import { useEffect, useRef, useState } from 'react'
import { useNavigate } from 'react-router-dom'
import { Alert, Button, Divider, Form, Input, Space, Typography, message } from 'antd'
import { LockOutlined, RightOutlined, SafetyCertificateOutlined, UserOutlined } from '@ant-design/icons'
import { authApi } from '../api'
import type { PreparedDeviceLogin } from '../types'
import { useAuth } from '../store/authContext'

type LoginForm = {
  username: string
  password: string
  smsCode: string
}

export default function Login() {
  const { login, applyLoginResult } = useAuth()
  const navigate = useNavigate()
  const [form] = Form.useForm<LoginForm>()
  const [loading, setLoading] = useState(false)
  const [sending, setSending] = useState(false)
  const [countdown, setCountdown] = useState(0)
  const [waiting, setWaiting] = useState(false)
  const [phoneMasked, setPhoneMasked] = useState('')
  const timerRef = useRef<number | null>(null)
  const submittingRef = useRef(false)

  useEffect(() => {
    return () => {
      if (timerRef.current) window.clearInterval(timerRef.current)
    }
  }, [])

  const startCountdown = (seconds: number) => {
    setCountdown(seconds)
    if (timerRef.current) window.clearInterval(timerRef.current)
    timerRef.current = window.setInterval(() => {
      setCountdown((current) => {
        if (current <= 1) {
          if (timerRef.current) window.clearInterval(timerRef.current)
          return 0
        }
        return current - 1
      })
    }, 1000)
  }

  const sendCode = async () => {
    try {
      const values = await form.validateFields(['username', 'password'])
      setSending(true)
      const result = await authApi.sendLoginSmsCode(values.username.trim(), values.password)
      setPhoneMasked(result.phoneMasked)
      startCountdown(60)
      message.success(`验证码已发送至 ${result.phoneMasked}`)
    } catch (error) {
      const text = error instanceof Error ? error.message : '验证码发送失败'
      if (text.includes('未绑定手机号')) {
        message.warning(`${text}，可使用下方「旧账号仅密码登录」`)
      } else {
        message.error(text)
      }
    } finally {
      setSending(false)
    }
  }

  const onFinish = async (values: LoginForm) => {
    if (submittingRef.current) return
    submittingRef.current = true
    setLoading(true)
    setWaiting(false)
    try {
      const prepared = await authApi.prepareLogin({
        username: values.username.trim(),
        password: values.password,
        smsCode: values.smsCode.trim(),
        apiBase: window.location.origin,
      })
      setPhoneMasked(prepared.phoneMasked)
      setWaiting(true)
      message.info('已发起本机验证，请在弹出的 DCAuth 窗口中确认')
      launchProtocol(prepared.launchUrl)

      const result = await waitForDevice(prepared)
      applyLoginResult(result)
      message.success('登录成功，欢迎回来！')
      navigate('/', { replace: true })
    } catch (error) {
      const text = error instanceof Error ? error.message : '登录失败，请检查账号密码'
      if (text.includes('未绑定手机号')) {
        message.warning(`${text}，可使用下方「旧账号仅密码登录」`)
      } else if (text.includes('绑定设备不一致')) {
        message.error('当前设备与账号绑定设备不一致，请联系管理员重置设备')
      } else {
        message.error(text)
      }
    } finally {
      submittingRef.current = false
      setLoading(false)
      setWaiting(false)
    }
  }

  const submitLegacyLogin = async () => {
    if (submittingRef.current) return
    let values: LoginForm
    try {
      values = await form.validateFields(['username', 'password'])
    } catch {
      return
    }
    submittingRef.current = true
    setLoading(true)
    try {
      await login(values.username.trim(), values.password)
      message.success('登录成功，欢迎回来！')
      navigate('/', { replace: true })
    } catch (error) {
      message.error(error instanceof Error ? error.message : '账号密码登录失败')
    } finally {
      submittingRef.current = false
      setLoading(false)
    }
  }

  return (
    <div className="login-wrapper">
      <div className="login-card">
        <Space direction="vertical" size="large" style={{ width: '100%' }}>
          <div style={{ textAlign: 'center' }}>
            <div className="login-logo">S</div>
            <Typography.Title level={3} style={{ margin: '0 0 6px 0', color: '#ffffff', fontWeight: 700 }}>
              Skin Hub 游戏皮肤分销平台
            </Typography.Title>
            <Typography.Text style={{ color: '#94a3b8', fontSize: 13 }}>
              账号密码 + 短信验证码 + DCAuth 本机设备签名
            </Typography.Text>
          </div>

          {waiting ? (
            <Alert
              type="info"
              showIcon
              message="等待本机确认"
              description="请在弹出的 DCAuth 窗口中点击确认。若未弹出，请先安装并运行一次 DCAuth 客户端。"
            />
          ) : null}

          <Form form={form} layout="vertical" onFinish={onFinish} requiredMark={false}>
            <Form.Item
              name="username"
              rules={[{ required: true, message: '请输入用户名' }]}
              style={{ marginBottom: 18 }}
            >
              <Input
                prefix={<UserOutlined style={{ color: '#64748b' }} />}
                placeholder="用户名（支持中文 / 英文）"
                size="large"
                autoComplete="username"
                style={{ borderRadius: 8 }}
              />
            </Form.Item>

            <Form.Item
              name="password"
              rules={[{ required: true, message: '请输入密码' }]}
              style={{ marginBottom: 18 }}
            >
              <Input.Password
                prefix={<LockOutlined style={{ color: '#64748b' }} />}
                placeholder="密码"
                size="large"
                autoComplete="current-password"
                style={{ borderRadius: 8 }}
              />
            </Form.Item>

            <Form.Item
              name="smsCode"
              rules={[{ required: true, message: '请输入短信验证码' }]}
              style={{ marginBottom: 24 }}
            >
              <Input
                prefix={<SafetyCertificateOutlined style={{ color: '#64748b' }} />}
                placeholder={`6 位短信验证码${phoneMasked ? `（${phoneMasked}）` : ''}`}
                size="large"
                maxLength={6}
                autoComplete="one-time-code"
                style={{ borderRadius: 8 }}
                addonAfter={
                  <Button
                    type="link"
                    size="small"
                    htmlType="button"
                    loading={sending}
                    disabled={countdown > 0}
                    onClick={() => void sendCode()}
                    style={{ padding: 0, height: 'auto' }}
                  >
                    {countdown > 0 ? `${countdown}s 后重发` : '获取验证码'}
                  </Button>
                }
              />
            </Form.Item>

            <Form.Item style={{ marginBottom: 12 }}>
              <Button
                type="primary"
                htmlType="submit"
                loading={loading}
                block
                size="large"
                icon={<RightOutlined />}
                style={{
                  height: 46,
                  borderRadius: 8,
                  fontSize: 15,
                  fontWeight: 600,
                  background: 'linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%)',
                  boxShadow: '0 4px 14px rgba(37, 99, 235, 0.4)',
                }}
              >
                安全登录 · 拉起本机验证
              </Button>
            </Form.Item>
          </Form>

          <Divider plain style={{ margin: '0 0 4px' }}>
            <Typography.Text style={{ color: '#64748b', fontSize: 12 }}>未绑定手机号的历史账号</Typography.Text>
          </Divider>
          <Button type="link" block disabled={loading} onClick={() => void submitLegacyLogin()}>
            旧账号仅密码登录
          </Button>

          <Typography.Paragraph
            style={{ fontSize: 12, margin: 0, textAlign: 'center', color: '#64748b' }}
          >
            已绑定手机号的账号必须通过短信验证码与 DCAuth 本机签名登录
          </Typography.Paragraph>
        </Space>
      </div>
    </div>
  )
}

async function waitForDevice(prepared: PreparedDeviceLogin) {
  for (let attempt = 0; attempt < 120; attempt += 1) {
    await sleep(1000)
    const status = await authApi.deviceChallengeStatus(prepared.challengeId, prepared.pollToken)
    if (status.status === 'authorized' && status.deviceTicket) {
      return authApi.completeLogin({
        challengeId: prepared.challengeId,
        pollToken: prepared.pollToken,
        deviceTicket: status.deviceTicket,
      })
    }
    if (status.status === 'expired' || status.status === 'rejected') {
      throw new Error(status.message || '本机验证已过期，请重新登录')
    }
    if (attempt === 4) {
      message.info('如果浏览器没有弹出 DCAuth，请先安装并运行一次 DCAuth 客户端')
    }
  }
  throw new Error('等待本机验证超时，请确认 DCAuth 已安装并允许浏览器唤起')
}

function launchProtocol(url: string) {
  const anchor = document.createElement('a')
  anchor.href = url
  anchor.style.display = 'none'
  document.body.appendChild(anchor)
  anchor.click()
  window.setTimeout(() => anchor.remove(), 1000)
}

function sleep(ms: number) {
  return new Promise((resolve) => window.setTimeout(resolve, ms))
}