Setup cli routing & other cleanup.

src/cli/cli.cc

@@ -0,0 +1,83 @@
+#include "cli.h"
+#include "commands/ed/ed.h"
+
+namespace crib::cli {
+struct Command {
+  void (*run)(int, char **);
+  std::string (*summary)();
+  void (*help)();
+};
+
+struct cli_error : std::runtime_error {
+  int exit_code;
+  cli_error(std::string msg, int code)
+      : std::runtime_error(std::move(msg)), exit_code(code) {}
+};
+
+static const std::unordered_map<std::string, Command> commands = {
+  {"ed",
+   {crib::commands::ed::run,
+    crib::commands::ed::summary,
+    crib::commands::ed::help}},
+};
+
+bool use_color() {
+  if (std::getenv("NO_COLOR"))
+    return false;
+  if (std::getenv("CLICOLOR_FORCE"))
+    return true;
+  if (!isatty(STDERR_FILENO))
+    return false;
+  const char *term = std::getenv("TERM");
+  if (!term || std::string_view(term) == "dumb" || std::string_view(term) == "xterm")
+    return false;
+  if (const char *clicolor = std::getenv("CLICOLOR"))
+    return std::string_view(clicolor) != "0";
+  return true;
+}
+
+bool use_colors = use_color();
+
+void help() {
+  std::cout << "Usage: crib <command> [options]\n\n"
+            << "Where command is one of\n";
+  for (auto &[name, cmd] : commands)
+    std::cout << "  " << name << " - " << cmd.summary() << "\n";
+}
+
+int execute(const std::string &name, const Command &cmd, int argc, char **argv) {
+  try {
+    cmd.run(argc - 1, argv + 1);
+    return 0;
+  } catch (const cli_error &e) {
+    std::cerr << "Error running " << name << ": " << e.what() << '\n';
+    return e.exit_code;
+  } catch (const std::exception &e) {
+    std::cerr << "Error running " << name << ": " << e.what() << '\n';
+    return 1;
+  } catch (...) {
+    std::cerr << "Unknown error running " << name << '\n';
+    return 1;
+  }
+}
+
+int run(int argc, char *argv[]) {
+  std::string invoked_as = std::filesystem::path(argv[0]).filename();
+
+  if (auto it = commands.find(invoked_as); it != commands.end())
+    return execute(it->first, it->second, argc, argv);
+
+  if (argc > 1)
+    if (auto it = commands.find(argv[1]); it != commands.end())
+      return execute(it->first, it->second, argc, argv);
+
+  if (argc > 1 && std::string(argv[1]) == "--help") {
+    help();
+    return 0;
+  }
+
+  std::cerr << "Invalid command given.\n\n";
+  help();
+  return 2;
+}
+} // namespace crib::cli