const ModuleFS = function() {
    const MODE_WRITE_TO_PERSISTENT = false;
    const MODE_READ_FROM_PERSISTENT = true;
    this.init = () => {
        return new Promise((resolve) => {
            FS.mkdir(config.fs.idbfsDir);
            // Then mount with IDBFS type
            FS.mount(IDBFS, {}, config.fs.idbfsDir);

            this.syncfs(MODE_READ_FROM_PERSISTENT)
                .then(() => {
                    // Then sync with true to get persistent data
                    if (!FS.analyzePath(config.fs.idbfsFontDir).exists) {
                        FS.mkdir(config.fs.idbfsFontDir);
                    }
                    if (!FS.analyzePath(config.fs.idbfsTmpDir).exists) {
                        FS.mkdir(config.fs.idbfsTmpDir);
                    }
                    resolve();
                });
        });
    };

    this.syncfs = (mode = MODE_READ_FROM_PERSISTENT) => {
        return new Promise((resolve, reject) => {
            FS.syncfs(mode, function(err) {
                if (err !== null) {
                    // Error
                    console.error(err);
                    reject(error);
                } else {
                    resolve();
                }
            });
        });
    };

    // check utils::uploadFile() for details of file
    this.save = (file) => {
        return new Promise((resolve) => {
            if (file.type.indexOf('font') >= 0 || file.hasOwnProperty('isFont') && file.isFont === true) {
                var uint8View = new Uint8Array(file.arrayBuffer);
                console.log('trying to save the font file, file, uint8View', file, uint8View);
                if (!FS.analyzePath(`${config.fs.idbfsFontDir}/${file.name}`).exists) {
                    FS.createDataFile(config.fs.idbfsFontDir, file.name, uint8View, true, true);
                }
                this.syncfs(MODE_WRITE_TO_PERSISTENT)
                    .then(() => {
                        resolve(true);
                    });
            } else if (file.type.indexOf('zip') >= 0 || file.hasOwnProperty('isZip') && file.isZip === true) {
                var uint8View = new Uint8Array(file.arrayBuffer);
                var filePath = `${config.fs.idbfsTmpDir}/${file.name}`;
                console.log(filePath);
                if (!FS.analyzePath(filePath).exists) {
                    FS.createDataFile(config.fs.idbfsTmpDir, file.name, uint8View, true, true);
                }
                this.syncfs(MODE_WRITE_TO_PERSISTENT)
                    .then(() => {
                        resolve(filePath);
                    });
            } else {
                resolve(false);
            }
        });
    };

    this.delete = (file) => {
            if (file.type.indexOf('zip') >= 0 || file.hasOwnProperty('isZip') && file.isZip === true) {
                var filePath = `${config.fs.idbfsTmpDir}/${file.name}`;
                if (!FS.analyzePath(filePath).exists) {
                    console.log(`moduleFS::delete(${filePath})`, `file does not exist`);
                } else {
                    FS.unlink(filePath);
                }
                this.syncfs(MODE_WRITE_TO_PERSISTENT)
                    .then(() => {
                        resolve(true);
                    });
            } else {
                resolve(false);
            }
    };
};

export {
    ModuleFS
};