module.exports = function(grunt) {
    require('load-grunt-tasks')(grunt);

    /* AVAILABLE GRUNT TASKS:
        grunt
            - runs default tasks with dev settings
        grunt serve
            - runs watch task with all dev settings + tiny local dev server
        grunt build
            - runs default tasks with production settings
    */

    grunt.initConfig({
        pkg: grunt.file.readJSON('package.json'),

        /* Stylesheet tasks for SCSS and PostCSS */
        sass: {
            dev: {
                // grunt sass:dev
                // - Enable sourcemaps
                options: {
                    outputStyle: 'compressed',
                    sourceMap: true
                },
                files: {
                    'deploy/css/screen.css': 'source/stylesheet/screen.scss'
                }
            },
            prod: {
                // grunt sass:prod
                // - Disable sourcemaps
                options: {
                    outputStyle: 'compressed',
                    sourceMap: false
                },
                files: {
                    'deploy/css/screen.css': 'source/stylesheet/screen.scss'
                }
            }
        },

        postcss: {
            // grunt postcss:dev
            // - Enable sourcemaps
            options: {
                map: true,
                processors: [
                    require('autoprefixer')({ grid: true, browsers: 'last 4 versions' }),
                    require('cssnano')({ zindex: false })
                ]
            },
            build: {
                files: {
                    'deploy/css/screen.css': 'deploy/css/screen.css'
                }
            }
        },

        /* JS tasks for Browserify, ESLint, and concatenating vendor JS */
        browserify: {
            dev: {
                // grunt browserify:dev
                // - Run Browserify with debug set to true
                files: {
                    'deploy/js/main.js': 'source/javascript/**/*.js'
                },
                options: {
                    transform: [['vueify'], ['babelify', { presets: ['env', 'minify'] }]],
                    browserifyOptions: {
                        debug: true
                    }
                }
            },
            prod: {
                // grunt browserify:prod
                // - Run Browserify with debug set to false
                files: {
                    'deploy/js/main.js': 'source/javascript/**/*.js'
                },
                options: {
                    transform: [['vueify'], ['babelify', { presets: ['env', 'minify'] }]],
                    browserifyOptions: {
                        debug: false
                    }
                }
            }
        },

        concat: {
            options: {
                separator: ';'
            },
            dist: {
                src: ['node_modules/list.js/dist/list.min.js', 'deploy/js/main.js'],
                dest: 'deploy/js/main.js'
            }
        },

        eslint: {
            src: 'source/javascript/**/*.js'
        },

        /* HTML tasks for includereplace templating, and HTMLHint */
        includereplace: {
            build: {
                files: [{
                    src: 'source/html/*.html',
                    dest: 'deploy/',
                    flatten: true,
                    expand: true
                }]
            }
        },

        htmlhint: {
            options: {
                htmlhintrc: '.htmlhintrc'
            },
            src: [
                'source/html/**/*.html',
                '!source/html/components/html-header.html',
                '!source/html/components/html-footer.html']
        },

        /* Assets tasks for copying static files in source folder */
        copy: {
            /* images folder */
            assets: {
                expand: true,
                cwd: 'source',
                src: 'images/**',
                dest: 'deploy/'
            },
            /* "sharing" folder (favicons, og:images, etc) */
            sharing: {
                expand: true,
                cwd: 'source',
                src: 'sharing/**',
                dest: 'deploy/'
            },
            /* font folder */
            fonts: {
                expand: true,
                cwd: 'source',
                src: 'font/**/*',
                dest: 'deploy/'
            }
        },

        /* Local dev server task */
        connect: {
            server: {
                options: {
                    base: 'deploy/',
                    port: 8080,
                    livereload: true
                }
            }
        },

        /* Watch tasks, runs everything except dev server */
        watch: {
            stylesheet: {
                files: ['source/stylesheet/**/*.scss'],
                tasks: ['sass:dev', 'postcss'],
                options: {
                    livereload: true,
                    spawn: false
                    // https://git.io/vxq9v
                }
            },

            javascript: {
                files: ['source/javascript/**/*.js', 'source/javascript/components/**/*.js'],
                tasks: ['eslint', 'browserify:dev', 'concat'],
                options: {
                    livereload: true
                }
            },

            html: {
                files: ['source/html/**/*.html'],
                tasks: ['includereplace', 'htmlhint'],
                options: {
                    livereload: true
                }
            },

            files: {
                files: ['source/images/**', 'source/sharing/**', 'source/font/**'],
                tasks: ['copy']
            }
        }
    });

    const previous_force_state = grunt.option('force');

    grunt.registerTask('force', function(set) {
        /*
        'force:on'
            - Force process to not exit on errors or warnings (e.g. in watch)
        'force:off'
            - Process will do a non-zero exit on error/warn (e.g. in prod build)
        'force:restore'
            - Reset default force value

        The global 'force' opts can be chained, meaning you can do:
            [
                'force:on',     // turns on the --force flag
                'devtask',      // will run with --force in effect
                'force:off',    // turns off the --force flag
                'prodtask',     // will run without --force flag
                'force:restore' // restore previous --force state
            ]
        This would make the 'devtask' to never exit on error/warn, and force
        the 'prodtask' to do a non-zero exit (effectively stopping execution)
        - More info: https://git.io/d_nZfw
        */

        if (set === 'on') {
            grunt.option('force', true);
        }
        else if (set === 'off') {
            grunt.option('force', false);
        }
        else if (set === 'restore') {
            grunt.option('force', previous_force_state);
        }
    });

    /* Task for dev (default) */
    grunt.registerTask('default',
        // grunt || grunt default
        // - Runs all tasks with dev settings once and then exit
        [
            'force:on',
            'sass:dev',
            'postcss',
            'eslint',
            'browserify:dev',
            'concat',
            'htmlhint',
            'includereplace',
            'copy',
            'force:restore'
        ]
    );

    /* Task for production */
    grunt.registerTask('build',
        // grunt build
        // - Run all tasks with prod settings once and then exit
        [
            'force:off',
            'sass:prod',
            'postcss',
            'eslint',
            'browserify:prod',
            'concat',
            'htmlhint',
            'includereplace',
            'copy'
        ]
    );

    grunt.registerTask('serve',
        // grunt serve
        // - Run local dev server and start watch process
        [
            'force:restore',
            'force:on',
            'connect',
            'watch'
        ]
    );
};