'use client'

import React, { useState, useTransition, useEffect, useRef, useCallback } from 'react'
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogDescription,
} from '@/components/ui/dialog'
import { UserPlus, Check, AlertCircle, Globe, Lock, Copy } from 'lucide-react'
import { createBrainstormShare } from '@/app/actions/brainstorm'
import { useUpdateBrainstormSettings } from '@/hooks/use-brainstorm'
import { useLanguage } from '@/lib/i18n'

interface BrainstormShareDialogProps {
  open: boolean
  onOpenChange: (open: boolean) => void
  sessionId: string
  seedIdea: string
  isPublic?: boolean
  guestCanEdit?: boolean
}

interface UserResult {
  id: string
  name: string | null
  email: string
  image: string | null
}

const FEEDBACK_BY_MESSAGE: Record<string, { key: string; type: 'success' | 'info' }> = {
  invited: { key: 'brainstorm.feedbackInviteSent', type: 'success' },
  re_invited: { key: 'brainstorm.feedbackInviteResent', type: 'success' },
  already_shared: {
    key: 'brainstorm.feedbackAlreadyShared',
    type: 'info',
  },
  already_pending: {
    key: 'brainstorm.feedbackAlreadyPending',
    type: 'info',
  },
}

export function BrainstormShareDialog({
  open,
  onOpenChange,
  sessionId,
  seedIdea,
  isPublic = false,
  guestCanEdit = false,
}: BrainstormShareDialogProps) {
  const { t } = useLanguage()
  const [query, setQuery] = useState('')
  const [results, setResults] = useState<UserResult[]>([])
  const [showDropdown, setShowDropdown] = useState(false)
  const [feedback, setFeedback] = useState<{
    text: string
    type: 'success' | 'error' | 'info'
  } | null>(null)
  const [isPending, startTransition] = useTransition()
  const debounceRef = useRef<ReturnType<typeof setTimeout> | null>(null)
  const dropdownRef = useRef<HTMLDivElement>(null)
  const [publicEnabled, setPublicEnabled] = useState(isPublic)
  const [guestEditEnabled, setGuestEditEnabled] = useState(guestCanEdit)
  const [linkCopied, setLinkCopied] = useState(false)
  const updateSettings = useUpdateBrainstormSettings(sessionId)

  useEffect(() => {
    setPublicEnabled(isPublic)
    setGuestEditEnabled(guestCanEdit)
  }, [isPublic, guestCanEdit])

  useEffect(() => {
    if (!open) {
      setQuery('')
      setResults([])
      setShowDropdown(false)
      setFeedback(null)
    }
  }, [open])

  const searchUsers = useCallback(async (q: string) => {
    if (q.length < 2) {
      setResults([])
      setShowDropdown(false)
      return
    }
    try {
      const res = await fetch(`/api/users/search?q=${encodeURIComponent(q)}`)
      const data = await res.json()
      setResults(data.users || [])
      setShowDropdown(data.users?.length > 0)
    } catch {
      setResults([])
    }
  }, [])

  const handleInputChange = (value: string) => {
    setQuery(value)
    setFeedback(null)
    if (debounceRef.current) clearTimeout(debounceRef.current)
    debounceRef.current = setTimeout(() => searchUsers(value), 200)
  }

  const selectUser = (user: UserResult) => {
    setQuery(user.email)
    setShowDropdown(false)
    setResults([])
  }

  const handleShare = (e: React.FormEvent) => {
    e.preventDefault()
    if (!query.trim()) return
    setShowDropdown(false)
    setFeedback(null)
    startTransition(async () => {
      try {
        const result = await createBrainstormShare(sessionId, query.trim())
        if (result.message && FEEDBACK_BY_MESSAGE[result.message]) {
          const m = FEEDBACK_BY_MESSAGE[result.message]
          setFeedback({ text: t(m.key), type: m.type })
        } else {
          setFeedback({ text: t('brainstorm.feedbackInviteSent'), type: 'success' })
        }
        if (result.message === 'invited' || result.message === 're_invited') {
          setQuery('')
        }
      } catch (err: any) {
        setFeedback({ text: err.message || t('brainstorm.feedbackGenericError'), type: 'error' })
      }
    })
  }

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent className="sm:max-w-md bg-white dark:bg-[#1A1A1A] border-border rounded-2xl">
        <DialogHeader>
          <DialogTitle className="flex items-center gap-2 text-foreground">
            <div className="w-7 h-7 rounded-lg bg-brand-accent/10 flex items-center justify-center">
              <UserPlus size={14} className="text-brand-accent" />
            </div>
            <span className="font-serif">{t('brainstorm.shareDialogTitle')}</span>
          </DialogTitle>
          <DialogDescription className="text-muted-foreground text-xs italic font-serif truncate">
            {seedIdea.length > 60 ? seedIdea.substring(0, 60) + '…' : seedIdea}
          </DialogDescription>
        </DialogHeader>

        <form onSubmit={handleShare} className="space-y-3 mt-2">
          <div className="relative" ref={dropdownRef}>
            <label className="text-[10px] font-bold uppercase tracking-[0.15em] text-muted-foreground mb-1.5 block">
              {t('brainstorm.shareSearchLabel')}
            </label>
            <input
              type="text"
              value={query}
              onChange={(e) => handleInputChange(e.target.value)}
              onFocus={() => results.length > 0 && setShowDropdown(true)}
              onBlur={() => setTimeout(() => setShowDropdown(false), 150)}
              placeholder={t('brainstorm.shareNameOrEmailPlaceholder')}
              className="w-full px-4 py-3 text-sm border border-border rounded-xl bg-transparent focus:outline-none focus:ring-2 focus:ring-brand-accent/20 focus:border-brand-accent/40 transition-all"
              autoFocus
            />

            {showDropdown && results.length > 0 && (
              <div className="absolute z-50 top-full left-0 right-0 mt-1 bg-white dark:bg-[#1A1A1A] border border-border rounded-xl shadow-xl overflow-hidden">
                {results.map((user) => (
                  <button
                    key={user.id}
                    type="button"
                    onMouseDown={(e) => {
                      e.preventDefault()
                      selectUser(user)
                    }}
                    className="w-full px-4 py-2.5 flex items-center gap-3 hover:bg-brand-accent/5 transition-colors text-left"
                  >
                    <div className="w-8 h-8 rounded-full bg-brand-accent/10 flex items-center justify-center text-xs font-bold text-brand-accent shrink-0">
                      {(user.name || user.email).charAt(0).toUpperCase()}
                    </div>
                    <div className="min-w-0 flex-1">
                      <p className="text-sm font-medium text-foreground truncate">
                        {user.name || t('brainstorm.unnamedPerson')}
                      </p>
                      <p className="text-[11px] text-muted-foreground truncate">
                        {user.email}
                      </p>
                    </div>
                  </button>
                ))}
              </div>
            )}
          </div>

          {feedback && (
            <div
              className={`flex items-center gap-1.5 px-1 text-[11px] font-medium ${
                feedback.type === 'success'
                  ? 'text-emerald-500'
                  : feedback.type === 'error'
                    ? 'text-rose-500'
                    : 'text-amber-500'
              }`}
            >
              {feedback.type === 'success' ? (
                <Check size={12} />
              ) : (
                <AlertCircle size={12} />
              )}
              {feedback.text}
            </div>
          )}

          <button
            type="submit"
            disabled={!query.trim() || isPending}
            className="w-full py-3 bg-brand-accent hover:bg-brand-accent/90 text-white text-[10px] font-bold uppercase tracking-[0.15em] rounded-xl disabled:opacity-50 transition-all flex items-center justify-center gap-1.5"
          >
            <UserPlus size={12} />
            {isPending ? t('brainstorm.shareSubmitting') : t('brainstorm.shareSubmit')}
          </button>
        </form>

        <p className="text-[10px] text-muted-foreground/60 text-center mt-1">
          {t('brainstorm.shareFooterHint')}
        </p>

        <div className="border-t border-border mt-4 pt-4">
          <div className="flex items-center justify-between mb-3">
            <div className="flex items-center gap-2">
              {publicEnabled ? (
                <Globe size={14} className="text-emerald-500" />
              ) : (
                <Lock size={14} className="text-muted-foreground" />
              )}
              <span className="text-[10px] font-bold uppercase tracking-[0.15em] text-muted-foreground">
                {t('brainstorm.sharePublicLink')}
              </span>
            </div>
            <button
              onClick={() => {
                const next = !publicEnabled
                setPublicEnabled(next)
                if (!next) setGuestEditEnabled(false)
                updateSettings.mutate({ isPublic: next, guestCanEdit: next ? guestEditEnabled : false })
              }}
              className={`relative w-10 h-5 rounded-full transition-colors ${publicEnabled ? 'bg-emerald-500' : 'bg-border'}`}
            >
              <div
                className={`absolute top-0.5 w-4 h-4 rounded-full bg-white shadow-sm transition-transform ${publicEnabled ? 'translate-x-5' : 'translate-x-0.5'}`}
              />
            </button>
          </div>

          {publicEnabled && (
            <>
              <div className="flex items-center gap-2 mb-3">
                <input
                  readOnly
                  value={`${typeof window !== 'undefined' ? window.location.origin : ''}/brainstorm?session=${sessionId}`}
                  className="flex-1 px-3 py-2 text-[11px] bg-foreground/5 border border-border rounded-lg text-muted-foreground truncate"
                />
                <button
                  onClick={() => {
                    navigator.clipboard.writeText(`${window.location.origin}/brainstorm?session=${sessionId}`)
                    setLinkCopied(true)
                    setTimeout(() => setLinkCopied(false), 2000)
                  }}
                  className="px-3 py-2 text-[10px] font-bold uppercase tracking-wider bg-foreground/5 hover:bg-foreground/10 rounded-lg transition-colors flex items-center gap-1"
                >
                  {linkCopied ? <Check size={12} className="text-emerald-500" /> : <Copy size={12} />}
                </button>
              </div>

              <div className="flex items-center justify-between">
                <span className="text-[10px] text-muted-foreground">
                  {t('brainstorm.shareGuestsCanEdit')}
                </span>
                <button
                  onClick={() => {
                    const next = !guestEditEnabled
                    setGuestEditEnabled(next)
                    updateSettings.mutate({ guestCanEdit: next })
                  }}
                  className={`relative w-10 h-5 rounded-full transition-colors ${guestEditEnabled ? 'bg-orange-500' : 'bg-border'}`}
                >
                  <div
                    className={`absolute top-0.5 w-4 h-4 rounded-full bg-white shadow-sm transition-transform ${guestEditEnabled ? 'translate-x-5' : 'translate-x-0.5'}`}
                  />
                </button>
              </div>
            </>
          )}
        </div>
      </DialogContent>
    </Dialog>
  )
}