import type { AuthOptions } from "next-auth"
import CredentialsProvider from "next-auth/providers/credentials"
import type { User } from "next-auth"
import bcrypt from 'bcryptjs'
import { db } from '@/lib/db'
import crypto from 'crypto'

type WeChatTokens = {
  access_token?: string
  refresh_token?: string
  expires_in?: number
  openid?: string
  unionid?: string
  scope?: string
  [key: string]: unknown
}

function WeChatProvider(): any {
  const appId = process.env.WECHAT_APP_ID
  const appSecret = process.env.WECHAT_APP_SECRET
  
  if (!appId || !appSecret) {
    console.error('❌ 微信登录配置缺失: WECHAT_APP_ID 或 WECHAT_APP_SECRET 未设置')
  } else {
    console.log('✅ 微信登录配置已加载:', { appId: appId.substring(0, 8) + '...' })
  }

  return {
    id: 'wechat',
    name: 'WeChat',
    type: 'oauth',
    version: '2.0',
    checks: ['pkce', 'state'],
    authorization: {
      url: 'https://open.weixin.qq.com/connect/qrconnect',
      params: {
        appid: appId,
        scope: 'snsapi_login',
        response_type: 'code',
        // redirect_uri 由 NextAuth 自动注入
      },
    },
    token: {
      url: 'https://api.weixin.qq.com/sns/oauth2/access_token',
      params: {
        appid: appId,
        secret: appSecret,
        grant_type: 'authorization_code',
      },
      async request({
        params,
        provider,
      }: {
        params: Record<string, string>
        provider: any
      }) {
        const url = `${provider.token!.url}?${new URLSearchParams(
          params as Record<string, string>
        ).toString()}`
        const res = await fetch(url, { method: 'GET' })
        if (!res.ok) {
          throw new Error(`WeChat token request failed: ${res.status}`)
        }
        const tokens = (await res.json()) as WeChatTokens
        return { tokens }
      },
    },
    userinfo: {
      // 需要 access_token + openid
      async request({ tokens }: { tokens: WeChatTokens }) {
        const accessToken = tokens.access_token as string
        const openid = (tokens as any).openid as string
        if (!accessToken || !openid) {
          throw new Error('Missing access_token or openid from WeChat')
        }
        const url = `https://api.weixin.qq.com/sns/userinfo?${new URLSearchParams({
          access_token: accessToken,
          openid,
          lang: 'zh_CN',
        }).toString()}`
        const res = await fetch(url)
        if (!res.ok) {
          throw new Error(`WeChat userinfo failed: ${res.status}`)
        }
        return res.json()
      },
    },
    profile(profile: any) {
      return {
        id: profile.unionid || profile.openid,
        name: profile.nickname || '微信用户',
        email: profile.email || `${profile.openid}@wechat.flnxi.com`,
        image: profile.headimgurl,
      }
    },
    clientId: appId,
    clientSecret: appSecret,
  }
}

export const authOptions: AuthOptions = {
  providers: [
    // 邮箱密码登录
    CredentialsProvider({
      name: 'credentials',
      credentials: {
        email: { label: "邮箱", type: "email", placeholder: "user@example.com" },
        password: { label: "密码", type: "password" }
      },
      async authorize(credentials): Promise<User | null> {
        try {
          if (!credentials?.email || !credentials?.password) {
            console.log('❌ 登录失败: 缺少邮箱或密码')
            return null
          }

          // 从数据库查询用户
          const user = await db.findUserByEmail(credentials.email)
          
          if (!user) {
            console.log('❌ 登录失败: 用户不存在 -', credentials.email)
            return null
          }

          // 使用 bcrypt 验证密码
          const isValidPassword = await bcrypt.compare(
            credentials.password,
            user.password
          )

          if (!isValidPassword) {
            console.log('❌ 登录失败: 密码错误 -', credentials.email)
            return null
          }

          console.log('✅ 登录成功:', {
            id: user.id,
            name: user.name,
            email: user.email,
          })

          // 返回用户信息（不包含密码）
          return {
            id: user.id.toString(),
            name: user.name,
            email: user.email,
          }
        } catch (error) {
          console.error('登录错误:', error)
          return null
        }
      }
    }),
    // 微信扫码登录
    WeChatProvider(),
  ],

  // 在 signIn 阶段将微信用户写入数据库
  callbacks: {
    async signIn({ user, account, profile }) {
      if (account?.provider === 'wechat') {
        const unionid = (profile as any)?.unionid || (profile as any)?.id
        const openid = (profile as any)?.openid
        const name = (profile as any)?.nickname || user.name || '微信用户'
        const email =
          (profile as any)?.email ||
          user.email ||
          `${openid || unionid || crypto.randomUUID()}@wechat.flnxi.com`
        const randomPassword = crypto.randomBytes(16).toString('hex')
        const hashedPassword = await bcrypt.hash(randomPassword, 10)

        const dbUser = await db.upsertWechatUser({
          name,
          email,
          unionid: unionid ?? null,
          openid: openid ?? null,
          hashedPassword,
        })

        // 将数据库中的 id/email/name 赋回 user，后续 jwt/session 使用
        user.id = dbUser.id.toString()
        user.email = dbUser.email
        user.name = dbUser.name
      }
      return true
    },
  
  // 自定义页面
  pages: {
    signIn: '/auth/signin',
  },
  
    async jwt({ token, user }) {
      if (user) {
        token.id = user.id
        token.email = user.email
        token.name = user.name
      }
      return token
    },
    async session({ session, token }) {
      if (session.user) {
        session.user.id = token.id as string
        session.user.email = token.email as string
        session.user.name = token.name as string
      }
      return session
    },
  },
  
  // 会话策略
  session: {
    strategy: "jwt",
    maxAge: 30 * 24 * 60 * 60, // 30 天
  },
  
  // 密钥
  secret: process.env.NEXTAUTH_SECRET,
  
  // 调试模式（生产环境设为false）
  debug: process.env.NODE_ENV === 'development',
}