using NUnit.Framework;
using ProjectM.Simulation;
using UnityEngine;

namespace ProjectM.Tests
{
    /// <summary>
    /// Tests the SaveData v2 structure-persistence schema (M7): a player-built structure set + the flat machine-I/O
    /// table round-trip through JsonUtility with fields intact; the REMAINING-ticks cooldown survives an epoch reset
    /// (RemainingTicks/RestoreNextTick); and a save JSON lacking the v2 arrays deserializes without throwing (degrades
    /// to no structures). The deeper instantiate-from-catalog restore is covered by the Play-mode validation pass.
    /// </summary>
    public class AutomationSaveRoundTripTests
    {
        [Test]
        public void StructuresAndIo_RoundTrip_PreservesFields()
        {
            var data = new SaveData
            {
                GoalCharge = 3,
                GoalTarget = 10,
                Structures = new[]
                {
                    new StructureSave { Type = StructureType.Harvester, CellX = 4, CellZ = -2, RemainingTicks = 12 },
                    new StructureSave { Type = StructureType.Conveyor, CellX = 5, CellZ = -2, Direction = 2, RemainingTicks = 3, ConveyorResId = ResourceId.Ore, ConveyorCount = 1 },
                    new StructureSave { Type = StructureType.Fabricator, CellX = 6, CellZ = -2, RemainingTicks = 40 },
                },
                StructureIo = new[]
                {
                    new StructureIoRow { StructureIndex = 0, Slot = 1, ResourceId = ResourceId.Ore, Count = 7 },
                    new StructureIoRow { StructureIndex = 2, Slot = 0, ResourceId = ResourceId.Ore, Count = 5 },
                },
            };

            var back = JsonUtility.FromJson<SaveData>(JsonUtility.ToJson(data));

            Assert.AreEqual(SaveData.CurrentVersion, back.Version);
            Assert.AreEqual(3, back.Structures.Length);
            Assert.AreEqual(StructureType.Conveyor, back.Structures[1].Type);
            Assert.AreEqual(2, back.Structures[1].Direction);
            Assert.AreEqual(ResourceId.Ore, back.Structures[1].ConveyorResId);
            Assert.AreEqual(1, back.Structures[1].ConveyorCount);
            Assert.AreEqual(12u, back.Structures[0].RemainingTicks);
            Assert.AreEqual(2, back.StructureIo.Length);
            Assert.AreEqual(2, back.StructureIo[1].StructureIndex);
            Assert.AreEqual(0, back.StructureIo[1].Slot);
            Assert.AreEqual(5, back.StructureIo[1].Count);
        }

        [Test]
        public void RemainingTicks_RestoreNextTick_PreservesCooldownGap_AcrossEpochs()
        {
            uint saveNow = 5000u, savedNext = 5037u;
            uint remaining = ProductionMath.RemainingTicks(savedNext, saveNow);
            Assert.AreEqual(37u, remaining);

            uint restoreNow = 11u;
            uint restoredNext = ProductionMath.RestoreNextTick(restoreNow, remaining);
            Assert.AreEqual(48u, restoredNext);
        }

        [Test]
        public void Save_Lacking_V2_Arrays_DeserializesWithoutThrowing()
        {
            SaveData back = null;
            Assert.DoesNotThrow(() => back = JsonUtility.FromJson<SaveData>("{\"Version\":2,\"GoalCharge\":1,\"GoalTarget\":10}"));
            Assert.IsNotNull(back);
            Assert.IsTrue(back.Structures == null || back.Structures.Length == 0);
        }
    }
}