/*
	CSS tasks.
		*)  The includes, variables and mixins are concatenated into the "input" dir.
		**) For a custom build, the includes and variables are copied from the specified "custom input" dir (--i flag), into the "input" dir.
*/

const { src, dest, watch, series, parallel } = require('gulp');

const sass = require('gulp-sass');
const autoprefixer = require('gulp-autoprefixer');
const cleancss = require('gulp-clean-css');
const concat = require('gulp-concat');

const dirs = require('./dirs');
var dir = {};

/** Run all scripts. */
exports.all = CSSall = cb => {
    dir = dirs(false);

    series(
        parallel(CSSconcatMixins, CSSconcatIncludes, CSSconcatVariables),
        CSScompile
    )(cb);
};

exports.custom = CSScustom = cb => {
    dir = dirs(true);

    const CSScompileCustom = cb => CSScompile(cb, dir.build + '/mmenu.scss');

    series(parallel(CSScopyIncludes, CSScopyVariables), CSScompileCustom)(cb);
};

/** Put a watch on all files. */
exports.watch = CSSwatch = cb => {
    dir = dirs(false);

    watch([
        dir.input + '/**/*.scss',
        '!' + dir.input + '/_includes.scss',
        '!' + dir.input + '/_variables.scss',
        '!' + dir.input + '/_mixins.scss'
    ]).on('change', path => {
        console.log('Change detected to .scss file "' + path + '"');
        var cb = () => {
            console.log('CSS compiled and concatenated.');
        };

        switch (true) {
            //	Changing an include, a variable or a mixin potentially affects all .scss files:
            //		- run all CSS tasks.
            case path.indexOf('_includes.scss') > -1:
            case path.indexOf('_variables.scss') > -1:
            case path.indexOf('_mixins.scss') > -1:
                CSSall(cb);
                break;

            //	Changing any other file should only affect the files in the same directory:
            //		- compile only the directory to css;
            //		- concatenate all.
            default:
                var files = path.split('/');
                files.pop();
                files.shift();
                files = files.join('/');

                var CSScompileOne = cb =>
                    CSScompile(
                        cb,
                        dir.input + '/' + files + '/*.scss',
                        dir.output + '/' + files
                    );

                series(CSScompileOne, CSScompile)(cb);
                break;
        }
    });

    cb();
};

// *) Concatenate includes into a single file.
const CSSconcatIncludes = cb => {
    var files = [
        dir.input + '/core/oncanvas/_includes.scss', // Include oncanvas includes first.
        dir.input + '/core/**/_includes.scss', // Include core add-ons includes next.
        dir.input + '/**/_includes.scss', // Include the rest of the includes.
        '!' + dir.input + '/_includes.scss' // Exclude the includes destination file.
    ];

    return src(files)
        .pipe(concat('_includes.scss'))
        .pipe(dest(dir.input));
};

// *) Concatenate variables into a single file.
const CSSconcatVariables = cb => {
    var files = [
        dir.input + '/core/oncanvas/_variables.scss', // Include oncanvas variables first.
        dir.input + '/core/**/_variables.scss', // Include core add-ons variables next.
        dir.input + '/**/_variables.scss', // Include the rest of the variables.
        '!' + dir.input + '/_variables.scss' // Exclude the variables destination file.
    ];

    return src(files)
        .pipe(concat('_variables.scss'))
        .pipe(dest(dir.input));
};

// Concatenate mixins into a single file.
const CSSconcatMixins = cb => {
    var files = [
        dir.input + '/core/oncanvas/_mixins.scss', // Include oncanvas mixins first.
        dir.input + '/core/**/_mixins.scss', // Include core add-ons mixins next.
        dir.input + '/**/_mixins.scss', // Include the rest of the mixins.
        '!' + dir.input + '/_mixins.scss' // Exclude the mixins destination file.
    ];

    return src(files)
        .pipe(concat('_mixins.scss'))
        .pipe(dest(dir.input));
};

// **) Copy includes from custom input into input.
const CSScopyIncludes = cb => {
    return src(dir.build + '/**/_includes.scss').pipe(dest(dir.input));
};

// **) Copy variables from custom input into input.
const CSScopyVariables = cb => {
    return src(dir.build + '/**/_variables.scss').pipe(dest(dir.input));
};

// Compile all (or some) SCSS files to CSS.
const CSScompile = (cb, input, output) => {
    return src(input || dir.input + '/**/*.scss')
        .pipe(sass().on('error', sass.logError))
        .pipe(autoprefixer(['> 5%', 'last 5 versions']))
        .pipe(cleancss())
        .pipe(dest(output || dir.output));
};