var ajax = require("easy-ajax");
var compile = require("./tools/compile").compile;

function generateGameFile (mainFilePath, then) {
    compileFile(mainFilePath, function (mainFile) {
        generateGameFileFromString(mainFile, then);
    });
}

function generateGameFileFromString (text, then) {

    var gameDocument = parseXml(text);
    var fileDefinitions = getFileDefinitions(gameDocument);

    compileFiles(fileDefinitions, function (files) {
        files.forEach(function (file, i) {

            var type = fileDefinitions[i].type;
            var parent = gameDocument.getElementsByTagName(type)[0];

            if (!parent) {
                parent = gameDocument.createElement(type);
                gameDocument.documentElement.appendChild(parent);
            }

            parent.innerHTML += "\n" + file + "\n";
        });

        then(gameDocument);
    });
}

function generateFromString (text, then) {
    generateGameFileFromString(compile(text), then);
}

function compileFiles (fileDefinitions, then) {

    var loaded = 0;
    var count = fileDefinitions.length;
    var files = [];

    fileDefinitions.forEach(function (definition, i) {

        compileFile(definition.url, function (file) {

            files[i] = file;
            loaded += 1;

            if (loaded >= count) {
                then(files);
            }
        });
    });

    if (count < 1) {
        then(files);
    }
}

function compileFile (path, then) {
    ajax.get(path + "?random=" + Math.random(), function (error, obj) {

        if (error) {
            console.error(error);
            return;
        }

        then(compile(obj.responseText));
    });
}

function parseXml (text) {
    return new DOMParser().parseFromString(text, "application/xml");
}

function getFileDefinitions (xml) {

    var elements = xml.getElementsByTagName("file");

    return [].map.call(elements, function (element) {
        return {
            type: element.getAttribute("type"),
            url: element.getAttribute("url")
        };
    });
}

module.exports = {
    generateGameFile: generateGameFile,
    generateFromString: generateFromString
};