import React, { useCallback, useEffect, useState } from 'react';
import { Upload, FileIcon, AlertCircle, Trash2 } from 'lucide-react';
import { Button } from '../button/button';

interface FileWithPreview extends File {
    preview?: string;
}

export interface FileUploaderProps {
    onFilesChange?: (files: File[]) => void;
    multiple?: boolean;
    supportedExtensions?: string[];
}

export const FileUploader: React.FC<FileUploaderProps> = ({
    onFilesChange,
    multiple,
    supportedExtensions,
}) => {
    const [files, setFiles] = useState<FileWithPreview[]>([]);
    const [isDragging, setIsDragging] = useState(false);
    const [error, setError] = useState<string | null>(null);

    const isFileSupported = useCallback(
        (file: File) => {
            if (!supportedExtensions) return true;
            const fileExtension = file.name.split('.').pop()?.toLowerCase();
            return fileExtension
                ? supportedExtensions.includes(`.${fileExtension}`)
                : false;
        },
        [supportedExtensions]
    );

    const handleFiles = useCallback(
        (selectedFiles: FileList) => {
            const newFiles = Array.from(selectedFiles)
                .filter((file) => {
                    if (!isFileSupported(file)) {
                        setError(
                            `File type not supported. Supported types: ${supportedExtensions?.join(', ')}`
                        );
                        return false;
                    }
                    return true;
                })
                .map((file) =>
                    Object.assign(file, { preview: URL.createObjectURL(file) })
                );

            if (newFiles.length === 0) return;

            setError(null);
            setFiles((prevFiles) => {
                if (multiple) {
                    return [...prevFiles, ...newFiles];
                } else {
                    return newFiles.slice(0, 1);
                }
            });
        },
        [multiple, supportedExtensions, isFileSupported]
    );

    const onDragOver = useCallback((e: React.DragEvent<HTMLDivElement>) => {
        e.preventDefault();
        setIsDragging(true);
    }, []);

    const onDragLeave = useCallback((e: React.DragEvent<HTMLDivElement>) => {
        e.preventDefault();
        setIsDragging(false);
    }, []);

    const onDrop = useCallback(
        (e: React.DragEvent<HTMLDivElement>) => {
            e.preventDefault();
            setIsDragging(false);
            if (e.dataTransfer.files && e.dataTransfer.files.length > 0) {
                handleFiles(e.dataTransfer.files);
            }
        },
        [handleFiles]
    );

    useEffect(() => {
        if (onFilesChange) {
            onFilesChange(files.length > 0 ? files : []);
        }
    }, [files, onFilesChange]);

    const removeFile = useCallback((fileToRemove: File) => {
        setFiles((prevFiles) =>
            prevFiles.filter((file) => file !== fileToRemove)
        );
    }, []);

    return (
        <div className="mx-auto w-full max-w-md">
            <div
                onDragOver={onDragOver}
                onDragLeave={onDragLeave}
                onDrop={onDrop}
                className={`cursor-pointer rounded-lg border-2 border-dashed p-8 text-center transition-colors ${
                    isDragging
                        ? 'border-primary bg-primary/10 dark:bg-primary/20'
                        : 'border-gray-300 hover:border-primary dark:border-gray-600 dark:hover:border-primary'
                }`}
            >
                <input
                    type="file"
                    multiple={multiple}
                    onChange={(e) =>
                        e.target.files && handleFiles(e.target.files)
                    }
                    className="hidden"
                    id="fileInput"
                    accept={supportedExtensions?.join(',')}
                />
                <label htmlFor="fileInput" className="cursor-pointer">
                    <Upload className="mx-auto size-12 text-gray-400 dark:text-gray-500" />
                    <p className="mt-2 text-sm text-gray-600 dark:text-gray-400">
                        {multiple
                            ? 'Drag and drop files here or click to select'
                            : 'Drag and drop a file here or click to select'}
                    </p>
                    {supportedExtensions ? (
                        <p className="mt-1 text-xs text-gray-500 dark:text-gray-400">
                            Supported types: {supportedExtensions.join(', ')}
                        </p>
                    ) : null}
                </label>
            </div>

            {error ? (
                <div className="mt-4 flex items-center rounded-lg bg-red-100 p-3 text-red-700 dark:bg-red-900 dark:text-red-200">
                    <AlertCircle className="mr-2 size-5" />
                    <span className="text-sm">{error}</span>
                </div>
            ) : null}

            {files.length > 0 ? (
                <ul className="mt-4 space-y-4">
                    {files.map((file) => (
                        <li
                            key={file.name}
                            className="flex items-center justify-between rounded-lg bg-gray-100 p-3 dark:bg-gray-800"
                        >
                            <div className="flex min-w-0 flex-1 items-center space-x-2">
                                <FileIcon className="size-5 text-primary" />
                                <span className="truncate text-sm font-medium text-gray-700 dark:text-gray-300">
                                    {file.name}
                                </span>
                            </div>
                            <Button
                                variant="ghost"
                                className="size-5 p-0 hover:bg-primary-foreground"
                                onClick={() => removeFile(file)}
                            >
                                <Trash2 className="size-3.5 text-red-700" />
                            </Button>
                        </li>
                    ))}
                </ul>
            ) : null}
        </div>
    );
};