var which = require('which');
var cache = require('gulp-cached');

// Gulp sketch-favicon task
// `gulp sketch-favicon` - Exports favicon sketch files to PNG files
module.exports = function ($, gulp, manifest) {
    return function () {

        var functions   = require('../functions/functions');
        var path        = manifest.paths;
        var globs       = manifest.globs;

        // This task needs sketchtool
        // Please download and install
        // http://bohemiancoding.com/sketch/tool/
        // For installation manual
        // https://news.layervault.com/stories/21828-sketchtool--a-commandline-app-for-exporting-pages-and-slices-out-of-sketch-docs
        try {
            which.sync('sketchtool');
        } catch(error){
            $.util.log("Sketchtool not found. Please install sketchtool. See http://bohemiancoding.com/sketch/tool/"); return;
        }

        // Import sketch files stream
        // @TODO sketch saves the file twice for some reason. See http://stackoverflow.com/questions/21608480/gulp-js-watch-task-runs-twice-when-saving-files
        gulp.src(path.source + 'sketch/assets.sketch')

            // Only run for changed files
            .pipe( cache('sketch') )

            // Export Sketch artboards to SVG/PNG files
            .pipe( $.sketch({
                export: 'artboards',
                formats: 'svg',
                saveForWeb: true,
                scales: 1.0,
                trimmed: true
            }))

            // Optimize exported images and SVG files
            .pipe($.imagemin({
                progressive: true,
                interlaced: true,
                svgoPlugins: [{removeUnknownsAndDefaults: false}]
            }))

            .pipe(gulp.dest(path.source + 'images'));

    };
};