const gulp = require('gulp');
const tap = require('gulp-tap');
const nunjucks = require('gulp-nunjucks-render');
const markdown = require('gulp-markdownit');
const grayMatter = require('gulp-gray-matter');
const data = require('gulp-data');
const path = require('path');
const fs = require('fs');

const CONTENT = 'content/**/*.md',
      TEMPLATES = 'src/views';

// Sets markdown contents to {{ contents }}
function getData(file) {
  file.data.contents = file.contents;
  return file.data;
}

// Writes template to file contents
function useTemplate(file) {
  const templatePath = path.resolve(TEMPLATES, file.data.template),
        template = fs.readFileSync(templatePath);

  file.contents = new Buffer(template);
  return;
}

// Generates static site from markdown
gulp.task('build:content', () => {
  return gulp.src(CONTENT)
    .pipe(grayMatter())
    .pipe(markdown())
    .pipe(data(getData))
    .pipe(tap(useTemplate))
    .pipe(nunjucks({ path: TEMPLATES }))
    .pipe(gulp.dest('dist'));
});