import type { FastifyInstance } from 'fastify';
import { z } from 'zod';
import type { Sql } from '../db.js';
import type { Broker } from '@boocode/server/broker';
import type { WsFrame } from '@boocode/server/ws-frames';
import { getSkillBody } from '@boocode/server/skills';
import {
  buildSkillInvokeSyntheticFrames,
  buildSkillInvokeUserFrames,
  DEFAULT_SKILL_USER_MESSAGE,
  runSkillInvokeTransaction,
} from '@boocode/server/skill-invoke';
import { resolveChatId } from './chat-resolve.js';

const SkillInvokeBody = z.object({
  pane_id: z.string().min(1).max(200),
  skill_name: z.string().min(1),
  user_message: z.string().max(64_000).nullable().optional(),
});

interface InferenceApi {
  enqueue: (sessionId: string, chatId: string, assistantId: string, user: string) => void;
  hasActive: (chatId: string) => boolean;
}

export function registerSkillRoutes(
  app: FastifyInstance,
  sql: Sql,
  broker: Broker,
  inference: InferenceApi,
): void {
  app.post<{ Params: { sessionId: string } }>(
    '/api/sessions/:sessionId/skill_invoke',
    async (req, reply) => {
      const parsed = SkillInvokeBody.safeParse(req.body);
      if (!parsed.success) {
        reply.code(400);
        return { error: 'invalid body', details: parsed.error.flatten() };
      }

      const sessionId = req.params.sessionId;
      const { pane_id, skill_name } = parsed.data;
      const sessionRows = await sql<{ id: string }[]>`
        SELECT id FROM sessions WHERE id = ${sessionId}
      `;
      if (sessionRows.length === 0) {
        reply.code(404);
        return { error: 'session not found' };
      }

      const chatId = await resolveChatId(sql, sessionId, pane_id);
      if (!chatId) {
        reply.code(404);
        return { error: 'pane not found' };
      }

      if (inference.hasActive(chatId)) {
        reply.code(409);
        return { error: 'inference already running on this chat' };
      }

      const userText = parsed.data.user_message?.trim()
        ? parsed.data.user_message
        : DEFAULT_SKILL_USER_MESSAGE;

      const body = await getSkillBody(skill_name);
      if (body === null) {
        reply.code(404);
        return { error: 'unknown_skill', message: `unknown skill: ${skill_name}` };
      }

      const { result, toolCall } = await runSkillInvokeTransaction(sql, {
        sessionId,
        chatId,
        skillName: skill_name,
        skillBody: body,
        userText,
      });

      for (const frame of buildSkillInvokeSyntheticFrames(chatId, result, toolCall, body)) {
        broker.publishFrame(sessionId, frame as WsFrame);
      }
      for (const frame of buildSkillInvokeUserFrames(chatId, result.user_message_id, userText)) {
        broker.publishFrame(sessionId, frame as WsFrame);
      }

      inference.enqueue(sessionId, chatId, result.assistant_message_id, 'default');

      reply.code(202);
      return result;
    },
  );
}