import { useState, useCallback } from 'react';
import { cn } from '@/lib/utils';
import { renderMarkdown } from '@/lib/markdown';
import { Bot, User, Copy, Trash2, ChevronDown, ChevronRight, RefreshCw, ArrowRight, Quote, Check, Brain } from 'lucide-react';
import type { Message } from '@/types';

type MessageState = 'streaming' | 'thinking' | 'done';

interface Props {
  message: Message;
  isLast?: boolean;
  isThinking?: boolean;
  onRegenerate?: (msgId: string) => void;
  onContinue?: () => void;
  onQuote?: (content: string) => void;
  onDelete?: (msgId: string) => void;
}

function getState(msg: Message, isLast: boolean, isThinking: boolean): MessageState {
  if (msg.role === 'user') return 'done';
  if (isThinking && isLast) return 'thinking';
  if (!msg.content && !msg.reasoningContent) return 'streaming';
  return 'done';
}

export function ChatMessage({ message, isLast, isThinking, onRegenerate, onContinue, onQuote, onDelete }: Props) {
  const isUser = message.role === 'user';
  const isTool = message.role === 'tool';
  const [copied, setCopied] = useState(false);
  const [reasoningOpen, setReasoningOpen] = useState(false);
  const state = getState(message, !!isLast, !!isThinking);

  const handleCopy = useCallback(() => {
    navigator.clipboard.writeText(message.content).then(() => {
      setCopied(true);
      setTimeout(() => setCopied(false), 2000);
    });
  }, [message.content]);

  // Tool messages
  if (isTool) {
    let toolName = '';
    try { const p = JSON.parse(message.content); toolName = p.tool || ''; } catch {}
    return (
      <div className="flex items-center gap-2 py-1 px-3">
        <Bot size={13} className="text-zinc-400" />
        <span className="text-xs text-zinc-400">工具调用: {toolName}</span>
      </div>
    );
  }

  const showActions = state === 'done' && !isUser && message.content;

  return (
    <div className={cn('flex gap-3 mb-5 group/msg', isUser ? 'flex-row-reverse' : 'flex-row')}>
      {/* Avatar */}
      <div className={cn(
        'w-7 h-7 rounded-full flex items-center justify-center flex-shrink-0 text-xs',
        isUser ? 'bg-indigo-600 text-white' : 'bg-zinc-100 text-zinc-500'
      )}>
        {isUser ? <User size={13} /> : <Bot size={13} />}
      </div>

      {/* Body */}
      <div className={cn('flex-1 max-w-[78%]', isUser && 'flex flex-col items-end')}>
        {/* Thinking indicator */}
        {state === 'thinking' && !message.content && !message.reasoningContent && (
          <div className="rounded-2xl px-3.5 py-2.5 bg-zinc-50 border border-zinc-100 rounded-tl-md">
            <div className="flex items-center gap-2 text-zinc-400 text-sm">
              <Brain size={14} className="animate-pulse" />
              <span>深度思考中...</span>
            </div>
          </div>
        )}

        {/* Reasoning block (collapsible) */}
        {message.reasoningContent && (
          <div className="mb-1.5 w-full">
            <button
              onClick={() => setReasoningOpen(!reasoningOpen)}
              className="flex items-center gap-1.5 text-xs text-zinc-400 hover:text-zinc-600 transition-colors py-1"
            >
              {state === 'streaming' || state === 'thinking' ? (
                <Brain size={12} className="animate-pulse text-indigo-400" />
              ) : (
                <Brain size={12} />
              )}
              <span>{state === 'done' ? '深度思考' : '思考中...'}</span>
              {state === 'done' && (
                reasoningOpen ? <ChevronDown size={12} /> : <ChevronRight size={12} />
              )}
            </button>
            {(reasoningOpen || state !== 'done') && (
              <div className="mt-1 px-3 py-2 rounded-lg bg-indigo-50/50 border border-indigo-100 text-xs text-zinc-500 leading-relaxed max-h-60 overflow-y-auto whitespace-pre-wrap">
                {message.reasoningContent}
              </div>
            )}
          </div>
        )}

        {/* Main content bubble */}
        {!(message.content === '(调用工具)' && state === 'done' && message.reasoningContent) && (
          <div className={cn(
            'rounded-2xl px-3.5 py-2.5 text-sm leading-relaxed',
            isUser
              ? 'bg-indigo-600 text-white rounded-tr-md'
              : 'bg-zinc-50 text-zinc-700 border border-zinc-100 rounded-tl-md'
          )}>
            {state === 'streaming' && !message.content ? (
              <div className="flex items-center gap-1 text-zinc-400">
                <span className="inline-block w-1.5 h-1.5 bg-zinc-300 rounded-full animate-pulse" />
                <span className="inline-block w-1.5 h-1.5 bg-zinc-300 rounded-full animate-pulse [animation-delay:100ms]" />
                <span className="inline-block w-1.5 h-1.5 bg-zinc-300 rounded-full animate-pulse [animation-delay:200ms]" />
              </div>
            ) : isUser ? (
              <p className="whitespace-pre-wrap">{message.content}</p>
            ) : (
              <div className="markdown-body prose prose-sm max-w-none" dangerouslySetInnerHTML={{ __html: renderMarkdown(message.content) }} />
            )}
          </div>
        )}

        {/* Actions - visible on hover or when done */}
        {showActions && (
          <div className="flex gap-0.5 mt-1 opacity-0 group-hover/msg:opacity-100 transition-opacity px-1">
            <button onClick={handleCopy}
              className="flex items-center gap-1 px-1.5 py-0.5 rounded text-[10px] text-zinc-400 hover:text-zinc-600 hover:bg-zinc-100 transition-colors">
              {copied ? <><Check size={10} />已复制</> : <><Copy size={10} />复制</>}
            </button>
            <button onClick={() => onQuote?.(message.content)}
              className="flex items-center gap-1 px-1.5 py-0.5 rounded text-[10px] text-zinc-400 hover:text-zinc-600 hover:bg-zinc-100 transition-colors">
              <Quote size={10} />引用
            </button>
            <button onClick={() => onDelete?.(message.id)}
              className="flex items-center gap-1 px-1.5 py-0.5 rounded text-[10px] text-zinc-400 hover:text-red-500 hover:bg-red-50 transition-colors">
              <Trash2 size={10} />删除
            </button>
            <button onClick={() => onRegenerate?.(message.id)}
              className="flex items-center gap-1 px-1.5 py-0.5 rounded text-[10px] text-zinc-400 hover:text-zinc-600 hover:bg-zinc-100 transition-colors">
              <RefreshCw size={10} />重新生成
            </button>
            <button onClick={() => onContinue?.()}
              className="flex items-center gap-1 px-1.5 py-0.5 rounded text-[10px] text-zinc-400 hover:text-zinc-600 hover:bg-zinc-100 transition-colors">
              <ArrowRight size={10} />继续
            </button>
          </div>
        )}
      </div>
    </div>
  );
}