var defaultCreateOut = require('./createOut');
var extend = require('raptor-util/extend');

function safeRender(renderFunc, finalData, finalOut, shouldEnd) {
    try {
        renderFunc(finalData, finalOut);

        if (shouldEnd) {
            finalOut.end();
        }
    } catch(err) {
        var actualEnd = finalOut.end;
        finalOut.end = function() {};

        setTimeout(function() {
            finalOut.end = actualEnd;
            finalOut.error(err);
        }, 0);
    }
    return finalOut;
}

module.exports = function(target, renderer) {
    var renderFunc = renderer && (renderer.renderer || renderer.render || renderer);
    var createOut = target.createOut || renderer.createOut || defaultCreateOut;

    return extend(target, {
        createOut: createOut,

        renderToString: function(data, callback) {
            var localData = data || {};
            var render = renderFunc || this._;
            var globalData = localData.$global;
            var out = createOut(globalData);

            out.global.template = this;

            if (globalData) {
                localData.$global = undefined;
            }

            if (callback) {
                out.on('finish', function() {
                       callback(null, out.toString(), out);
                   })
                   .once('error', callback);

                return safeRender(render, localData, out, true);
            } else {
                out.sync();
                render(localData, out);
                return out.toString();
            }
        },

        renderSync: function(data) {
            var localData = data || {};
            var render = renderFunc || this._;
            var globalData = localData.$global;
            var out = createOut(globalData);
            out.sync();

            out.global.template = this;

            if (globalData) {
                localData.$global = undefined;
            }

            render(localData, out);
            return out.$__getResult();
        },

        /**
         * Renders a template to either a stream (if the last
         * argument is a Stream instance) or
         * provides the output to a callback function (if the last
         * argument is a Function).
         *
         * Supported signatures:
         *
         * render(data)
         * render(data, out)
         * render(data, stream)
         * render(data, callback)
         *
         * @param  {Object} data The view model data for the template
         * @param  {AsyncStream/AsyncVDOMBuilder} out A Stream, an AsyncStream/AsyncVDOMBuilder instance, or a callback function
         * @return {AsyncStream/AsyncVDOMBuilder} Returns the AsyncStream/AsyncVDOMBuilder instance that the template is rendered to
         */
        render: function(data, out) {
            var callback;
            var finalOut;
            var finalData;
            var globalData;
            var render = renderFunc || this._;
            var shouldBuffer = this.$__shouldBuffer;
            var shouldEnd = true;

            if (data) {
                finalData = data;
                if ((globalData = data.$global)) {
                    finalData.$global = undefined;
                }
            } else {
                finalData = {};
            }

            if (out && out.$__isOut) {
                finalOut = out;
                shouldEnd = false;
                extend(out.global, globalData);
            } else if (typeof out == 'function') {
                finalOut = createOut(globalData);
                callback = out;
            } else {
                finalOut = createOut(
                    globalData, // global
                    out, // writer(AsyncStream) or parentNode(AsyncVDOMBuilder)
                    null, // state
                    shouldBuffer // ignored by AsyncVDOMBuilder
                );
            }

            if (callback) {
                finalOut
                    .on('finish', function() {
                        callback(null, finalOut.$__getResult());
                    })
                    .once('error', callback);
            }

            globalData = finalOut.global;

            globalData.template = globalData.template || this;

            return safeRender(render, finalData, finalOut, shouldEnd);
        }
    });
};