// View rendering, template loading, and Handlebars registration helpers.

const fs = require('fs');
const path = require('path');
const Handlebars = require('handlebars');
const { version: appVersion } = require('#root/package.json');
const { hasPermission, hasAnyPermission } = require('../rbac');
const { registerHandlebars } = require('./handlebars');
const { getMessageVariant: inferMessageVariant } = require('./public/js/toast');

const VIEWS_ROOT = path.join(__dirname, 'views');
const cache = new Map();
const SIGNAGE_VIEW_PREFIXES = new Set(['dashboard', 'clients', 'screens', 'playlists', 'slides', 'canvas-sizes', 'templates']);

registerHandlebars(Handlebars, {
  viewsRoot: VIEWS_ROOT,
  hasPermission: hasPermission,
  hasAnyPermission: hasAnyPermission
});

function resolveTemplatePath(relativePath) {
  const firstSegment = String(relativePath || '').split(/[\\/]/)[0];
  if (SIGNAGE_VIEW_PREFIXES.has(firstSegment)) {
    return path.join(VIEWS_ROOT, 'signage', relativePath);
  }

  return path.join(VIEWS_ROOT, relativePath);
}

function loadTemplate(relativePath) {
  const filePath = resolveTemplatePath(relativePath);
  const stat = fs.statSync(filePath);
  const cached = cache.get(filePath);
  if (cached && cached.mtimeMs === stat.mtimeMs) {
    return cached.template;
  }
  const template = Handlebars.compile(fs.readFileSync(filePath, 'utf8'));
  cache.set(filePath, { mtimeMs: stat.mtimeMs, template: template });
  return template;
}

function renderView(viewName, context) {
  const viewContext = Object.assign({ stylesheets: [], scripts: [], appVersion: appVersion }, context || {});
  if (!viewContext.messageVariant) {
    viewContext.messageVariant = inferMessageVariant(viewContext.message, 'primary');
  }
  const page = loadTemplate(`${viewName}.hbs`);
  const layout = loadTemplate(path.join('shared', 'layout.hbs'));
  const body = page(viewContext);
  return layout(Object.assign({}, viewContext, { body: body }));
}

function renderFragment(viewName, context) {
  const viewContext = Object.assign({ stylesheets: [], scripts: [], appVersion: appVersion }, context || {});
  if (!viewContext.messageVariant) {
    viewContext.messageVariant = inferMessageVariant(viewContext.message, 'primary');
  }
  const page = loadTemplate(`${viewName}.hbs`);
  const layout = loadTemplate(path.join('shared', 'frame-layout.hbs'));
  const body = page(viewContext);
  return layout(Object.assign({}, viewContext, { body: body }));
}

module.exports = {
  renderView,
  renderFragment
};