// 统一的 API 客户端

const API_BASE = '' // 生产环境由 Nginx 代理

import { ErrorCodes, matchErrorCode } from './errorCodes.js'

// 错误处理
class ApiError extends Error {
  constructor(message, status, data, code = null) {
    super(message)
    this.name = 'ApiError'
    this.status = status
    this.data = data
    this.code = code || matchErrorCode(status, message).code
  }
  
  // 获取格式化的错误信息
  get formattedMessage() {
    return `${this.code}: ${this.message}`
  }
}

// 获取 Token
const getToken = () => localStorage.getItem('token')

// 统一请求方法
async function request(endpoint, options = {}) {
  const token = getToken()
  
  const defaultHeaders = {
    'Content-Type': 'application/json',
  }
  
  if (token) {
    defaultHeaders['Authorization'] = `Bearer ${token}`
  }
  
  const config = {
    ...options,
    headers: {
      ...defaultHeaders,
      ...(options.headers || {})
    }
  }
  
  try {
    const response = await fetch(`${API_BASE}${endpoint}`, config)
    
    const data = await response.json()
    
    if (!response.ok) {
      // 处理 401 未授权
      if (response.status === 401) {
        localStorage.removeItem('token')
        localStorage.removeItem('user')
        window.location.hash = '#/login'
        throw new ApiError(
          data.detail || data.message || '登录已过期，请重新登录',
          401,
          data,
          'E00010'
        )
      }
      
      // 处理 422 验证错误
      if (response.status === 422 && data.detail) {
        const detail = Array.isArray(data.detail) ? data.detail[0] : data.detail
        const field = detail.loc ? detail.loc.join('.') : ''
        const msg = detail.msg || detail.message || data.message
        
        throw new ApiError(
          `${field}: ${msg}`,
          422,
          data
        )
      }
      
      // 其他错误
      throw new ApiError(
        data.detail || data.message || data.error || '请求失败',
        response.status,
        data
      )
    }
    
    return data
  } catch (error) {
    // 网络错误
    if (error.name === 'TypeError' && error.message.includes('fetch')) {
      throw new ApiError('网络连接失败，请检查网络', 0, null, 'E00001')
    }
    throw error
  }
}

// API 模块
export const api = {
  // 认证
  auth: {
    login: async (username, password) => {
      // 登录时不使用 token
      const params = new URLSearchParams()
      params.append('username', username)
      params.append('password', password)
      
      const response = await fetch(`${API_BASE}/api/auth/login`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
        body: params.toString()
      })
      
      const data = await response.json()
      
      if (!response.ok) {
        // 优先使用 error.code 和 error.message（后端标准格式）
        const errorCode = data.error?.code || data.code
        const errorMsg = data.error?.message || data.detail || data.message || '登录失败'
        
        const error = new ApiError(errorMsg, response.status, data)
        if (errorCode) error.code = errorCode
        throw error
      }
      
      return data
    },
    
    register: (data) => request('/api/auth/register', {
      method: 'POST',
      body: JSON.stringify(data)
    })
  },
  
  // 当前用户
  user: {
    me: async () => {
      const token = getToken()
      if (!token) throw new ApiError('未登录', 401, null, 'E00010')
      
      const response = await fetch(`${API_BASE}/api/users/me`, {
        headers: { 'Authorization': `Bearer ${token}` }
      })
      
      const data = await response.json()
      
      if (!response.ok) {
        throw new ApiError(
          data.detail || data.message || '获取用户信息失败',
          response.status,
          data
        )
      }
      
      return data
    },
    update: (data) => request('/api/users/me', {
      method: 'PUT',
      body: JSON.stringify(data)
    })
  },
  
  // 藏品
  collections: {
    // 列表
    list: (params = {}) => {
      const query = new URLSearchParams(params).toString()
      return request(`/api/collections${query ? '?' + query : ''}`)
    },
    
    // 详情
    get: (id) => request(`/api/collections/${id}`),
    
    // 创建
    create: (data) => request('/api/collections', {
      method: 'POST',
      body: JSON.stringify(data)
    }),
    
    // 更新
    update: (id, data) => request(`/api/collections/${id}`, {
      method: 'PUT',
      body: JSON.stringify(data)
    }),
    
    // 删除
    delete: (id) => request(`/api/collections/${id}`, {
      method: 'DELETE'
    }),
    
    // 下一个编号
    nextCode: () => request('/api/collections/next-code'),
    
    // 统计
    stats: (params = {}) => {
      const query = new URLSearchParams(params).toString()
      return request(`/api/collections/stats${query ? '?' + query : ''}`)
    },
    
    // 导出
    export: (params) => request(`/api/collections/export?${new URLSearchParams(params)}`)
  },
  
  // OCR
  ocr: {
    recognize: (file) => {
      const formData = new FormData()
      formData.append('image', file)
      
      return request('/api/ocr/recognize', {
        method: 'POST',
        body: formData
      })
    }
  },
  
  // 用户管理（仅管理员）
  admin: {
    users: {
      list: (page = 1, limit = 20) => request(`/api/admin/users?page=${page}&limit=${limit}`),
      get: (userId) => request(`/api/admin/users/${userId}`),
      collections: (userId) => request(`/api/admin/users/${userId}/collections`),
      count: (userId) => request(`/api/admin/users/${userId}/count`)
    }
  }
}

// 导出错误类
export { ApiError }

// 默认导出
export default api