const cheerio = require('gulp-cheerio');
const env = process.env.CAMEL_ENV || 'development';
const gulp = require('gulp');
const htmlmin = require('gulp-htmlmin');
const inject = require('gulp-inject')

/**
 * We minify all HTML files using htmlmin, this is to make them smaller in size
 * as we generate quite big HTML files in the documentation. We do not do this
 * unless the environment variable `CAMEL_ENV` is set to 'production' to help
 * with the development turnaround as this takes quite a while to do.
 */
gulp.task('minify', (done) => {
  if (env !== 'production') {
    done();
    return;
  }

  return gulp.src('public/**/*.html')
    .pipe(htmlmin({
      collapseBooleanAttributes: true,
      collapseWhitespace: true,
      collapseInlineTagWhitespace: true,
      conservativeCollapse: true,
      useShortDoctype: true,
      processScripts: ['application/ld+json']
    }))
    .pipe(gulp.dest('public'));
});

/*
 * Appends `sitemap-website.xml` to the `sitemap.xml`.
 *
 * We have sitemaps generated by Antora for each documentation component, these
 * are generated in `documentation/sitemap-*.xml` along with the
 * `documentation/sitemap.xml` that is a sitemap index pointing to each
 * component sitemap.
 *
 * Hugo also generates a sitemap in `public/sitemap-website.xml` containing all
 * pages generated from `content/` and other sources. We need to add the
 * `sitemap-website.xml` to the `sitemap.xml` so that we have a sitemap index
 * containing pointers to all individual sitemaps.
 *
 * Sitemaps are used by search engines (Google, Algolia, ...) to help them crawl
 * and index the website.
 */
gulp.task('sitemap', (done) => {
  return gulp.src('public/sitemap.xml')
    .pipe(cheerio(($, f) =>
      $('sitemapindex').append(`<sitemap>
<loc>https://camel.apache.org/sitemap-website.xml</loc>
</sitemap>`)
    ))
    .pipe(gulp.dest('public'));
});

gulp.task('htaccess', (done) => {
  return gulp.src(`static/.htaccess`)
    .pipe(
      inject(
        gulp.src('documentation/.htaccess'),
        {
          starttag:'<!-- inject:htaccess:docs -->',
          removeTags: true,
          transform: (filename, file) => {
            return versionlessRedirects(file.contents.toString('utf8'))
          },
        }
      )
    )
    // redirect un-hashed resources (e.g. `/_/img/logo-d.svg`) to hashed resources (e.g. `/_/img/logo-d-f21b25ba38.svg`)
    // so we don't break backward compatibility
    .pipe(
      inject(
        gulp.src('documentation/_/data/rev-manifest.json'),
        {
          starttag:'<!-- inject:htaccess:resources -->',
          removeTags: true,
          transform: (filename, file) => {
            const data = JSON.parse(file.contents)
            let rules = ''
            for (const [key, value] of Object.entries(data)) {
              if (key.endsWith('.svg') || key.endsWith('.png')) {
                rules += `Redirect 301 /_/${key} /_/${value}\n`
              }
            }
            return rules
          },
        }
      )
    )
    .pipe(gulp.dest('public'))
});

const REDIRECT_RX = /^Redirect 302 \/(?<component>c.*)\/latest \/\k<component>\/(?<version>.*)$/

function versionlessRedirects (text) {
  const lines = text.split('\n')
  const processed = lines.reduce((accum, line) => {
    accum.push(line)
    const m = line.match(REDIRECT_RX)
    if (m) {
      accum.push(`RedirectMatch 302 "^/${m.groups.component}(/?)$" "/${m.groups.component}/${m.groups.version}/"`)
      // The first line redirects **/next to **/next/ so the second line does not match.
      // Apparently it needs to be a match or it will transform **/next/ to **/next//
      accum.push(`RedirectMatch 301 "^/${m.groups.component}/next$" "/${m.groups.component}/next/"`)
      accum.push(`RedirectMatch 302 "^/${m.groups.component}/(?![0-9].*|next/)(.+)$" "/${m.groups.component}/${m.groups.version}/$1"`)
      // As an alternative, the following line works as long as no file names start with 'next'
      // accum.push(`RedirectMatch 302 "^/${m.groups.component}/(?![0-9].*|next)(.+)$" "/${m.groups.component}/${m.groups.version}/$1"`)
    }
    return accum
  }, [])
  return processed.join('\n')
}

/*
 * Removes the content from the `public` directory.
 */
gulp.task('clean', () => {
  return require('del')('public');
});