import { useState, useEffect, useRef } from 'react'
import { useForm } from 'react-hook-form'
import { zodResolver } from '@hookform/resolvers/zod'
import { z } from 'zod'
import { useAuthStore } from '@/store/auth'
import { usersApi, telegramApi, authApi } from '@/api'
import type { UserStats } from '@/types'
import { useToast } from '@/store/toast'
import {
  NeonButton, Input, GlassCard, StatsCard, clearAvatarCache
} from '@/components/ui'
import {
  User, Camera, Trophy, Target, CheckCircle, Flame,
  Loader2, MessageCircle, Link2, Link2Off, ExternalLink,
  Eye, EyeOff, Save, KeyRound, Shield
} from 'lucide-react'

// Schemas
const nicknameSchema = z.object({
  nickname: z.string().min(2, 'Минимум 2 символа').max(50, 'Максимум 50 символов'),
})

const passwordSchema = z.object({
  current_password: z.string().min(6, 'Минимум 6 символов'),
  new_password: z.string().min(6, 'Минимум 6 символов').max(100, 'Максимум 100 символов'),
  confirm_password: z.string(),
}).refine((data) => data.new_password === data.confirm_password, {
  message: 'Пароли не совпадают',
  path: ['confirm_password'],
})

type NicknameForm = z.infer<typeof nicknameSchema>
type PasswordForm = z.infer<typeof passwordSchema>

export function ProfilePage() {
  const { user, updateUser, avatarVersion, bumpAvatarVersion } = useAuthStore()
  const toast = useToast()

  // State
  const [stats, setStats] = useState<UserStats | null>(null)
  const [isLoadingStats, setIsLoadingStats] = useState(true)
  const [isUploadingAvatar, setIsUploadingAvatar] = useState(false)
  const [showPasswordForm, setShowPasswordForm] = useState(false)
  const [showCurrentPassword, setShowCurrentPassword] = useState(false)
  const [showNewPassword, setShowNewPassword] = useState(false)
  const [avatarBlobUrl, setAvatarBlobUrl] = useState<string | null>(null)
  const [isLoadingAvatar, setIsLoadingAvatar] = useState(true)

  // Telegram state
  const [telegramLoading, setTelegramLoading] = useState(false)
  const [isPolling, setIsPolling] = useState(false)
  const pollingRef = useRef<ReturnType<typeof setInterval> | null>(null)

  const fileInputRef = useRef<HTMLInputElement>(null)

  // Forms
  const nicknameForm = useForm<NicknameForm>({
    resolver: zodResolver(nicknameSchema),
    defaultValues: { nickname: user?.nickname || '' },
  })

  const passwordForm = useForm<PasswordForm>({
    resolver: zodResolver(passwordSchema),
    defaultValues: { current_password: '', new_password: '', confirm_password: '' },
  })

  // Load stats
  useEffect(() => {
    loadStats()
    return () => {
      if (pollingRef.current) clearInterval(pollingRef.current)
    }
  }, [])

  // Ref для отслеживания текущего blob URL
  const avatarBlobRef = useRef<string | null>(null)

  // Load avatar via API
  useEffect(() => {
    if (!user?.id || !user?.avatar_url) {
      setIsLoadingAvatar(false)
      return
    }

    let cancelled = false
    const bustCache = avatarVersion > 0

    setIsLoadingAvatar(true)
    usersApi.getAvatarUrl(user.id, bustCache)
      .then(url => {
        if (cancelled) {
          URL.revokeObjectURL(url)
          return
        }
        // Очищаем старый blob URL
        if (avatarBlobRef.current) {
          URL.revokeObjectURL(avatarBlobRef.current)
        }
        avatarBlobRef.current = url
        setAvatarBlobUrl(url)
      })
      .catch(() => {
        if (!cancelled) {
          setAvatarBlobUrl(null)
        }
      })
      .finally(() => {
        if (!cancelled) {
          setIsLoadingAvatar(false)
        }
      })

    return () => {
      cancelled = true
    }
  }, [user?.id, user?.avatar_url, avatarVersion])

  // Cleanup blob URL on unmount
  useEffect(() => {
    return () => {
      if (avatarBlobRef.current) {
        URL.revokeObjectURL(avatarBlobRef.current)
      }
    }
  }, [])

  // Update nickname form when user changes
  useEffect(() => {
    if (user?.nickname) {
      nicknameForm.reset({ nickname: user.nickname })
    }
  }, [user?.nickname])

  const loadStats = async () => {
    try {
      const data = await usersApi.getMyStats()
      setStats(data)
    } catch (error) {
      console.error('Failed to load stats:', error)
    } finally {
      setIsLoadingStats(false)
    }
  }

  // Update nickname
  const onNicknameSubmit = async (data: NicknameForm) => {
    try {
      const updatedUser = await usersApi.updateNickname(data)
      updateUser({ nickname: updatedUser.nickname })
      toast.success('Никнейм обновлен')
    } catch {
      toast.error('Не удалось обновить никнейм')
    }
  }

  // Upload avatar
  const handleAvatarClick = () => {
    fileInputRef.current?.click()
  }

  const handleAvatarChange = async (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0]
    if (!file) return

    if (!file.type.startsWith('image/')) {
      toast.error('Файл должен быть изображением')
      return
    }
    if (file.size > 5 * 1024 * 1024) {
      toast.error('Максимальный размер файла 5 МБ')
      return
    }

    setIsUploadingAvatar(true)
    try {
      const updatedUser = await usersApi.uploadAvatar(file)
      updateUser({ avatar_url: updatedUser.avatar_url })
      if (user?.id) {
        clearAvatarCache(user.id)
      }
      // Bump version - это вызовет перезагрузку через useEffect
      bumpAvatarVersion()
      toast.success('Аватар обновлен')
    } catch {
      toast.error('Не удалось загрузить аватар')
    } finally {
      setIsUploadingAvatar(false)
    }
  }

  // Change password
  const onPasswordSubmit = async (data: PasswordForm) => {
    try {
      await usersApi.changePassword({
        current_password: data.current_password,
        new_password: data.new_password,
      })
      toast.success('Пароль успешно изменен')
      passwordForm.reset()
      setShowPasswordForm(false)
    } catch (error: unknown) {
      const err = error as { response?: { data?: { detail?: string } } }
      const message = err.response?.data?.detail || 'Не удалось сменить пароль'
      toast.error(message)
    }
  }

  // Telegram functions
  const startPolling = () => {
    setIsPolling(true)
    let attempts = 0
    pollingRef.current = setInterval(async () => {
      attempts++
      try {
        const userData = await authApi.me()
        if (userData.telegram_id) {
          updateUser({
            telegram_id: userData.telegram_id,
            telegram_username: userData.telegram_username,
            telegram_first_name: userData.telegram_first_name,
            telegram_last_name: userData.telegram_last_name,
            telegram_avatar_url: userData.telegram_avatar_url,
          })
          toast.success('Telegram привязан!')
          setIsPolling(false)
          if (pollingRef.current) clearInterval(pollingRef.current)
        }
      } catch { /* ignore */ }
      if (attempts >= 60) {
        setIsPolling(false)
        if (pollingRef.current) clearInterval(pollingRef.current)
      }
    }, 5000)
  }

  const handleLinkTelegram = async () => {
    setTelegramLoading(true)
    try {
      const { bot_url } = await telegramApi.generateLinkToken()
      window.open(bot_url, '_blank')
      startPolling()
    } catch {
      toast.error('Не удалось сгенерировать ссылку')
    } finally {
      setTelegramLoading(false)
    }
  }

  const handleUnlinkTelegram = async () => {
    setTelegramLoading(true)
    try {
      await telegramApi.unlinkTelegram()
      updateUser({
        telegram_id: null,
        telegram_username: null,
        telegram_first_name: null,
        telegram_last_name: null,
        telegram_avatar_url: null,
      })
      toast.success('Telegram отвязан')
    } catch {
      toast.error('Не удалось отвязать Telegram')
    } finally {
      setTelegramLoading(false)
    }
  }

  const isLinked = !!user?.telegram_id
  const displayAvatar = avatarBlobUrl || user?.telegram_avatar_url

  return (
    <div className="max-w-3xl mx-auto space-y-6">
      {/* Header */}
      <div className="mb-8">
        <h1 className="text-3xl font-bold text-white mb-2">Мой профиль</h1>
        <p className="text-gray-400">Настройки вашего аккаунта</p>
      </div>

      {/* Profile Card */}
      <GlassCard variant="neon">
        <div className="flex flex-col sm:flex-row items-center sm:items-start gap-6">
          {/* Avatar */}
          <div className="relative group flex-shrink-0">
            {isLoadingAvatar ? (
              <div className="w-28 h-28 rounded-2xl bg-dark-700 skeleton" />
            ) : (
              <button
                onClick={handleAvatarClick}
                disabled={isUploadingAvatar}
                className="relative w-28 h-28 rounded-2xl overflow-hidden bg-dark-700 border-2 border-neon-500/30 hover:border-neon-500 transition-all group-hover:shadow-[0_0_20px_rgba(34,211,238,0.25)]"
              >
                {displayAvatar ? (
                  <img
                    src={displayAvatar}
                    alt={user?.nickname}
                    className="w-full h-full object-cover"
                  />
                ) : (
                  <div className="w-full h-full flex items-center justify-center bg-gradient-to-br from-neon-500/20 to-accent-500/20">
                    <User className="w-12 h-12 text-gray-500" />
                  </div>
                )}
                <div className="absolute inset-0 bg-dark-900/70 flex items-center justify-center opacity-0 group-hover:opacity-100 transition-opacity">
                  {isUploadingAvatar ? (
                    <Loader2 className="w-8 h-8 text-neon-500 animate-spin" />
                  ) : (
                    <Camera className="w-8 h-8 text-neon-500" />
                  )}
                </div>
              </button>
            )}
            <input
              ref={fileInputRef}
              type="file"
              accept="image/*"
              onChange={handleAvatarChange}
              className="hidden"
            />
          </div>

          {/* Nickname Form */}
          <div className="flex-1 w-full sm:w-auto">
            <form onSubmit={nicknameForm.handleSubmit(onNicknameSubmit)} className="space-y-4">
              <Input
                label="Никнейм"
                {...nicknameForm.register('nickname')}
                error={nicknameForm.formState.errors.nickname?.message}
              />
              <NeonButton
                type="submit"
                size="sm"
                isLoading={nicknameForm.formState.isSubmitting}
                disabled={!nicknameForm.formState.isDirty}
                icon={<Save className="w-4 h-4" />}
              >
                Сохранить
              </NeonButton>
            </form>
          </div>
        </div>
      </GlassCard>

      {/* Stats */}
      <div>
        <h2 className="text-xl font-semibold text-white mb-4 flex items-center gap-2">
          <Trophy className="w-5 h-5 text-yellow-500" />
          Статистика
        </h2>
        {isLoadingStats ? (
          <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
            {[...Array(4)].map((_, i) => (
              <div key={i} className="glass rounded-xl p-4">
                <div className="w-12 h-12 bg-dark-700 rounded-lg mb-3 skeleton" />
                <div className="h-8 w-16 bg-dark-700 rounded mb-2 skeleton" />
                <div className="h-4 w-20 bg-dark-700 rounded skeleton" />
              </div>
            ))}
          </div>
        ) : stats ? (
          <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
            <StatsCard
              label="Марафонов"
              value={stats.marathons_count}
              icon={<Target className="w-6 h-6" />}
              color="neon"
            />
            <StatsCard
              label="Побед"
              value={stats.wins_count}
              icon={<Trophy className="w-6 h-6" />}
              color="purple"
            />
            <StatsCard
              label="Заданий"
              value={stats.completed_assignments}
              icon={<CheckCircle className="w-6 h-6" />}
              color="neon"
            />
            <StatsCard
              label="Очков"
              value={stats.total_points_earned}
              icon={<Flame className="w-6 h-6" />}
              color="pink"
            />
          </div>
        ) : (
          <GlassCard className="text-center py-8">
            <p className="text-gray-400">Не удалось загрузить статистику</p>
          </GlassCard>
        )}
      </div>

      {/* Telegram */}
      <GlassCard>
        <div className="flex items-center gap-3 mb-6">
          <div className="w-12 h-12 rounded-xl bg-blue-500/20 flex items-center justify-center">
            <MessageCircle className="w-6 h-6 text-blue-400" />
          </div>
          <div>
            <h2 className="text-lg font-semibold text-white">Telegram</h2>
            <p className="text-sm text-gray-400">
              {isLinked ? 'Аккаунт привязан' : 'Привяжите для уведомлений'}
            </p>
          </div>
        </div>

        {isLinked ? (
          <div className="space-y-4">
            <div className="flex items-center gap-4 p-4 bg-dark-700/50 rounded-xl border border-dark-600">
              <div className="w-14 h-14 rounded-xl bg-blue-500/20 flex items-center justify-center overflow-hidden border border-blue-500/30">
                {user?.telegram_avatar_url ? (
                  <img
                    src={user.telegram_avatar_url}
                    alt="Telegram avatar"
                    className="w-full h-full object-cover"
                  />
                ) : (
                  <Link2 className="w-7 h-7 text-blue-400" />
                )}
              </div>
              <div className="flex-1">
                <p className="text-white font-medium">
                  {user?.telegram_first_name} {user?.telegram_last_name}
                </p>
                {user?.telegram_username && (
                  <p className="text-blue-400 text-sm">@{user.telegram_username}</p>
                )}
              </div>
              <NeonButton
                variant="danger"
                size="sm"
                onClick={handleUnlinkTelegram}
                isLoading={telegramLoading}
                icon={<Link2Off className="w-4 h-4" />}
              >
                Отвязать
              </NeonButton>
            </div>
          </div>
        ) : (
          <div className="space-y-4">
            <p className="text-gray-400">
              Привяжите Telegram для получения уведомлений о событиях и марафонах.
            </p>
            {isPolling ? (
              <div className="p-4 bg-blue-500/10 border border-blue-500/30 rounded-xl">
                <div className="flex items-center gap-3">
                  <Loader2 className="w-5 h-5 text-blue-400 animate-spin" />
                  <p className="text-blue-400">Ожидание привязки...</p>
                </div>
              </div>
            ) : (
              <NeonButton
                onClick={handleLinkTelegram}
                isLoading={telegramLoading}
                icon={<ExternalLink className="w-4 h-4" />}
              >
                Привязать Telegram
              </NeonButton>
            )}
          </div>
        )}
      </GlassCard>

      {/* Security */}
      <GlassCard>
        <div className="flex items-center gap-3 mb-6">
          <div className="w-12 h-12 rounded-xl bg-accent-500/20 flex items-center justify-center">
            <Shield className="w-6 h-6 text-accent-400" />
          </div>
          <div>
            <h2 className="text-lg font-semibold text-white">Безопасность</h2>
            <p className="text-sm text-gray-400">Управление паролем</p>
          </div>
        </div>

        {!showPasswordForm ? (
          <NeonButton
            onClick={() => setShowPasswordForm(true)}
            icon={<KeyRound className="w-4 h-4" />}
          >
            Сменить пароль
          </NeonButton>
        ) : (
          <form onSubmit={passwordForm.handleSubmit(onPasswordSubmit)} className="space-y-4">
            <div className="relative">
              <Input
                label="Текущий пароль"
                type={showCurrentPassword ? 'text' : 'password'}
                {...passwordForm.register('current_password')}
                error={passwordForm.formState.errors.current_password?.message}
              />
              <button
                type="button"
                onClick={() => setShowCurrentPassword(!showCurrentPassword)}
                className="absolute right-3 top-9 text-gray-400 hover:text-white transition-colors"
              >
                {showCurrentPassword ? <EyeOff className="w-5 h-5" /> : <Eye className="w-5 h-5" />}
              </button>
            </div>

            <div className="relative">
              <Input
                label="Новый пароль"
                type={showNewPassword ? 'text' : 'password'}
                {...passwordForm.register('new_password')}
                error={passwordForm.formState.errors.new_password?.message}
              />
              <button
                type="button"
                onClick={() => setShowNewPassword(!showNewPassword)}
                className="absolute right-3 top-9 text-gray-400 hover:text-white transition-colors"
              >
                {showNewPassword ? <EyeOff className="w-5 h-5" /> : <Eye className="w-5 h-5" />}
              </button>
            </div>

            <Input
              label="Подтвердите новый пароль"
              type={showNewPassword ? 'text' : 'password'}
              {...passwordForm.register('confirm_password')}
              error={passwordForm.formState.errors.confirm_password?.message}
            />

            <div className="flex gap-3">
              <NeonButton
                type="submit"
                isLoading={passwordForm.formState.isSubmitting}
                icon={<Save className="w-4 h-4" />}
              >
                Сменить пароль
              </NeonButton>
              <NeonButton
                type="button"
                variant="ghost"
                onClick={() => {
                  setShowPasswordForm(false)
                  passwordForm.reset()
                }}
              >
                Отмена
              </NeonButton>
            </div>
          </form>
        )}
      </GlassCard>
    </div>
  )
}