Elm.Native.Debug = {};
Elm.Native.Debug.make = function(elm) {
    elm.Native = elm.Native || {};
    elm.Native.Debug = elm.Native.Debug || {};
    if (elm.Native.Debug.values) return elm.Native.Debug.values;
    if ('values' in Elm.Native.Debug)
        return elm.Native.Debug.values = Elm.Native.Debug.values;

    var show = Elm.Native.Show.make(elm).show;
    var replace = Elm.Native.Utils.make(elm).replace;

    function log(tag, value) {
        var msg = tag + ': ' + show(value);
        var process = process || {};
        if (process.stdout) {
            process.stdout.write(msg);
        } else {
            console.log(msg);
        }
        return value;
    }

    function tracePath(debugId, form) {
        return replace([["debugTracePathId",debugId]], form);
    }

    function WatchTracker() {
        this.frames = [{}];
        this.clear = function() {
            this.watches = {};
        };
        this.pushFrame = function() {
            var lastFrame = this.frames[this.frames.length - 1];
            this.frames.push(lastFrame);
        }
        this.notify = function(tag, value) {
            this.frames[this.frames.length - 1][tag] = value;
        };
    }
    var watchTracker = new WatchTracker();

    function watch(tag, value) {
        watchTracker.notify(tag, value);
        return value;
    }

    function watchSummary(tag, f, value) {
        watchTracker.notify(tag, f(value));
        return value;
    }

    Elm.Native.Debug.values = {
        tracePath: F2(tracePath),
        log: F2(log),
        watch: F2(watch),
        watchSummary:F3(watchSummary),
        watchTracker: watchTracker
    };
    return elm.Native.Debug.values = Elm.Native.Debug.values;
};