import logUtils from 'mmir-tooling/utils/log-utils';
const warn = logUtils.warn;

interface PackageJson {
    version: string;
}

function saveRequire(pkg: string): any {
    try {
        return require(pkg);
    } catch(err){
        warn('mmir-webpack: could not initialize '+pkg+', may need to install it  '+err, err);
    }
}

var readUp: &{sync(options: {cwd?: string}): {packageJson?: PackageJson, pkg?: PackageJson} };
function initPackageReader(): typeof readUp {
    if(!readUp){
        readUp = saveRequire('read-pkg-up');
    }
    return readUp;
}

var semVer: &{satisfies(version: string, requirement: string): boolean};
function initSemVer(): typeof semVer {
    if(!semVer){
        semVer = saveRequire('semver');
    }
    return semVer;
}

function getPackageVersion(packageId: string): PackageJson {
    initPackageReader();
    if(!readUp){
        warn('mmir-webpack: could not load package '+packageId+', because of missing dependencies!');
        return void(0);
    }
    const workerLoaderPkg = readUp.sync({cwd: require.resolve(packageId)});
    return workerLoaderPkg && (workerLoaderPkg.packageJson || workerLoaderPkg.pkg);
}

function checkPackageVersion(packageId: string, versionRequirement: string): boolean | undefined {
    const packageJson = getPackageVersion(packageId);
    initSemVer();
    if(!packageJson || !semVer){
        warn('mmir-webpack: could not determine version of package '+packageId+', because of missing dependencies!');
        return void(0);
    }
    try {
        return semVer.satisfies(packageJson.version, versionRequirement);
    } catch(err){
        warn('mmir-webpack: could not determine version of '+packageId+'! '+err, err);
    }
}

/**
 * HELPER for setting option-values to different option-names, depending on the package version
 *
 * @param  options the options object (INOUT parameter)
 * @param  optionNameIfTrue the option name in case `packageVersionRequirement` evaluates to `true` (if `null` and the version is matching, then the option will be omitted)
 * @param  optionNameIfFalse the option name in case `packageVersionRequirement` evaluates to `false` (if `null` and the version is not matching, then the option will be omitted)
 * @param  value the option value
 * @param  useIfNone the option-name to use, in case the version could not be determined (i.e. `true` for `optionNameIfTrue`, `false` for `optionNameIfFalse`)
 * @param  packageId the package ID, e.g. "worker-loader"
 * @param  packageVersionRequirement the requirement for the package version (according to `sem-ver.satisfy()`), e.g. ">= 3.0.0"
 * @return the options
 */
function setOptionIf(options: {[options: string]: any}, optionNameIfTrue: string | null, optionNameIfFalse: string | null, value: any, useIfNone: boolean, packageId: string, packageVersionRequirement: string): {[options: string]: any} {

    let isReqTrue: boolean = checkPackageVersion(packageId, packageVersionRequirement);
    if(typeof isReqTrue !== 'boolean'){
        isReqTrue = useIfNone;
    }
    const optionName = isReqTrue? optionNameIfTrue : optionNameIfFalse;
    if(optionName){
        options[optionName] = value;
    }
    return options;
}

export = {
    getPackageVersion: getPackageVersion,
    checkPackageVersion: checkPackageVersion,
    setOptionIf: setOptionIf
}