}

        public string Color

        {

            get {

                return color;

            }

        }

        public PaintRecipe Recipe

        {

            get {

                return recipe;

            }

        }

    }

    public class RecipeGenerator

    {

        public enum SearchType {

            DEPTH_FIRST,

            BREADTH_FIRST

        };

        public SearchType Mode { get; set; }

        public uint MaxQuantity { get; private set; } // maximum number of total ingredients

        public uint MaxReagents { get; private set; } // maximum number of reagents to use in the recipe

        public uint MinReagents { get; private set; } // minimum number of reagents to use in the recipe

        public uint FullQuantityDepth { get; private set; } // at or equal this number of reagents, ignore ingredient settings for max quantity

        public uint FullQuantity { get; private set; }  // The max number of a reagent to use at full quantity

        ReactionSet reactions;

        bool running = false;

        int runningThreads = 0;

        SortedDictionary<string, uint> recipeCosts = new SortedDictionary<string, uint>();

        SortedDictionary<string, PaintRecipe> recipes = new SortedDictionary<string, PaintRecipe>();

        uint totalReagents;

        List<Reagent> costSortedReagents = new List<Reagent>();

        ConcurrentQueue<RecipeSearchNode> searchQueue = new ConcurrentQueue<RecipeSearchNode>();

        ulong recipeCount = 0;

        List<Thread> generatorThreads = new List<Thread>();

        Object workerLock = new Object();

        bool requestCancel = false;

        StreamWriter log;

        // events

        public event EventHandler Finished;

        public event EventHandler Progress;

        public event EventHandler<NewRecipeEventArgs> NewRecipe;

        public RecipeGenerator(ReactionSet reactions)

        {

            Mode = SearchType.BREADTH_FIRST;

            this.reactions = reactions;

                    initialNode.MaxReagents = maxReagents;

                    searchQueue.Enqueue(initialNode);

                }

            }

            recipeCount = 0;

            if (log != null)

            {

                log.WriteLine("Begin recipe generation: MaxQuantity={0} MinReagents={1} MaxReagents={2} FullQuantity={3} FullQuantityDepth={4}", MaxQuantity, MinReagents, MaxReagents, FullQuantity, FullQuantityDepth);

            }

            // start worker threads to do the actual work

            ResumeRecipeGeneration();

        }

        public void ResumeRecipeGeneration()

        {

            if (running)

            {

                // Already running - don't start again

                return;

            }

            running = true;

            requestCancel = false;

            if (log != null)

            {

                log.WriteLine("Resuming recipe generation: pre-threads={0} reagent count={1} search queue={2}", runningThreads, costSortedReagents.Count, searchQueue.Count);

            }

            runningThreads = 0; // presumably!

            if (threadCount == 0)

            {

                if (Finished != null)

                {

                    Finished(this, null);

                }

            }

            generatorThreads.Clear();

            for (int i = 0; i < threadCount; ++i)

            {

                Thread thr = new Thread(new ThreadStart(this.Generate));

                generatorThreads.Add(thr);

            }

            foreach (Thread thr in generatorThreads)

            {

                thr.Start();

            }

        }

        public bool SaveState(string file)

        {

            if (running)

            {

                // can't save state while running

                return false;

            }

            using (StreamWriter writer = new StreamWriter(file, false))

            {

                writer.WriteLine("MinReagents: {0}", MinReagents);

                writer.WriteLine("MaxReagents: {0}", MaxReagents);

                writer.WriteLine("FullQuantityDepth: {0}", FullQuantityDepth);

                writer.WriteLine("FullQuantity: {0}", FullQuantity);

                writer.WriteLine("TotalReagents: {0}", totalReagents);

                writer.WriteLine("RecipeCount: {0}", recipeCount);

                writer.WriteLine("SearchType: {0}", Mode.ToString());

                foreach (KeyValuePair<string, PaintRecipe> pair in recipes)

                {

                    PaintRecipe recipe = pair.Value;

                    string colorName = Palette.FindNearest(recipe.ReactedColor);

                    writer.WriteLine("BeginRecipe: {0}", colorName);

                    foreach (PaintRecipe.RecipeIngredient ingredient in recipe.Ingredients)

                    {

            recipeList.AppendColumn(recipeColorColumn);

            recipeColorColumn.AddAttribute(recipeColumnCell, "text", 0);

            colorStore.Clear();

            colorStore.SetSortColumnId(0, Gtk.SortType.Ascending);

            recipeList.Model = RecipeModel;

            recipeList.Selection.Changed += OnColorSelected;

            recipeIngredientsView.AppendColumn("Quantity", new Gtk.CellRendererText(), "text", 0);

            recipeIngredientsView.AppendColumn("Ingredient", new Gtk.CellRendererText(), "text", 1);

            recipeIngredientsView.Model = new Gtk.ListStore(typeof(string), typeof(string));

            profile.LoadRecipes();

            // init UI

            foreach (KeyValuePair<string, PaintRecipe> pair in profile.Recipes)

            {

                if (pair.Value.IsValid)

                {

                    string colorName = pair.Key;

                    colorStore.AppendValues(colorName);

                }

            }

            canceling = false;

            running = false;

            pauseForCheckpoint = false;

            generator = new RecipeGenerator(profile.Reactions);

            generator.InitRecipes(profile.Recipes);

            generator.Progress += OnProgress;

            generator.Finished += OnFinished;

            generator.NewRecipe += OnNewRecipe;

            string stateFile = System.IO.Path.Combine(profile.Directory, STATE_FILE);

            if (System.IO.File.Exists(stateFile))

            {

                generator.LoadState(stateFile);

                if (generator.CanResume)

                {

                    beginButton.Label = "Restart";

                    stopResumeButton.Label = "Resume";

                    stopResumeButton.Sensitive = true;

                    maxRecipeSpinButton.Value = Math.Max(generator.MaxQuantity, 14); //

                    fullQuantitySpinButton.Value = generator.FullQuantity; // TODO: read/save profile info

                    fullQuantityDepthSpinButton.Value = generator.FullQuantityDepth; // TODO: read/save profile info

                    maxIngredientsSpinButton.Value = generator.MaxReagents;

                }

            }

            //generator.Log = System.IO.Path.Combine(profile.Directory, "dp_log.txt");

            countLabel.Text = String.Format("{0} / {1}", profile.RecipeCount, Palette.Count);

            Destroyed += OnDestroyed;

            notifyFinished = new Gtk.ThreadNotify(new Gtk.ReadyEvent(HandleFinished));

            notifyProgress = new Gtk.ThreadNotify(new Gtk.ReadyEvent(HandleProgress));

            notifyNewRecipe = new Gtk.ThreadNotify(new Gtk.ReadyEvent(HandleNewRecipe));

            // initialize reagent list