#include <getopt.h>
#include <locale.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "allocator.h"
#include "binding.h"
#include "bits/getopt_core.h"
#include "bits/getopt_ext.h"
#include "buffer.h"
#include "buffers.h"
#include "display.h"
#include "lang.h"
#include "minibuffer.h"
#include "reactor.h"
#include "settings.h"

struct frame_allocator frame_allocator;

void *frame_alloc(size_t sz) {
  return frame_allocator_alloc(&frame_allocator, sz);
}

bool running = true;

void terminate() { running = false; }

static struct display *display = NULL;
static bool display_resized = false;
void resized() {
  if (display != NULL) {
    display_resize(display);
  }
  display_resized = true;

  signal(SIGWINCH, resized);
}

int32_t _abort(struct command_ctx ctx, int argc, const char *argv[]) {
  minibuffer_abort_prompt();
  minibuffer_echo_timeout(4, "💣 aborted");
  return 0;
}

int32_t unimplemented_command(struct command_ctx ctx, int argc,
                              const char *argv[]) {
  minibuffer_echo("TODO: %s is not implemented", (const char *)ctx.userdata);
  return 0;
}

int32_t exit_editor(struct command_ctx ctx, int argc, const char *argv[]) {
  terminate();
  return 0;
}

static struct command GLOBAL_COMMANDS[] = {
    {.name = "find-file", .fn = find_file},
    {.name = "write-file", .fn = write_file},
    {.name = "run-command-interactive", .fn = run_interactive},
    {.name = "switch-buffer", .fn = switch_buffer},
    {.name = "abort", .fn = _abort},
    {.name = "exit", .fn = exit_editor}};

uint64_t calc_frame_time_ns(struct timespec *timers, uint32_t num_timer_pairs) {
  uint64_t total = 0;
  for (uint32_t ti = 0; ti < num_timer_pairs * 2; ti += 2) {
    struct timespec *start_timer = &timers[ti];
    struct timespec *end_timer = &timers[ti + 1];

    total +=
        ((uint64_t)end_timer->tv_sec * 1e9 + (uint64_t)end_timer->tv_nsec) -
        ((uint64_t)start_timer->tv_sec * 1e9 + (uint64_t)start_timer->tv_nsec);
  }

  return total;
}

void usage() { printf("TODO: print usage\n"); }

int main(int argc, char *argv[]) {

  static struct option longopts[] = {{"line", required_argument, NULL, 'l'},
                                     {"end", no_argument, NULL, 'e'},
                                     {NULL, 0, NULL, 0}};

  char *filename = NULL;
  uint32_t jumpline = 1;
  bool goto_end = false;
  char ch;
  while ((ch = getopt_long(argc, argv, "el:", longopts, NULL)) != -1) {
    switch (ch) {
    case 'l':
      jumpline = atoi(optarg);
      break;
    case 'e':
      goto_end = true;
      break;
    default:
      usage();
      return 1;
    }
  }
  argc -= optind;
  argv += optind;

  if (argc > 1) {
    fprintf(stderr, "More than one file to open is not supported\n");
    return 2;
  } else if (argc == 1) {
    filename = strdup(argv[0]);
  }

  setlocale(LC_ALL, "");

  signal(SIGTERM, terminate);

  struct commands commands = command_registry_create(32);
  settings_init(64, &commands);
  languages_init(true);
  buffer_static_init(&commands);

  frame_allocator = frame_allocator_create(16 * 1024 * 1024);

  // create reactor
  struct reactor *reactor = reactor_create();

  // initialize display
  display = display_create();
  display_clear(display);
  signal(SIGWINCH, resized);

  // init keyboard
  struct keyboard kbd = keyboard_create(reactor);

  // global commands, TODO: move these, they should exist even if main does not
  register_commands(&commands, GLOBAL_COMMANDS,
                    sizeof(GLOBAL_COMMANDS) / sizeof(GLOBAL_COMMANDS[0]));

  // keymaps
  struct keymap *current_keymap = NULL;
  struct keymap global_keymap = keymap_create("global", 32);
  struct keymap ctrlx_map = keymap_create("c-x", 32);
  struct binding global_binds[] = {
      PREFIX(Ctrl, 'X', &ctrlx_map),
      BINDING(Ctrl, 'G', "abort"),
      BINDING(Meta, 'x', "run-command-interactive"),
  };
  struct binding ctrlx_bindings[] = {
      BINDING(Ctrl, 'C', "exit"),
      BINDING(Ctrl, 'S', "buffer-write-to-file"),
      BINDING(Ctrl, 'F', "find-file"),
      BINDING(Ctrl, 'W', "write-file"),
      BINDING(None, 'b', "switch-buffer"),
  };
  keymap_bind_keys(&global_keymap, global_binds,
                   sizeof(global_binds) / sizeof(global_binds[0]));
  keymap_bind_keys(&ctrlx_map, ctrlx_bindings,
                   sizeof(ctrlx_bindings) / sizeof(ctrlx_bindings[0]));

  struct buffers buflist = {0};
  buffers_init(&buflist, 32);
  struct buffer initial_buffer = buffer_create("welcome", true);
  if (filename != NULL) {
    buffer_destroy(&initial_buffer);
    initial_buffer = buffer_from_file(filename);
    if (goto_end) {
      buffer_goto_end(&initial_buffer);
    } else
      buffer_goto(&initial_buffer, jumpline > 0 ? jumpline - 1 : 0, 0);
  } else {
    const char *welcome_txt = "Welcome to the editor for datagubbar 👴\n";
    buffer_add_text(&initial_buffer, (uint8_t *)welcome_txt,
                    strlen(welcome_txt));
  }

  // one main window
  struct window main_window = (struct window){
      .buffer = buffers_add(&buflist, initial_buffer),
      .prev_buffer = NULL,
      .height = display_height(display) - 1,
      .width = display_width(display),
      .x = 0,
      .y = 0,
  };

  // and one for the minibuffer
  struct buffer minibuffer = buffer_create("minibuffer", false);

  minibuffer_init(&minibuffer);
  struct window minibuffer_window = (struct window){
      .buffer = &minibuffer,
      .prev_buffer = NULL,
      .x = 0,
      .y = display_height(display) - 1,
      .height = 1,
      .width = display_width(display),
  };

  struct timespec buffer_begin, buffer_end, display_begin, display_end,
      keyboard_begin, keyboard_end;

  uint64_t frame_time = 0;

  struct window *windows[2] = {
      &minibuffer_window,
      &main_window,
  };

  struct command_list *command_lists[2] = {0};

  // TODO: not always
  struct window *active_window = &main_window;

  while (running) {

    clock_gettime(CLOCK_MONOTONIC, &buffer_begin);

    if (display_resized) {
      minibuffer_window.width = display_width(display);
      minibuffer_window.y = display_height(display) - 1;

      main_window.height = display_height(display) - 1;
      main_window.width = display_width(display);

      display_resized = false;
    }

    // update windows
    uint32_t dot_line = 0, dot_col = 0;
    for (uint32_t windowi = 0; windowi < sizeof(windows) / sizeof(windows[0]);
         ++windowi) {
      struct window *win = windows[windowi];
      // TODO: better capacity
      command_lists[windowi] =
          command_list_create(win->height * win->width, frame_alloc, win->x,
                              win->y, win->buffer->name);

      uint32_t relline, relcol;
      window_update_buffer(win, command_lists[windowi], frame_time, &relline,
                           &relcol);

      if (win == active_window) {
        dot_line = relline;
        dot_col = relcol;
      }
    }

    clock_gettime(CLOCK_MONOTONIC, &buffer_end);

    // update screen
    clock_gettime(CLOCK_MONOTONIC, &display_begin);
    uint32_t relline, relcol;

    display_begin_render(display);
    for (uint32_t windowi = 0; windowi < sizeof(windows) / sizeof(windows[0]);
         ++windowi) {
      display_render(display, command_lists[windowi]);
    }
    display_move_cursor(display, dot_line + active_window->y,
                        dot_col + active_window->x);
    display_end_render(display);
    clock_gettime(CLOCK_MONOTONIC, &display_end);

    // this blocks for events, so if nothing has happened we block here.
    reactor_update(reactor);

    clock_gettime(CLOCK_MONOTONIC, &keyboard_begin);
    struct keymap *local_keymaps = NULL;
    uint32_t nbuffer_keymaps =
        buffer_keymaps(active_window->buffer, &local_keymaps);
    struct keyboard_update kbd_upd =
        keyboard_update(&kbd, reactor, frame_alloc);

    uint32_t input_data_idx = 0;
    for (uint32_t ki = 0; ki < kbd_upd.nkeys; ++ki) {
      struct key *k = &kbd_upd.keys[ki];

      struct lookup_result res = {.found = false};
      if (current_keymap != NULL) {
        res = lookup_key(current_keymap, 1, k, &commands);
      } else {
        // check first the global keymap, then the buffer ones
        res = lookup_key(&global_keymap, 1, k, &commands);
        if (!res.found) {
          res = lookup_key(local_keymaps, nbuffer_keymaps, k, &commands);
        }
      }

      if (res.found) {
        switch (res.type) {
        case BindingType_Command: {
          if (res.command == NULL) {
            minibuffer_echo_timeout(
                4, "binding found for key %s but not command", k);
          } else {
            int32_t ec = execute_command(res.command, &commands, active_window,
                                         &buflist, 0, NULL);
            if (ec != 0 && !minibuffer_displaying()) {
              minibuffer_echo_timeout(4, "command %s failed with exit code %d",
                                      res.command->name, ec);
            }
          }
          current_keymap = NULL;
          break;
        }
        case BindingType_Keymap: {
          char keyname[16];
          key_name(k, keyname, 16);
          current_keymap = res.keymap;
          minibuffer_echo("%s", current_keymap->name);
          break;
        }
        }
      } else if (k->mod == 0) {
        buffer_add_text(active_window->buffer, &kbd_upd.raw[k->start],
                        k->end - k->start);
      } else {
        char keyname[16];
        key_name(k, keyname, 16);
        if (current_keymap == NULL) {
          minibuffer_echo_timeout(4, "key \"%s\" is not bound!", keyname);
        } else {
          minibuffer_echo_timeout(4, "key \"%s %s\" is not bound!",
                                  current_keymap->name, keyname);
        }
        current_keymap = NULL;
      }
    }
    clock_gettime(CLOCK_MONOTONIC, &keyboard_end);

    // calculate frame time
    struct timespec timers[] = {buffer_begin, buffer_end,     display_begin,
                                display_end,  keyboard_begin, keyboard_end};
    frame_time = calc_frame_time_ns(timers, 3);

    if (minibuffer_focused()) {
      active_window = &minibuffer_window;
    } else {
      // TODO: not this
      active_window = &main_window;
    }

    frame_allocator_clear(&frame_allocator);
  }

  minibuffer_destroy();
  buffer_destroy(&minibuffer);
  buffers_destroy(&buflist);
  display_clear(display);
  display_destroy(display);
  keymap_destroy(&global_keymap);
  keymap_destroy(&ctrlx_map);
  command_registry_destroy(&commands);
  reactor_destroy(reactor);
  frame_allocator_destroy(&frame_allocator);
  buffer_static_teardown();
  settings_destroy();

  return 0;
}