using System.Collections.Generic;
using NUnit.Framework;
using Newtonsoft.Json;
using BaseGames.Core.Save;

namespace BaseGames.Tests.EditMode
{
    /// <summary>
    /// 存档系统单元测试（EditMode，纯 C# 逻辑，无 MonoBehaviour 依赖）。
    /// 覆盖：SaveMigrator 迁移链、SaveData 序列化/反序列化往返、字段完整性。
    /// </summary>
    [TestFixture]
    public class SaveSystemTests
    {
        // ── SaveMigrator · 边界输入 ──────────────────────────────────────────

        [Test]
        public void Migrate_NullInput_ReturnsNull()
        {
            var result = SaveMigrator.Migrate(null);
            Assert.IsNull(result, "null 输入应安全返回 null");
        }

        [Test]
        public void Migrate_NullMeta_ReturnsSameObject()
        {
            var data = new SaveData { Meta = null };
            var result = SaveMigrator.Migrate(data);
            Assert.AreSame(data, result, "Meta 为 null 时应返回原对象");
        }

        // ── SaveMigrator · 版本迁移 ──────────────────────────────────────────

        [Test]
        public void Migrate_EmptyVersion_MigratesTo_2_1()
        {
            var data = new SaveData();
            data.Meta.Version = "";
            var result = SaveMigrator.Migrate(data);
            Assert.AreEqual(SaveMigrator.CurrentVersion, result.Meta.Version);
        }

        [Test]
        public void Migrate_OldVersion_FillsMissingSubObjects()
        {
            var data = new SaveData();
            data.Meta.Version    = "1.0";
            data.Tutorial        = null;
            data.Settings        = null;
            data.EventChains     = null;
            data.ChallengeRooms  = null;

            var result = SaveMigrator.Migrate(data);

            Assert.IsNotNull(result.Tutorial,       "迁移后 Tutorial 不应为 null");
            Assert.IsNotNull(result.Settings,       "迁移后 Settings 不应为 null");
            Assert.IsNotNull(result.EventChains,    "迁移后 EventChains 不应为 null");
            Assert.IsNotNull(result.ChallengeRooms, "迁移后 ChallengeRooms 不应为 null");
            Assert.IsNull(result.NGPlus,            "迁移后 NGPlus 应为 null（非 NG+ 模式）");
        }

        [Test]
        public void Migrate_OldVersion_DeathShade_RemainsNull()
        {
            var data = new SaveData();
            data.Meta.Version      = "1.0";
            data.Player.DeathShade = null;

            var result = SaveMigrator.Migrate(data);

            Assert.IsNull(result.Player.DeathShade,
                "无遗骸时 DeathShade 应保持 null，由 DeathShadeManager 按需创建");
        }

        [Test]
        public void Migrate_Version2_0_FillsMapPins()
        {
            var data = new SaveData();
            data.Meta.Version = "2.0";
            data.Map.Pins     = null;

            var result = SaveMigrator.Migrate(data);

            Assert.IsNotNull(result.Map.Pins, "从 2.0 迁移后 Map.Pins 不应为 null");
            Assert.IsEmpty(result.Map.Pins,   "Map.Pins 应初始化为空列表");
        }

        [Test]
        public void Migrate_CurrentVersion_NoChange()
        {
            var data = new SaveData();
            data.Meta.Version = SaveMigrator.CurrentVersion;
            var result = SaveMigrator.Migrate(data);
            Assert.AreEqual(SaveMigrator.CurrentVersion, result.Meta.Version);
        }

        // ── SaveData · JSON 序列化往返 ───────────────────────────────────────

        [Test]
        public void SaveData_SerializeDeserialize_PreservesPlayerData()
        {
            var original = new SaveData();
            original.Player.CurrentHP      = 55;
            original.Player.MaxHP          = 100;
            original.Player.CurrentLingZhu = 1234;
            original.Player.Scene          = "TestRoom";

            string json = JsonConvert.SerializeObject(original, Formatting.None);
            var restored = JsonConvert.DeserializeObject<SaveData>(json);

            Assert.AreEqual(original.Player.CurrentHP,      restored.Player.CurrentHP);
            Assert.AreEqual(original.Player.MaxHP,          restored.Player.MaxHP);
            Assert.AreEqual(original.Player.CurrentLingZhu, restored.Player.CurrentLingZhu);
            Assert.AreEqual(original.Player.Scene,          restored.Player.Scene);
        }

        [Test]
        public void SaveData_SerializeDeserialize_PreservesAbilityFlags()
        {
            var original = new SaveData();
            original.Player.AbilityFlags = 0xDEADBEEFu;

            string json = JsonConvert.SerializeObject(original, Formatting.None);
            var restored = JsonConvert.DeserializeObject<SaveData>(json);

            Assert.AreEqual(original.Player.AbilityFlags, restored.Player.AbilityFlags,
                "AbilityFlags uint 不应因符号扩展而错误");
        }

        [Test]
        public void SaveData_SerializeDeserialize_NGPlusNull_StaysNull()
        {
            var original = new SaveData();
            original.NGPlus = null;

            string json = JsonConvert.SerializeObject(original, Formatting.None);
            var restored = JsonConvert.DeserializeObject<SaveData>(json);

            Assert.IsNull(restored.NGPlus, "NGPlus null 应序列化/反序列化保持 null");
        }

        [Test]
        public void SaveData_SerializeDeserialize_MetaVersionPreserved()
        {
            var original = new SaveData();
            original.Meta.Version   = SaveMigrator.CurrentVersion;
            original.Meta.SlotIndex = 2;
            original.Meta.SaveCount = 42;

            string json = JsonConvert.SerializeObject(original, Formatting.None);
            var restored = JsonConvert.DeserializeObject<SaveData>(json);

            Assert.AreEqual(SaveMigrator.CurrentVersion, restored.Meta.Version);
            Assert.AreEqual(2,  restored.Meta.SlotIndex);
            Assert.AreEqual(42, restored.Meta.SaveCount);
        }

        [Test]
        public void SaveData_ExtensionData_PreservesUnknownFields()
        {
            // 模拟未来版本存档包含当前版本未知的字段
            string futureJson = @"{
                ""Meta"": { ""Version"": ""3.0"", ""SlotIndex"": 0 },
                ""Player"": { ""CurrentHP"": 80 },
                ""FutureFeature"": { ""SomeValue"": 123 }
            }";

            var restored = JsonConvert.DeserializeObject<SaveData>(futureJson);

            Assert.IsNotNull(restored);
            Assert.AreEqual(80, restored.Player.CurrentHP);
            Assert.IsTrue(restored.ExtensionData.ContainsKey("FutureFeature"),
                "ExtensionData 应保留未知字段，确保向前兼容");
        }

        // ── SaveMeta · Checksum 字段 ─────────────────────────────────────────

        [Test]
        public void SaveMeta_Checksum_DefaultIsNull()
        {
            var meta = new SaveMeta();
            Assert.IsNull(meta.Checksum, "新建 SaveMeta 的 Checksum 默认应为 null");
        }

        [Test]
        public void SaveData_Serialize_WithNullChecksum_NotThrow()
        {
            var data = new SaveData();
            data.Meta.Checksum = null;
            Assert.DoesNotThrow(
                () => JsonConvert.SerializeObject(data, Formatting.None));
        }

        // ── SaveMeta · IsSteelSoul ────────────────────────────────────────────

        [Test]
        public void SaveMeta_IsSteelSoul_DefaultIsFalse()
        {
            var meta = new SaveMeta();
            Assert.IsFalse(meta.IsSteelSoul, "IsSteelSoul 默认应为 false");
        }
    }
}