import { useState, useEffect } from 'react'
import { useParams, useNavigate, Link } from 'react-router-dom'
import { marathonsApi } from '@/api'
import type { Marathon } from '@/types'
import { Button, Card, CardContent } from '@/components/ui'
import { useAuthStore } from '@/store/auth'
import { Users, Calendar, Trophy, Play, Settings, Copy, Check, Loader2, Trash2, Globe, Lock, CalendarCheck, UserPlus, Gamepad2, ArrowLeft } from 'lucide-react'
import { format } from 'date-fns'

export function MarathonPage() {
  const { id } = useParams<{ id: string }>()
  const navigate = useNavigate()
  const user = useAuthStore((state) => state.user)
  const [marathon, setMarathon] = useState<Marathon | null>(null)
  const [isLoading, setIsLoading] = useState(true)
  const [copied, setCopied] = useState(false)
  const [isDeleting, setIsDeleting] = useState(false)
  const [isJoining, setIsJoining] = useState(false)

  useEffect(() => {
    loadMarathon()
  }, [id])

  const loadMarathon = async () => {
    if (!id) return
    try {
      const data = await marathonsApi.get(parseInt(id))
      setMarathon(data)
    } catch (error) {
      console.error('Failed to load marathon:', error)
      navigate('/marathons')
    } finally {
      setIsLoading(false)
    }
  }

  const copyInviteCode = () => {
    if (marathon) {
      navigator.clipboard.writeText(marathon.invite_code)
      setCopied(true)
      setTimeout(() => setCopied(false), 2000)
    }
  }

  const handleDelete = async () => {
    if (!marathon || !confirm('Вы уверены, что хотите удалить этот марафон? Это действие нельзя отменить.')) return

    setIsDeleting(true)
    try {
      await marathonsApi.delete(marathon.id)
      navigate('/marathons')
    } catch (error) {
      console.error('Failed to delete marathon:', error)
      alert('Не удалось удалить марафон')
    } finally {
      setIsDeleting(false)
    }
  }

  const handleJoinPublic = async () => {
    if (!marathon) return

    setIsJoining(true)
    try {
      const updated = await marathonsApi.joinPublic(marathon.id)
      setMarathon(updated)
    } catch (err: unknown) {
      const error = err as { response?: { data?: { detail?: string } } }
      alert(error.response?.data?.detail || 'Не удалось присоединиться')
    } finally {
      setIsJoining(false)
    }
  }

  if (isLoading || !marathon) {
    return (
      <div className="flex justify-center py-12">
        <Loader2 className="w-8 h-8 animate-spin text-primary-500" />
      </div>
    )
  }

  const isOrganizer = marathon.my_participation?.role === 'organizer' || user?.role === 'admin'
  const isParticipant = !!marathon.my_participation
  const isCreator = marathon.creator.id === user?.id
  const canDelete = isCreator || user?.role === 'admin'

  return (
    <div className="max-w-4xl mx-auto">
      {/* Back button */}
      <Link to="/marathons" className="inline-flex items-center gap-2 text-gray-400 hover:text-white mb-4 transition-colors">
        <ArrowLeft className="w-4 h-4" />
        К списку марафонов
      </Link>

      {/* Header */}
      <div className="flex justify-between items-start mb-8">
        <div>
          <div className="flex items-center gap-3 mb-2">
            <h1 className="text-3xl font-bold text-white">{marathon.title}</h1>
            <span className={`flex items-center gap-1 text-xs px-2 py-1 rounded ${
              marathon.is_public
                ? 'bg-green-900/50 text-green-400'
                : 'bg-gray-700 text-gray-300'
            }`}>
              {marathon.is_public ? (
                <><Globe className="w-3 h-3" /> Открытый</>
              ) : (
                <><Lock className="w-3 h-3" /> Закрытый</>
              )}
            </span>
          </div>
          {marathon.description && (
            <p className="text-gray-400">{marathon.description}</p>
          )}
        </div>

        <div className="flex gap-2">
          {/* Кнопка присоединиться для открытых марафонов */}
          {marathon.is_public && !isParticipant && marathon.status !== 'finished' && (
            <Button onClick={handleJoinPublic} isLoading={isJoining}>
              <UserPlus className="w-4 h-4 mr-2" />
              Присоединиться
            </Button>
          )}

          {/* Настройка для организаторов */}
          {marathon.status === 'preparing' && isOrganizer && (
            <Link to={`/marathons/${id}/lobby`}>
              <Button variant="secondary">
                <Settings className="w-4 h-4 mr-2" />
                Настройка
              </Button>
            </Link>
          )}

          {/* Предложить игру для участников (не организаторов) если разрешено */}
          {marathon.status === 'preparing' && isParticipant && !isOrganizer && marathon.game_proposal_mode === 'all_participants' && (
            <Link to={`/marathons/${id}/lobby`}>
              <Button variant="secondary">
                <Gamepad2 className="w-4 h-4 mr-2" />
                Предложить игру
              </Button>
            </Link>
          )}

          {marathon.status === 'active' && isParticipant && (
            <Link to={`/marathons/${id}/play`}>
              <Button>
                <Play className="w-4 h-4 mr-2" />
                Играть
              </Button>
            </Link>
          )}

          <Link to={`/marathons/${id}/leaderboard`}>
            <Button variant="secondary">
              <Trophy className="w-4 h-4 mr-2" />
              Рейтинг
            </Button>
          </Link>

          {canDelete && (
            <Button
              variant="ghost"
              onClick={handleDelete}
              isLoading={isDeleting}
              className="text-red-400 hover:text-red-300 hover:bg-red-900/20"
            >
              <Trash2 className="w-4 h-4" />
            </Button>
          )}
        </div>
      </div>

      {/* Stats */}
      <div className="grid md:grid-cols-5 gap-4 mb-8">
        <Card>
          <CardContent className="text-center py-4">
            <div className="text-2xl font-bold text-white">{marathon.participants_count}</div>
            <div className="text-sm text-gray-400 flex items-center justify-center gap-1">
              <Users className="w-4 h-4" />
              Участников
            </div>
          </CardContent>
        </Card>

        <Card>
          <CardContent className="text-center py-4">
            <div className="text-2xl font-bold text-white">{marathon.games_count}</div>
            <div className="text-sm text-gray-400">Игр</div>
          </CardContent>
        </Card>

        <Card>
          <CardContent className="text-center py-4">
            <div className="text-2xl font-bold text-white">
              {marathon.start_date ? format(new Date(marathon.start_date), 'd MMM') : '-'}
            </div>
            <div className="text-sm text-gray-400 flex items-center justify-center gap-1">
              <Calendar className="w-4 h-4" />
              Начало
            </div>
          </CardContent>
        </Card>

        <Card>
          <CardContent className="text-center py-4">
            <div className="text-2xl font-bold text-white">
              {marathon.end_date ? format(new Date(marathon.end_date), 'd MMM') : '-'}
            </div>
            <div className="text-sm text-gray-400 flex items-center justify-center gap-1">
              <CalendarCheck className="w-4 h-4" />
              Конец
            </div>
          </CardContent>
        </Card>

        <Card>
          <CardContent className="text-center py-4">
            <div className={`text-2xl font-bold ${
              marathon.status === 'active' ? 'text-green-500' :
              marathon.status === 'preparing' ? 'text-yellow-500' : 'text-gray-400'
            }`}>
              {marathon.status === 'active' ? 'Активен' : marathon.status === 'preparing' ? 'Подготовка' : 'Завершён'}
            </div>
            <div className="text-sm text-gray-400">Статус</div>
          </CardContent>
        </Card>
      </div>

      {/* Invite code */}
      {marathon.status !== 'finished' && (
        <Card className="mb-8">
          <CardContent>
            <h3 className="font-medium text-white mb-3">Код приглашения</h3>
            <div className="flex items-center gap-3">
              <code className="flex-1 px-4 py-2 bg-gray-900 rounded-lg text-primary-400 font-mono">
                {marathon.invite_code}
              </code>
              <Button variant="secondary" onClick={copyInviteCode}>
                {copied ? (
                  <>
                    <Check className="w-4 h-4 mr-2" />
                    Скопировано!
                  </>
                ) : (
                  <>
                    <Copy className="w-4 h-4 mr-2" />
                    Копировать
                  </>
                )}
              </Button>
            </div>
            <p className="text-sm text-gray-500 mt-2">
              Поделитесь этим кодом с друзьями, чтобы они могли присоединиться к марафону
            </p>
          </CardContent>
        </Card>
      )}

      {/* My stats */}
      {marathon.my_participation && (
        <Card>
          <CardContent>
            <h3 className="font-medium text-white mb-4">Ваша статистика</h3>
            <div className="grid grid-cols-3 gap-4 text-center">
              <div>
                <div className="text-2xl font-bold text-primary-500">
                  {marathon.my_participation.total_points}
                </div>
                <div className="text-sm text-gray-400">Очков</div>
              </div>
              <div>
                <div className="text-2xl font-bold text-yellow-500">
                  {marathon.my_participation.current_streak}
                </div>
                <div className="text-sm text-gray-400">Серия</div>
              </div>
              <div>
                <div className="text-2xl font-bold text-gray-400">
                  {marathon.my_participation.drop_count}
                </div>
                <div className="text-sm text-gray-400">Пропусков</div>
              </div>
            </div>
          </CardContent>
        </Card>
      )}
    </div>
  )
}