var marked = require('marked');
var fs = require('fs');
var hljs = require('highlight.js');

var TOS = fs.readFileSync('resources/TOS.md', 'utf-8');
var pageTemplate = fs.readFileSync('resources/template.html', 'utf-8');
var footerTemplate = fs.readFileSync('resources/footer.html', 'utf-8');
var editTemplate = fs.readFileSync('resources/edit.html', 'utf-8');
var header = fs.readFileSync(process.env.HEADER || '/dev/null', 'utf-8');

var deriveTitle = text => text
    .split(/[\n\r]/)[0].slice(0,25)
    .replace(/[`~!@#\$%^&\*_|\+=\?;:'",.<>\{\}\\\/]/g, '');

var renderPage = (id, title, content, footer, blackList) => pageTemplate
    .replace('%HEADER%', blackList && blackList.has(id) ? header : '')
    .replace('%TITLE%', title)
    .replace('%CONTENT%', content.replace(/<meta.*?>/gi, '').replace(/<script[\s\S.]*?\/script>/gi, ''))
    .replace('%FOOTER%', footer || '');

marked.setOptions({
    langPrefix: 'hljs lang-',
    highlight: code => hljs.highlightAuto(code).value,
});

module.exports.renderPage = renderPage;

module.exports.renderStats = note => renderPage(note.id, deriveTitle(note.text), 
    `<h2>Statistics</h2>
  <table>
    <tr><td>Published</td><td>${note.published}</td></tr>
    <tr><td>Edited</td><td>${note.edited || 'N/A'}</td></tr>
    <tr><td>Views</td><td>${note.views}</td></tr>
  </table>`);

module.exports.renderTOS = () =>  renderPage('tos', 'Terms of Service', marked(TOS));

module.exports.renderNote = (note, blackList) => renderPage(note.id,
    deriveTitle(note.text), 
    marked(note.text),
    footerTemplate.replace(/%LINK%/g, note.id),
    blackList);

module.exports.newNotePage = session => editTemplate
    .replace('%ACTION%', 'POST')
    .replace('%SESSION%', session)
    .replace('%CONTENT%', 'Loading...');

module.exports.editNotePage = (session, note) => editTemplate
    .replace('%ACTION%', 'UPDATE')
    .replace('%SESSION%', session)
    .replace('%ID%', note.id)
    .replace('%CONTENT%', escape$(note.text));

var escape$ = s => s.split('').map(chr => chr == '$' ? '$$' : chr).join('');