
+  char *line = next_line(it, &len);
+  if (!line) {
+    free(it);
+    return result;
+  }
+  if (len > 0 && line[len - 1] == '\n')
+    --len;
+  bool iterator_ahead = true;
+  while (number > 0) {
+    if (col == 0) {
+      if (row == 0)
+        break;
+      if (iterator_ahead) {
+        free(prev_line(it, nullptr));
+        iterator_ahead = false;
+      }
+      free(line);
+      line = nullptr;
+      row--;
+      line = prev_line(it, &len);
+      if (!line)
+        break;
+      if (len > 0 && line[len - 1] == '\n')
+        --len;
+      col = len;
+    } else {
+      uint32_t new_col = 0;
+      while (new_col < col) {
+        uint32_t inc =
+            grapheme_next_character_break_utf8(line + new_col, len - new_col);
+        if (new_col + inc >= col)
+          break;
+        new_col += inc;
+      }
+      col = new_col;
+    }
+    number--;
+  }
+  if (line)
+    free(line);
+  free(it);
+  result.row = row;
+  result.col = col;
+  return result;
+}
+
+Coord move_right(Editor *editor, Coord cursor, uint32_t number) {
+  Coord result = cursor;
+  if (!editor || !editor->root || number == 0)
+    return result;
+  uint32_t row = result.row;
+  uint32_t col = result.col;
+  uint32_t line_len = 0;
+  LineIterator *it = begin_l_iter(editor->root, row);
+  char *line = next_line(it, &line_len);
+  free(it);
+  if (!line)
+    return result;
+  if (line_len > 0 && line[line_len - 1] == '\n')
+    --line_len;
+  while (number > 0) {
+    if (col >= line_len) {
+      free(line);
+      line = nullptr;
+      uint32_t next_row = next_unfolded_row(editor, row + 1);
       if (next_row >= editor->root->line_count) {
         col = line_len;
         break;
@@ -702,26 +366,43 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
   uint32_t len = 0;
   LineIterator *it = begin_l_iter(editor->root, row);
   char *line = next_line(it, &len);
+  if (!line) {
     free(it);
-  if (!line)
     return result;
+  }
   if (len > 0 && line[len - 1] == '\n')
     --len;
+  bool iterator_ahead = true;
   while (number > 0) {
     if (col == 0) {
-      free(line);
-      line = nullptr;
       if (row == 0)
         break;
-      int32_t prev_row = row - 1;
+      if (iterator_ahead) {
-      while (prev_row >= 0 && editor->folded[prev_row] != 0)
+        free(prev_line(it, nullptr));
-        prev_row--;
+        iterator_ahead = false;
-      if (prev_row < 0)
+      }
+      free(line);
+      line = nullptr;
+      while (row > 0) {
+        row--;
+        line = prev_line(it, &len);
+        if (!line)
           break;
-      row = prev_row;
+        const Fold *fold = fold_for_line(editor->folds, row);
-      it = begin_l_iter(editor->root, row);
+        if (fold) {
-      line = next_line(it, &len);
+          while (line && row > fold->start) {
-      free(it);
+            free(line);
+            line = prev_line(it, &len);
+            row--;
+          }
+          if (line) {
+            free(line);
+            line = nullptr;
+          }
+          continue;
+        }
+        break;
+      }
       if (!line)
         break;
       if (len > 0 && line[len - 1] == '\n')
@@ -742,6 +423,7 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
   }
   if (line)
     free(line);
+  free(it);
   result.row = row;
   result.col = col;
   return result;
@@ -750,64 +432,75 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
 void cursor_down(Editor *editor, uint32_t number) {
   if (!editor || !editor->root || number == 0)
     return;
-  LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
   uint32_t len;
+  LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
   char *line_content = next_line(it, &len);
+  free(it);
   if (line_content == nullptr)
     return;
   if (editor->cursor_preffered == UINT32_MAX)
     editor->cursor_preffered =
         get_visual_col_from_bytes(line_content, len, editor->cursor.col);
   uint32_t visual_col = editor->cursor_preffered;
-  do {
   free(line_content);
-    line_content = next_line(it, &len);
+  uint32_t target_row = editor->cursor.row;
-    editor->cursor.row += 1;
+  while (number > 0 && target_row < editor->root->line_count - 1) {
-    if (editor->cursor.row >= editor->root->line_count) {
+    target_row = next_unfolded_row(editor, target_row + 1);
-      editor->cursor.row = editor->root->line_count - 1;
+    if (target_row >= editor->root->line_count) {
+      target_row = editor->root->line_count - 1;
       break;
-    };
+    }
-    if (editor->folded[editor->cursor.row] != 0)
+    number--;
-      number++;
+  }
-  } while (--number > 0);
+  it = begin_l_iter(editor->root, target_row);
+  line_content = next_line(it, &len);
   free(it);
-  if (line_content == nullptr)
+  if (!line_content)
     return;
+  if (len > 0 && line_content[len - 1] == '\n')
+    --len;
+  editor->cursor.row = target_row;
   editor->cursor.col = get_bytes_from_visual_col(line_content, len, visual_col);
   free(line_content);
 }
 
 void cursor_up(Editor *editor, uint32_t number) {
-  if (!editor || !editor->root || number == 0)
+  if (!editor || !editor->root || number == 0 || editor->cursor.row == 0)
     return;
-  LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
   uint32_t len;
+  LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
   char *line_content = next_line(it, &len);
-  if (!line_content) {
   free(it);
+  if (!line_content)
     return;
-  }
   if (editor->cursor_preffered == UINT32_MAX)
     editor->cursor_preffered =
         get_visual_col_from_bytes(line_content, len, editor->cursor.col);
   uint32_t visual_col = editor->cursor_preffered;
   free(line_content);
-  while (number > 0 && editor->cursor.row > 0) {
+  uint32_t target_row = editor->cursor.row;
-    editor->cursor.row--;
+  while (number > 0 && target_row > 0) {
-    if (editor->folded[editor->cursor.row] != 0)
+    target_row = prev_unfolded_row(editor, target_row - 1);
-      continue;
+    if (target_row == 0) {
+      number--;
+      break;
+    }
     number--;
   }
-  free(it);
+  it = begin_l_iter(editor->root, target_row);
-  it = begin_l_iter(editor->root, editor->cursor.row);
   line_content = next_line(it, &len);
-  if (!line_content) {
   free(it);
-    return;
+  if (line_content) {
-  }
+    if (len > 0 && line_content[len - 1] == '\n')
-  editor->cursor.col = get_bytes_from_visual_col(line_content, len, visual_col);
+      --len;
+    editor->cursor.row = target_row;
+    editor->cursor.col =
+        get_bytes_from_visual_col(line_content, len, visual_col);
     free(line_content);
-  free(it);
+  } else {
+    editor->cursor.row = 0;
+    editor->cursor.col = 0;
+  }
 }
 
 void cursor_right(Editor *editor, uint32_t number) {
@@ -837,13 +530,21 @@ void move_line_up(Editor *editor) {
       lock.unlock();
       return;
     }
+    if (line_len > 0 && line[line_len - 1] == '\n')
+      line_len--;
     line_cluster_len = count_clusters(line, line_len, 0, line_len);
+    uint32_t target_row = prev_unfolded_row(editor, editor->cursor.row - 1);
+    uint32_t up_by = editor->cursor.row - target_row;
+    if (up_by > 1)
+      up_by--;
     lock.unlock();
     Coord cursor = editor->cursor;
     edit_erase(editor, {cursor.row, 0}, line_cluster_len);
-    edit_insert(editor, {cursor.row - 1, 0}, line, line_len);
+    edit_erase(editor, {cursor.row, 0}, -1);
+    edit_insert(editor, {cursor.row - up_by, 0}, (char *)"\n", 1);
+    edit_insert(editor, {cursor.row - up_by, 0}, line, line_len);
     free(line);
-    editor->cursor = {cursor.row - 1, cursor.col};
+    editor->cursor = {cursor.row - up_by, cursor.col};
   } else if (mode == SELECT) {
     uint32_t start_row = MIN(editor->cursor.row, editor->selection.row);
     uint32_t end_row = MAX(editor->cursor.row, editor->selection.row);
@@ -880,22 +581,45 @@ void move_line_down(Editor *editor) {
       lock.unlock();
       return;
     }
+    if (line_len && line[line_len - 1] == '\n')
+      line_len--;
     line_cluster_len = count_clusters(line, line_len, 0, line_len);
+    uint32_t target_row = next_unfolded_row(editor, editor->cursor.row + 1);
+    if (target_row >= editor->root->line_count) {
+      free(line);
+      lock.unlock();
+      return;
+    }
+    uint32_t down_by = target_row - editor->cursor.row;
+    if (down_by > 1)
+      down_by--;
+    uint32_t ln;
+    line_to_byte(editor->root, editor->cursor.row + down_by - 1, &ln);
     lock.unlock();
     Coord cursor = editor->cursor;
     edit_erase(editor, {cursor.row, 0}, line_cluster_len);
-    edit_insert(editor, {cursor.row + 1, 0}, line, line_len);
+    edit_erase(editor, {cursor.row, 0}, -1);
+    edit_insert(editor, {cursor.row + down_by, 0}, (char *)"\n", 1);
+    edit_insert(editor, {cursor.row + down_by, 0}, line, line_len);
     free(line);
-    editor->cursor = {cursor.row + 1, cursor.col};
+    editor->cursor = {cursor.row + down_by, cursor.col};
   } else if (mode == SELECT) {
     if (editor->cursor.row >= editor->root->line_count - 1 ||
         editor->selection.row >= editor->root->line_count - 1)
       return;
+    std::shared_lock lock(editor->knot_mtx);
     uint32_t start_row = MIN(editor->cursor.row, editor->selection.row);
     uint32_t end_row = MAX(editor->cursor.row, editor->selection.row);
+    uint32_t target_row = next_unfolded_row(editor, end_row + 1);
+    if (target_row >= editor->root->line_count)
+      return;
+    uint32_t down_by = target_row - end_row;
+    if (down_by > 1)
+      down_by--;
     uint32_t start_byte = line_to_byte(editor->root, start_row, nullptr);
     uint32_t end_byte = line_to_byte(editor->root, end_row + 1, nullptr);
     char *selected_text = read(editor->root, start_byte, end_byte - start_byte);
+    lock.unlock();
     if (!selected_text)
       return;
     uint32_t selected_len = count_clusters(selected_text, end_byte - start_byte,
@@ -903,11 +627,11 @@ void move_line_down(Editor *editor) {
     Coord cursor = editor->cursor;
     Coord selection = editor->selection;
     edit_erase(editor, {start_row, 0}, selected_len);
-    edit_insert(editor, {start_row + 1, 0}, selected_text,
+    edit_insert(editor, {start_row + down_by, 0}, selected_text,
                 end_byte - start_byte);
     free(selected_text);
-    editor->cursor = {cursor.row + 1, cursor.col};
+    editor->cursor = {cursor.row + down_by, cursor.col};
-    editor->selection = {selection.row + 1, selection.col};
+    editor->selection = {selection.row + down_by, selection.col};
   }
 }
 
@@ -921,7 +645,7 @@ void edit_erase(Editor *editor, Coord pos, int64_t len) {
         editor->cursor.col;
     TSPoint old_point = {pos.row, pos.col};
     uint32_t byte_pos = line_to_byte(editor->root, pos.row, nullptr) + pos.col;
-    Coord point = move_left(editor, pos, -len);
+    Coord point = move_left_pure(editor, pos, -len);
     uint32_t start = line_to_byte(editor->root, point.row, nullptr) + point.col;
     if (cursor_original > start && cursor_original <= byte_pos) {
       editor->cursor = point;
@@ -934,6 +658,9 @@ void edit_erase(Editor *editor, Coord pos, int64_t len) {
       editor->cursor_preffered = UINT32_MAX;
     }
     lock_1.unlock();
+    uint32_t start_row = point.row;
+    uint32_t end_row = pos.row;
+    apply_line_deletion(editor, start_row + 1, end_row);
     std::unique_lock lock_2(editor->knot_mtx);
     editor->root = erase(editor->root, start, byte_pos - start);
     lock_2.unlock();
@@ -961,7 +688,7 @@ void edit_erase(Editor *editor, Coord pos, int64_t len) {
         editor->cursor.col;
     TSPoint old_point = {pos.row, pos.col};
     uint32_t byte_pos = line_to_byte(editor->root, pos.row, nullptr) + pos.col;
-    Coord point = move_right(editor, pos, len);
+    Coord point = move_right_pure(editor, pos, len);
     uint32_t end = line_to_byte(editor->root, point.row, nullptr) + point.col;
     if (cursor_original > byte_pos && cursor_original <= end) {
       editor->cursor = pos;
@@ -974,6 +701,9 @@ void edit_erase(Editor *editor, Coord pos, int64_t len) {
       editor->cursor_preffered = UINT32_MAX;
     }
     lock_1.unlock();
+    uint32_t start_row = pos.row;
+    uint32_t end_row = point.row;
+    apply_line_deletion(editor, start_row + 1, end_row);
     std::unique_lock lock_2(editor->knot_mtx);
     editor->root = erase(editor->root, byte_pos, end - byte_pos);
     lock_2.unlock();
@@ -1013,8 +743,6 @@ void edit_insert(Editor *editor, Coord pos, char *data, uint32_t len) {
   lock_1.unlock();
   std::unique_lock lock_2(editor->knot_mtx);
   editor->root = insert(editor->root, byte_pos, data, len);
-  if (memchr(data, '\n', len))
-    editor->folded.resize(editor->root->line_count + 2);
   lock_2.unlock();
   uint32_t cols = 0;
   uint32_t rows = 0;
@@ -1026,6 +754,7 @@ void edit_insert(Editor *editor, Coord pos, char *data, uint32_t len) {
       cols++;
     }
   }
+  apply_line_insertion(editor, pos.row, rows);
   if (editor->tree) {
     TSInputEdit edit = {
         .start_byte = byte_pos,
@@ -1122,3 +851,95 @@ void apply_edit(std::vector<Span> &spans, uint32_t x, int64_t y) {
       ++i;
   }
 }
+
+std::vector<Fold>::iterator find_fold_iter(Editor *editor, uint32_t line) {
+  auto &folds = editor->folds;
+  auto it = std::lower_bound(
+      folds.begin(), folds.end(), line,
+      [](const Fold &fold, uint32_t value) { return fold.start < value; });
+  if (it != folds.end() && it->start == line)
+    return it;
+  if (it != folds.begin()) {
+    --it;
+    if (it->contains(line))
+      return it;
+  }
+  return folds.end();
+}
+
+bool add_fold(Editor *editor, uint32_t start, uint32_t end) {
+  if (!editor || !editor->root)
+    return false;
+  if (start > end)
+    std::swap(start, end);
+  if (start >= editor->root->line_count)
+    return false;
+  end = std::min(end, editor->root->line_count - 1);
+  if (start == end)
+    return false;
+
+  Fold new_fold{start, end};
+  auto &folds = editor->folds;
+  auto it = std::lower_bound(
+      folds.begin(), folds.end(), new_fold.start,
+      [](const Fold &fold, uint32_t value) { return fold.start < value; });
+
+  if (it != folds.begin()) {
+    auto prev = std::prev(it);
+    if (prev->end + 1 >= new_fold.start) {
+      new_fold.start = std::min(new_fold.start, prev->start);
+      new_fold.end = std::max(new_fold.end, prev->end);
+      it = folds.erase(prev);
+    }
+  }
+  while (it != folds.end() && it->start <= new_fold.end + 1) {
+    new_fold.end = std::max(new_fold.end, it->end);
+    it = folds.erase(it);
+  }
+  folds.insert(it, new_fold);
+  return true;
+}
+
+bool remove_fold(Editor *editor, uint32_t line) {
+  auto it = find_fold_iter(editor, line);
+  if (it == editor->folds.end())
+    return false;
+  editor->folds.erase(it);
+  return true;
+}
+
+void apply_line_insertion(Editor *editor, uint32_t line, uint32_t rows) {
+  for (auto it = editor->folds.begin(); it != editor->folds.end();) {
+    if (line <= it->start) {
+      it->start += rows;
+      it->end += rows;
+      ++it;
+    } else if (line <= it->end) {
+      it = editor->folds.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
+void apply_line_deletion(Editor *editor, uint32_t removal_start,
+                         uint32_t removal_end) {
+  if (removal_start > removal_end)
+    return;
+  uint32_t rows_removed = removal_end - removal_start + 1;
+  std::vector<Fold> updated;
+  updated.reserve(editor->folds.size());
+  for (auto fold : editor->folds) {
+    if (removal_end < fold.start) {
+      fold.start -= rows_removed;
+      fold.end -= rows_removed;
+      updated.push_back(fold);
+      continue;
+    }
+    if (removal_start > fold.end) {
+      updated.push_back(fold);
+      continue;
+    }
+  }
+  editor->folds.swap(updated);
+}

src/editor_events.cc

@@ -0,0 +1,520 @@
+#include "../include/editor.h"
+#include "../include/main.h"
+#include "../include/ts.h"
+
+void handle_editor_event(Editor *editor, KeyEvent event) {
+  static std::chrono::steady_clock::time_point last_click_time =
+      std::chrono::steady_clock::now();
+  static uint32_t click_count = 0;
+  static Coord last_click_pos = {UINT32_MAX, UINT32_MAX};
+  if (event.key_type == KEY_MOUSE) {
+    auto now = std::chrono::steady_clock::now();
+    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(
+                        now - last_click_time)
+                        .count();
+    switch (event.mouse_state) {
+    case SCROLL:
+      switch (event.mouse_direction) {
+      case SCROLL_UP:
+        scroll_up(editor, 10);
+        ensure_cursor(editor);
+        break;
+      case SCROLL_DOWN:
+        scroll_down(editor, 10);
+        ensure_cursor(editor);
+        break;
+      case SCROLL_LEFT:
+        cursor_left(editor, 10);
+        break;
+      case SCROLL_RIGHT:
+        cursor_right(editor, 10);
+        break;
+      }
+      break;
+    case PRESS:
+      if (event.mouse_button == LEFT_BTN) {
+        Coord cur_pos = {event.mouse_x, event.mouse_y};
+        if (duration < 250 && last_click_pos == cur_pos)
+          click_count++;
+        else
+          click_count = 1;
+        last_click_time = now;
+        last_click_pos = cur_pos;
+        Coord p = editor_hit_test(editor, event.mouse_x, event.mouse_y);
+        if (p.row == UINT32_MAX && p.col == UINT32_MAX)
+          return;
+        editor->cursor_preffered = UINT32_MAX;
+        if (click_count == 1) {
+          editor->cursor = p;
+          editor->selection = p;
+          if (mode == SELECT) {
+            mode = NORMAL;
+            editor->selection_active = false;
+          }
+        } else if (click_count == 2) {
+          uint32_t prev_col, next_col;
+          word_boundaries(editor, editor->cursor, &prev_col, &next_col, nullptr,
+                          nullptr);
+          if (editor->cursor < editor->selection)
+            editor->cursor = {editor->cursor.row, prev_col};
+          else
+            editor->cursor = {editor->cursor.row, next_col};
+          editor->cursor_preffered = UINT32_MAX;
+          editor->selection_type = WORD;
+          mode = SELECT;
+          editor->selection_active = true;
+        } else if (click_count >= 3) {
+          if (editor->cursor < editor->selection) {
+            editor->cursor = {p.row, 0};
+          } else {
+            uint32_t line_len;
+            LineIterator *it = begin_l_iter(editor->root, p.row);
+            char *line = next_line(it, &line_len);
+            free(it);
+            if (!line)
+              return;
+            if (line_len > 0 && line[line_len - 1] == '\n')
+              line_len--;
+            free(line);
+            editor->cursor = {p.row, line_len};
+          }
+          editor->cursor_preffered = UINT32_MAX;
+          editor->selection_type = LINE;
+          mode = SELECT;
+          editor->selection_active = true;
+          click_count = 3;
+        }
+      }
+      break;
+    case DRAG:
+      if (event.mouse_button == LEFT_BTN) {
+        Coord p = editor_hit_test(editor, event.mouse_x, event.mouse_y);
+        if (p.row == UINT32_MAX && p.col == UINT32_MAX)
+          return;
+        editor->cursor_preffered = UINT32_MAX;
+        mode = SELECT;
+        if (!editor->selection_active) {
+          editor->selection_active = true;
+          editor->selection_type = CHAR;
+        }
+        uint32_t prev_col, next_col, line_len;
+        switch (editor->selection_type) {
+        case CHAR:
+          editor->cursor = p;
+          break;
+        case WORD:
+          word_boundaries(editor, p, &prev_col, &next_col, nullptr, nullptr);
+          if (editor->cursor < editor->selection)
+            editor->cursor = {p.row, prev_col};
+          else
+            editor->cursor = {p.row, next_col};
+          break;
+        case LINE:
+          if (editor->cursor < editor->selection) {
+            editor->cursor = {p.row, 0};
+          } else {
+            LineIterator *it = begin_l_iter(editor->root, p.row);
+            char *line = next_line(it, &line_len);
+            free(it);
+            if (!line)
+              return;
+            if (line_len > 0 && line[line_len - 1] == '\n')
+              line_len--;
+            free(line);
+            editor->cursor = {p.row, line_len};
+          }
+          break;
+        }
+      }
+      break;
+    case RELEASE:
+      if (event.mouse_button == LEFT_BTN)
+        if (editor->cursor.row == editor->selection.row &&
+            editor->cursor.col == editor->selection.col) {
+          mode = NORMAL;
+          editor->selection_active = false;
+        }
+      break;
+    }
+  }
+  if (event.key_type == KEY_SPECIAL) {
+    switch (event.special_modifier) {
+    case 0:
+      switch (event.special_key) {
+      case KEY_DOWN:
+        cursor_down(editor, 1);
+        break;
+      case KEY_UP:
+        cursor_up(editor, 1);
+        break;
+      case KEY_LEFT:
+        cursor_left(editor, 1);
+        break;
+      case KEY_RIGHT:
+        cursor_right(editor, 1);
+        break;
+      }
+      break;
+    case CNTRL:
+      uint32_t prev_col, next_col;
+      word_boundaries(editor, editor->cursor, &prev_col, &next_col, nullptr,
+                      nullptr);
+      switch (event.special_key) {
+      case KEY_DOWN:
+        cursor_down(editor, 5);
+        break;
+      case KEY_UP:
+        cursor_up(editor, 5);
+        break;
+      case KEY_LEFT:
+        editor->cursor_preffered = UINT32_MAX;
+        if (prev_col == editor->cursor.col)
+          cursor_left(editor, 1);
+        else
+          editor->cursor = {editor->cursor.row, prev_col};
+        break;
+      case KEY_RIGHT:
+        editor->cursor_preffered = UINT32_MAX;
+        if (next_col == editor->cursor.col)
+          cursor_right(editor, 1);
+        else
+          editor->cursor = {editor->cursor.row, next_col};
+        break;
+      }
+      break;
+    case ALT:
+      switch (event.special_key) {
+      case KEY_DOWN:
+        move_line_down(editor);
+        break;
+      case KEY_UP:
+        move_line_up(editor);
+        break;
+      case KEY_LEFT:
+        cursor_left(editor, 8);
+        break;
+      case KEY_RIGHT:
+        cursor_right(editor, 8);
+        break;
+      }
+      break;
+    }
+  }
+  switch (mode) {
+  case NORMAL:
+    if (event.key_type == KEY_CHAR && event.len == 1) {
+      switch (event.c[0]) {
+      case 'u':
+        if (editor->root->line_count > 0) {
+          editor->cursor.row = editor->root->line_count - 1;
+          LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
+          if (!it)
+            break;
+          uint32_t line_len;
+          char *line = next_line(it, &line_len);
+          if (!line)
+            break;
+          if (line_len > 0 && line[line_len - 1] == '\n')
+            line_len--;
+          free(it);
+          line_len = count_clusters(line, line_len, 0, line_len);
+          free(line);
+          editor->cursor.col = line_len;
+          editor->cursor_preffered = UINT32_MAX;
+          mode = SELECT;
+          editor->selection_active = true;
+          editor->selection = {0, 0};
+          editor->selection_type = LINE;
+        }
+        break;
+      case 'a':
+        mode = INSERT;
+        cursor_right(editor, 1);
+        break;
+      case 'i':
+        mode = INSERT;
+        break;
+      case 'n':
+        mode = JUMPER;
+        editor->jumper_set = true;
+        break;
+      case 'm':
+        mode = JUMPER;
+        editor->jumper_set = false;
+        break;
+      case 'N':
+        for (uint8_t i = 0; i < 94; i++)
+          if (editor->hooks[i] == editor->cursor.row + 1) {
+            editor->hooks[i] = 0;
+            break;
+          }
+        break;
+      case 's':
+      case 'v':
+        mode = SELECT;
+        editor->selection_active = true;
+        editor->selection = editor->cursor;
+        editor->selection_type = CHAR;
+        break;
+      case ';':
+      case ':':
+        mode = RUNNER;
+        break;
+      case 0x7F:
+        cursor_left(editor, 1);
+        break;
+      case ' ':
+        cursor_right(editor, 1);
+        break;
+      case '\r':
+      case '\n':
+        cursor_down(editor, 1);
+        break;
+      case '\\':
+      case '|':
+        cursor_up(editor, 1);
+        break;
+      case CTRL('d'):
+        scroll_down(editor, 1);
+        ensure_cursor(editor);
+        break;
+      case CTRL('u'):
+        scroll_up(editor, 1);
+        ensure_cursor(editor);
+        break;
+      case 'p':
+        uint32_t len;
+        char *text = get_from_clipboard(&len);
+        if (text) {
+          edit_insert(editor, editor->cursor, text, len);
+          uint32_t grapheme_len = count_clusters(text, len, 0, len);
+          cursor_right(editor, grapheme_len);
+          free(text);
+        }
+        break;
+      }
+    }
+    break;
+  case INSERT:
+    if (event.key_type == KEY_CHAR) {
+      if (event.len == 1) {
+        if (event.c[0] == '\t') {
+          edit_insert(editor, editor->cursor, (char *)"  ", 2);
+          cursor_right(editor, 2);
+        } else if (event.c[0] == '\n' || event.c[0] == '\r') {
+          edit_insert(editor, editor->cursor, (char *)"\n", 1);
+          cursor_right(editor, 1);
+        } else if (event.c[0] == CTRL('W')) {
+          uint32_t prev_col_byte, prev_col_cluster;
+          word_boundaries(editor, editor->cursor, &prev_col_byte, nullptr,
+                          &prev_col_cluster, nullptr);
+          if (prev_col_byte == editor->cursor.col)
+            edit_erase(editor, editor->cursor, -1);
+          else
+            edit_erase(editor, editor->cursor, -(int64_t)prev_col_cluster);
+        } else if (isprint((unsigned char)(event.c[0]))) {
+          char c = event.c[0];
+          char closing = 0;
+          if (c == '{')
+            closing = '}';
+          else if (c == '(')
+            closing = ')';
+          else if (c == '[')
+            closing = ']';
+          else if (c == '"')
+            closing = '"';
+          else if (c == '\'')
+            closing = '\'';
+          if (closing) {
+            char pair[2] = {c, closing};
+            edit_insert(editor, editor->cursor, pair, 2);
+            cursor_right(editor, 1);
+          } else {
+            edit_insert(editor, editor->cursor, event.c, 1);
+            cursor_right(editor, 1);
+          }
+        } else if (event.c[0] == 0x7F || event.c[0] == 0x08) {
+          Coord prev_pos = editor->cursor;
+          if (prev_pos.col > 0)
+            prev_pos.col--;
+          LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
+          if (!it)
+            return;
+          char *line = next_line(it, nullptr);
+          free(it);
+          char prev_char = line[prev_pos.col];
+          char next_char = line[editor->cursor.col];
+          free(line);
+          bool is_pair = (prev_char == '{' && next_char == '}') ||
+                         (prev_char == '(' && next_char == ')') ||
+                         (prev_char == '[' && next_char == ']') ||
+                         (prev_char == '"' && next_char == '"') ||
+                         (prev_char == '\'' && next_char == '\'');
+          if (is_pair) {
+            edit_erase(editor, editor->cursor, 1);
+            edit_erase(editor, prev_pos, 1);
+          } else {
+            edit_erase(editor, editor->cursor, -1);
+          }
+        } else if (event.c[0] == 0x1B) {
+          mode = NORMAL;
+          cursor_left(editor, 1);
+        }
+      } else if (event.len > 1) {
+        edit_insert(editor, editor->cursor, event.c, event.len);
+        cursor_right(editor, 1);
+      }
+    } else if (event.key_type == KEY_SPECIAL &&
+               event.special_key == KEY_DELETE) {
+      switch (event.special_modifier) {
+      case 0:
+        edit_erase(editor, editor->cursor, 1);
+        break;
+      case CNTRL:
+        uint32_t next_col_byte, next_col_cluster;
+        word_boundaries(editor, editor->cursor, nullptr, &next_col_byte,
+                        nullptr, &next_col_cluster);
+        if (next_col_byte == editor->cursor.col)
+          edit_erase(editor, editor->cursor, 1);
+        else
+          edit_erase(editor, editor->cursor, next_col_cluster);
+        break;
+      }
+    }
+    break;
+  case SELECT:
+    if (event.key_type == KEY_CHAR && event.len == 1) {
+      uint32_t len;
+      char *text;
+      switch (event.c[0]) {
+      case 'f':
+        if (editor->cursor.row != editor->selection.row) {
+          uint32_t start = MIN(editor->cursor.row, editor->selection.row);
+          uint32_t end = MAX(editor->cursor.row, editor->selection.row);
+          add_fold(editor, start, end);
+        }
+        cursor_left(editor, 1);
+        cursor_down(editor, 1);
+        editor->selection_active = false;
+        mode = NORMAL;
+        break;
+      case 0x1B:
+      case 's':
+      case 'v':
+        editor->selection_active = false;
+        mode = NORMAL;
+        break;
+      case 'y':
+        text = get_selection(editor, &len);
+        copy_to_clipboard(text, len);
+        free(text);
+        editor->selection_active = false;
+        mode = NORMAL;
+        break;
+      case 'x':
+        text = get_selection(editor, &len);
+        copy_to_clipboard(text, len);
+        edit_erase(editor, MIN(editor->cursor, editor->selection), len);
+        free(text);
+        editor->selection_active = false;
+        mode = NORMAL;
+        break;
+      case 'p':
+        text = get_from_clipboard(&len);
+        if (text) {
+          Coord start, end;
+          if (editor->cursor >= editor->selection) {
+            start = editor->selection;
+            end = move_right(editor, editor->cursor, 1);
+          } else {
+            start = editor->cursor;
+            end = move_right(editor, editor->selection, 1);
+          }
+          uint32_t start_byte =
+              line_to_byte(editor->root, start.row, nullptr) + start.col;
+          uint32_t end_byte =
+              line_to_byte(editor->root, end.row, nullptr) + end.col;
+          edit_erase(editor, start, end_byte - start_byte);
+          edit_insert(editor, editor->cursor, text, len);
+          free(text);
+        }
+        editor->selection_active = false;
+        mode = NORMAL;
+        break;
+      }
+    }
+    break;
+  case JUMPER:
+    if (event.key_type == KEY_CHAR && event.len == 1 &&
+        (event.c[0] >= '!' && event.c[0] <= '~')) {
+      if (editor->jumper_set) {
+        for (uint8_t i = 0; i < 94; i++)
+          if (editor->hooks[i] == editor->cursor.row + 1) {
+            editor->hooks[i] = 0;
+            break;
+          }
+        editor->hooks[event.c[0] - '!'] = editor->cursor.row + 1;
+      } else {
+        uint32_t line = editor->hooks[event.c[0] - '!'];
+        if (line > 0) {
+          if (line_is_folded(editor->folds, --line))
+            break;
+          editor->cursor = {line, 0};
+          editor->cursor_preffered = UINT32_MAX;
+        }
+      }
+    }
+    mode = NORMAL;
+    break;
+  case RUNNER:
+    if (event.key_type == KEY_CHAR && event.len == 1) {
+      switch (event.c[0]) {
+      case 0x1B:
+        mode = NORMAL;
+        break;
+      }
+    }
+    break;
+  }
+  ensure_scroll(editor);
+  if (event.key_type == KEY_CHAR && event.c)
+    free(event.c);
+}
+
+static Highlight HL_UNDERLINE = {0, 0, 1 << 2, 100};
+
+void editor_worker(Editor *editor) {
+  if (!editor || !editor->root)
+    return;
+  if (editor->parser && editor->query)
+    ts_collect_spans(editor);
+  uint32_t prev_col, next_col;
+  word_boundaries_exclusive(editor, editor->cursor, &prev_col, &next_col);
+  if (next_col - prev_col > 0 && next_col - prev_col < 256 - 4) {
+    std::shared_lock lock(editor->knot_mtx);
+    uint32_t offset = line_to_byte(editor->root, editor->cursor.row, nullptr);
+    char *word = read(editor->root, offset + prev_col, next_col - prev_col);
+    if (word) {
+      char buf[256];
+      snprintf(buf, sizeof(buf), "\\b%s\\b", word);
+      std::vector<std::pair<size_t, size_t>> results =
+          search_rope(editor->root, buf);
+      std::unique_lock lock(editor->def_spans.mtx);
+      editor->def_spans.spans.clear();
+      for (const auto &match : results) {
+        Span s;
+        s.start = match.first;
+        s.end = match.first + match.second;
+        s.hl = &HL_UNDERLINE;
+        editor->def_spans.spans.push_back(s);
+      }
+      std::sort(editor->def_spans.spans.begin(), editor->def_spans.spans.end());
+      lock.unlock();
+      free(word);
+    }
+  } else {
+    std::unique_lock lock(editor->def_spans.mtx);
+    editor->def_spans.spans.clear();
+    lock.unlock();
+  }
+}

src/editor_scroll.cc

@@ -1,4 +1,3 @@
-#include <cstdint>
 extern "C" {
 #include "../libs/libgrapheme/grapheme.h"
 }
@@ -6,72 +5,129 @@ extern "C" {
 #include "../include/utils.h"
 #include <cmath>
 
-void scroll_up(Editor *editor, uint32_t number) {
+void scroll_up(Editor *editor, int32_t number) {
-  number++;
+  if (!editor || number == 0)
+    return;
   uint32_t numlen =
       EXTRA_META + static_cast<int>(std::log10(editor->root->line_count + 1));
   uint32_t render_width = editor->size.col - numlen;
-  Coord *scroll_queue = (Coord *)malloc(sizeof(Coord) * number);
+  uint32_t line_index = editor->scroll.row;
-  uint32_t q_head = 0;
-  uint32_t q_size = 0;
-  int line_index = editor->scroll.row - number;
-  line_index = line_index < 0 ? 0 : line_index;
   LineIterator *it = begin_l_iter(editor->root, line_index);
-  if (!it) {
+  if (!it)
-    free(scroll_queue);
+    return;
+  uint32_t len;
+  char *line = next_line(it, &len);
+  if (!line) {
+    free(it);
     return;
   }
-  for (uint32_t i = line_index; i <= editor->scroll.row; i++) {
+  if (len > 0 && line[len - 1] == '\n')
-    uint32_t line_len;
+    len--;
-    char *line = next_line(it, &line_len);
+  uint32_t current_byte_offset = 0;
-    if (!line)
-      break;
-    if (line[line_len - 1] == '\n')
-      --line_len;
-    uint32_t offset = 0;
   uint32_t col = 0;
-    if (q_size < number) {
+  std::vector<uint32_t> segment_starts;
-      scroll_queue[(q_head + q_size) % number] = {i, 0};
+  segment_starts.reserve(16);
-      q_size++;
+  if (current_byte_offset < editor->scroll.col)
-    } else {
+    segment_starts.push_back(0);
-      scroll_queue[q_head] = {i, 0};
+  while (current_byte_offset < editor->scroll.col &&
-      q_head = (q_head + 1) % number;
+         current_byte_offset < len) {
-    }
+    uint32_t cluster_len = grapheme_next_character_break_utf8(
-    if (i == editor->scroll.row && 0 == editor->scroll.col) {
+        line + current_byte_offset, len - current_byte_offset);
-      editor->scroll = scroll_queue[q_head];
+    int width = display_width(line + current_byte_offset, cluster_len);
-      free(line);
-      free(it);
-      free(scroll_queue);
-      return;
-    }
-    while (offset < line_len) {
-      uint32_t inc =
-          grapheme_next_character_break_utf8(line + offset, line_len - offset);
-      int width = display_width(line + offset, inc);
     if (col + width > render_width) {
-        if (q_size < number) {
+      segment_starts.push_back(current_byte_offset);
-          scroll_queue[(q_head + q_size) % number] = {i, offset};
-          q_size++;
-        } else {
-          scroll_queue[q_head] = {i, offset};
-          q_head = (q_head + 1) % number;
-        }
-        if (i == editor->scroll.row && offset >= editor->scroll.col) {
-          editor->scroll = scroll_queue[q_head];
-          free(line);
-          free(it);
-          free(scroll_queue);
-          return;
-        }
       col = 0;
     }
+    current_byte_offset += cluster_len;
     col += width;
-      offset += inc;
+  }
+  for (auto it_seg = segment_starts.rbegin(); it_seg != segment_starts.rend();
+       ++it_seg) {
+    if (--number == 0) {
+      editor->scroll = {line_index, *it_seg};
+      free(line);
+      free(it);
+      return;
+    }
   }
   free(line);
-  }
+  line = prev_line(it, &len);
+  if (!line) {
     editor->scroll = {0, 0};
-  free(scroll_queue);
+    free(it);
+    return;
+  }
+  free(line);
+  do {
+    line_index--;
+    line = prev_line(it, &len);
+    if (!line) {
+      editor->scroll = {0, 0};
+      free(it);
+      return;
+    }
+    const Fold *fold = fold_for_line(editor->folds, line_index);
+    if (fold) {
+      while (line && line_index > fold->start) {
+        free(line);
+        line = prev_line(it, &len);
+        line_index--;
+        if (!line) {
+          editor->scroll = {0, 0};
+          free(it);
+          return;
+        }
+      }
+      if (--number == 0) {
+        editor->scroll = {fold->start, 0};
+        free(line);
+        free(it);
+        return;
+      }
+      free(line);
+      if (fold->start == 0) {
+        editor->scroll = {0, 0};
+        free(it);
+        return;
+      }
+      line_index = fold->start - 1;
+      line = prev_line(it, &len);
+      if (!line) {
+        editor->scroll = {0, 0};
+        free(it);
+        return;
+      }
+      continue;
+    }
+    if (len > 0 && line[len - 1] == '\n')
+      len--;
+    current_byte_offset = 0;
+    col = 0;
+    std::vector<uint32_t> segment_starts;
+    segment_starts.reserve(16);
+    segment_starts.push_back(0);
+    while (current_byte_offset < len) {
+      uint32_t cluster_len = grapheme_next_character_break_utf8(
+          line + current_byte_offset, len - current_byte_offset);
+      int width = display_width(line + current_byte_offset, cluster_len);
+      if (col + width > render_width) {
+        segment_starts.push_back(current_byte_offset);
+        col = 0;
+      }
+      current_byte_offset += cluster_len;
+      col += width;
+    }
+    for (auto it_seg = segment_starts.rbegin(); it_seg != segment_starts.rend();
+         ++it_seg) {
+      if (--number == 0) {
+        editor->scroll = {line_index, *it_seg};
+        free(line);
+        free(it);
+        return;
+      }
+    }
+    free(line);
+  } while (number > 0);
   free(it);
 }
 
@@ -92,9 +148,9 @@ void scroll_down(Editor *editor, uint32_t number) {
   uint32_t visual_seen = 0;
   bool first_visual_line = true;
   while (true) {
-    if (editor->folded[line_index]) {
+    const Fold *fold = fold_for_line(editor->folds, line_index);
-      if (editor->folded[line_index] == 2) {
+    if (fold) {
-        Coord fold_coord = {line_index, 0};
+      Coord fold_coord = {fold->start, 0};
       if (q_size < max_visual_lines) {
         scroll_queue[(q_head + q_size) % max_visual_lines] = fold_coord;
         q_size++;
@@ -107,8 +163,8 @@ void scroll_down(Editor *editor, uint32_t number) {
         editor->scroll = scroll_queue[q_head];
         break;
       }
-      }
+      uint32_t skip_until = fold->end;
-      do {
+      while (line_index <= skip_until) {
         char *line = next_line(it, nullptr);
         if (!line) {
           free(scroll_queue);
@@ -117,7 +173,7 @@ void scroll_down(Editor *editor, uint32_t number) {
         }
         free(line);
         line_index++;
-      } while (editor->folded[line_index] == 1);
+      }
       continue;
     }
     uint32_t line_len;
@@ -181,7 +237,11 @@ void scroll_down(Editor *editor, uint32_t number) {
 void ensure_cursor(Editor *editor) {
   std::shared_lock knot_lock(editor->knot_mtx);
   if (editor->cursor < editor->scroll) {
-    editor->cursor = editor->scroll;
+    uint32_t line_idx = next_unfolded_row(editor, editor->scroll.row);
+    editor->cursor.row = line_idx;
+    editor->cursor.col =
+        line_idx == editor->scroll.row ? editor->scroll.col : 0;
+    editor->cursor_preffered = UINT32_MAX;
     return;
   }
   uint32_t numlen =
@@ -197,23 +257,19 @@ void ensure_cursor(Editor *editor) {
   while (true) {
     if (visual_rows >= editor->size.row)
       break;
-    if (editor->folded[line_index]) {
+    const Fold *fold = fold_for_line(editor->folds, line_index);
-      if (editor->folded[line_index] == 2) {
+    if (fold) {
-        Coord c = {line_index, 0};
+      Coord c = {fold->start, 0};
       last_visible = c;
       visual_rows++;
-        if (line_index == editor->cursor.row) {
+      uint32_t skip_until = fold->end;
-          free(it);
+      while (line_index <= skip_until) {
-          return;
-        }
-      }
-      do {
         char *line = next_line(it, nullptr);
         if (!line)
           break;
         free(line);
         line_index++;
-      } while (editor->folded[line_index] == 1);
+      }
       continue;
     }
     uint32_t line_len;
@@ -260,7 +316,15 @@ void ensure_cursor(Editor *editor) {
     free(line);
     line_index++;
   }
-  editor->cursor = last_visible;
+  uint32_t last_real_row = last_visible.row;
+  const Fold *last_fold = fold_for_line(editor->folds, last_visible.row);
+  if (last_fold) {
+    last_visible.row = last_fold->start == 0 ? 0 : last_fold->start - 1;
+    last_visible.col = 0;
+  }
+  editor->cursor.row = last_visible.row;
+  editor->cursor.col = last_visible.row == last_real_row ? last_visible.col : 0;
+  editor->cursor_preffered = UINT32_MAX;
   free(it);
 }
 
@@ -319,9 +383,9 @@ void ensure_scroll(Editor *editor) {
     uint32_t q_size = 0;
     bool first_visual_line = true;
     while (true) {
-      if (editor->folded[line_index]) {
+      const Fold *fold = fold_for_line(editor->folds, line_index);
-        if (editor->folded[line_index] == 2) {
+      if (fold) {
-          Coord fold_coord = {line_index, 0};
+        Coord fold_coord = {fold->start, 0};
         if (q_size < max_visual_lines) {
           scroll_queue[(q_head + q_size) % max_visual_lines] = fold_coord;
           q_size++;
@@ -329,19 +393,19 @@ void ensure_scroll(Editor *editor) {
           scroll_queue[q_head] = fold_coord;
           q_head = (q_head + 1) % max_visual_lines;
         }
-          if (line_index == editor->cursor.row) {
+        if (fold->start <= editor->cursor.row &&
+            editor->cursor.row <= fold->end) {
           editor->scroll = scroll_queue[q_head];
           break;
         }
-        }
+        uint32_t skip_until = fold->end;
-        do {
+        while (line_index <= skip_until) {
           char *line = next_line(it, nullptr);
           if (!line)
             break;
           free(line);
           line_index++;
-        } while (line_index < editor->size.row &&
+        }
-                 editor->folded[line_index] == 1);
         continue;
       }
       uint32_t line_len;

src/knot.cc

@@ -520,6 +520,86 @@ LineIterator *begin_l_iter(Knot *root, uint32_t start_line) {
   return it;
 }
 
+static inline void iter_retreat_leaf(LineIterator *it) {
+  if (it->top == 0) {
+    it->node = nullptr;
+    return;
+  }
+  Knot *curr = it->stack[--it->top];
+  while (it->top > 0) {
+    Knot *parent = it->stack[it->top - 1];
+    if (parent->right == curr && parent->left) {
+      Knot *target = parent->left;
+      while (target) {
+        it->stack[it->top++] = target;
+        if (!target->left && !target->right) {
+          if (target->char_count == 0)
+            break;
+          it->node = target;
+          it->offset = target->char_count;
+          return;
+        }
+        target = (target->right) ? target->right : target->left;
+      }
+    }
+    curr = it->stack[--it->top];
+  }
+  it->node = nullptr;
+}
+
+static void str_reverse(char *begin, char *end) {
+  char temp;
+  while (begin < end) {
+    temp = *begin;
+    *begin++ = *end;
+    *end-- = temp;
+  }
+}
+
+char *prev_line(LineIterator *it, uint32_t *out_len) {
+  if (!it || !it->node)
+    return nullptr;
+  size_t capacity = 128;
+  size_t len = 0;
+  char *buffer = (char *)malloc(capacity);
+  if (!buffer)
+    return nullptr;
+  while (it->node) {
+    if (it->offset == 0) {
+      iter_retreat_leaf(it);
+      if (!it->node)
+        break;
+    }
+    it->offset--;
+    char c = it->node->data[it->offset];
+    if (c == '\n') {
+      if (len > 0) {
+        it->offset++;
+        break;
+      }
+    }
+    if (len + 1 >= capacity) {
+      capacity *= 2;
+      char *new_buf = (char *)realloc(buffer, capacity);
+      if (!new_buf) {
+        free(buffer);
+        return nullptr;
+      }
+      buffer = new_buf;
+    }
+    buffer[len++] = c;
+  }
+  if (len > 0) {
+    buffer[len] = '\0';
+    str_reverse(buffer, buffer + len - 1);
+    if (out_len)
+      *out_len = len;
+    return buffer;
+  }
+  free(buffer);
+  return nullptr;
+}
+
 static inline void iter_advance_leaf(LineIterator *it) {
   if (it->top == 0) {
     it->node = nullptr;
@@ -533,6 +613,8 @@ static inline void iter_advance_leaf(LineIterator *it) {
       while (curr) {
         it->stack[it->top++] = curr;
         if (!curr->left && !curr->right) {
+          if (curr->char_count == 0)
+            break;
           it->node = curr;
           it->offset = 0;
           return;

src/utils.cc

@@ -17,6 +17,15 @@ extern "C" {
 #include <unistd.h>
 #include <unordered_map>
 
+uint64_t fnv1a_64(const char *s, size_t len) {
+  uint64_t hash = 1469598103934665603ull;
+  for (size_t i = 0; i < len; ++i) {
+    hash ^= (uint8_t)s[i];
+    hash *= 1099511628211ull;
+  }
+  return hash;
+}
+
 char *get_from_clipboard(uint32_t *out_len) {
   FILE *pipe = popen("xclip -selection clipboard -o", "r");
   if (!pipe) {