import React, { useRef, useState, useEffect } from 'react';
import { useDispatch } from 'react-redux';
import { uploadDocument, getKnowledgeBaseDocuments } from '../../../../store/knowledgeBase/knowledgeBase.thunks';

/**
 * 文件上传模态框组件
 */
const FileUploadModal = ({ show, knowledgeBaseId, onClose }) => {
    const dispatch = useDispatch();
    const fileInputRef = useRef(null);
    const modalRef = useRef(null);
    const [selectedFile, setSelectedFile] = useState(null);
    const [isUploading, setIsUploading] = useState(false);
    const [fileError, setFileError] = useState('');

    // 处理上传区域点击事件
    const handleUploadAreaClick = () => {
        fileInputRef.current?.click();
    };

    // 处理拖拽事件
    const handleDragOver = (e) => {
        e.preventDefault();
        e.stopPropagation();
    };

    const handleDrop = (e) => {
        e.preventDefault();
        e.stopPropagation();

        if (e.dataTransfer.files && e.dataTransfer.files.length > 0) {
            handleFileSelected(e.dataTransfer.files[0]);
        }
    };

    const handleFileChange = (e) => {
        if (e.target.files && e.target.files.length > 0) {
            handleFileSelected(e.target.files[0]);
        }
    };

    const handleFileSelected = (file) => {
        setFileError('');
        setSelectedFile(file);
    };

    const resetFileInput = () => {
        setSelectedFile(null);
        setFileError('');
        if (fileInputRef.current) {
            fileInputRef.current.value = '';
        }
    };

    const handleUpload = async () => {
        if (!selectedFile) {
            setFileError('请选择要上传的文件');
            return;
        }

        setIsUploading(true);

        try {
            await dispatch(
                uploadDocument({
                    knowledge_base_id: knowledgeBaseId,
                    file: selectedFile,
                })
            ).unwrap();

            // 成功上传后刷新文档列表
            dispatch(getKnowledgeBaseDocuments({ knowledge_base_id: knowledgeBaseId }));

            // Reset the file input
            resetFileInput();

            // 上传成功后关闭模态框
            onClose();
        } catch (error) {
            console.error('Upload failed:', error);
            setFileError('文件上传失败: ' + (error?.message || '未知错误'));

            // 清空选中的文件
            resetFileInput();
        } finally {
            setIsUploading(false);
        }
    };

    const handleClose = () => {
        // 只有在非上传状态才允许关闭
        if (!isUploading) {
            resetFileInput();
            onClose();
        }
    };

    // 清理函数
    useEffect(() => {
        return () => {
            // 确保在组件卸载时清理所有引用
            if (fileInputRef.current) {
                fileInputRef.current.value = '';
            }
            if (modalRef.current) {
                modalRef.current = null;
            }
        };
    }, []);

    if (!show) return null;

    return (
        <div
            ref={modalRef}
            className='modal-backdrop'
            style={{
                position: 'fixed',
                top: 0,
                left: 0,
                right: 0,
                bottom: 0,
                backgroundColor: 'rgba(0, 0, 0, 0.5)',
                display: 'flex',
                alignItems: 'center',
                justifyContent: 'center',
                zIndex: 1050,
            }}
        >
            <div
                className='modal-content bg-white rounded shadow'
                style={{
                    width: '500px',
                    maxWidth: '90%',
                    padding: '20px',
                }}
            >
                <div className='modal-header d-flex justify-content-between align-items-center mb-3'>
                    <h5 className='modal-title m-0'>上传文档</h5>
                    <button
                        type='button'
                        className='btn-close'
                        onClick={handleClose}
                        disabled={isUploading}
                        aria-label='Close'
                    ></button>
                </div>
                <div className='modal-body'>
                    <div
                        className={`mb-3 p-4 border rounded text-center ${
                            fileError ? 'border-danger' : 'border-dashed'
                        }`}
                        style={{ cursor: isUploading ? 'not-allowed' : 'pointer' }}
                        onClick={!isUploading ? handleUploadAreaClick : undefined}
                        onDrop={!isUploading ? handleDrop : undefined}
                        onDragOver={handleDragOver}
                    >
                        <input
                            type='file'
                            ref={fileInputRef}
                            className='d-none'
                            onChange={handleFileChange}
                            accept='.pdf,.doc,.docx,.txt,.md,.csv,.xlsx,.xls'
                            disabled={isUploading}
                        />
                        {selectedFile ? (
                            <div>
                                <p className='mb-1'>已选择文件：</p>
                                <p className='fw-bold mb-0'>{selectedFile.name}</p>
                            </div>
                        ) : (
                            <div>
                                <p className='mb-1'>点击或拖拽文件到此处上传</p>
                                <p className='text-muted small mb-0'>
                                    支持 PDF, Word, Excel, TXT, Markdown, CSV 等格式
                                </p>
                            </div>
                        )}
                        {fileError && <div className='text-danger mt-2'>{fileError}</div>}
                    </div>
                </div>
                <div className='modal-footer gap-2'>
                    <button type='button' className='btn btn-secondary' onClick={handleClose} disabled={isUploading}>
                        关闭
                    </button>
                    <button
                        type='button'
                        className='btn btn-dark'
                        onClick={handleUpload}
                        disabled={!selectedFile || isUploading}
                    >
                        {isUploading ? (
                            <>
                                <span
                                    className='spinner-border spinner-border-sm me-2'
                                    role='status'
                                    aria-hidden='true'
                                ></span>
                                上传中...
                            </>
                        ) : (
                            '上传文档'
                        )}
                    </button>
                </div>
            </div>
        </div>
    );
};

export default FileUploadModal;