import { readFileSync } from 'graceful-fs';
import { join, normalize, resolve } from 'path';

import { wchDeliveryUrlFromApiUrl } from './wchtools';

function _readPackageConfig(aPackageDir: string): any {
    // read the config
    const filename = join(aPackageDir, 'package.json');
    // read
    try {
        return JSON.parse(readFileSync(filename, 'utf-8')).config || {};
    } catch (e) {
        return {};
    }
}

function _getDataDir(aPackageDir: string, aConfig: any): string | undefined {
    // check if we have a configured application name
    return (aConfig && aConfig.data) ? normalize(join(aPackageDir, aConfig.data)) : undefined;
}

function _getDefaultDataDir(aPackageDir: string): string | undefined {
    // check if we have a configured application name
    return normalize(join(aPackageDir, 'data'));
}

/**
 * Returns the directory of the application, typcially './src'
 *
 * @param aPackageDir   package directory
 * @param aConfig       config directory
 */
function _getAppDir(aPackageDir: string, aConfig: any): string | undefined {
    // check if we have a configured application name
    return (aConfig && aConfig.src) ? normalize(join(aPackageDir, aConfig.src)) : normalize(join(aPackageDir, 'src'));
}

/**
 * Returns the directory of the application, typcially './src'
 *
 * @param aPackageDir   package directory
 * @param aConfig       config directory
 */
function _getDefaultAppDir(aPackageDir: string): string {
    return normalize(join(aPackageDir, 'src'));
}

function _getAppName(aPackageDir: string, aConfig: any): string | undefined {
    // check if we have a configured application name
    return (aConfig && aConfig.name) ? aConfig.name : undefined;
}

function _getContextRoot(aPackageDir: string, aConfig: any): string | undefined {
    // check if we have a configured application name
    return (aConfig && aConfig.root) ? aConfig.root : undefined;
}

// trim slashes at the beginning and the end
const TRIM_REGEXP = /^[\/]+|[\/]+$/g;

/**
 * Trims leading and trailing slashes
 *
 * @param aAppName  the app name
 * @return the trimmed slashes
 */
function _trimSlashes(aAppName?: string): string {
    return aAppName ? aAppName.replace(TRIM_REGEXP, '') : '';
}

function _createUrl(aAppName: string, aApiBaseUrl: string): string {
    // build
    const deliveryUrl = wchDeliveryUrlFromApiUrl(aApiBaseUrl);
    const trimmedName = _trimSlashes(aAppName);
    // build the base URL
    return trimmedName ? `${deliveryUrl}${encodeURIComponent(trimmedName)}/` : deliveryUrl;
}

function _getIndexDirFromContextRoot(aContextRoot: string, aDataDir: string): string {
    // split the root into path elements
    return resolve(normalize(join(aDataDir, 'assets', ...aContextRoot.split('/').map(decodeURIComponent))));
}

export {
    _readPackageConfig as configReadPackageConfig,
    _getDataDir as configGetDataDir,
    _getAppDir as configGetAppDir,
    _getDefaultDataDir as configGetDefaultDataDir,
    _getDefaultAppDir as configGetDefaultAppDir,
    _getAppName as configGetAppName,
    _getContextRoot as configGetContextRoot,
    _createUrl as configGetBaseUrl,
    _trimSlashes as configTrimSlashes,
    _getIndexDirFromContextRoot as configIndexDirFromContextRoot
};