var Stream = require( 'stream' );
var minimatch = require( 'minimatch' );
var Minimatch = minimatch.Minimatch;

module.exports = glob;

function glob( globs, options ) {

	options = this.makeOptions( options );
	if ( typeof globs === 'string' ) globs = [ globs ];

	var self = this;
	var positives = [];
	var negatives = [];
	globs.forEach( function ( glob ) {

		var mm = new Minimatch( self.join( '/', glob ), options );
		mm.base = mmBase( mm );

		if ( mm.negate ) negatives.push( mm );
		else positives.push( mm );

	} );

	var stream = new Stream.PassThrough( { objectMode: true } );
	var scanning = 0;

	// get file list and write to stream on match.
	// recursively scan on partial match.
	function scan( path, mm ) {

		++scanning;
		self.mlsdOrList( path, onList );

		function onList( err, files ) {

			if ( err ) return stream.emit( 'error', err );

			files.forEach( function ( file ) {

				if ( self.isDirectory( file ) && mm.match( file.path, true ) ) {

					scan( file.path, mm );

				}

				write( file ); // do this after scan; next stream might change file.path

			} );

			--scanning;

			if ( scanning === 0 ) stream.emit( 'end' );

		}

	}

	// write file on match. check it only once.
	var seen = {};

	function write( file ) {

		if ( !seen[ file.path ] ) {

			seen[ file.path ] = true;
			if ( match( file ) ) stream.write( file );

		}

	}

	function match( file ) {

		var ok = false;
		var base;
		var i, l;

		for ( i = 0, l = positives.length; i < l; ++i ) {

			if ( positives[ i ].match( file.path ) ) {

				ok = true;
				base = options.base || positives[ i ].base;
				break;

			}

		}

		if ( !ok ) return false;

		for ( i = 0, l = negatives.length; i < l; ++i ) {

			if ( !negatives[ i ].match( file.path ) ) return false;

		}

		file.cwd = options.cwd || '/';
		file.base = base;
		return true;

	}

	// scan each positive glob
	positives.forEach( function ( mm ) {

		mm.set.forEach( function ( parts ) {

			scan( partsBase( parts ), mm );

		} );

	} );

	return stream;

}

//

// get base path of minimatch instance
function mmBase( mm ) {

	var first =  mm.set[ 0 ];
	var i, l;

	PARTS: for ( i = 0, l = first.length - 1; i < l; ++i ) {

		if ( typeof first[ i ] !== 'string' ) break PARTS;

		for ( var j = 1, k = mm.set.length; j < k; ++j ) {

			if ( mm.set[ j ][ i ] !== first[ i ] ) break PARTS;

		}

	}

	return first.slice( 0, i ).join( '/' );

}

// get base path of minimatch parts
function partsBase( parts ) {

	for ( var i = 0, l = parts.length - 1; i < l; ++i ) {

		if ( typeof parts[ i ] !== 'string' ) break;

	}

	return parts.slice( 0, i ).join( '/' );

}