import type { ExtensionAPI } from '@earendil-works/pi-coding-agent';
import { Text } from '@earendil-works/pi-tui';
import { executeTodo, type TodoToolDetails } from './execute.ts';
import { registerGuardEvents } from './guards.ts';
import {
  prepareTodoArguments,
  TOOL_NAME,
  TodoToolParametersSchema,
} from './model.ts';
import {
  type BoardLifecycle,
  commitBoard,
  createTodoStore,
  registerBoardContext,
  registerSessionRefreshEvents,
  restoreAndRefreshBoard,
  restoreBoard,
  TODO_WIDGET_REFRESH_EVENT,
  type TodoStore,
} from './session.ts';
import { createTodoBoardOverlayController } from './ui.ts';

export const TODO_DESCRIPTION =
  'Maintain a live, user-visible work board. propose replaces the full board; update patches existing items by id.';

export const TODO_PROMPT_SNIPPET =
  'Maintain the live work board with propose and update.';

export const TODO_PROMPT_GUIDELINES = [
  'Use sideroom_todo to maintain a live work board when implementation has more than one step.',
  'While any item is pending, exactly one must be in_progress.',
  'Update at task milestones, not after each tool call. Complete the current item and start the next item in the same update call.',
  'propose is interactive-TUI-only; update also works in print, JSON, and RPC modes.',
];

const BOARD_SHORTCUT = 'f9';

export default function registerTodo(pi: ExtensionAPI): void {
  const store = createTodoStore();
  const overlay = createTodoBoardOverlayController(() => store.items);
  const restore: BoardLifecycle = (ctx) => {
    restoreBoard(store, ctx);
  };
  const notifyWidgetRefresh: BoardLifecycle = (ctx) => {
    pi.events.emit(TODO_WIDGET_REFRESH_EVENT, ctx);
  };
  const restoreAndRefresh: BoardLifecycle = (ctx) => {
    restoreAndRefreshBoard(store, ctx);
    notifyWidgetRefresh(ctx);
  };

  registerSessionRefreshEvents(pi, store, restoreAndRefresh);
  registerGuardEvents(pi, store, restore);
  registerBoardContext(pi, store, restoreAndRefresh);
  registerTodoTool(pi, store, notifyWidgetRefresh);
  pi.registerShortcut(BOARD_SHORTCUT, {
    description: 'Toggle the work board',
    handler: (ctx) => overlay.toggle(ctx),
  });
}

function registerTodoTool(
  pi: ExtensionAPI,
  store: TodoStore,
  notifyWidgetRefresh: BoardLifecycle,
): void {
  pi.registerTool({
    name: TOOL_NAME,
    label: 'Sideroom Todo',
    description: TODO_DESCRIPTION,
    promptSnippet: TODO_PROMPT_SNIPPET,
    promptGuidelines: TODO_PROMPT_GUIDELINES,
    parameters: TodoToolParametersSchema,
    prepareArguments: prepareTodoArguments,
    executionMode: 'sequential',
    execute: async (_toolCallId, params, _signal, _onUpdate, ctx) => {
      const result = executeTodo(params, ctx, store.items);
      if (result.details.error !== undefined) {
        return result;
      }

      commitBoard(store, pi, ctx, result.details.items);
      notifyWidgetRefresh(ctx);
      return result;
    },
    renderCall(args, theme) {
      const text = `${theme.fg('toolTitle', theme.bold(`${TOOL_NAME} `))}${theme.fg('muted', args.action)}`;
      return new Text(text, 0, 0);
    },
    renderResult(result, _options, theme) {
      const details = result.details as TodoToolDetails | undefined;
      if (details?.error !== undefined) {
        return new Text(theme.fg('error', details.error), 0, 0);
      }
      const text = result.content[0];
      return new Text(
        theme.fg('success', text?.type === 'text' ? text.text : ''),
        0,
        0,
      );
    },
  });
}