text: #include "system/stacktrace.h"
  
  #include "ebisp/gc.h"
  #include "ebisp/interpreter.h"
  #include "ebisp/parser.h"
  #include "ebisp/scope.h"
  #include "ebisp/std.h"
  #include "game/level.h"
  #include "sdl/renderer.h"
  #include "system/log.h"
  #include "system/log_script.h"
  #include "system/lt.h"
  #include "system/nth_alloc.h"
  #include "ui/console.h"
  #include "ui/console_log.h"
  #include "ui/edit_field.h"
  #include "ui/history.h"
  #include "broadcast.h"
  
  #define FONT_WIDTH_SCALE 3.0f
  #define FONT_HEIGHT_SCALE 3.0f
  
  #define CONSOLE_LOG_CAPACITY 10
  #define HISTORY_CAPACITY 20
  #define PROMPT_HEIGHT (FONT_HEIGHT_SCALE * FONT_CHAR_HEIGHT)
  #define CONSOLE_LOG_HEIGHT (FONT_HEIGHT_SCALE * FONT_CHAR_HEIGHT * CONSOLE_LOG_CAPACITY)
  
  #define CONSOLE_HEIGHT (CONSOLE_LOG_HEIGHT + PROMPT_HEIGHT)
  
  #define SLIDE_DOWN_TIME 0.4f
  
  #define CONSOLE_ALPHA (0.80f)
  #define CONSOLE_BACKGROUND (rgba(0.20f, 0.20f, 0.20f, CONSOLE_ALPHA))
  #define CONSOLE_FOREGROUND (rgba(0.80f, 0.80f, 0.80f, CONSOLE_ALPHA))
  #define CONSOLE_ERROR (rgba(0.80f, 0.50f, 0.50f, CONSOLE_ALPHA))
  
  #define CONSOLE_EVAL_RESULT_SIZE 256
  
  struct Console
  {
      Lt *lt;
      Gc *gc;
      struct Scope scope;
      Edit_field *edit_field;
      Console_Log *console_log;
      History *history;
      float a;
  };
  
  /* TODO(#356): Console does not support autocompletion */
  /* TODO(#357): Console does not show the state of the GC of the script */
  /* TODO(#358): Console does not support copy, cut, paste operations */
  
  Console *create_console(Broadcast *broadcast)
  {
      trace_assert(broadcast);
  
      Lt *lt = create_lt();
  
      Console *console = PUSH_LT(lt, nth_calloc(1, sizeof(Console)), free);
      if (console == NULL) {
          RETURN_LT(lt, NULL);
      }
      console->lt = lt;
  
      console->gc = PUSH_LT(lt, create_gc(), destroy_gc);
      if (console->gc == NULL) {
          RETURN_LT(lt, NULL);
      }
  
      console->scope.expr = CONS(console->gc,
                                 NIL(console->gc),
                                 NIL(console->gc));
  
      load_std_library(console->gc, &console->scope);
      load_log_library(console->gc, &console->scope);
      /* TODO(#669): how to report EvalResult error from create_console? */
      broadcast_load_library(broadcast, console->gc, &console->scope);
  
      console->edit_field = PUSH_LT(
          lt,
          create_edit_field(
              vec(FONT_WIDTH_SCALE, FONT_HEIGHT_SCALE),
              CONSOLE_FOREGROUND),
          destroy_edit_field);
      if (console->edit_field == NULL) {
          RETURN_LT(lt, NULL);
      }
  
      console->console_log = PUSH_LT(
          lt,
          create_console_log(
              vec(FONT_WIDTH_SCALE, FONT_HEIGHT_SCALE),
              CONSOLE_LOG_CAPACITY),
          destroy_console_log);
  
      console->a = 0;
  
      console->history = PUSH_LT(
          lt,
          create_history(HISTORY_CAPACITY),
          destroy_history);
      if (console->history == NULL) {
          RETURN_LT(lt, NULL);
      }
  
      return console;
  }
  
  void destroy_console(Console *console)
  {
      trace_assert(console);
      RETURN_LT0(console->lt);
  }
  
  static int console_eval_input(Console *console)
  {
      const char *source_code = edit_field_as_text(console->edit_field);
  
      /* TODO(#387): console pushes empty strings to the history */
      if (history_push(console->history, source_code) < 0) {
          return -1;
      }
  
      if (console_log_push_line(console->console_log, source_code, CONSOLE_FOREGROUND) < 0) {
          return -1;
      }
  
      while (*source_code != 0) {
          struct ParseResult parse_result = read_expr_from_string(console->gc,
                                                                  source_code);
  
          if (parse_result.is_error) {
              if (console_log_push_line(console->console_log, parse_result.error_message, CONSOLE_ERROR)) {
                  return -1;
              }
  
              edit_field_clean(console->edit_field);
  
              return 0;
          }
  
          struct EvalResult eval_result = eval(
              console->gc,
              &console->scope,
              parse_result.expr);
  
          char buffer[CONSOLE_EVAL_RESULT_SIZE];
  
          if (expr_as_sexpr(
                  eval_result.expr,
                  buffer,
                  CONSOLE_EVAL_RESULT_SIZE) < 0) {
              return -1;
          }
  
          if (console_log_push_line(console->console_log,
                                    buffer,
                                    eval_result.is_error ?
                                    CONSOLE_ERROR :
                                    CONSOLE_FOREGROUND)) {
              return -1;
          }
  
          source_code = next_token(parse_result.end).begin;
      }
  
      gc_collect(console->gc, console->scope.expr);
      edit_field_clean(console->edit_field);
  
      return 0;
  }
  
  int console_handle_event(Console *console,
                           const SDL_Event *event)
  {
      switch(event->type) {
      case SDL_KEYDOWN: {
          switch(event->key.keysym.sym) {
          case SDLK_RETURN:
              return console_eval_input(console);
  
          case SDLK_UP:
              edit_field_replace(
                  console->edit_field,
                  history_current(console->history));
              history_prev(console->history);
              return 0;
  
          case SDLK_p: {
              if (event->key.keysym.mod & KMOD_CTRL) {
                  edit_field_replace(
                      console->edit_field, history_current(console->history));
                  history_prev(console->history);
                  return 0;
              }
          } break;
  
          case SDLK_DOWN:
              edit_field_replace(
                  console->edit_field,
                  history_current(console->history));
              history_next(console->history);
              return 0;
  
          case SDLK_n: {
              if (event->key.keysym.mod & KMOD_CTRL) {
                  edit_field_replace(
                      console->edit_field, history_current(console->history));
                  history_next(console->history);
                  return 0;
              }
          } break;
          }
      } break;
      }
  
      return edit_field_event(console->edit_field, event);
  }
  
  int console_render(const Console *console,
                     const Camera *camera)
  {
      /* TODO(#364): console doesn't have any padding around the edit fields */
      SDL_Rect view_port;
      SDL_RenderGetViewport(camera->renderer, &view_port);
  
      const float e = console->a * (2 - console->a);
      const float y = -(1.0f - e) * CONSOLE_HEIGHT;
  
      if (camera_fill_rect_screen(
              camera,
              rect(0.0f, y,
                   (float) view_port.w,
                   CONSOLE_HEIGHT),
              CONSOLE_BACKGROUND) < 0) {
          return -1;
      }
  
      if (console_log_render(console->console_log,
                             camera,
                             vec(0.0f, y)) < 0) {
          return -1;
      }
  
      if (edit_field_render_screen(console->edit_field,
                                   camera,
                                   vec(0.0f, y + CONSOLE_LOG_HEIGHT)) < 0) {
          return -1;
      }
  
      return 0;
  }
  
  int console_update(Console *console, float delta_time)
  {
      trace_assert(console);
  
      if (console->a < 1.0f) {
          console->a += 1.0f / SLIDE_DOWN_TIME * delta_time;
  
          if (console->a > 1.0f) {
              console->a = 1.0f;
          }
      }
  
      return 0;
  }
  
  void console_slide_down(Console *console)
  {
      trace_assert(console);
      console->a = 0.0f;
  }
  