using GFramework.Core.Abstractions.versioning;
using GFramework.Core.extensions;
using GFramework.Core.model;
using GFramework.Game.Abstractions.setting;

namespace GFramework.Game.setting;

/// <summary>
///     设置模型类，用于管理不同类型的应用程序设置部分
/// </summary>
public class SettingsModel : AbstractModel, ISettingsModel
{
    private readonly Dictionary<Type, IApplyAbleSettings> _applicators = new();
    private readonly Dictionary<Type, ISettingsData> _dataSettings = new();
    private readonly Dictionary<(Type type, int from), ISettingsMigration> _migrations = new();

    private ISettingsPersistence? _persistence;

    // -----------------------------
    // Data
    // -----------------------------

    /// <summary>
    /// 获取指定类型的设置数据实例，如果不存在则创建新的实例
    /// </summary>
    /// <typeparam name="T">设置数据类型，必须实现ISettingsData接口并提供无参构造函数</typeparam>
    /// <returns>指定类型的设置数据实例</returns>
    public T GetData<T>() where T : class, ISettingsData, new()
    {
        var type = typeof(T);
        if (_dataSettings.TryGetValue(type, out var data))
            return (T)data;

        var created = new T();
        _dataSettings[type] = created;
        return created;
    }

    /// <summary>
    /// 获取所有设置数据的枚举集合
    /// </summary>
    /// <returns>所有设置数据的枚举集合</returns>
    public IEnumerable<ISettingsData> AllData()
        => _dataSettings.Values;

    // -----------------------------
    // Applicator
    // -----------------------------

    /// <summary>
    /// 获取所有设置应用器的枚举集合
    /// </summary>
    /// <returns>所有设置应用器的枚举集合</returns>
    public IEnumerable<IApplyAbleSettings> AllApplicators()
        => _applicators.Values;

    /// <summary>
    /// 注册设置应用器到模型中
    /// </summary>
    /// <typeparam name="T">设置应用器类型，必须实现IApplyAbleSettings接口</typeparam>
    /// <param name="applicator">要注册的设置应用器实例</param>
    /// <returns>当前设置模型实例，支持链式调用</returns>
    public ISettingsModel RegisterApplicator<T>(T applicator)
        where T : class, IApplyAbleSettings
    {
        _applicators[typeof(T)] = applicator;
        return this;
    }

    /// <summary>
    /// 获取指定类型的设置应用器实例
    /// </summary>
    /// <typeparam name="T">设置应用器类型，必须实现IApplyAbleSettings接口</typeparam>
    /// <returns>指定类型的设置应用器实例，如果不存在则返回null</returns>
    public T? GetApplicator<T>() where T : class, IApplyAbleSettings
    {
        return _applicators.TryGetValue(typeof(T), out var app)
            ? (T)app
            : null;
    }

    // -----------------------------
    // Section lookup
    // -----------------------------

    /// <summary>
    /// 尝试获取指定类型的设置节
    /// </summary>
    /// <param name="type">要查找的设置类型</param>
    /// <param name="section">输出参数，找到的设置节实例</param>
    /// <returns>如果找到对应类型的设置节则返回true，否则返回false</returns>
    public bool TryGet(Type type, out ISettingsSection section)
    {
        if (_dataSettings.TryGetValue(type, out var data))
        {
            section = data;
            return true;
        }

        if (_applicators.TryGetValue(type, out var applicator))
        {
            section = applicator;
            return true;
        }

        section = null!;
        return false;
    }

    // -----------------------------
    // Migration
    // -----------------------------

    /// <summary>
    /// 注册设置迁移器到模型中
    /// </summary>
    /// <param name="migration">要注册的设置迁移器实例</param>
    /// <returns>当前设置模型实例，支持链式调用</returns>
    public ISettingsModel RegisterMigration(ISettingsMigration migration)
    {
        _migrations[(migration.SettingsType, migration.FromVersion)] = migration;
        return this;
    }

    /// <summary>
    /// 如果需要的话，对设置节进行版本迁移
    /// </summary>
    /// <param name="section">待检查和迁移的设置节</param>
    /// <returns>迁移后的设置节</returns>
    private ISettingsSection MigrateIfNeeded(ISettingsSection section)
    {
        if (section is not IVersioned versioned)
            return section;

        var type = section.GetType();
        var current = section;

        while (_migrations.TryGetValue((type, versioned.Version), out var migration))
        {
            current = migration.Migrate(current);
            versioned = (IVersioned)current;
        }

        return current;
    }

    // -----------------------------
    // Load / Init
    // -----------------------------

    /// <summary>
    /// 异步初始化设置模型，加载指定类型的设置数据
    /// </summary>
    /// <param name="settingTypes">要初始化的设置类型数组</param>
    public async Task InitializeAsync(params Type[] settingTypes)
    {
        foreach (var type in settingTypes)
        {
            if (!typeof(ISettingsData).IsAssignableFrom(type) ||
                !type.IsClass ||
                type.GetConstructor(Type.EmptyTypes) == null)
                continue;

            // Load<T>()
            var method = typeof(ISettingsPersistence)
                .GetMethod(nameof(ISettingsPersistence.LoadAsync))!
                .MakeGenericMethod(type);

            var task = (Task)method.Invoke(_persistence, null)!;
            await task;

            var loaded = (ISettingsSection)((dynamic)task).Result;

            // ★ 关键：迁移
            var migrated = MigrateIfNeeded(loaded);

            _dataSettings[type] = (ISettingsData)migrated;
        }
    }

    /// <summary>
    /// 初始化方法，用于获取设置持久化服务
    /// </summary>
    protected override void OnInit()
    {
        _persistence = this.GetUtility<ISettingsPersistence>();
    }
}