/**
 * Sessions API Routes
 *
 * 会话管理相关的 REST API
 */

import { Hono } from 'hono';
import { getSessionManager } from '../session/manager.js';
import {
  CreateSessionInputSchema,
  type ToolCallInfo,
  type Message,
  type MessagePart,
} from '../types.js';
import type { MessageInfo, Part, ToolPart, ApiPart } from '@ai-assistant/core';
import { MessageStorage, PartStorage, partsToApiFormat, getToolInput, getToolDuration } from '@ai-assistant/core';

export const sessionsRouter = new Hono();

const sessionManager = getSessionManager();

/**
 * GET /sessions - 列出所有会话
 */
sessionsRouter.get('/', (c) => {
  const sessions = sessionManager.list();
  return c.json({
    success: true,
    data: sessions,
  });
});

/**
 * POST /sessions - 创建新会话
 */
sessionsRouter.post('/', async (c) => {
  try {
    const body = await c.req.json();
    const input = CreateSessionInputSchema.parse(body);
    const session = await sessionManager.create(input);

    return c.json(
      {
        success: true,
        data: session,
      },
      201
    );
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Invalid input',
      },
      400
    );
  }
});

/**
 * GET /sessions/:id - 获取单个会话
 */
sessionsRouter.get('/:id', (c) => {
  const id = c.req.param('id');
  const session = sessionManager.get(id);

  if (!session) {
    return c.json(
      {
        success: false,
        error: 'Session not found',
      },
      404
    );
  }

  return c.json({
    success: true,
    data: session,
  });
});

/**
 * DELETE /sessions/:id - 删除会话
 */
sessionsRouter.delete('/:id', async (c) => {
  const id = c.req.param('id');

  if (!sessionManager.exists(id)) {
    return c.json(
      {
        success: false,
        error: 'Session not found',
      },
      404
    );
  }

  await sessionManager.delete(id);

  return c.json({
    success: true,
    message: 'Session deleted',
  });
});

/**
 * POST /sessions/:id/clear - 清空会话消息
 *
 * 删除会话的所有消息和相关数据，但保留会话本身
 */
sessionsRouter.post('/:id/clear', async (c) => {
  const id = c.req.param('id');

  if (!sessionManager.exists(id)) {
    return c.json(
      {
        success: false,
        error: 'Session not found',
      },
      404
    );
  }

  try {
    // 删除会话的所有消息
    await MessageStorage.removeBySession(id);

    // 重置会话状态
    sessionManager.updateStatus(id, 'idle');

    return c.json({
      success: true,
      message: 'Session messages cleared',
    });
  } catch (error) {
    console.error('[Sessions] Failed to clear messages:', error);
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to clear messages',
      },
      500
    );
  }
});

/**
 * GET /sessions/:id/messages - 获取会话消息
 *
 * 从 Core 存储读取消息，直接返回（存储层已经是 2-message 格式）
 *
 * 存储格式：
 * - user 消息：TextPart（文本内容）
 * - assistant 消息：TextPart（文本） + ToolPart（工具调用，含状态机）
 */
sessionsRouter.get('/:id/messages', async (c) => {
  const id = c.req.param('id');

  if (!sessionManager.exists(id)) {
    return c.json(
      {
        success: false,
        error: 'Session not found',
      },
      404
    );
  }

  try {
    // 获取消息列表（按创建时间排序）
    const messageInfos = await MessageStorage.listBySession(id);

    // 转换为前端格式
    const messages: Message[] = [];
    for (const msgInfo of messageInfos) {
      const parts = await PartStorage.getByIds(msgInfo.id, msgInfo.partIds);

      // 使用 Core 的转换函数将 Parts 转换为 API 格式
      const apiParts = partsToApiFormat(parts);
      // 类型兼容：ApiPart 与 MessagePart 结构相同
      const messageParts = apiParts as MessagePart[];

      // 兼容字段：提取文本内容
      const textContent = parts
        .filter((p) => p.type === 'text')
        .map((p) => p.text ?? '')
        .join('');

      // 兼容字段：提取工具调用（使用 Core 工具函数）
      const toolCalls: ToolCallInfo[] = parts
        .filter((p): p is ToolPart => p.type === 'tool')
        .map((p) => ({
          id: p.toolCallId ?? '',
          name: p.toolName ?? '',
          arguments: getToolInput(p),
          status: p.state.status,
          result: p.state.status === 'completed' ? (p.state as { output: unknown }).output : undefined,
          error: p.state.status === 'error' ? (p.state as { error: string }).error : undefined,
          duration: getToolDuration(p),
        }));

      messages.push({
        id: msgInfo.id,
        sessionId: msgInfo.sessionId,
        role: msgInfo.role,
        timestamp: new Date(msgInfo.createdAt).toISOString(),
        parts: messageParts,
        content: textContent || undefined,
        toolCalls: toolCalls.length > 0 ? toolCalls : undefined,
      });
    }

    return c.json({
      success: true,
      data: messages,
    });
  } catch (error) {
    console.error('[Sessions] Failed to load messages:', error);
    return c.json({
      success: true,
      data: [],
    });
  }
});