'use client';

import { useState, useRef } from 'react';
import { Plus, ArrowUp, Upload } from 'lucide-react';
import { ModelSelector } from './ModelSelector';
import { ToolsDropdown } from './ToolsDropdown';
import { FilePreviewList } from './FilePreviewList';
import { useFileUpload } from '@/hooks/useFileUpload';
import { cn } from '@/lib/utils';
import type { Model, Tool } from '@/types';
import type { UploadFile } from '@/types/file-upload';

interface ChatInputProps {
  models: Model[];
  selectedModel: Model;
  onModelSelect: (model: Model) => void;
  tools: Tool[];
  onToolToggle: (toolId: string) => void;
  onEnableAllTools: (enabled: boolean) => void;
  onSend: (message: string, files?: UploadFile[]) => void;
  placeholder?: string;
  className?: string;
}

export function ChatInput({
  models,
  selectedModel,
  onModelSelect,
  tools,
  onToolToggle,
  onEnableAllTools,
  onSend,
  placeholder = 'How can I help you today?',
  className,
}: ChatInputProps) {
  const [message, setMessage] = useState('');
  const fileInputRef = useRef<HTMLInputElement>(null);

  // 使用文件上传 Hook
  const {
    files,
    isDragging,
    addFiles,
    removeFile,
    clearFiles,
    handleDragEnter,
    handleDragLeave,
    handleDragOver,
    handleDrop,
    handlePaste,
  } = useFileUpload();

  const handleSend = () => {
    if (message.trim() || files.length > 0) {
      onSend(message, files.length > 0 ? files : undefined);
      setMessage('');
      clearFiles();
    }
  };

  const handleKeyDown = (e: React.KeyboardEvent) => {
    // 检查是否正在使用输入法组合（如中文输入法选词时按回车）
    // isComposing 为 true 时，表示用户正在用输入法选词，此时不应发送消息
    if (e.key === 'Enter' && !e.shiftKey && !e.nativeEvent.isComposing) {
      e.preventDefault();
      handleSend();
    }
  };

  // 处理文件选择
  const handleFileSelect = (e: React.ChangeEvent<HTMLInputElement>) => {
    const selectedFiles = e.target.files;
    if (selectedFiles && selectedFiles.length > 0) {
      addFiles(selectedFiles);
    }
    // 重置 input 以允许重复选择同一文件
    if (fileInputRef.current) {
      fileInputRef.current.value = '';
    }
  };

  // 打开文件选择对话框
  const openFileDialog = () => {
    fileInputRef.current?.click();
  };

  return (
    <div className={cn('w-full max-w-[var(--input-max-width)] mx-auto', className)}>
      <div
        className={cn(
          'relative flex flex-col bg-[var(--color-bg-primary)] border border-[var(--color-border)] rounded-md p-4 shadow-[var(--shadow-input)]',
          'transition-all duration-150',
          'focus-within:border-[var(--color-border-focus)] focus-within:shadow-[var(--shadow-input-focus)]',
          isDragging && 'border-[var(--color-primary)] border-2 bg-[var(--color-primary)]/5'
        )}
        onDragEnter={handleDragEnter}
        onDragLeave={handleDragLeave}
        onDragOver={handleDragOver}
        onDrop={handleDrop}
      >
        {/* 拖拽覆盖层 */}
        {isDragging && (
          <div className="absolute inset-0 z-10 flex flex-col items-center justify-center bg-[var(--color-bg-primary)]/90 rounded-md border-2 border-dashed border-[var(--color-primary)]">
            <Upload className="w-8 h-8 text-[var(--color-primary)] mb-2" />
            <p className="text-sm font-medium text-[var(--color-primary)]">
              释放以添加文件
            </p>
            <p className="text-xs text-[var(--color-text-tertiary)] mt-1">
              支持图片、PDF、文档等格式
            </p>
          </div>
        )}

        {/* 文件预览区域 */}
        {files.length > 0 && (
          <div className="mb-3">
            <FilePreviewList files={files} onRemove={removeFile} />
          </div>
        )}

        {/* 第一行：输入区域 */}
        <div className="w-full mb-3">
          <input
            type="text"
            value={message}
            onChange={(e) => setMessage(e.target.value)}
            onKeyDown={handleKeyDown}
            onPaste={handlePaste}
            placeholder={files.length > 0 ? '添加描述（可选）...' : placeholder}
            className="w-full border-none outline-none text-[var(--color-text-primary)] bg-transparent py-2 placeholder:text-[var(--color-text-placeholder)]"
          />
        </div>

        {/* 第二行：功能按钮区域 */}
        <div className="flex items-center justify-between w-full">
          {/* 左侧按钮 */}
          <div className="flex items-center gap-1">
            {/* 添加附件 */}
            <button
              onClick={openFileDialog}
              className={cn(
                'w-8 h-8 flex items-center justify-center rounded-lg transition-colors',
                'text-[var(--color-text-tertiary)] hover:bg-[var(--color-bg-hover)] hover:text-[var(--color-text-secondary)]',
                files.length > 0 && 'text-[var(--color-primary)]'
              )}
              title="添加附件"
            >
              <Plus size={20} />
            </button>

            {/* 隐藏的文件输入 */}
            <input
              ref={fileInputRef}
              type="file"
              multiple
              accept="image/*,.pdf,.doc,.docx,.xls,.xlsx,.txt,.md,.json,.js,.ts,.jsx,.tsx,.py,.java,.c,.cpp,.go,.rs,.html,.css"
              onChange={handleFileSelect}
              className="hidden"
            />

            {/* 工具下拉 */}
            <ToolsDropdown
              tools={tools}
              onToolToggle={onToolToggle}
              onEnableAllToggle={onEnableAllTools}
            />
          </div>

          {/* 右侧按钮 */}
          <div className="flex items-center gap-3">
            {/* 模型选择器 */}
            <ModelSelector
              models={models}
              selectedModel={selectedModel}
              onSelect={onModelSelect}
            />

            {/* 发送按钮 */}
            <button
              onClick={handleSend}
              disabled={!message.trim() && files.length === 0}
              className={cn(
                'w-[38px] h-[38px] flex items-center justify-center bg-[var(--color-primary)] text-white rounded-xl transition-all duration-150',
                message.trim() || files.length > 0
                  ? 'hover:bg-[var(--color-primary-hover)] hover:-translate-y-0.5'
                  : 'opacity-50 cursor-not-allowed'
              )}
              title="Send message"
            >
              <ArrowUp size={18} />
            </button>
          </div>
        </div>
      </div>

      {/* 提示文字 */}
      <p className="text-xs text-[var(--color-text-tertiary)] text-center mt-2">
        可拖拽文件到此处或使用 Ctrl+V 粘贴图片
      </p>
    </div>
  );
}