module.exports = function(environment) {
    var Dimension = require("../less/tree/dimension"),
    Expression = require("../less/tree/expression"),
    functionRegistry = require("./../less/functions/function-registry");

    function imageSize(functionContext, filePathNode) {
        var filePath = filePathNode.value;
        var currentFileInfo = functionContext.currentFileInfo;
        var currentDirectory = currentFileInfo.relativeUrls ?
        currentFileInfo.currentDirectory : currentFileInfo.entryPath;

        var fragmentStart = filePath.indexOf('#');
        var fragment = '';
        if (fragmentStart !== -1) {
            fragment = filePath.slice(fragmentStart);
            filePath = filePath.slice(0, fragmentStart);
        }

        var fileManager = environment.getFileManager(filePath, currentDirectory, functionContext.context, environment, true);

        if (!fileManager) {
            throw {
                type: "File",
                message: "Can not set up FileManager for " + filePathNode
            };
        }

        var fileSync = fileManager.loadFileSync(filePath, currentDirectory, functionContext.context, environment);

        if (fileSync.error) {
            throw fileSync.error;
        }

        var sizeOf = require('image-size');
        return sizeOf(fileSync.filename);
    }

    var imageFunctions = {
        "image-size": function(filePathNode) {
            var size = imageSize(this, filePathNode);
            return new Expression([
                new Dimension(size.width, "px"),
                new Dimension(size.height, "px")
            ]);
        },
        "image-width": function(filePathNode) {
            var size = imageSize(this, filePathNode);
            return new Dimension(size.width, "px");
        },
        "image-height": function(filePathNode) {
            var size = imageSize(this, filePathNode);
            return new Dimension(size.height, "px");
        }
    };

    functionRegistry.addMultiple(imageFunctions);
};