#include "../api/rope.hpp"
#include <chrono>
#include <cmath>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <regex>
#include <string>

// Include the user's header

// --- Timer Helper ---
class Timer {
  using Clock = std::chrono::high_resolution_clock;
  std::chrono::time_point<Clock> start_time;

public:
  Timer() { reset(); }
  void reset() { start_time = Clock::now(); }
  double elapsed_ms() {
    auto end_time = Clock::now();
    return std::chrono::duration<double, std::milli>(end_time - start_time)
        .count();
  }
};

// --- Formatting Helper ---
void print_result(const std::string &test_name, double rope_ms, double str_ms) {
  std::cout << std::left << std::setw(25) << test_name
            << " | Rope: " << std::setw(10) << std::fixed
            << std::setprecision(3) << rope_ms << " ms"
            << " | String: " << std::setw(10) << str_ms << " ms"
            << " | Ratio (Str/Rope): " << std::setprecision(2) << std::setw(10)
            << (str_ms / rope_ms) << "x" << " | " << std::fixed << " So "
            << ((str_ms - rope_ms) <= 0 ? "string" : "rope  ")
            << " is faster by " << std::fabs(str_ms - rope_ms) << " ms"
            << std::endl;
}

int main() {
  // 1. DATA GENERATION
  std::cout << "Generating ~1GiB dataset..." << std::endl;
  const std::string pattern = "The quick brown fox jumps over the lzy dog.\n";
  // Target ~100 MiB (100 * 1024 * 1024 bytes)
  const size_t target_size = 1024 * 1024 * 1024;
  std::string source_data;
  source_data.reserve(target_size + pattern.size());

  while (source_data.size() < target_size)
    source_data.append(pattern);

  uint32_t total_len = static_cast<uint32_t>(source_data.size());
  std::cout << "Dataset generated. Size: " << total_len << " bytes.\n"
            << std::endl;

  Timer t;
  double rope_time, str_time;

  // ==========================================
  // TEST 1: LOAD / CREATION
  // ==========================================

  // Rope Load
  t.reset();
  uint32_t chunk_size = optimal_chunk_size(total_len);
  // Note: Cast to char* because header asks for char*, usually strings are
  // const char*
  Knot *root =
      load(const_cast<char *>(source_data.c_str()), total_len, chunk_size);
  rope_time = t.elapsed_ms();

  // String Load (Copy)
  t.reset();
  std::string str_copy = source_data;
  str_time = t.elapsed_ms();

  print_result("Load / Create", rope_time, str_time);

  // ==========================================
  // TEST 2: INSERT (Middle)
  // ==========================================
  std::string insert_pattern = " [INSERTED TEXT] ";
  uint32_t insert_pos = total_len / 2;

  // Rope Insert
  t.reset();
  root = insert(root, insert_pos, const_cast<char *>(insert_pattern.c_str()),
                (uint32_t)insert_pattern.size());
  rope_time = t.elapsed_ms();

  // String Insert
  t.reset();
  str_copy.insert(insert_pos, insert_pattern);
  str_time = t.elapsed_ms();

  print_result("Insert (Middle)", rope_time, str_time);

  // ==========================================
  // TEST 3: READ / SUBSTR
  // ==========================================
  uint32_t read_len = 1024;
  uint32_t read_pos = total_len / 2; // Read from where we just inserted

  // Rope Read
  t.reset();
  char *rope_read_res = read(root, read_pos, read_len);
  rope_time = t.elapsed_ms();
  free(rope_read_res); // Free result as per header

  // String Substr
  t.reset();
  std::string str_read_res = str_copy.substr(read_pos, read_len);
  str_time = t.elapsed_ms();

  print_result("Read / Substr (1KiB)", rope_time, str_time);

  // ==========================================
  // TEST 4: CONCATENATION
  // ==========================================
  // Create a temporary rope to append
  Knot *suffix_rope = load(const_cast<char *>(pattern.c_str()),
                           (uint32_t)pattern.size(), chunk_size);

  // Rope Concat
  t.reset();
  root = concat(root, suffix_rope);
  rope_time = t.elapsed_ms();

  // String Append
  t.reset();
  str_copy += pattern;
  str_time = t.elapsed_ms();

  print_result("Concat (Append small)", rope_time, str_time);

  Knot *large_rope =
      load(const_cast<char *>(source_data.c_str()), total_len, chunk_size);

  // Rope Concat
  t.reset();
  root = concat(root, large_rope);
  rope_time = t.elapsed_ms();

  Knot *L = nullptr;
  Knot *R = nullptr;
  split(root, total_len, &L, &R);
  root = L;
  free_rope(R);

  // String Append
  t.reset();
  str_copy += source_data;
  str_time = t.elapsed_ms();

  print_result("Concat (Append large)", rope_time, str_time);

  // ==========================================
  // TEST 5: ERASE
  // ==========================================
  uint32_t erase_len = 5000; // Erase 5KB
  uint32_t erase_pos = total_len / 4;

  // Rope Erase
  t.reset();
  root = erase(root, erase_pos, erase_len);
  rope_time = t.elapsed_ms();

  // String Erase
  t.reset();
  str_copy.erase(erase_pos, erase_len);
  str_time = t.elapsed_ms();

  print_result("Erase (5KB)", rope_time, str_time);

  // ==========================================
  // TEST 6: LINE TO BYTE (Indexing)
  // ==========================================
  // Pick a line number deep in the file
  uint32_t target_line = 100000;
  uint32_t out_len = 0;

  // Rope Line Lookup
  t.reset();
  volatile uint32_t r_offset = line_to_byte(root, target_line, &out_len);
  rope_time = t.elapsed_ms();

  // String Line Lookup (Simulated: Must scan for newlines)
  t.reset();
  size_t current_line = 0;
  size_t s_offset = 0;
  // Manual scan is the standard way for std::string
  for (size_t i = 0; i < str_copy.size(); ++i) {
    if (str_copy[i] == '\n') {
      current_line++;
      if (current_line == target_line) {
        s_offset = i + 1; // Start of next line
        break;
      }
    }
  }
  str_time = t.elapsed_ms();

  print_result("Line -> Byte Offset", rope_time, str_time);

  // ==========================================
  // TEST 7: BYTE TO LINE
  // ==========================================
  uint32_t target_offset = total_len / 2;

  // Rope Byte Lookup
  t.reset();
  volatile uint32_t r_line = byte_to_line(root, target_offset);
  rope_time = t.elapsed_ms();

  // String Byte Lookup (Simulated scan backwards or from start)
  t.reset();
  size_t s_line = 0;
  for (size_t i = 0; i < target_offset && i < str_copy.size(); ++i) {
    if (str_copy[i] == '\n')
      s_line++;
  }
  str_time = t.elapsed_ms();

  print_result("Byte Offset -> Line", rope_time, str_time);

  // ==========================================
  // TEST 8: LINE ITERATION (Next 1000 lines)
  // ==========================================
  int lines_to_read = 1000;
  uint32_t start_iter_line = 50000;

  // Rope Iteration
  t.reset();
  LineIterator *lit = begin_l_iter(root, start_iter_line);
  for (int i = 0; i < lines_to_read; ++i) {
    char *line = next_line(lit);
    if (line)
      free(line); // Must free per header
    else
      break;
  }
  // Note: Assuming `free(lit)` or similar is needed,
  // though header says "returned iterator must be freed".
  // I will assume standard `delete` or `free` works on the struct pointer.
  free(lit);
  rope_time = t.elapsed_ms();

  // String Iteration
  // To be fair, we find the starting offset, then read lines
  t.reset();
  size_t iter_offset = 0;
  size_t cur_ln = 0;
  // Fast forward (cost of finding start)
  while (cur_ln < start_iter_line && iter_offset < str_copy.size()) {
    if (str_copy[iter_offset++] == '\n')
      cur_ln++;
  }
  // Read loop
  for (int i = 0; i < lines_to_read && iter_offset < str_copy.size(); ++i) {
    size_t next_nl = str_copy.find('\n', iter_offset);
    if (next_nl == std::string::npos)
      break;
    // Simulate extracting the string
    volatile std::string temp =
        str_copy.substr(iter_offset, next_nl - iter_offset);
    iter_offset = next_nl + 1;
  }
  str_time = t.elapsed_ms();

  print_result("Iterate 1000 Lines", rope_time, str_time);

  // ==========================================
  // TEST 9: SEARCH (Regex)
  // ==========================================
  // Search for a specific pattern that occurs
  const char *search_pattern = "brown fox";

  // Rope Search (DFA/PCRE as per header)
  t.reset();
  auto rope_matches = search_rope(root, search_pattern);
  rope_time = t.elapsed_ms();

  t.reset();
  try {
    std::regex re(search_pattern);
    auto words_begin =
        std::sregex_iterator(str_copy.begin(), str_copy.end(), re);
    auto words_end = std::sregex_iterator();
    size_t count = 0;
    for (std::sregex_iterator i = words_begin; i != words_end; ++i) {
      count++;
      // Don't iterate millions of times for the benchmark if it takes forever
      if (count > 1000)
        break;
    }
  } catch (...) {
  }
  str_time = t.elapsed_ms();

  print_result("Search (Regex)", rope_time, str_time);

  // ==========================================
  // TEST 10: SPLIT
  // ==========================================
  uint32_t split_point = total_len / 2;
  Knot *left_side = nullptr;
  Knot *right_side = nullptr;

  // Rope Split
  t.reset();
  // split consumes 'root', so root is invalid after this
  split(root, split_point, &left_side, &right_side);
  rope_time = t.elapsed_ms();

  // String Split (Simulated via substr copies)
  t.reset();
  std::string s_left = str_copy.substr(0, split_point);
  std::string s_right = str_copy.substr(split_point);
  str_time = t.elapsed_ms();

  print_result("Split (Half)", rope_time, str_time);

  // ==========================================
  // CLEANUP
  // ==========================================
  t.reset();
  free_rope(left_side);
  free_rope(right_side);
  rope_time = t.elapsed_ms();

  // std::string cleans up automatically, but let's time the destruction
  t.reset();
  {
    std::string temp1 = std::move(s_left);
    std::string temp2 = std::move(s_right);
  } // destructors run here
  str_time = t.elapsed_ms();

  print_result("Free / Destruct", rope_time, str_time);

  return 0;
}