export const COMMON_MIME_TYPES = new Map([
    ['avi', 'video/avi'],
    ['gif', 'image/gif'],
    ['ico', 'image/x-icon'],
    ['jpeg', 'image/jpeg'],
    ['jpg', 'image/jpeg'],
    ['mkv', 'video/x-matroska'],
    ['mov', 'video/quicktime'],
    ['mp4', 'video/mp4'],
    ['pdf', 'application/pdf'],
    ['png', 'image/png'],
    ['zip', 'application/zip'],
    ['doc', 'application/msword'],
    ['docx', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document']
]);


export function toFileWithPath(file: FileWithPath, path?: string): FileWithPath {
    const f = withMimeType(file);
    if (typeof f.path !== 'string') { // on electron, path is already set to the absolute path
        const {webkitRelativePath} = file as FileWithWebkitPath;
        Object.defineProperty(f, 'path', {
            value: typeof path === 'string'
                ? path
                // If <input webkitdirectory> is set,
                // the File will have a {webkitRelativePath} property
                // https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement/webkitdirectory
                : typeof webkitRelativePath === 'string' && webkitRelativePath.length > 0
                    ? webkitRelativePath
                    : file.name,
            writable: false,
            configurable: false,
            enumerable: true
        });
    }

    return f;
}

interface DOMFile extends Blob {
    readonly lastModified: number;
    readonly name: string;
}

export interface FileWithPath extends DOMFile {
    readonly path?: string;
}

interface FileWithWebkitPath extends File {
    readonly webkitRelativePath?: string;
}

function withMimeType(file: FileWithPath) {
    const {name} = file;
    const hasExtension = name && name.lastIndexOf('.') !== -1;

    if (hasExtension && !file.type) {
        const ext = name.split('.')
            .pop()!.toLowerCase();
        const type = COMMON_MIME_TYPES.get(ext);
        if (type) {
            Object.defineProperty(file, 'type', {
                value: type,
                writable: false,
                configurable: false,
                enumerable: true
            });
        }
    }

    return file;
}