var frontMatter = require('gulp-front-matter');
var rss = require('gulp-rss')

gulp.task('rss', function() {
  gulp.files('./posts/*.md')  // Read input files
    .pipe(frontMatter())      // Extract YAML Front-Matter
    .pipe(rss(                // Generate RSS data
      // Configuration
      {
        // How we deal with contextual data (typically Front-Matter)
        properties: {
          data:         'frontMatter',  // name of property containing the data, typically extracted front-matter
          // Proparty names mapping
          title:        'title',        // post's title (means plugin will read `file.frontMatter.title`, mandatory)
          link:         'permalink',    // post's URL (mandatory)
          description:  'description',  // post's description (optional)
          author:       'author',       // post's author (optional)
          date:         'date',         // post's publication date (mandatory, default = now)
          image:        'image'         // post's thumbnail (optional)
        },

        // Feed configuration
        render:       'atom-1.0',                     // Feed type (atom-1.0 or rss-2.0)
        title:        'My blog',                      // Feed title (mandatory)
        description:  'My very own blog',             // Feed description (optional)
        link:         'http://my.bl.og',              // Feed link (optional)
        author:       { name: 'Nicolas Chambrier' },  // Blog's author (optional)
        // etc…
      }

    ))
    .pipe(gulp.dest('./public/feed.xml')) // Write output
});