const path = require( 'path' );
const getAppRoot = require( './app-root' );
const fs = require('fs');
const mkdirp = require( 'mkdirp' );
const request = require('request');
const StreamZip = require('node-stream-zip');

/**
 * Upload a plugin zip from a remote location, such as a GitHub URL or other hosted location.
 *
 * @param {string} fileUrl The URL where the zip file is located.
 * @returns {string} The path where the zip file is located.
 */
const getRemotePluginZip = async ( fileUrl ) => {
	const appPath = getAppRoot();
	const savePath = path.resolve( appPath, 'tests/e2e/plugins' );
	mkdirp.sync( savePath );

	// Pull the filename from the end of the URL
	let fileName = fileUrl.split('/').pop();
	let filePath = path.join( savePath, fileName );

	// First, download the zip file
	await downloadZip( fileUrl, filePath );

	// Check for a nested zip and update the filepath
	filePath = await checkNestedZip( filePath, savePath );

	return filePath;
};

/**
 * Get the latest release zip for a plugin from a GiHub repository.
 *
 * @param {string} owner The owner of the plugin repository.
 * @param {string} repository The repository name.
 * @param {boolean} getPrerelease Flag on whether to get a prelease or not.
 * @param {number} perPage Limit of entries returned from the latest releases list, defaults to 3.
 * @returns {Promise<string>}} Returns the URL for the release zip file.
 */
const getLatestReleaseZipUrl = async ( owner, repository, getPrerelease = false, perPage = 3 ) => {
	let requesturl;

	if ( getPrerelease ) {
		requesturl = `https://api.github.com/repos/${owner}/${repository}/releases?per_page=${perPage}`;
	} else {
		requesturl = `https://api.github.com/repos/${owner}/${repository}/releases/latest`;
	}

	const options = {
		url: requesturl,
		method: 'GET',
		json: true,
		headers: {'user-agent': 'node.js'}
	};

	// Wrap in a promise to make the request async
	return new Promise( function( resolve, reject ) {
		request.get(options, function( err, resp, body ) {
			if ( err ) {
				reject( err );
			} else {
				if ( getPrerelease ) {
					// Loop until we find the first pre-release, then return it.
					body.forEach(release => {
						if ( release.prerelease ) {
							resolve( release.assets[0].browser_download_url );
						}
					});
				} else {
					resolve( body.assets[0].browser_download_url );
				}
			}
		})
	});
}

/**
 * Check the zip file for any nested zips. If one is found, extract it.
 *
 * @param {string} zipFilePath The location of the zip file.
 * @param {string} savePath The location where to save a nested zip if found.
 * @returns {string} The path where the zip file is located.
 */
const checkNestedZip = async ( zipFilePath, savePath ) => {
	const zip = new StreamZip.async( { file: zipFilePath } );
	const entries = await zip.entries();

	for (const entry of Object.values( entries )) {
		if ( entry.name.match( /.zip/ )) {
			await zip.extract( null, savePath );
			await zip.close();
			return path.join( savePath, entry.name );
		}
	}

	return zipFilePath;
}

/**
 * Download the zip file from a remote location.
 *
 * @param {string} fileUrl The URL where the zip file is located.
 * @param {string} downloadPath The location where to download the zip to.
 * @returns {Promise<void>}
 */
const downloadZip = async ( fileUrl, downloadPath ) => {
	const options = {
		url: fileUrl,
		method: 'GET',
		encoding: null,
	};

	// Wrap in a promise to make the request async
	return new Promise( function( resolve, reject ) {
		request.get(options, function( err, resp, body ) {
			if ( err ) {
				reject( err );
			} else {
				resolve( body );
			}
		})
	  .pipe( fs.createWriteStream( downloadPath ) );
	});
};

module.exports = {
	getRemotePluginZip,
	getLatestReleaseZipUrl,
	checkNestedZip,
	downloadZip,
};