import * as FileSystem from 'expo-file-system';

// 将 HEIC/HEIF 图片转为 JPEG
export const convertHeicToJpeg = async (uri: string): Promise<File> => {
    try {
        // 1. 将文件复制到缓存目录
        const cacheDir = FileSystem.cacheDirectory;
        if (!cacheDir) {
            throw new Error('Cache directory not available');
        }
        const tempUri = `${cacheDir}${Date.now()}.heic`;
        await FileSystem.copyAsync({ from: uri, to: tempUri });
        // 2. 检查文件是否存在
        const fileInfo = await FileSystem.getInfoAsync(tempUri);
        if (!fileInfo.exists) {
            throw new Error('Temporary file was not created');
        }
        // 3. 读取文件为 base64
        const base64 = await FileSystem.readAsStringAsync(tempUri, {
            encoding: FileSystem.EncodingType.Base64,
        });
        if (!base64) {
            throw new Error('Failed to read file as base64');
        }
        // 4. 创建 Blob
        const response = await fetch(`data:image/jpeg;base64,${base64}`);
        if (!response.ok) {
            throw new Error(`Fetch failed with status ${response.status}`);
        }
        const blob = await response.blob();
        if (!blob || blob.size === 0) {
            throw new Error('Failed to create blob from base64');
        }
        // 5. 创建文件名
        const originalName = uri.split('/').pop() || 'converted';
        const filename = originalName.replace(/\.(heic|heif)$/i, '.jpg');
        // 清理临时文件
        try {
            await FileSystem.deleteAsync(tempUri, { idempotent: true });
        } catch (cleanupError) {
            console.warn('Failed to clean up temporary file:', cleanupError);
        }
        return new File([blob], filename, { type: 'image/jpeg' });
    } catch (error: unknown) {
        throw new Error(`Failed to convert HEIC image: ${error instanceof Error ? error.message : 'An unknown error occurred'}`);
    }
};