'use strict';

const Handlebars = require('handlebars');
const _          = require('lodash');

module.exports = function(fractal){

    return function render(handle){

        let context;
        let source = fractal.components;
        const opts = arguments[arguments.length-1].hash;
        const root = arguments[arguments.length-1].data.root;
        const merge = opts.merge || false;
        if (arguments.length >= 3) {
            context = arguments[1];
        } else if (arguments.length == 2) {
            context = null;
        } else if (arguments.length == 1) {
            throw new Error(`You must provide a component handle to the render helper.`);
        }
        const entity = source.find(handle);
        if (!entity) {
            throw new Error(`Could not render component '${handle}' - component not found.`);
        }
        const defaultContext = entity.isComponent ? entity.variants().default().context : entity.context;
        if (!context) {
            context = defaultContext;
        } else if (merge) {
            context = _.defaultsDeep(context, defaultContext);
        }
        
        return source.resolve(context).then(context => {
            // fix env for rendered components
            let env = JSON.parse(JSON.stringify(root._env));
            _.set(context, '_env', env);

            return entity.render(context).then(html => new Handlebars.SafeString(html));
        });
    };

};