import { useEffect, useState, useCallback, useRef } from 'react';
import { useParams, useNavigate } from 'react-router-dom';
import { useAppStore } from '@/store';
import { useChat } from '@/hooks/useChat';
import { ChatMessage } from './ChatMessage';
import { ChatInput } from './ChatInput';
import { PipelineProgress } from './PipelineProgress';
import { ScrollArea } from '@/components/ui/scroll-area';
import { Button } from '@/components/ui/button';
import { RefreshCw, Loader2, StopCircle, X } from 'lucide-react';
import { api } from '@/lib/api';
import type { Account, Message } from '@/types';

export function ChatView() {
  const { conversationId } = useParams<{ conversationId?: string }>();
  const navigate = useNavigate();
  const { setConversations, selectedAccountId, setSelectedAccountId } = useAppStore();
  const { messages, connected, thinking, toolStatus, pipeline, send, stop, createConversation } = useChat(conversationId || null);
  const [manifestPath, setManifestPath] = useState<string | null>(null);
  const [accounts, setAccounts] = useState<Account[]>([]);
  const [quote, setQuote] = useState<string | null>(null);
  const creatingRef = useRef(false);

  useEffect(() => { api.listAccounts().then(setAccounts).catch(() => {}); }, []);

  useEffect(() => {
    fetch('/api/pipeline/conversations')
      .then((r) => r.json()).then(setConversations).catch(() => {});
  }, [messages]);

  useEffect(() => {
    const toolMsgs = messages.filter((m) => m.role === 'tool');
    if (toolMsgs.length > 0) {
      try {
        const lastTool = JSON.parse(toolMsgs[toolMsgs.length - 1].content);
        if (lastTool.manifest) setManifestPath(lastTool.manifest);
      } catch {}
    }
  }, [messages]);

  useEffect(() => {
    if (selectedAccountId && conversationId && connected && messages.length === 0) {
      const account = accounts.find((a) => a.id === selectedAccountId);
      if (account) {
        send(`已选择账号「${account.name}」：${account.description || ''}。生图:${account.imageModel} 视频:${account.videoModel} 画幅:${account.defaultFormat}`);
      }
    }
  }, [selectedAccountId, conversationId, connected]);

  const handleNewConversation = useCallback(() => {
    if (creatingRef.current) return;
    creatingRef.current = true;
    createConversation('新对话', selectedAccountId || undefined);
    setTimeout(() => {
      fetch('/api/pipeline/conversations').then((r) => r.json()).then((list) => {
        setConversations(list);
        if (list.length > 0) navigate(`/chat/${list[0].id}`);
        creatingRef.current = false;
      });
    }, 500);
  }, [createConversation, selectedAccountId]);

  const handleResume = async () => {
    if (!manifestPath) return;
    await fetch('/api/pipeline/resume', {
      method: 'POST', headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ manifest: manifestPath }),
    });
  };

  const findPrecedingUser = useCallback((msgId: string): Message | null => {
    const idx = messages.findIndex((m) => m.id === msgId);
    if (idx <= 0) return null;
    for (let i = idx - 1; i >= 0; i--) {
      if (messages[i].role === 'user') return messages[i];
    }
    return null;
  }, [messages]);

  const handleRegenerate = useCallback((msgId: string) => {
    const prev = findPrecedingUser(msgId);
    if (prev) send(prev.content);
  }, [findPrecedingUser, send]);

  const handleContinue = useCallback(() => { send('请继续'); }, [send]);
  const handleQuote = useCallback((content: string) => { setQuote(content.slice(0, 200)); }, []);

  const handleSend = useCallback((content: string) => {
    if (quote) { send(`> ${quote}\n\n${content}`); setQuote(null); }
    else send(content);
  }, [send, quote]);

  const handleStop = useCallback(() => { stop(); }, [stop]);

  if (!conversationId) {
    return (
      <div className="flex-1 flex flex-col items-center justify-center gap-4">
        <div className="text-4xl mb-2">💬</div>
        <h2 className="text-lg font-semibold text-zinc-800">开始新对话</h2>
        <p className="text-sm text-zinc-500">选择左侧对话或创建新的创作会话</p>
        <div className="flex gap-2 mt-2">
          {accounts.length > 0 && (
            <select
              value={selectedAccountId || ''}
              onChange={(e) => setSelectedAccountId(e.target.value || null)}
              className="h-9 rounded-md border border-zinc-200 bg-white px-3 text-sm text-zinc-700"
            >
              <option value="">不指定账号</option>
              {accounts.map((a) => <option key={a.id} value={a.id}>{a.name}</option>)}
            </select>
          )}
          <button
            onClick={handleNewConversation}
            disabled={creatingRef.current}
            className="px-4 py-2 rounded-lg bg-indigo-600 text-white text-sm font-medium hover:bg-indigo-700 transition-colors disabled:opacity-50"
          >
            {creatingRef.current ? '创建中...' : '开始对话'}
          </button>
        </div>
      </div>
    );
  }

  return (
    <div className="flex-1 flex flex-col bg-white">
      <div className="px-4 py-2 border-b border-zinc-200 flex items-center justify-between">
        <div className="flex items-center gap-3">
          <div className="flex items-center gap-1.5">
            <div className={`w-1.5 h-1.5 rounded-full ${connected ? 'bg-green-500' : 'bg-red-400'}`} />
            <span className="text-xs text-zinc-400">{connected ? '在线' : '连接中'}</span>
          </div>
          <select
            value={selectedAccountId || ''}
            onChange={(e) => setSelectedAccountId(e.target.value || null)}
            className="h-7 rounded border border-zinc-200 bg-zinc-50 px-2 text-xs text-zinc-600"
          >
            <option value="">切换账号</option>
            {accounts.map((a) => <option key={a.id} value={a.id}>{a.name}</option>)}
          </select>
        </div>
        <div className="flex items-center gap-2">
          {manifestPath && (
            <Button size="sm" variant="outline" className="h-7 text-xs" onClick={handleResume}>
              <RefreshCw size={12} className="mr-1" />断点续跑
            </Button>
          )}
          {thinking && (
            <Button size="sm" variant="outline" className="h-7 text-xs text-red-500 border-red-200 hover:bg-red-50" onClick={handleStop}>
              <StopCircle size={12} className="mr-1" />停止
            </Button>
          )}
        </div>
      </div>

      <ScrollArea className="flex-1 px-4 py-4">
        {messages.map((msg) => (
          <ChatMessage
            key={msg.id}
            message={msg}
            onRegenerate={msg.role === 'assistant' ? handleRegenerate : undefined}
            onContinue={msg.role === 'assistant' ? handleContinue : undefined}
            onQuote={handleQuote}
          />
        ))}

        {pipeline && (
          <PipelineProgress
            phase={pipeline.phase}
            progress={pipeline.progress}
            currentItem={pipeline.currentItem}
            totalItems={pipeline.totalItems}
            status={pipeline.status}
          />
        )}

        {thinking && !pipeline && (
          <div className="flex items-center gap-2 text-zinc-400 text-sm py-2">
            <Loader2 size={14} className="animate-spin" />
            {toolStatus || '思考中...'}
          </div>
        )}
      </ScrollArea>

      {quote && (
        <div className="mx-4 px-3 py-1.5 bg-zinc-50 border border-zinc-200 rounded-lg flex items-center gap-2 text-xs text-zinc-500">
          <span className="flex-1 truncate">引用: {quote}</span>
          <button onClick={() => setQuote(null)} className="text-zinc-400 hover:text-zinc-600"><X size={12} /></button>
        </div>
      )}

      <ChatInput onSend={handleSend} disabled={thinking} />
    </div>
  );
}