import * as LibFs from 'fs';
import * as LibPath from 'path';
import * as handlebars from 'handlebars';
import * as helpers from 'handlebars-helpers';

helpers({ handlebars: handlebars });
handlebars.registerHelper('curlyLeft', () => '{');
handlebars.registerHelper('curlyRight', () => '}');

const TPL_BASE_PATH = LibPath.join(__dirname, '..', 'template');

export namespace TplEngine {

  export function registerHelper(name: string, fn: Function, inverse?: boolean): void {
    handlebars.registerHelper(name, fn, inverse);
  }

  export function render(templateName: string, params: { [key: string]: any }): string {
    return compile(templateName)(params);
  }

  export function compile(templateName: string): HandlebarsTemplateDelegate {
    return handlebars.compile(
      LibFs.readFileSync(`${LibPath.join(TPL_BASE_PATH, templateName)}.hbs`).toString(),
    );
  }

}