import { useState, useEffect } from 'react'
import { Plus, Trash2, ChevronUp, ChevronDown, Pencil, Check, X, Loader2, ListChecks, ToggleLeft, ToggleRight } from 'lucide-react'
import { api, type ChecklistTemplate, type ChecklistItem } from '../lib/api'
import { useAuth } from '../contexts/AuthContext'
import { cn } from '../lib/utils'

const TASK_TYPE_LABELS: Record<string, string> = {
  checkout: 'После выезда',
  daily:    'Ежедневная',
  deep:     'Генеральная',
}

function InlineEdit({ value, onSave, onCancel }: {
  value: string
  onSave: (v: string) => void
  onCancel: () => void
}) {
  const [v, setV] = useState(value)
  return (
    <div className="flex items-center gap-1.5 flex-1">
      <input
        autoFocus
        value={v}
        onChange={e => setV(e.target.value)}
        onKeyDown={e => {
          if (e.key === 'Enter') onSave(v.trim())
          if (e.key === 'Escape') onCancel()
        }}
        className="input flex-1 py-1 text-sm"
      />
      <button onClick={() => onSave(v.trim())} className="p-1 rounded text-emerald-600 hover:bg-emerald-50 dark:hover:bg-emerald-900/20">
        <Check size={14} />
      </button>
      <button onClick={onCancel} className="p-1 rounded text-slate-400 hover:bg-slate-100 dark:hover:bg-slate-700">
        <X size={14} />
      </button>
    </div>
  )
}

export function ChecklistSettingsPage() {
  const { user } = useAuth()
  const slug = user?.hotelSlug ?? ''

  const [templates, setTemplates] = useState<ChecklistTemplate[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)

  // New template form
  const [newName, setNewName] = useState('')
  const [newType, setNewType] = useState('')
  const [adding, setAdding] = useState(false)

  // Editing states
  const [editingTemplateId, setEditingTemplateId] = useState<string | null>(null)
  const [editingItemId, setEditingItemId] = useState<string | null>(null)
  const [newItemText, setNewItemText] = useState<Record<string, string>>({})

  useEffect(() => {
    if (!slug) return
    api.checklists.listTemplates(slug)
      .then(t => setTemplates(t))
      .catch(() => setError('Не удалось загрузить шаблоны'))
      .finally(() => setLoading(false))
  }, [slug])

  const addTemplate = async () => {
    if (!newName.trim()) return
    setAdding(true)
    try {
      const tpl = await api.checklists.createTemplate(slug, {
        name: newName.trim(),
        taskType: newType || undefined,
      })
      setTemplates(prev => [...prev, tpl])
      setNewName('')
      setNewType('')
    } catch {
      setError('Не удалось создать шаблон')
    } finally {
      setAdding(false)
    }
  }

  const updateTemplateName = async (id: string, name: string) => {
    try {
      const updated = await api.checklists.updateTemplate(slug, id, { name })
      setTemplates(prev => prev.map(t => t.id === id ? { ...t, name: updated.name } : t))
    } catch { /* ignore */ }
    setEditingTemplateId(null)
  }

  const toggleActive = async (t: ChecklistTemplate) => {
    try {
      const updated = await api.checklists.updateTemplate(slug, t.id, { isActive: !t.isActive })
      setTemplates(prev => prev.map(x => x.id === t.id ? { ...x, isActive: updated.isActive } : x))
    } catch { /* ignore */ }
  }

  const deleteTemplate = async (id: string) => {
    if (!confirm('Удалить шаблон вместе со всеми пунктами?')) return
    try {
      await api.checklists.deleteTemplate(slug, id)
      setTemplates(prev => prev.filter(t => t.id !== id))
    } catch { /* ignore */ }
  }

  const addItem = async (templateId: string) => {
    const text = newItemText[templateId]?.trim()
    if (!text) return
    try {
      const item = await api.checklists.addItem(slug, templateId, { text })
      setTemplates(prev => prev.map(t => t.id === templateId
        ? { ...t, items: [...t.items, item] }
        : t,
      ))
      setNewItemText(prev => ({ ...prev, [templateId]: '' }))
    } catch { /* ignore */ }
  }

  const updateItemText = async (templateId: string, item: ChecklistItem, text: string) => {
    try {
      const updated = await api.checklists.updateItem(slug, templateId, item.id, { text })
      setTemplates(prev => prev.map(t => t.id === templateId
        ? { ...t, items: t.items.map(i => i.id === item.id ? { ...i, text: updated.text } : i) }
        : t,
      ))
    } catch { /* ignore */ }
    setEditingItemId(null)
  }

  const deleteItem = async (templateId: string, itemId: string) => {
    try {
      await api.checklists.deleteItem(slug, templateId, itemId)
      setTemplates(prev => prev.map(t => t.id === templateId
        ? { ...t, items: t.items.filter(i => i.id !== itemId) }
        : t,
      ))
    } catch { /* ignore */ }
  }

  const moveItem = async (templateId: string, itemId: string, dir: 'up' | 'down') => {
    const tpl = templates.find(t => t.id === templateId)
    if (!tpl) return
    const idx = tpl.items.findIndex(i => i.id === itemId)
    if (dir === 'up' && idx === 0) return
    if (dir === 'down' && idx === tpl.items.length - 1) return

    const newItems = [...tpl.items]
    const swapIdx = dir === 'up' ? idx - 1 : idx + 1
    ;[newItems[idx], newItems[swapIdx]] = [newItems[swapIdx], newItems[idx]]

    // Update sort_order for both
    const a = newItems[idx]
    const b = newItems[swapIdx]
    const sortA = a.sortOrder
    const sortB = b.sortOrder

    setTemplates(prev => prev.map(t => t.id === templateId ? { ...t, items: newItems } : t))

    try {
      await Promise.all([
        api.checklists.updateItem(slug, templateId, a.id, { sortOrder: sortA }),
        api.checklists.updateItem(slug, templateId, b.id, { sortOrder: sortB }),
      ])
    } catch { /* ignore */ }
  }

  if (loading) {
    return (
      <div className="flex items-center justify-center h-64">
        <Loader2 size={24} className="animate-spin text-brand-600" />
      </div>
    )
  }

  return (
    <div className="p-4 md:p-6 space-y-6 max-w-3xl">
      <div>
        <h1 className="text-xl font-bold text-slate-900 dark:text-slate-100 flex items-center gap-2">
          <ListChecks size={22} className="text-brand-600" />
          Шаблоны чек-листов
        </h1>
        <p className="text-sm text-slate-500 dark:text-slate-400 mt-1">
          Настройте пункты проверки для задач уборки. Шаблон применяется автоматически по типу задачи.
        </p>
      </div>

      {error && (
        <div className="rounded-lg bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800 p-3 text-sm text-red-700 dark:text-red-300">
          {error}
        </div>
      )}

      {/* Add template form */}
      <div className="card p-4 space-y-3">
        <h3 className="font-semibold text-slate-800 dark:text-slate-200 text-sm">Новый шаблон</h3>
        <div className="flex gap-2">
          <input
            value={newName}
            onChange={e => setNewName(e.target.value)}
            placeholder="Название шаблона"
            className="input flex-1"
            onKeyDown={e => e.key === 'Enter' && addTemplate()}
          />
          <select
            value={newType}
            onChange={e => setNewType(e.target.value)}
            className="input w-44"
          >
            <option value="">Любой тип</option>
            <option value="checkout">После выезда</option>
            <option value="daily">Ежедневная</option>
            <option value="deep">Генеральная</option>
          </select>
          <button
            onClick={addTemplate}
            disabled={!newName.trim() || adding}
            className="btn-primary flex items-center gap-1.5"
          >
            {adding ? <Loader2 size={14} className="animate-spin" /> : <Plus size={14} />}
            Добавить
          </button>
        </div>
      </div>

      {/* Templates list */}
      <div className="space-y-4">
        {templates.length === 0 && (
          <div className="text-center py-12 text-slate-400 dark:text-slate-500">
            Нет шаблонов. Создайте первый шаблон чек-листа.
          </div>
        )}
        {templates.map(tpl => (
          <div key={tpl.id} className={cn(
            'border rounded-xl overflow-hidden',
            tpl.isActive
              ? 'border-slate-200 dark:border-slate-700'
              : 'border-dashed border-slate-200 dark:border-slate-700 opacity-60',
          )}>
            {/* Template header */}
            <div className="flex items-center gap-2 px-4 py-3 bg-slate-50 dark:bg-slate-800/50">
              {editingTemplateId === tpl.id ? (
                <InlineEdit
                  value={tpl.name}
                  onSave={name => updateTemplateName(tpl.id, name)}
                  onCancel={() => setEditingTemplateId(null)}
                />
              ) : (
                <>
                  <span className="font-semibold text-slate-800 dark:text-slate-200 flex-1">{tpl.name}</span>
                  {tpl.taskType && (
                    <span className="text-xs px-2 py-0.5 rounded-full bg-brand-100 text-brand-700 dark:bg-brand-900/30 dark:text-brand-300">
                      {TASK_TYPE_LABELS[tpl.taskType] ?? tpl.taskType}
                    </span>
                  )}
                  {!tpl.taskType && (
                    <span className="text-xs px-2 py-0.5 rounded-full bg-slate-100 text-slate-600 dark:bg-slate-700 dark:text-slate-400">
                      Любой тип
                    </span>
                  )}
                  <button onClick={() => setEditingTemplateId(tpl.id)} className="p-1.5 rounded hover:bg-slate-200 dark:hover:bg-slate-600 text-slate-400">
                    <Pencil size={13} />
                  </button>
                  <button onClick={() => toggleActive(tpl)} className={cn('p-1.5 rounded text-slate-400 hover:bg-slate-200 dark:hover:bg-slate-600', tpl.isActive ? 'text-brand-600' : 'text-slate-400')}>
                    {tpl.isActive ? <ToggleRight size={16} /> : <ToggleLeft size={16} />}
                  </button>
                  <button onClick={() => deleteTemplate(tpl.id)} className="p-1.5 rounded hover:bg-red-50 dark:hover:bg-red-900/20 text-slate-400 hover:text-red-500">
                    <Trash2 size={13} />
                  </button>
                </>
              )}
            </div>

            {/* Items */}
            <div className="p-4 bg-white dark:bg-slate-900 space-y-1.5">
              {tpl.items.map((item, idx) => (
                <div key={item.id} className="flex items-center gap-2 group">
                  <span className="text-slate-400 text-xs w-5 text-right shrink-0">{idx + 1}.</span>
                  {editingItemId === item.id ? (
                    <InlineEdit
                      value={item.text}
                      onSave={text => updateItemText(tpl.id, item, text)}
                      onCancel={() => setEditingItemId(null)}
                    />
                  ) : (
                    <>
                      <span className="flex-1 text-sm text-slate-700 dark:text-slate-300">{item.text}</span>
                      <div className="flex items-center gap-0.5 opacity-0 group-hover:opacity-100 transition-opacity">
                        <button onClick={() => moveItem(tpl.id, item.id, 'up')} disabled={idx === 0} className="p-1 rounded hover:bg-slate-100 dark:hover:bg-slate-700 text-slate-400 disabled:opacity-30">
                          <ChevronUp size={13} />
                        </button>
                        <button onClick={() => moveItem(tpl.id, item.id, 'down')} disabled={idx === tpl.items.length - 1} className="p-1 rounded hover:bg-slate-100 dark:hover:bg-slate-700 text-slate-400 disabled:opacity-30">
                          <ChevronDown size={13} />
                        </button>
                        <button onClick={() => setEditingItemId(item.id)} className="p-1 rounded hover:bg-slate-100 dark:hover:bg-slate-700 text-slate-400">
                          <Pencil size={13} />
                        </button>
                        <button onClick={() => deleteItem(tpl.id, item.id)} className="p-1 rounded hover:bg-red-50 dark:hover:bg-red-900/20 text-slate-400 hover:text-red-500">
                          <Trash2 size={13} />
                        </button>
                      </div>
                    </>
                  )}
                </div>
              ))}

              {/* Add item */}
              <div className="flex items-center gap-2 mt-2 pt-2 border-t border-slate-100 dark:border-slate-700">
                <input
                  value={newItemText[tpl.id] ?? ''}
                  onChange={e => setNewItemText(prev => ({ ...prev, [tpl.id]: e.target.value }))}
                  placeholder="Новый пункт..."
                  className="input flex-1 py-1.5 text-sm"
                  onKeyDown={e => e.key === 'Enter' && addItem(tpl.id)}
                />
                <button
                  onClick={() => addItem(tpl.id)}
                  disabled={!newItemText[tpl.id]?.trim()}
                  className="btn-secondary py-1.5 px-3 text-sm flex items-center gap-1"
                >
                  <Plus size={14} />
                  Добавить
                </button>
              </div>
            </div>
          </div>
        ))}
      </div>
    </div>
  )
}