const { createReadStream, readFileSync, readFile, stat } = require( 'fs' );
const { join, extname }                                  = require( 'path' );

const mimes = JSON.parse( readFileSync( join( __dirname, 'mimes.json' ) ) );

module.exports = ( baseDir, indexFile ) => {
  if (!baseDir) throw new Error('The argument "baseDir" is required for the extension "kirbe:static"');
  
  indexFile = typeof indexFile === 'string' ? indexFile : 'index.html';
  return( req, res, next ) => {
    if( req.method !== 'GET' ) { next(); return; }

    let requestedPath = req.parsedUrl.pathname.replace( /\/.\.\//g, '' );
    let requestedExt  = extname( requestedPath );
    
    const filePath = join( baseDir, requestedPath );

    stat( filePath, ( err, stats ) => {
      if( err ) { next(); return; }

      if( stats.isFile() ) {
        stats.mtime.setMilliseconds( 0 );
				if ( stats.mtime <= new Date( req.headers[ 'if-modified-since' ] ) ) res.status( 304 ).end();
				else createReadStream( filePath ).pipe( res.status( 200 ).coreRes );
      } else {
        if ( req.parsedUrl.pathname.charAt( req.parsedUrl.pathname.length -1 ) !== '/' ) {
					res.status(302).header({ 'Location': `${req.parsedUrl.pathname}/` }).end();
					return;
        }
        
        requestedPath = join( filePath, indexFile );
				requestedExt  = extname( requestedPath );

				readFile( requestedPath, ( err, data ) => {
					if (err) next();
					else {
						res.body( data ).status(200).header({
							'Content-Type': ( mimes.hasOwnProperty( requestedExt ) ? mimes[ requestedExt ] : 'application/octet-stream' ),
							'Last-Modified': stats.mtime.toString()
						}).end();
					}
				});
      }
    });
  };
};