"use client"

import { ArrowLeft, ImagePlus, Lock, Send } from "lucide-react"
import Image from "next/image"
import Link from "next/link"
import { use, useMemo, useRef, useState } from "react"
import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar"
import { Badge } from "@/components/ui/badge"
import { Button } from "@/components/ui/button"
import { Card } from "@/components/ui/card"
import { Input } from "@/components/ui/input"
import { ScrollArea } from "@/components/ui/scroll-area"
import { sendImageMessage, sendTextMessage } from "@/lib/api/chat"
import { cn } from "@/lib/utils"
import { notifyInfo } from "@/lib/toast"
import { useAuthStore } from "@/store/auth"
import { useChatStore } from "@/store/chat"

export default function ChatDetailPage({ params }: { params: Promise<{ id: string }> }) {
  const { id } = use(params)
  const session = useChatStore((state) => state.sessions.find((item) => item.id === id))
  const allMessages = useChatStore((state) => state.messages)
  // Filter logic runs here via useMemo rather than inside the Zustand selector.
  // useSyncExternalStore requires a stable snapshot reference on each render.
  // Inline filter in a selector creates a new array per call and can trigger
  // infinite re-render loops in Zustand v5 (pmndrs/zustand#1936).
  const messages = useMemo(
    () => allMessages.filter((item) => item.sessionId === id),
    [allMessages, id],
  )
  const [input, setInput] = useState("")
  const imageInputRef = useRef<HTMLInputElement>(null)
  const { user } = useAuthStore()

  if (!session) {
    return (
      <div className="container mx-auto py-8 px-4 text-center text-muted-foreground">
        会话不存在
      </div>
    )
  }

  if (!user?.id) {
    return (
      <div className="container mx-auto py-8 px-4 text-center text-muted-foreground">
        请先登录后查看会话
      </div>
    )
  }

  const userId = user.id
  const isParticipant = session.participants.some((participant) => participant.id === userId)
  if (!isParticipant) {
    return (
      <div className="container mx-auto py-8 px-4 text-center text-muted-foreground">
        仅会话参与方可查看并发送消息
      </div>
    )
  }

  const other = session.participants.find((p) => p.id !== userId) ?? session.participants[0]

  return (
    <div className="container mx-auto max-w-3xl px-4 py-8 h-[calc(100vh-3.5rem)] flex flex-col">
      <Card className="flex-1 flex flex-col overflow-hidden hover:shadow-[var(--shadow-card)]">
        <div className="border-b px-4 py-3 flex items-center gap-3 bg-muted/30">
          <Link href="/chat" className="text-muted-foreground hover:text-foreground">
            <ArrowLeft className="h-5 w-5" />
          </Link>
          <Avatar className="h-8 w-8">
            <AvatarImage src={other.avatar} />
            <AvatarFallback>{other.name[0]}</AvatarFallback>
          </Avatar>
          <div>
            <span className="text-sm font-medium">{other.name}</span>
            <div className="flex items-center gap-1">
              <Badge variant="outline" className="text-[10px] px-1.5 py-0">
                {session.type === "order" ? "订单会话" : "咨询会话"}
              </Badge>
              {session.readonly && (
                <span className="text-[10px] text-muted-foreground flex items-center gap-0.5">
                  <Lock className="h-3 w-3" />
                  只读
                </span>
              )}
            </div>
          </div>
        </div>

        <ScrollArea className="flex-1 p-4">
          <div className="space-y-4">
            {messages.map((msg) => {
              if (msg.type === "system") {
                return (
                  <div key={msg.id} className="text-center">
                    <span className="text-xs text-muted-foreground bg-muted px-2 py-1 rounded">
                      {msg.content}
                    </span>
                  </div>
                )
              }
              const isMine = msg.senderId === userId
              return (
                <div key={msg.id} className={cn("flex gap-2", isMine && "flex-row-reverse")}>
                  <Avatar className="h-8 w-8 shrink-0">
                    <AvatarImage src={msg.senderAvatar} />
                    <AvatarFallback>{msg.senderName[0]}</AvatarFallback>
                  </Avatar>
                  <div className={cn("max-w-[70%]", isMine && "text-right")}>
                    {msg.type === "image" ? (
                      <Image
                        src={msg.content}
                        alt="聊天图片"
                        width={256}
                        height={192}
                        unoptimized
                        className="inline-block rounded-lg max-h-48 max-w-64 border"
                      />
                    ) : (
                      <p
                        className={cn(
                          "inline-block rounded-lg px-3 py-2 text-sm",
                          isMine ? "bg-primary text-primary-foreground" : "bg-muted",
                        )}
                      >
                        {msg.content}
                      </p>
                    )}
                    <p className="text-[10px] text-muted-foreground mt-1">
                      {new Date(msg.createdAt).toLocaleTimeString("zh-CN", {
                        hour: "2-digit",
                        minute: "2-digit",
                      })}
                    </p>
                  </div>
                </div>
              )
            })}
          </div>
        </ScrollArea>

        {!session.readonly ? (
          <div className="border-t p-4 bg-muted/30">
            <input
              ref={imageInputRef}
              type="file"
              accept="image/*"
              className="hidden"
              onChange={(event) => {
                const file = event.target.files?.[0]
                if (!file) return
                const result = sendImageMessage(session.id, URL.createObjectURL(file))
                if (result && !result.ok) notifyInfo(result.message ?? "发送失败")
                event.target.value = ""
              }}
            />
            <form
              className="flex gap-2"
              onSubmit={(e) => {
                e.preventDefault()
                const text = input.trim()
                if (!text) return

                const result = sendTextMessage(session.id, text)
                if (result && !result.ok) {
                  notifyInfo(result.message ?? "发送失败")
                  return
                }
                setInput("")
              }}
            >
              <Input
                value={input}
                onChange={(e) => setInput(e.target.value)}
                placeholder="输入消息..."
                className="flex-1"
              />
              <Button
                type="button"
                size="icon"
                variant="outline"
                onClick={() => imageInputRef.current?.click()}
              >
                <ImagePlus className="h-4 w-4" />
              </Button>
              <Button type="submit" size="icon" disabled={!input.trim()}>
                <Send className="h-4 w-4" />
              </Button>
            </form>
          </div>
        ) : (
          <div className="border-t p-4 text-center text-sm text-muted-foreground bg-muted/30">
            <Lock className="h-4 w-4 inline mr-1" />
            订单已关闭，会话为只读状态
          </div>
        )}
      </Card>
    </div>
  )
}