// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE

using System;
using System.Collections.Generic;
using osu.Framework.Graphics;
using osu.Game.Configuration;
using osu.Game.Rulesets.Configuration;

namespace osu.Game.Rulesets
{
    /// <summary>
    /// A cache that provides a single <see cref="IRulesetConfigManager"/> per-ruleset.
    /// This is done to support referring to and updating ruleset configs from multiple locations in the absence of inter-config bindings.
    /// </summary>
    public class RulesetConfigCache : Component
    {
        private readonly Dictionary<int, IRulesetConfigManager> configCache = new Dictionary<int, IRulesetConfigManager>();
        private readonly SettingsStore settingsStore;

        public RulesetConfigCache(SettingsStore settingsStore)
        {
            this.settingsStore = settingsStore;
        }

        /// <summary>
        /// Retrieves the <see cref="IRulesetConfigManager"/> for a <see cref="Ruleset"/>.
        /// </summary>
        /// <param name="ruleset">The <see cref="Ruleset"/> to retrieve the <see cref="IRulesetConfigManager"/> for.</param>
        /// <returns>The <see cref="IRulesetConfigManager"/> defined by <paramref name="ruleset"/>, null if <paramref name="ruleset"/> doesn't define one.</returns>
        /// <exception cref="InvalidOperationException">If <paramref name="ruleset"/> doesn't have a valid <see cref="RulesetInfo.ID"/>.</exception>
        public IRulesetConfigManager GetConfigFor(Ruleset ruleset)
        {
            if (ruleset.RulesetInfo.ID == null)
                throw new InvalidOperationException("The provided ruleset doesn't have a valid id.");

            if (configCache.TryGetValue(ruleset.RulesetInfo.ID.Value, out var existing))
                return existing;

            return configCache[ruleset.RulesetInfo.ID.Value] = ruleset.CreateConfig(settingsStore);
        }
    }
}