const https = require( 'http' );

/**
	For convenience, this method will convert between a display-friendly version format and one used
	internally by wp-env. We lean towards using WordPress.org ZIPs which requires us to reference
	the full URL to the archive. For instance, instead of needing the action to fully define the
	URL to the nightly build we can pass "nightly" to this function and retrieve it.
	
	@param {string} wpVersion The display-friendly version. Supports ("master", "trunk", "nightly",
				  "latest", "X.X" for version lines, and "X.X.X" for specific versions)
	@return {Promise.<string>} The wp-env "core" property".
**/
module.exports = async function parseWPVersion( wpVersion ) {
    	// Start with versions we can infer immediately.
	switch ( wpVersion ) {
        	case 'master':
		case 'trunk': {
			return 'WordPress/WordPress#master';
		}

		case 'nightly': {
			return 'https://wordpress.org/nightly-builds/wordpress-latest.zip';
		}

		case 'latest': {
			return 'https://wordpress.org/latest.zip';
		}
	}

	return new Promise( ( resolve, reject ) => {
		// We're going to download the correct zip archive based on the version they're requesting.
		const parsedVersion = wpVersion.match( /([0-9]+)\.([0-9]+)(?:\.([0-9]+))?/ );
		if ( ! parsedVersion ) {
			throw new Error( `Invalid 'wp-version': ${ wpVersion } must be 'trunk', 'nightly', 'latest', 'X.X', or 'X.X.X'.` );
		}

		// When they've provided a specific version we can just provide that.
		if ( parsedVersion[ 3 ] !== undefined ) {
			let zipVersion = `${ parsedVersion[ 1 ] }.${ parsedVersion[ 2 ] }`;
			// .0 versions do not have a patch.
			if ( parsedVersion[ 3 ] !== '0' ) {
				zipVersion += `.${ parsedVersion[ 3 ] }`;
			}

			resolve( `https://wordpress.org/wordpress-${ zipVersion }.zip` );
		}

		const request = https.get(
			'http://api.wordpress.org/core/stable-check/1.0/',
			( response ) => {
				// Listen for the response data.
				let data = '';
				response.on('data', (chunk) => {
					data += chunk;
				});

				// Once we have the entire response we can process it.
				response.on('end', () => {
					// Parse the response and find the latest version of every minor release.
					const latestVersions = {};
					const rawVersions = JSON.parse( data );
					for ( const v in rawVersions ) {
						// Parse the version so we can find the latest.
						const matches = v.match( /([0-9]+)\.([0-9]+)(?:\.([0-9]+))?/ );
						const minor = `${ matches[1] }.${ matches[2] }`;
						const patch = matches[ 3 ] === undefined ? 0 : parseInt( matches[ 3 ] );

						// We will only be keeping the latest release of each minor.
						if ( latestVersions[ minor ] === undefined || patch > latestVersions[ minor ] ) {
							latestVersions[ minor ] = patch;
						}
					}

					let zipVersion = `${ parsedVersion[ 1 ] }.${ parsedVersion[ 2 ] }`;
					// .0 versions do not have a patch.
					if ( latestVersions[ zipVersion ] !== 0 ) {
						zipVersion += `.${ latestVersions[ zipVersion ]}`;
					}

					resolve( `https://wordpress.org/wordpress-${ zipVersion }.zip` );
				});
			},
		);

		request.on( 'error', ( error ) => {
			reject( error );
		} );
	} );
}