// Google Identity Services (GIS) 配置
// const GOOGLE_CLIENT_ID = process.env.NEXT_PUBLIC_GOOGLE_CLIENT_ID!
const GOOGLE_CLIENT_ID = "606396962663-9pagar3g9vuhovi37vq9jqob6q1gngns.apps.googleusercontent.com"

// Google OAuth scopes
const GOOGLE_SCOPES = [
  'https://www.googleapis.com/auth/userinfo.email',
  'https://www.googleapis.com/auth/userinfo.profile'
].join(' ')

export interface GoogleUser {
  id: string
  email: string
  verified_email: boolean
  name: string
  given_name: string
  family_name: string
  picture?: string
  locale?: string
}

// Google Identity Services 响应类型
export interface GoogleCredentialResponse {
  credential: string // JWT ID token
  select_by?: string
  clientId?: string
}

// Google OAuth Code Response (使用 Code Model)
export interface GoogleCodeResponse {
  code: string // Authorization code
  scope: string
  authuser?: string
  prompt?: string
}

// 声明 Google Identity Services 全局对象
declare global {
  interface Window {
    google?: {
      accounts: {
        id: {
          initialize: (config: GoogleIdConfiguration) => void
          prompt: (momentListener?: (notification: PromptMomentNotification) => void) => void
          renderButton: (parent: HTMLElement, options: GsiButtonConfiguration) => void
          disableAutoSelect: () => void
          cancel: () => void
        }
        oauth2: {
          initCodeClient: (config: CodeClientConfig) => CodeClient
          initTokenClient: (config: TokenClientConfig) => TokenClient
        }
      }
    }
  }
}

interface GoogleIdConfiguration {
  client_id: string
  callback?: (response: GoogleCredentialResponse) => void
  auto_select?: boolean
  cancel_on_tap_outside?: boolean
  context?: 'signin' | 'signup' | 'use'
  ux_mode?: 'popup' | 'redirect'
  login_uri?: string
  native_callback?: (response: GoogleCredentialResponse) => void
  itp_support?: boolean
}

interface GsiButtonConfiguration {
  type?: 'standard' | 'icon'
  theme?: 'outline' | 'filled_blue' | 'filled_black'
  size?: 'large' | 'medium' | 'small'
  text?: 'signin_with' | 'signup_with' | 'continue_with' | 'signin'
  shape?: 'rectangular' | 'pill' | 'circle' | 'square'
  logo_alignment?: 'left' | 'center'
  width?: string
  locale?: string
}

interface PromptMomentNotification {
  isDisplayMoment: () => boolean
  isDisplayed: () => boolean
  isNotDisplayed: () => boolean
  getNotDisplayedReason: () => string
  isSkippedMoment: () => boolean
  getSkippedReason: () => string
  isDismissedMoment: () => boolean
  getDismissedReason: () => string
  getMomentType: () => string
}

interface CodeClientConfig {
  client_id: string
  scope: string
  callback: (response: GoogleCodeResponse) => void
  error_callback?: (error: { type: string; message: string }) => void
  ux_mode?: 'popup' | 'redirect'
  redirect_uri?: string
  state?: string
}

interface CodeClient {
  requestCode: () => void
}

interface TokenClientConfig {
  client_id: string
  scope: string
  callback: (response: { access_token: string; expires_in: number; scope: string; token_type: string }) => void
  error_callback?: (error: { type: string; message: string }) => void
}

interface TokenClient {
  requestAccessToken: () => void
}

export const googleOAuth = {
  clientId: GOOGLE_CLIENT_ID,
  scopes: GOOGLE_SCOPES,
  
  // 加载 Google Identity Services SDK
  loadScript: (): Promise<void> => {
    return new Promise((resolve, reject) => {
      // 检查是否已加载
      if (window.google?.accounts) {
        resolve()
        return
      }

      // 创建 script 标签
      const script = document.createElement('script')
      script.src = 'https://accounts.google.com/gsi/client'
      script.async = true
      script.defer = true
      script.onload = () => resolve()
      script.onerror = () => reject(new Error('Failed to load Google Identity Services SDK'))
      
      document.head.appendChild(script)
    })
  },

  // 初始化 Code Client（推荐方式，获取授权码）
  initCodeClient: (callback: (response: GoogleCodeResponse) => void, errorCallback?: (error: any) => void) => {
    if (!window.google?.accounts?.oauth2) {
      throw new Error('Google Identity Services SDK not loaded')
    }

    return window.google.accounts.oauth2.initCodeClient({
      client_id: GOOGLE_CLIENT_ID,
      scope: GOOGLE_SCOPES,
      ux_mode: 'popup', // 使用 popup 模式，不需要 redirect_uri
      callback,
      error_callback: errorCallback
    })
  },

  // 初始化 Token Client（直接获取 access token）
  initTokenClient: (callback: (response: { access_token: string; expires_in: number; scope: string; token_type: string }) => void, errorCallback?: (error: any) => void) => {
    if (!window.google?.accounts?.oauth2) {
      throw new Error('Google Identity Services SDK not loaded')
    }

    return window.google.accounts.oauth2.initTokenClient({
      client_id: GOOGLE_CLIENT_ID,
      scope: GOOGLE_SCOPES,
      callback,
      error_callback: errorCallback
    })
  },

  // 初始化 Google Identity (获取 ID Token - JWT)
  initGoogleId: (callback: (response: GoogleCredentialResponse) => void) => {
    if (!window.google?.accounts?.id) {
      throw new Error('Google Identity Services SDK not loaded')
    }

    window.google.accounts.id.initialize({
      client_id: GOOGLE_CLIENT_ID,
      callback,
      auto_select: false,
      cancel_on_tap_outside: true,
      ux_mode: 'popup'
    })
  },

  // 触发 One Tap 流程
  promptOneTap: (callback: (response: GoogleCredentialResponse) => void) => {
    googleOAuth.initGoogleId(callback)
    
    if (window.google?.accounts?.id) {
      window.google.accounts.id.prompt((notification) => {
        if (notification.isNotDisplayed() || notification.isSkippedMoment()) {
          console.log('One Tap not displayed:', notification.getNotDisplayedReason() || notification.getSkippedReason())
        }
      })
    }
  },

  // 使用 FedCM (Federated Credential Management) 方式获取 ID Token
  // 这种方式会弹出标准的 Google 登录窗口,无需用户预先登录
  renderButton: (parent: HTMLElement, callback: (response: GoogleCredentialResponse) => void, options?: Partial<GsiButtonConfiguration>) => {
    if (!window.google?.accounts?.id) {
      throw new Error('Google Identity Services SDK not loaded')
    }

    // 先初始化
    window.google.accounts.id.initialize({
      client_id: GOOGLE_CLIENT_ID,
      callback,
      auto_select: false,
      cancel_on_tap_outside: true
    })

    // 渲染 Google 标准按钮
    window.google.accounts.id.renderButton(parent, {
      type: 'standard',
      theme: 'outline',
      size: 'large',
      text: 'continue_with',
      shape: 'rectangular',
      logo_alignment: 'left',
      ...options
    })
  }
}