/*
 * Copyright (c) 2016 Martin Donath <martin.donath@squidfunk.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

/* ----------------------------------------------------------------------------
 * Imports
 * ------------------------------------------------------------------------- */

var gulp       = require('gulp');
var addsrc     = require('gulp-add-src');
var args       = require('yargs').argv;
var autoprefix = require('autoprefixer');
var changed    = require('gulp-changed');
var child      = require('child_process');
var clean      = require('del');
var compact    = require('gulp-remove-empty-lines');
var concat     = require('gulp-concat');
var ignore     = require('gulp-ignore');
var gulpif     = require('gulp-if');
var mincss     = require('gulp-cssnano');
var minhtml    = require('gulp-htmlmin');
var minsvg     = require('gulp-svgmin');
var modernizr  = require('gulp-modernizr');
var mqpacker   = require('css-mqpacker');
var notifier   = require('node-notifier');
var path       = require('path');
var plumber    = require('gulp-plumber');
var postcss    = require('gulp-postcss');
var replace    = require('gulp-replace');
var rev        = require('gulp-rev');
var sass       = require('gulp-sass');
var sasslint   = require('gulp-sass-lint');
var sourcemaps = require('gulp-sourcemaps');
var stream     = require('webpack-stream');
var uglify     = require('gulp-uglify');
var util       = require('gulp-util');
var vinyl      = require('vinyl-paths');
var version    = require('gulp-rev-replace');
var webpack    = require('webpack');

/* ----------------------------------------------------------------------------
 * Locals
 * ------------------------------------------------------------------------- */

/* MkDocs server */
var server = null;

/* Watching context */
var watch = false;

/* ----------------------------------------------------------------------------
 * Overrides
 * ------------------------------------------------------------------------- */

/*
 * Override gulp.src() for nicer error handling.
 */
var src = gulp.src;
gulp.src = function() {
  return src.apply(gulp, arguments)
    .pipe(
      plumber(function(error) {
        util.log(util.colors.red(
          'Error (' + error.plugin + '): ' + error.message
        ));

        /* Extract file where error happened, if existent */
        var file = error.relativePath
          ? error.relativePath.split('/').pop()
          : '';

        /* Dispatch system-level notification */
        notifier.notify({
          title: 'Error (' + error.plugin + '): ' + file,
          message: error.messageOriginal
        });
        this.emit('end');
      }));
};

/* ----------------------------------------------------------------------------
 * Asset pipeline
 * ------------------------------------------------------------------------- */

/*
 * Clean stylesheets generated by build.
 */
gulp.task('assets:clean:stylesheets', function() {
  return gulp.src('material/assets/stylesheets/*')
    .pipe(vinyl(clean));
});

/*
 * Clean javascripts generated by build.
 */
gulp.task('assets:clean:javascripts', function() {
  return gulp.src('material/assets/javascripts/*')
    .pipe(vinyl(clean));
});

/*
 * Clean images generated by build.
 */
gulp.task('assets:clean:images', function() {
  return gulp.src('material/assets/images/*')
    .pipe(vinyl(clean));
});

/*
 * Clean files generated by build.
 */
gulp.task('assets:clean', [
  'assets:clean:stylesheets',
  'assets:clean:javascripts',
  'assets:clean:images'
]);

/*
 * Build stylesheets from SASS source.
 */
gulp.task('assets:build:stylesheets', args.production ? [
  'assets:clean:stylesheets',
  'assets:build:images',
] : [], function() {
  return gulp.src('src/assets/stylesheets/*.scss')
    .pipe(gulpif(args.sourcemaps, sourcemaps.init()))
    .pipe(
      sass({
        includePaths: [
          'node_modules/modularscale-sass/stylesheets',
          'node_modules/material-design-color',
          'node_modules/material-shadows'
        ]
      }))
    .pipe(
      postcss([
        autoprefix(),
        mqpacker
      ]))
    .pipe(gulpif(args.sourcemaps, sourcemaps.write()))
    .pipe(gulpif(args.production, mincss()))
    .pipe(gulpif(args.production, rev()))
    .pipe(gulpif(args.production,
      version({ manifest: gulp.src('manifest.json') })))
    .pipe(gulp.dest('material/assets/stylesheets'))
    .pipe(gulpif(args.production,
      rev.manifest('manifest.json', {
        base: 'material/assets',
        merge: true
      })))
    .pipe(gulpif(args.production, gulp.dest('material/assets')));
});

/*
 * Build javascripts by transpiling ES6 with babel.
 */
gulp.task('assets:build:javascripts', args.production ? [
  'assets:clean:javascripts'
] : [], function() {
  return gulp.src('src/assets/javascripts/**/*.js')
    .pipe(
      stream({
        entry: 'application.js',
        output: {
          filename: 'application.js'
        },
        module: {
          loaders: [{
            loader: 'babel-loader',
            test: path.join(__dirname, 'src/assets/javascripts'),
            query: {
              presets: 'es2015'
            }
          }]
        },
        plugins: [
          new webpack.NoErrorsPlugin(),
        ].concat(
          args.production ? [
            new webpack.optimize.UglifyJsPlugin({
              compress: {
                warnings: false
              }
            })
          ] : []),
        stats: {
          colors: true
        },
        resolve: {
          modulesDirectories: [
            'src/assets/javascripts',
            'node_modules'
          ],
          extensions: [
            '', '.js'
          ]
        },
        devtool: args.sourcemaps ? 'source-map' : ''
      }))
    .pipe(gulpif(args.production, rev()))
    .pipe(gulp.dest('material/assets/javascripts'))
    .pipe(gulpif(args.production,
      rev.manifest('manifest.json', {
        base: 'material/assets',
        merge: true
      })))
    .pipe(gulpif(args.production, gulp.dest('material/assets')));
});

/*
 * Create a customized modernizr build.
 */
gulp.task('assets:build:modernizr', [
  'assets:build:stylesheets',
  'assets:build:javascripts'
], function() {
  return gulp.src([
    'material/assets/stylesheets/*.css',
    'material/assets/javascripts/*.js'
  ]).pipe(
      modernizr({
        options: [
          'addTest',                   /* Add custom tests */
          'fnBind',                    /* Use function.bind */
          'html5printshiv',            /* HTML5 support for IE */
          'setClasses',                /* Add CSS classes to root tag */
          'testProp'                   /* Test for properties */
        ]
      }))
    .pipe(concat('modernizr.js'))
    .pipe(gulpif(args.production, uglify()))
    .pipe(gulpif(args.production, rev()))
    .pipe(gulp.dest('material/assets/javascripts'))
    .pipe(gulpif(args.production,
      rev.manifest('manifest.json', {
        base: 'material/assets',
        merge: true
      })))
    .pipe(gulpif(args.production, gulp.dest('material/assets')));
});

/*
 * Copy and minify vector graphics.
 */
gulp.task('assets:build:images:svg', function() {
  return gulp.src('src/assets/images/**/*.svg')
    .pipe(gulpif(watch, changed('material/assets/images')))
    .pipe(gulpif(args.production, minsvg()))
    .pipe(gulpif(args.production, rev()))
    .pipe(gulp.dest('material/assets/images'))
    .pipe(gulpif(args.production,
      rev.manifest('manifest.json', {
        base: 'material/assets',
        merge: true
      })))
    .pipe(gulpif(args.production, gulp.dest('material/assets')));
});

/*
 * Copy favicon.
 */
gulp.task('assets:build:images:ico', function() {
  return gulp.src('src/assets/images/**/*.ico')
    .pipe(gulp.dest('material/assets/images'))
});

/*
 * Copy images.
 */
gulp.task('assets:build:images', [
  'assets:clean:images'
], function() {
  return gulp.start([
    'assets:build:images:svg',
    'assets:build:images:ico'
  ]);
});

/*
 * Minify views.
 */
gulp.task('assets:build:views', args.production ? [
  'assets:build:stylesheets',
  'assets:build:modernizr',
  'assets:build:images'
] : [], function() {
  var metadata = require('./package.json');
  return gulp.src('src/**/*.html')
    .pipe(gulpif(watch, changed('material')))
    .pipe(
      minhtml({
        collapseBooleanAttributes: true,
        removeComments: true,
        removeScriptTypeAttributes: true,
        removeStyleLinkTypeAttributes: true,
        customAttrCollapse: /(content)/
      }))
    .pipe(replace('$theme-name$', metadata.name))
    .pipe(replace('$theme-version$', metadata.version))
    .pipe(compact())
    .pipe(gulpif(args.production,
      version({ manifest: gulp.src('manifest.json') })))
    .pipe(gulp.dest('material'));
});

/*
 * Build assets.
 */
gulp.task('assets:build', [
  'assets:build:stylesheets',
  'assets:build:javascripts',
  'assets:build:modernizr',
  'assets:build:images',
  'assets:build:views'
]);

/*
 * Watch assets for changes and rebuild on the fly.
 */
gulp.task('assets:watch', function() {
  watch = true;

  /* Rebuild stylesheets */
  gulp.watch([
    'src/assets/stylesheets/**/*.scss'
  ], ['assets:build:stylesheets']);

  /* Rebuild javascripts */
  gulp.watch([
    'src/assets/javascripts/**/*.js'
  ], ['assets:build:javascripts']);

  /* Copy images */
  gulp.watch([
    'src/assets/images/**/*'
  ], ['assets:build:images']);

  /* Minify views */
  gulp.watch([
    'src/**/*.html'
  ], ['assets:build:views']);
});

/* ----------------------------------------------------------------------------
 * Application server
 * ------------------------------------------------------------------------- */

/*
 * Build documentation.
 */
gulp.task('mkdocs:build', [
  'assets:build'
], function() {
  return child.spawnSync('mkdocs', ['build']);
});

/*
 * Restart MkDocs server.
 */
gulp.task('mkdocs:serve', function() {
  if (server)
    server.kill();

  /* Spawn MkDocs server */
  server = child.spawn('mkdocs', ['serve', '-a', '0.0.0.0:8000']);

  /* Pretty print server log output */
  server.stdout.on('data', function(data) {
    var lines = data.toString().split('\n')
    for (var l in lines)
      if (lines[l].length)
        util.log(lines[l]);
  });

  /* Print errors to stdout */
  server.stderr.on('data', function(data) {
    process.stdout.write(data.toString());
  });
});

/* ----------------------------------------------------------------------------
 * Interface
 * ------------------------------------------------------------------------- */

/*
 * Build assets and documentation.
 */
gulp.task('build', [
  'assets:clean',
  'assets:build'
].concat(args.mkdocs
  ? 'mkdocs:build'
  : []));

/*
 * Start asset and MkDocs watchdogs.
 */
gulp.task('watch', [
  'assets:clean',
  'assets:build'
], function() {
  return gulp.start([
    'assets:watch'
  ].concat(args.mkdocs
    ? 'mkdocs:serve'
    : []));
});

/*
 * Build assets by default.
 */
gulp.task('default', ['build']);