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 { resolveChatId } from './chat-resolve.js';

const AnswerUserInputBody = z.object({
  tool_call_id: z.string().min(1),
  answers: z
    .array(
      z.object({
        question: z.string(),
        selected_options: z.array(z.string()),
        free_text: z.string().nullable(),
      }),
    )
    .min(1)
    .max(3),
});

const AskUserInputArgs = z.object({
  questions: z
    .array(
      z.object({
        question: z.string(),
        type: z.enum(['single_select', 'multi_select']),
        options: z.array(z.string()).min(1),
      }),
    )
    .min(1)
    .max(3),
});

const SendBody = z.object({
  content: z.string().min(1).max(64_000),
  pane_id: z.string().min(1).max(200),
  chat_id: z.string().uuid().optional(),
  provider: z.string().max(100).optional(),
  model: z.string().max(200).optional(),
  mode_id: z.string().max(200).optional(),
  thinking_option_id: z.string().max(200).optional(),
});

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

interface MessageRow {
  id: string;
  role: string;
  content: string | null;
  status: string | null;
  tool_calls: Array<{ id: string; name: string; args?: Record<string, unknown> }> | null;
  tool_results: {
    tool_call_id: string;
    output: unknown;
    truncated?: boolean;
    error?: string;
  } | null;
  reasoning_parts: Array<{ text?: string }> | null;
}

function mapCoderMessageRow(row: MessageRow) {
  if (row.role === 'tool') {
    if (!row.tool_results?.tool_call_id) return null;
    return {
      id: row.id,
      role: 'tool' as const,
      tool_results: row.tool_results,
    };
  }
  if (row.role !== 'user' && row.role !== 'assistant' && row.role !== 'system') {
    return null;
  }
  const tool_calls = row.tool_calls?.map((tc) => ({
    id: tc.id,
    function: {
      name: tc.name,
      arguments: JSON.stringify(tc.args ?? {}),
    },
  }));
  const reasoningText = row.reasoning_parts?.map((p) => p.text ?? '').join('') ?? '';
  return {
    id: row.id,
    role: row.role as 'user' | 'assistant' | 'system',
    content: row.content ?? '',
    status: (row.status ?? 'complete') as 'streaming' | 'complete' | 'failed',
    ...(reasoningText ? { reasoning_text: reasoningText } : {}),
    ...(tool_calls?.length ? { tool_calls } : {}),
  };
}

export function registerMessageRoutes(
  app: FastifyInstance,
  sql: Sql,
  broker: Broker,
  inference: InferenceApi,
): void {
  // GET /api/sessions/:sessionId/messages — hydrate CoderPane on load / reconnect
  app.get<{ Params: { sessionId: string }; Querystring: { chat_id?: string } }>(
    '/api/sessions/:sessionId/messages',
    async (req, reply) => {
      const sessionId = req.params.sessionId;
      const chatId = req.query.chat_id;
      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' };
      }

      if (chatId) {
        const chatRows = await sql<{ id: string }[]>`
          SELECT id FROM chats
          WHERE id = ${chatId} AND session_id = ${sessionId} AND status = 'open'
        `;
        if (chatRows.length === 0) {
          reply.code(404);
          return { error: 'chat not found or not open in this session' };
        }
      }

      const rows = chatId
        ? await sql<MessageRow[]>`
            SELECT id, role, content, status, tool_calls, tool_results, reasoning_parts
            FROM messages_with_parts
            WHERE session_id = ${sessionId} AND chat_id = ${chatId}
            ORDER BY created_at ASC, id ASC
          `
        : await sql<MessageRow[]>`
            SELECT id, role, content, status, tool_calls, tool_results, reasoning_parts
            FROM messages_with_parts
            WHERE session_id = ${sessionId}
            ORDER BY created_at ASC, id ASC
          `;

      return rows.map(mapCoderMessageRow).filter((m) => m !== null);
    },
  );

  // POST /api/sessions/:sessionId/messages — send a user message + kick off inference
  app.post<{ Params: { sessionId: string } }>(
    '/api/sessions/:sessionId/messages',
    async (req, reply) => {
      const parsed = SendBody.safeParse(req.body);
      if (!parsed.success) {
        reply.code(400);
        return { error: 'invalid body', details: parsed.error.flatten() };
      }

      const sessionId = req.params.sessionId;
      const { content, pane_id, chat_id: explicitChatId, provider, model, mode_id, thinking_option_id } =
        parsed.data;
      const isExternal = provider && provider !== 'boocode';

      // Validate session exists
      const sessionRows = await sql<{ id: string; project_id: string }[]>`
        SELECT id, project_id FROM sessions WHERE id = ${sessionId}
      `;
      if (sessionRows.length === 0) {
        reply.code(404);
        return { error: 'session not found' };
      }

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

      let chatId = resolved;
      if (explicitChatId) {
        const chatRows = await sql<{ id: string }[]>`
          SELECT id FROM chats WHERE id = ${explicitChatId} AND session_id = ${sessionId} AND status = 'open'
        `;
        if (chatRows.length === 0) {
          reply.code(404);
          return { error: 'chat not found or not open in this session' };
        }
        chatId = explicitChatId;
      }

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

      // Create user message
      const [userMsg] = await sql<{ id: string }[]>`
        INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
        VALUES (${sessionId}, ${chatId}, 'user', ${content}, 'complete', clock_timestamp())
        RETURNING id
      `;
      await sql`UPDATE sessions SET updated_at = clock_timestamp() WHERE id = ${sessionId}`;
      await sql`UPDATE chats SET updated_at = clock_timestamp() WHERE id = ${chatId}`;

      // Publish user message frames
      broker.publishFrame(sessionId, {
        type: 'message_started',
        message_id: userMsg!.id,
        chat_id: chatId,
        role: 'user',
      } as unknown as WsFrame);
      broker.publishFrame(sessionId, {
        type: 'delta',
        message_id: userMsg!.id,
        chat_id: chatId,
        content,
      } as unknown as WsFrame);
      broker.publishFrame(sessionId, {
        type: 'message_complete',
        message_id: userMsg!.id,
        chat_id: chatId,
      } as unknown as WsFrame);

      if (isExternal) {
        // External provider: create a task for the dispatcher
        const projectId = sessionRows[0]!.project_id;
        const [task] = await sql<{ id: string; state: string }[]>`
          INSERT INTO tasks (project_id, input, agent, model, mode_id, thinking_option_id, session_id)
          VALUES (${projectId}, ${content}, ${provider}, ${model ?? null}, ${mode_id ?? null}, ${thinking_option_id ?? null}, ${sessionId})
          RETURNING id, state
        `;
        reply.code(202);
        return { user_message_id: userMsg!.id, task_id: task!.id, dispatched: true };
      }

      // Native provider: create streaming assistant row + enqueue inference
      const [assistantMsg] = await sql<{ id: string }[]>`
        INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
        VALUES (${sessionId}, ${chatId}, 'assistant', '', 'streaming', clock_timestamp())
        RETURNING id
      `;

      inference.enqueue(sessionId, chatId, assistantMsg!.id, 'default');

      reply.code(202);
      return { user_message_id: userMsg!.id, assistant_message_id: assistantMsg!.id };
    },
  );

  // POST /api/chats/:id/answer_user_input — answer a pending ask_user_input
  app.post<{ Params: { id: string } }>(
    '/api/chats/:id/answer_user_input',
    async (req, reply) => {
      const parsed = AnswerUserInputBody.safeParse(req.body);
      if (!parsed.success) {
        reply.code(400);
        return { error: 'invalid_body', details: parsed.error.flatten() };
      }
      const { tool_call_id, answers } = parsed.data;

      const chatRows = await sql<{ id: string; session_id: string }[]>`
        SELECT id, session_id FROM chats WHERE id = ${req.params.id} AND status = 'open'
      `;
      if (chatRows.length === 0) {
        reply.code(404);
        return { error: 'chat_not_found' };
      }
      const chat = chatRows[0]!;
      const sessionId = chat.session_id;

      const callerRows = await sql<{
        message_id: string;
        payload: { id: string; name: string; args: Record<string, unknown> };
      }[]>`
        SELECT p.message_id, p.payload
        FROM message_parts p
        JOIN messages m ON m.id = p.message_id
        WHERE m.chat_id = ${chat.id}
          AND m.role = 'assistant'
          AND p.kind = 'tool_call'
          AND p.payload->>'id' = ${tool_call_id}
        ORDER BY m.created_at DESC
        LIMIT 1
      `;
      if (!callerRows[0]) {
        reply.code(404);
        return { error: 'unknown_tool_call_id' };
      }
      const foundCall = callerRows[0].payload;
      if (foundCall.name !== 'ask_user_input') {
        reply.code(400);
        return { error: 'tool_call_not_ask_user_input' };
      }

      const argsParsed = AskUserInputArgs.safeParse(foundCall.args);
      if (!argsParsed.success) {
        reply.code(400);
        return { error: 'mismatched_answer_shape', detail: 'tool_call args invalid' };
      }
      const questions = argsParsed.data.questions;
      if (answers.length !== questions.length) {
        reply.code(400);
        return { error: 'mismatched_answer_shape', detail: `expected ${questions.length} answer(s), got ${answers.length}` };
      }
      for (let i = 0; i < questions.length; i++) {
        const q = questions[i]!;
        const a = answers[i]!;
        for (const sel of a.selected_options) {
          if (!q.options.includes(sel)) {
            reply.code(400);
            return { error: 'mismatched_answer_shape', detail: `answer ${i + 1} option not in question: ${sel}` };
          }
        }
        if (q.type === 'single_select' && a.selected_options.length > 1) {
          reply.code(400);
          return { error: 'mismatched_answer_shape', detail: `answer ${i + 1} multi on single_select` };
        }
        if (a.selected_options.length === 0 && (!a.free_text || !a.free_text.trim())) {
          reply.code(400);
          return { error: 'mismatched_answer_shape', detail: `answer ${i + 1} is empty` };
        }
      }

      const toolRows = await sql<{
        message_id: string;
        payload: { tool_call_id: string; output: unknown };
      }[]>`
        SELECT p.message_id, p.payload
        FROM message_parts p
        JOIN messages m ON m.id = p.message_id
        WHERE m.chat_id = ${chat.id}
          AND m.role = 'tool'
          AND p.kind = 'tool_result'
          AND p.payload->>'tool_call_id' = ${tool_call_id}
        ORDER BY m.created_at DESC
        LIMIT 1
      `;
      if (!toolRows[0]) {
        reply.code(404);
        return { error: 'unknown_tool_call_id', detail: 'tool message not found' };
      }
      if (toolRows[0].payload?.output !== null) {
        reply.code(409);
        return { error: 'tool_call_already_answered' };
      }

      const answerSet = { answers };
      const newToolResults = { tool_call_id, output: answerSet, truncated: false };
      const toolMessageId = toolRows[0].message_id;

      const result = await sql.begin(async (tx) => {
        await tx`DELETE FROM message_parts WHERE message_id = ${toolMessageId} AND kind = 'tool_result'`;
        await tx`
          INSERT INTO message_parts (message_id, sequence, kind, payload)
          VALUES (${toolMessageId}, 0, 'tool_result', ${tx.json(newToolResults as never)})
        `;
        const [assistantMsg] = await tx<{ id: string }[]>`
          INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
          VALUES (${sessionId}, ${chat.id}, 'assistant', '', 'streaming', clock_timestamp())
          RETURNING id
        `;
        await tx`UPDATE sessions SET updated_at = clock_timestamp() WHERE id = ${sessionId}`;
        await tx`UPDATE chats SET updated_at = clock_timestamp() WHERE id = ${chat.id}`;
        return { tool_message_id: toolMessageId, assistant_message_id: assistantMsg!.id };
      });

      broker.publishFrame(sessionId, {
        type: 'tool_result',
        tool_message_id: result.tool_message_id,
        tool_call_id,
        chat_id: chat.id,
        output: answerSet,
        truncated: false,
      } as unknown as WsFrame);
      inference.enqueue(sessionId, chat.id, result.assistant_message_id, 'default');

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

  // POST /api/sessions/:sessionId/stop — cancel active inference
  app.post<{ Params: { sessionId: string } }>(
    '/api/sessions/:sessionId/stop',
    async (req, reply) => {
      const sessionId = req.params.sessionId;

      // Find active chats in this session
      const chats = await sql<{ id: string }[]>`
        SELECT id FROM chats WHERE session_id = ${sessionId} AND status = 'open'
      `;
      let cancelled = false;
      for (const chat of chats) {
        if (inference.hasActive(chat.id)) {
          cancelled = await inference.cancel(sessionId, chat.id);
          break;
        }
      }

      return { cancelled };
    },
  );
}