const express = require('express');
const bodyParser = require('body-parser');
const Mock = require('mockjs');
const fs = require('fs-extra');
const dayjs = require('dayjs');
const swaggerUi = require('swagger-ui-express');
const swaggerJSDoc = require('swagger-jsdoc');
const { Low, JSONFile } = require('lowdb');

const app = express();
const PORT = 3000;
const CONFIG_PATH = './mock-config.json';
const DB_PATH = './mock-db.json';

app.use(bodyParser.json());

function formatResponse(data, code = 200, message = 'success') {
  return {
    code,
    type: code === 200 ? 'success' : 'error',
    message,
    result: data,
    extras: null,
    time: dayjs().format('YYYY-MM-DD HH:mm:ss')
  };
}

function registerMockApi(config) {
  const { method, path, response } = config;
  const methodName = method.toLowerCase();

  app[methodName](path, async (req, res) => {
    try {
      // 地址模块逻辑
      if (path === '/api/user/address/list') {
        await global.db.read();
        return res.json(formatResponse({ list: global.db.data.addresses }));
      }
      if (path === '/api/user/address/add') {
        const newItem = { id: Date.now(), ...req.body };
        await global.db.read();
        global.db.data.addresses.push(newItem);
        await global.db.write();
        return res.json(formatResponse({ id: newItem.id }, 200, '地址新增成功'));
      }
      if (path === '/api/user/address/update') {
        const { id, ...rest } = req.body;
        await global.db.read();
        const item = global.db.data.addresses.find(i => i.id == id);
        if (item) Object.assign(item, rest);
        await global.db.write();
        return res.json(formatResponse(null, 200, '地址已更新'));
      }
      if (path === '/api/user/address/delete') {
        const { id } = req.body;
        await global.db.read();
        global.db.data.addresses = global.db.data.addresses.filter(i => i.id != id);
        await global.db.write();
        return res.json(formatResponse(null, 200, '地址已删除'));
      }
      if (path === '/api/user/address/set-default') {
        const { id } = req.body;
        await global.db.read();
        global.db.data.addresses.forEach(i => i.isDefault = i.id == id);
        await global.db.write();
        return res.json(formatResponse(null, 200, '已设置为默认地址'));
      }
      if (path === '/api/user/address/detail') {
        const { id } = req.query;
        await global.db.read();
        const item = global.db.data.addresses.find(i => i.id == id);
        return res.json(formatResponse(item || null));
      }

      // 其他静态 mock 响应
      const data = Mock.mock(response);
      res.json(formatResponse(data));
    } catch (err) {
      res.json(formatResponse(null, 500, err.message));
    }
  });
}

async function startServer() {
  // 初始化 lowdb
  const adapter = new JSONFile(DB_PATH);
  const db = new Low(adapter);
  await db.read();
  db.data ||= { addresses: [], products: [], orders: [] };
  await db.write();
  global.db = db;

  // 加载配置文件
  let mockConfigs = fs.existsSync(CONFIG_PATH) ? fs.readJsonSync(CONFIG_PATH) : [];
  global.mockConfigs = mockConfigs;
  mockConfigs.forEach(registerMockApi);

  // 添加 mock 接口
  app.post('/mock-api/add', async (req, res) => {
    const config = req.body;
    if (!config.method || !config.path || !config.response) {
      return res.json(formatResponse(null, 400, '参数不完整'));
    }
    registerMockApi(config);
    global.mockConfigs.push(config);
    await fs.writeJson(CONFIG_PATH, global.mockConfigs, { spaces: 2 });
    res.json(formatResponse({ path: config.path }, 200, '接口已添加'));
  });

  app.get('/mock-api/list', (req, res) => {
    res.json(formatResponse(global.mockConfigs));
  });

  app.get('/mock-api/routes', (req, res) => {
    const list = global.mockConfigs.map(({ method, path }) => ({ method, path }));
    res.json(list);
  });

  const swaggerDefinition = {
    openapi: '3.0.0',
    info: {
      title: 'Mock API Docs',
      version: '1.0.0',
      description: 'Dynamically registered mock APIs'
    },
    servers: []
  };

  function buildSwaggerSpecFromMocks(configs) {
    const paths = {};
    configs.forEach(({ method, path, swagger }) => {
      const cleanPath = path.replace(/:([^/]+)/g, '{$1}');
      const methodName = method.toLowerCase();
      const summary = swagger?.summary || `Mocked ${method} ${path}`;
      const description = swagger?.description || '';
      const responses = swagger?.responses || {
        200: {
          description: 'Mock response',
          content: {
            'application/json': {
              schema: { type: 'object' }
            }
          }
        }
      };
      paths[cleanPath] = paths[cleanPath] || {};
      paths[cleanPath][methodName] = { summary, description, responses };
    });
    return { ...swaggerDefinition, paths };
  }

  app.use('/swagger', (req, res, next) => {
    res.setHeader('Cache-Control', 'no-store');
    next();
  });

  app.use('/swagger', swaggerUi.serve, (req, res, next) => {
    const protocol = req.headers['x-forwarded-proto'] || req.protocol;
    const host = req.get('host');
    const dynamicSwaggerDefinition = {
      ...swaggerDefinition,
      servers: [
        { url: `${protocol}://${host}`, description: 'Current host' }
      ]
    };
    const spec = buildSwaggerSpecFromMocks(global.mockConfigs);
    const dynamicSpec = { ...spec, servers: dynamicSwaggerDefinition.servers };
    swaggerUi.setup(dynamicSpec)(req, res, next);
  });

  app.listen(PORT, () => {
    console.log(`✅ Mock Server is running at http://localhost:${PORT}`);
    console.log(`📚 Swagger UI available at http://localhost:${PORT}/swagger`);
  });
}

startServer();