import React, { useState, useEffect, useCallback } from 'react'
import {
  getComments,
  addComment,
  replyComment,
  deleteComment as apiDeleteComment,
  type CommentOut,
} from '../api'
import { useToast } from './Toast'
import { useTranslation } from '../i18n'
import { useDateFormatter } from '../utils/dateUtils'

interface CommentSectionProps {
  consultationId: string
}

export default function CommentSection({ consultationId }: CommentSectionProps) {
  const toast = useToast()
  const { t } = useTranslation()
  const { formatDateTime } = useDateFormatter()
  const [comments, setComments] = useState<CommentOut[]>([])
  const [total, setTotal] = useState(0)
  const [loading, setLoading] = useState(true)
  const [newComment, setNewComment] = useState('')
  const [submitting, setSubmitting] = useState(false)
  const [replyingTo, setReplyingTo] = useState<string | null>(null)
  const [replyContent, setReplyContent] = useState('')
  const [replySubmitting, setReplySubmitting] = useState(false)
  const [deletingId, setDeletingId] = useState<string | null>(null)

  const loadComments = useCallback(async () => {
    try {
      const data = await getComments(consultationId)
      setComments(data.comments)
      setTotal(data.total)
    } catch {
      // 静默失败
    } finally {
      setLoading(false)
    }
  }, [consultationId])

  useEffect(() => {
    loadComments()
  }, [loadComments])

  const handleAddComment = async () => {
    const trimmed = newComment.trim()
    if (!trimmed || submitting) return
    setSubmitting(true)
    try {
      await addComment(consultationId, trimmed)
      setNewComment('')
      toast.success(t('components.comment.posted'))
      await loadComments()
    } catch (e: any) {
      toast.error(e?.message || t('components.comment.postFailed'))
    } finally {
      setSubmitting(false)
    }
  }

  const handleReply = async (commentId: string) => {
    const trimmed = replyContent.trim()
    if (!trimmed || replySubmitting) return
    setReplySubmitting(true)
    try {
      await replyComment(consultationId, commentId, trimmed)
      setReplyContent('')
      setReplyingTo(null)
      toast.success(t('components.comment.replyPosted'))
      await loadComments()
    } catch (e: any) {
      toast.error(e?.message || t('components.comment.replyFailed'))
    } finally {
      setReplySubmitting(false)
    }
  }

  const handleDelete = async (commentId: string) => {
    if (!window.confirm(t('components.comment.confirmDelete'))) return
    setDeletingId(commentId)
    try {
      await apiDeleteComment(consultationId, commentId)
      toast.success(t('components.comment.deleted'))
      await loadComments()
    } catch (e: any) {
      toast.error(e?.message || t('components.comment.deleteFailed'))
    } finally {
      setDeletingId(null)
    }
  }

  const formatTime = (iso: string) => {
    try {
      return formatDateTime(iso)
    } catch {
      return iso
    }
  }

  if (loading) {
    return (
      <div className="card p-4 md:p-6 max-w-3xl mx-auto mt-6">
        <div className="text-center text-gray-400 text-sm py-4">{t('components.comment.loading')}</div>
      </div>
    )
  }

  return (
    <div className="card p-4 md:p-6 max-w-3xl mx-auto mt-6">
      <h4 className="text-sm font-bold text-gray-700 mb-4 flex items-center gap-2">
        <svg className="w-5 h-5 text-gray-500" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
          <path strokeLinecap="round" strokeLinejoin="round" d="M8 12h.01M12 12h.01M16 12h.01M21 12c0 4.418-4.03 8-9 8a9.863 9.863 0 01-4.255-.949L3 20l1.395-3.72C3.512 15.042 3 13.574 3 12c0-4.418 4.03-8 9-8s9 3.582 9 8z" />
        </svg>
        {t('components.comment.title')} ({total})
      </h4>

      {/* 新增评论 */}
      <div className="mb-4">
        <div className="flex gap-2">
          <textarea
            className="flex-1 text-sm border border-gray-200 rounded-lg px-3 py-2 focus:ring-2 focus:ring-medical-500 focus:border-medical-500 outline-none resize-none min-h-[44px]"
            placeholder={t('components.comment.placeholder')}
            value={newComment}
            onChange={(e) => setNewComment(e.target.value)}
            onKeyDown={(e) => {
              if (e.key === 'Enter' && !e.shiftKey) {
                e.preventDefault()
                handleAddComment()
              }
            }}
            rows={2}
          />
          <button
            onClick={handleAddComment}
            disabled={submitting || !newComment.trim()}
            className="btn-primary text-xs px-4 py-2 min-h-[44px] disabled:opacity-50 shrink-0"
          >
            {submitting ? t('components.comment.sending') : t('components.comment.send')}
          </button>
        </div>
      </div>

      {/* 评论列表 */}
      {comments.length === 0 ? (
        <div className="text-center text-gray-400 text-sm py-6">{t('components.comment.noComments')}</div>
      ) : (
        <div className="space-y-3">
          {comments.map((comment) => (
            <CommentItem
              key={comment.id}
              comment={comment}
              consultationId={consultationId}
              replyingTo={replyingTo}
              replyContent={replyContent}
              replySubmitting={replySubmitting}
              deletingId={deletingId}
              onReplyClick={(id) => {
                setReplyingTo(id)
                setReplyContent('')
              }}
              onReplyCancel={() => setReplyingTo(null)}
              onReplyChange={setReplyContent}
              onReplySubmit={handleReply}
              onDelete={handleDelete}
              formatTime={formatTime}
              depth={0}
            />
          ))}
        </div>
      )}
    </div>
  )
}

// ================================================================
// 单个评论（递归渲染回复）
// ================================================================

function CommentItem({
  comment,
  consultationId,
  replyingTo,
  replyContent,
  replySubmitting,
  deletingId,
  onReplyClick,
  onReplyCancel,
  onReplyChange,
  onReplySubmit,
  onDelete,
  formatTime,
  depth,
}: {
  comment: CommentOut
  consultationId: string
  replyingTo: string | null
  replyContent: string
  replySubmitting: boolean
  deletingId: string | null
  onReplyClick: (id: string) => void
  onReplyCancel: () => void
  onReplyChange: (v: string) => void
  onReplySubmit: (id: string) => void
  onDelete: (id: string) => void
  formatTime: (iso: string) => string
  depth: number
}) {
  const { t } = useTranslation()
  const isDeleting = deletingId === comment.id
  const maxDepth = 4 // 最大嵌套层级

  return (
    <div className={`${depth > 0 ? 'ml-6 border-l-2 border-gray-100 pl-3' : ''}`}>
      <div className={`rounded-lg p-3 ${comment.is_deleted ? 'bg-gray-50' : 'bg-gray-50/50'}`}>
        {/* 头像 + 信息 + 时间 */}
        <div className="flex items-start gap-2 mb-1">
          {/* 头像 */}
          <div className="w-7 h-7 rounded-full bg-medical-100 text-medical-700 flex items-center justify-center text-xs font-bold shrink-0">
            {comment.user?.nickname?.charAt(0) || '?'}
          </div>
          <div className="flex-1 min-w-0">
            <div className="flex items-center gap-2 flex-wrap">
              <span className="text-xs font-medium text-gray-700">
                {comment.is_deleted ? t('components.comment.deleted') : comment.user?.nickname || t('components.comment.anonymous')}
              </span>
              <span className="text-[10px] text-gray-400">
                {formatTime(comment.created_at)}
              </span>
              {comment.is_deleted && (
                <span className="text-[10px] text-gray-400 italic">{t('components.comment.deletedByAuthor')}</span>
              )}
            </div>
            {/* 内容 */}
            <p className="text-sm text-gray-700 mt-1 whitespace-pre-wrap break-words">
              {comment.content}
            </p>
          </div>
        </div>

        {/* 操作按钮 */}
        {!comment.is_deleted && (
          <div className="flex gap-3 ml-9">
            {depth < maxDepth && (
              <button
                onClick={() => onReplyClick(comment.id)}
                className="text-[11px] text-gray-400 hover:text-medical-600 transition-colors"
              >
                {t('components.comment.reply')}
              </button>
            )}
            <button
              onClick={() => onDelete(comment.id)}
              disabled={isDeleting}
              className="text-[11px] text-gray-400 hover:text-red-500 transition-colors disabled:opacity-50"
            >
              {isDeleting ? t('components.comment.deleting') : t('components.comment.delete')}
            </button>
          </div>
        )}

        {/* 回复输入框 */}
        {replyingTo === comment.id && (
          <div className="ml-9 mt-2 flex gap-2">
            <textarea
              className="flex-1 text-xs border border-gray-200 rounded-lg px-3 py-1.5 focus:ring-2 focus:ring-medical-500 focus:border-medical-500 outline-none resize-none min-h-[32px]"
              placeholder={t('components.comment.replyPlaceholder')}
              value={replyContent}
              onChange={(e) => onReplyChange(e.target.value)}
              onKeyDown={(e) => {
                if (e.key === 'Enter' && !e.shiftKey) {
                  e.preventDefault()
                  onReplySubmit(comment.id)
                }
              }}
              rows={2}
              autoFocus
            />
            <div className="flex flex-col gap-1">
              <button
                onClick={() => onReplySubmit(comment.id)}
                disabled={replySubmitting || !replyContent.trim()}
                className="btn-primary text-[10px] px-2 py-1 min-h-[28px] disabled:opacity-50"
              >
                {t('components.comment.reply')}
              </button>
              <button
                onClick={onReplyCancel}
                className="text-[10px] text-gray-400 hover:text-gray-600 min-h-[24px]"
              >
                {t('components.comment.cancel')}
              </button>
            </div>
          </div>
        )}
      </div>

      {/* 递归渲染子回复 */}
      {comment.replies && comment.replies.length > 0 && (
        <div className="mt-1">
          {comment.replies.map((reply) => (
            <CommentItem
              key={reply.id}
              comment={reply}
              consultationId={consultationId}
              replyingTo={replyingTo}
              replyContent={replyContent}
              replySubmitting={replySubmitting}
              deletingId={deletingId}
              onReplyClick={onReplyClick}
              onReplyCancel={onReplyCancel}
              onReplyChange={onReplyChange}
              onReplySubmit={onReplySubmit}
              onDelete={onDelete}
              formatTime={formatTime}
              depth={depth + 1}
            />
          ))}
        </div>
      )}
    </div>
  )
}