using System.Collections.Generic;
using System.Globalization;
using UnityEngine;
using Yarn.Unity;

namespace Ichni.Story.Dialogue
{
    /// <summary>
    /// 自定义 Yarn 变量存储。直接读写 <see cref="StorySaveModule.variables"/>（全局剧情变量），
    /// 让 Yarn 对话中的 <c>&lt;&lt;set $var to ...&gt;&gt;</c> 与故事树解锁条件共享同一份数据来源，
    /// 并借助存档模块的 ES3 序列化持久化。
    /// <para>变量名沿用 Yarn 约定（带 <c>$</c> 前缀）；解锁条件中的变量名也应保持一致。</para>
    /// </summary>
    public class StoryVariableStorage : VariableStorageBehaviour
    {
        // GameSaveManager 尚未就绪（编辑器早期 / 场景未初始化）时的兜底容器
        private readonly StoryVariablesSave _fallback = new StoryVariablesSave();

        /// <summary>当前生效的变量容器：优先取存档模块，缺失时用本地兜底容器。</summary>
        private StoryVariablesSave Variables
        {
            get
            {
                if (GameSaveManager.instance != null && GameSaveManager.instance.StorySaveModule != null)
                    return GameSaveManager.instance.StorySaveModule.variables;
                return _fallback;
            }
        }

        // ── IVariableStorage 实现 ────────────────────────────────────────────────

        public override bool TryGetValue<T>(string variableName, out T result)
        {
            StoryVariablesSave vars = Variables;

            if (vars.floatVariables.TryGetValue(variableName, out float f))
                return TryConvert(f, out result);

            if (vars.boolVariables.TryGetValue(variableName, out bool b))
                return TryConvert(b, out result);

            if (vars.stringVariables.TryGetValue(variableName, out string s))
                return TryConvert(s, out result);

            result = default;
            return false;
        }

        public override void SetValue(string variableName, string stringValue)
        {
            RemoveStaleEntries(variableName, keepFloat: false, keepString: true, keepBool: false);
            Variables.stringVariables[variableName] = stringValue;
            NotifyVariableChanged(variableName, stringValue);
        }

        public override void SetValue(string variableName, float floatValue)
        {
            RemoveStaleEntries(variableName, keepFloat: true, keepString: false, keepBool: false);
            Variables.floatVariables[variableName] = floatValue;
            NotifyVariableChanged(variableName, floatValue);
        }

        public override void SetValue(string variableName, bool boolValue)
        {
            RemoveStaleEntries(variableName, keepFloat: false, keepString: false, keepBool: true);
            Variables.boolVariables[variableName] = boolValue;
            NotifyVariableChanged(variableName, boolValue);
        }

        public override bool Contains(string variableName)
        {
            StoryVariablesSave vars = Variables;
            return vars.floatVariables.ContainsKey(variableName)
                || vars.boolVariables.ContainsKey(variableName)
                || vars.stringVariables.ContainsKey(variableName);
        }

        public override void Clear()
        {
            StoryVariablesSave vars = Variables;
            vars.floatVariables.Clear();
            vars.stringVariables.Clear();
            vars.boolVariables.Clear();
        }

        public override void SetAllVariables(
            Dictionary<string, float> floats,
            Dictionary<string, string> strings,
            Dictionary<string, bool> bools,
            bool clear = true)
        {
            StoryVariablesSave vars = Variables;

            if (clear)
            {
                vars.floatVariables.Clear();
                vars.stringVariables.Clear();
                vars.boolVariables.Clear();
            }

            if (floats != null)
                foreach (KeyValuePair<string, float> kv in floats) vars.floatVariables[kv.Key] = kv.Value;
            if (strings != null)
                foreach (KeyValuePair<string, string> kv in strings) vars.stringVariables[kv.Key] = kv.Value;
            if (bools != null)
                foreach (KeyValuePair<string, bool> kv in bools) vars.boolVariables[kv.Key] = kv.Value;
        }

        public override (Dictionary<string, float> FloatVariables,
                         Dictionary<string, string> StringVariables,
                         Dictionary<string, bool> BoolVariables) GetAllVariables()
        {
            StoryVariablesSave vars = Variables;
            return (
                new Dictionary<string, float>(vars.floatVariables),
                new Dictionary<string, string>(vars.stringVariables),
                new Dictionary<string, bool>(vars.boolVariables)
            );
        }

        // ── 供故事树解锁条件复用的便捷读取 ────────────────────────────────────────

        /// <summary>读取变量的整数近似值（float 四舍五入、bool 取 0/1）；不存在返回 0。</summary>
        public int GetIntVariable(string variableName)
        {
            StoryVariablesSave vars = Variables;
            if (vars.floatVariables.TryGetValue(variableName, out float f))
                return Mathf.RoundToInt(f);
            if (vars.boolVariables.TryGetValue(variableName, out bool b))
                return b ? 1 : 0;
            return 0;
        }

        /// <summary>该变量是否存在于任一类型的存储中。</summary>
        public bool HasVariable(string variableName) => Contains(variableName);

        // ── 内部 ────────────────────────────────────────────────────────────────

        // 当变量被重新赋值为其它类型时，从旧类型字典移除，避免同名变量残留多份
        private void RemoveStaleEntries(string name, bool keepFloat, bool keepString, bool keepBool)
        {
            StoryVariablesSave vars = Variables;
            if (!keepFloat) vars.floatVariables.Remove(name);
            if (!keepString) vars.stringVariables.Remove(name);
            if (!keepBool) vars.boolVariables.Remove(name);
        }

        // 将存储中的原始值转换为 Yarn 请求的类型（float / bool / string / int 之间互转）
        private static bool TryConvert<T>(object value, out T result)
        {
            if (value is T typed)
            {
                result = typed;
                return true;
            }

            try
            {
                if (typeof(T) == typeof(float) || typeof(T) == typeof(double) || typeof(T) == typeof(int))
                {
                    float f = value switch
                    {
                        float fv => fv,
                        bool bv => bv ? 1f : 0f,
                        string sv => float.TryParse(sv, NumberStyles.Any, CultureInfo.InvariantCulture, out float p) ? p : 0f,
                        _ => 0f
                    };
                    result = (T)System.Convert.ChangeType(f, typeof(T), CultureInfo.InvariantCulture);
                    return true;
                }

                if (typeof(T) == typeof(bool))
                {
                    bool b = value switch
                    {
                        bool bv => bv,
                        float fv => fv != 0f,
                        string sv => bool.TryParse(sv, out bool p) && p,
                        _ => false
                    };
                    result = (T)(object)b;
                    return true;
                }

                if (typeof(T) == typeof(string))
                {
                    string s = value switch
                    {
                        string sv => sv,
                        float fv => fv.ToString(CultureInfo.InvariantCulture),
                        bool bv => bv.ToString(),
                        _ => value != null ? value.ToString() : string.Empty
                    };
                    result = (T)(object)s;
                    return true;
                }
            }
            catch
            {
                // 转换失败时落到下方失败分支
            }

            result = default;
            return false;
        }
    }
}