import React, { useState, useEffect, useCallback } from 'react'
import { useAuth } from './auth/AuthContext'
import LoadingError from './LoadingError'
import Toast from './Toast'
import './WishlistDetail.css'

const API_URL = '/api/wishlist'

function WishlistDetail({ wishlistId, onNavigate, onRefresh }) {
  const { authFetch } = useAuth()
  const [wishlistItem, setWishlistItem] = useState(null)
  const [loading, setLoading] = useState(true)
  const [loadingWishlist, setLoadingWishlist] = useState(true)
  const [error, setError] = useState(null)
  const [isCompleting, setIsCompleting] = useState(false)
  const [isDeleting, setIsDeleting] = useState(false)
  const [toastMessage, setToastMessage] = useState(null)

  const fetchWishlistDetail = useCallback(async () => {
    try {
      setLoadingWishlist(true)
      setLoading(true)
      setError(null)
      const response = await authFetch(`${API_URL}/${wishlistId}`)
      if (!response.ok) {
        throw new Error('Ошибка загрузки желания')
      }
      const data = await response.json()
      setWishlistItem(data)
    } catch (err) {
      setError(err.message)
      console.error('Error fetching wishlist detail:', err)
    } finally {
      setLoading(false)
      setLoadingWishlist(false)
    }
  }, [wishlistId, authFetch])

  useEffect(() => {
    if (wishlistId) {
      fetchWishlistDetail()
    } else {
      setWishlistItem(null)
      setLoading(true)
      setLoadingWishlist(true)
      setError(null)
    }
  }, [wishlistId, fetchWishlistDetail])

  const handleEdit = () => {
    onNavigate?.('wishlist-form', { wishlistId: wishlistId })
  }

  const handleComplete = async () => {
    if (!wishlistItem || !wishlistItem.unlocked) return

    setIsCompleting(true)
    try {
      const response = await authFetch(`${API_URL}/${wishlistId}/complete`, {
        method: 'POST',
      })

      if (!response.ok) {
        throw new Error('Ошибка при завершении')
      }

      if (onRefresh) {
        onRefresh()
      }
      if (onNavigate) {
        onNavigate('wishlist')
      }
    } catch (err) {
      console.error('Error completing wishlist:', err)
      setToastMessage({ text: err.message || 'Ошибка при завершении', type: 'error' })
    } finally {
      setIsCompleting(false)
    }
  }

  const handleUncomplete = async () => {
    if (!wishlistItem || !wishlistItem.completed) return

    setIsCompleting(true)
    try {
      const response = await authFetch(`${API_URL}/${wishlistId}/uncomplete`, {
        method: 'POST',
      })

      if (!response.ok) {
        throw new Error('Ошибка при отмене завершения')
      }

      if (onRefresh) {
        onRefresh()
      }
      fetchWishlistDetail()
    } catch (err) {
      console.error('Error uncompleting wishlist:', err)
      setToastMessage({ text: err.message || 'Ошибка при отмене завершения', type: 'error' })
    } finally {
      setIsCompleting(false)
    }
  }

  const handleDelete = async () => {
    if (!wishlistItem) return

    if (!window.confirm('Вы уверены, что хотите удалить это желание?')) {
      return
    }

    setIsDeleting(true)
    try {
      const response = await authFetch(`${API_URL}/${wishlistId}`, {
        method: 'DELETE',
      })

      if (!response.ok) {
        throw new Error('Ошибка при удалении')
      }

      if (onRefresh) {
        onRefresh()
      }
      if (onNavigate) {
        onNavigate('wishlist')
      }
    } catch (err) {
      console.error('Error deleting wishlist:', err)
      setToastMessage({ text: err.message || 'Ошибка при удалении', type: 'error' })
    } finally {
      setIsDeleting(false)
    }
  }

  const formatPrice = (price) => {
    return new Intl.NumberFormat('ru-RU', {
      style: 'currency',
      currency: 'RUB',
      minimumFractionDigits: 0,
      maximumFractionDigits: 0,
    }).format(price)
  }

  const renderUnlockConditions = () => {
    if (!wishlistItem || !wishlistItem.unlock_conditions || wishlistItem.unlock_conditions.length === 0) {
      return null
    }

    return (
      <div className="wishlist-detail-conditions">
        <h3 className="wishlist-detail-section-title">Условия разблокировки:</h3>
        {wishlistItem.unlock_conditions.map((condition, index) => {
          let conditionText = ''
          let progress = null
          
          if (condition.type === 'task_completion') {
            conditionText = condition.task_name || 'Задача'
            const isCompleted = condition.task_completed === true
            progress = {
              type: 'task',
              completed: isCompleted
            }
          } else {
            const requiredPoints = condition.required_points || 0
            const currentPoints = condition.current_points || 0
            const project = condition.project_name || 'Проект'
            let period = ''
            if (condition.period_type) {
              const periodLabels = {
                week: 'за неделю',
                month: 'за месяц',
                year: 'за год',
              }
              period = ' ' + periodLabels[condition.period_type] || ''
            }
            conditionText = `${requiredPoints} в ${project}${period}`
            progress = {
              type: 'points',
              current: currentPoints,
              required: requiredPoints,
              percentage: requiredPoints > 0 ? Math.min(100, (currentPoints / requiredPoints) * 100) : 0
            }
          }

          const isMet = wishlistItem.unlocked || (progress?.type === 'task' && progress.completed) || 
                       (progress?.type === 'points' && progress.current >= progress.required)

          return (
            <div key={index} className={`wishlist-detail-condition ${isMet ? 'met' : 'not-met'}`}>
              <div className="condition-header">
                <svg className="condition-icon" width="16" height="16" viewBox="0 0 24 24" fill="currentColor">
                  {isMet ? (
                    <path d="M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z"/>
                  ) : (
                    <path d="M18 8h-1V6c0-2.76-2.24-5-5-5S7 3.24 7 6v2H6c-1.1 0-2 .9-2 2v10c0 1.1.9 2 2 2h12c1.1 0 2-.9 2-2V10c0-1.1-.9-2-2-2zM9 6c0-1.66 1.34-3 3-3s3 1.34 3 3v2H9V6zm9 14H6V10h12v10zm-6-3c1.1 0 2-.9 2-2s-.9-2-2-2-2 .9-2 2 .9 2 2 2z"/>
                  )}
                </svg>
                <span className="condition-text">{conditionText}</span>
              </div>
              {progress && progress.type === 'points' && !isMet && (
                <div className="condition-progress">
                  <div className="progress-bar">
                    <div 
                      className="progress-fill" 
                      style={{ width: `${progress.percentage}%` }}
                    ></div>
                  </div>
                  <div className="progress-text">
                    {Math.round(progress.current)} / {Math.round(progress.required)}
                  </div>
                </div>
              )}
            </div>
          )
        })}
      </div>
    )
  }

  if (loadingWishlist) {
    return (
      <div className="wishlist-detail">
        <div className="fixed inset-0 bottom-20 flex justify-center items-center">
          <div className="flex flex-col items-center">
            <div className="w-12 h-12 border-4 border-indigo-200 border-t-indigo-600 rounded-full animate-spin mb-4"></div>
            <div className="text-gray-600 font-medium">Загрузка...</div>
          </div>
        </div>
      </div>
    )
  }

  return (
    <div className="wishlist-detail">
      <button className="close-x-button" onClick={() => onNavigate?.('wishlist')}>
        ✕
      </button>
      <h2>{wishlistItem ? wishlistItem.name : 'Желание'}</h2>

      <div className="wishlist-detail-content">
        {error && (
          <LoadingError onRetry={fetchWishlistDetail} />
        )}

        {!error && wishlistItem && (
            <>
              {/* Изображение */}
              {wishlistItem.image_url && (
                <div className="wishlist-detail-image">
                  <img src={wishlistItem.image_url} alt={wishlistItem.name} />
                </div>
              )}

              {/* Цена */}
              {wishlistItem.price && (
                <div className="wishlist-detail-price">
                  {formatPrice(wishlistItem.price)}
                </div>
              )}

              {/* Ссылка */}
              {wishlistItem.link && (
                <div className="wishlist-detail-link">
                  <a href={wishlistItem.link} target="_blank" rel="noopener noreferrer">
                    Открыть ссылку
                  </a>
                </div>
              )}

              {/* Условия разблокировки */}
              {renderUnlockConditions()}

              {/* Кнопка завершения */}
              {wishlistItem.unlocked && !wishlistItem.completed && (
                <div className="wishlist-detail-actions">
                  <button
                    onClick={handleComplete}
                    disabled={isCompleting}
                    className="wishlist-detail-complete-button"
                  >
                    {isCompleting ? 'Завершение...' : 'Завершить'}
                  </button>
                </div>
              )}
          </>
        )}
      </div>
      {toastMessage && (
        <Toast
          message={toastMessage.text}
          type={toastMessage.type}
          onClose={() => setToastMessage(null)}
        />
      )}
    </div>
  )
}

export default WishlistDetail