var istanbul = require('gulp-istanbul-custom-reports');
var COVERAGE_VARIABLE = '$$1cov_' + new Date().getTime() + '$$';
var covObj;
var istanbulCoverageSourceMap = require('istanbul-coverage-source-map');
var sourceFiles = 'lib/bundled/**/*.js'
 
gulp.src(sourceFiles)
    .pipe(istanbul({coverageVariable: COVERAGE_VARIABLE})) // Covering files - must wait for finish event before continuing
    .on('finish', function () {
        gulp.src(sourceFiles)
            ... run tests
            .on('end', function () {
            
                //get original coverage object
                covObj = JSON.stringify(global[COVERAGE_VARIABLE]);
 
                //translate coverage object
                covObj = istanbulCoverageSourceMap(covObj);
 
                //pass translated coverage object back to istanbul
                global[COVERAGE_VARIABLE] = JSON.parse(covObj);
 
                //generate report
                gulp.src(sourceFiles)
                    .pipe(istanbul.writeReports({
                        coverageVariable: COVERAGE_VARIABLE,
                        reporters: [ 'html']
                    }))
                    .on('end', done);
            });
    });