namespace LivingVillage.Kernel.Tests

open System
open System.IO
open Microsoft.VisualStudio.TestTools.UnitTesting
open LivingVillage.Kernel
open LivingVillage.Kernel.Sim
open LivingVillage.Desktop

module private M6aHarness =

    let zeroInput = { Input = { MoveX = 0.0f; MoveY = 0.0f } }

    let atNpc (id: int) (world: World) : World =
        let npc = world.Npcs.[id]
        { world with Avatar = { world.Avatar with Pos = npc.Pos } }

    let readyForChat (world: World) : World =
        { world with
            Npcs =
                world.Npcs
                |> Array.map (fun npc ->
                    { npc with
                        Mind =
                            { npc.Mind with
                                Action = Wander
                                Target = actionTarget Wander
                                ActionAge = minActionTicks
                                EffectDone = true } }) }

    let withDialogue (world: World) : World =
        match Sim.chooseDialogue (NpcId 0) SmallTalk (atNpc 0 world) with
        | DialogueSucceeded (_, next) -> next
        | DialogueRejected (failure, _) -> Assert.Fail($"dialogue rejected: {failure}"); Unchecked.defaultof<World>

    let withChat (world: World) : World =
        match Sim.chat { Narrator = NpcId 0; Receiver = NpcId 1 } (readyForChat world) with
        | ChatSucceeded (Some _, next) -> next
        | ChatSucceeded (None, _) -> Assert.Fail("chat should create a rumor"); Unchecked.defaultof<World>
        | ChatRejected (failure, _) -> Assert.Fail($"chat rejected: {failure}"); Unchecked.defaultof<World>

    let withTrade (world: World) : World =
        match Sim.trade { Buyer = NpcId 0; Seller = NpcId 1; Item = Food; Quantity = 1 } world with
        | TradeSucceeded next -> next
        | TradeRejected (failure, _) -> Assert.Fail($"trade rejected: {failure}"); Unchecked.defaultof<World>

    let advance (inputs: Input list) (world: World) : World =
        inputs |> List.fold (fun current input -> Sim.step { Input = input } current) world

    let advanceTrace (inputs: Input list) (world: World) : World list =
        inputs
        |> List.scan (fun current input -> Sim.step { Input = input } current) world
        |> List.tail

    let withTempSave (action: string -> unit) =
        let id = Guid.NewGuid().ToString("N")
        let path = Path.Combine(Path.GetTempPath(), $"living-village-m6a-{id}.save")
        try
            action path
        finally
            if File.Exists path then File.Delete path

[<TestClass>]
type M6aTests () =

    [<TestMethod>]
    member _.SaveLoadPreservesWorldAndDeterministicContinuation () =
        let world =
            Sim.initialWorldN 7UL 4
            |> M6aHarness.withDialogue
            |> M6aHarness.withChat
            |> M6aHarness.withTrade
            |> fun current ->
                let tick = 22L * (Sim.ticksPerDay / 24L)
                { current with Tick = tick; Time = float tick * Sim.dtSeconds }

        M6aHarness.withTempSave (fun path ->
            WorldSave.saveToFile path world

            match WorldSave.loadFromFile path with
            | Error failure -> Assert.Fail($"save should load: {failure}")
            | Ok restored ->
                Assert.AreEqual<string>(WorldSave.save world, WorldSave.save restored)
                Assert.AreEqual<float>(world.Time, restored.Time)
                Assert.IsTrue(Sim.isNightTick restored.Tick)
                Assert.AreEqual<Needs>(world.Avatar.Mind.Needs, restored.Avatar.Mind.Needs)
                Assert.AreEqual<float32>(world.Avatar.Mind.Needs.Money, restored.Avatar.Mind.Needs.Money)
                CollectionAssert.AreEqual(world.Npcs, restored.Npcs)
                Assert.AreEqual<Map<ItemKind, int>>(world.Npcs.[0].Inventory, restored.Npcs.[0].Inventory)
                Assert.AreEqual<InteractionEvent list>(world.Events, restored.Events)
                Assert.AreEqual<RumorEvent list>(world.Rumors, restored.Rumors)
                Assert.AreEqual<AnnalEntry list>(world.Annals, restored.Annals)
                Assert.AreEqual<uint64>(world.Rng.State, restored.Rng.State)

                let inputs =
                    [ { MoveX = 0.5f; MoveY = -0.25f }
                      { MoveX = 0.0f; MoveY = 0.0f }
                      { MoveX = -1.0f; MoveY = 0.75f }
                      { MoveX = 0.25f; MoveY = 0.0f } ]
                let continued = M6aHarness.advanceTrace inputs world
                let restoredContinued = M6aHarness.advanceTrace inputs restored
                Assert.AreEqual<string list>(continued |> List.map WorldSave.save, restoredContinued |> List.map WorldSave.save)
                Assert.AreEqual<uint64 list>(continued |> List.map (fun next -> next.Rng.State), restoredContinued |> List.map (fun next -> next.Rng.State))
                Assert.AreEqual<InteractionEvent list list>(continued |> List.map (fun next -> next.Events), restoredContinued |> List.map (fun next -> next.Events))
                Assert.AreEqual<string>(WorldSave.save (List.last continued), WorldSave.save (List.last restoredContinued)))

    [<TestMethod>]
    member _.RejectedFilesDoNotReplaceCurrentWorld () =
        let currentWorld = Sim.initialWorldN 99UL 2
        let before = WorldSave.save currentWorld
        let mutable current = currentWorld

        let reject path =
            match WorldSave.loadFromFile path with
            | Ok loaded ->
                current <- loaded
                Assert.Fail("invalid save must not load")
            | Error _ -> ()
            Assert.AreEqual<string>(before, WorldSave.save current)

        M6aHarness.withTempSave (fun path ->
            reject (path + ".missing")

            File.WriteAllText(path, "LV_WORLD_SAVE_V0")
            reject path

            File.WriteAllText(path, WorldSave.save currentWorld + "|trailing-corruption")
            reject path)

    [<TestMethod>]
    member _.CorruptNumericAndInventoryValuesAreRejected () =
        let world = Sim.initialWorldN 7UL 2

        M6aHarness.withTempSave (fun path ->
            let nonFinite = { world with Time = Double.NaN }
            WorldSave.saveToFile path nonFinite
            match WorldSave.loadFromFile path with
            | Ok _ -> Assert.Fail("non-finite time must be rejected")
            | Error _ -> ()

            let invalidInventory =
                { world with
                    Npcs =
                        [| { world.Npcs.[0] with Inventory = Map.ofList [ Food, -1 ] }
                           world.Npcs.[1] |] }
            WorldSave.saveToFile path invalidInventory
            match WorldSave.loadFromFile path with
            | Ok _ -> Assert.Fail("negative inventory must be rejected")
            | Error _ -> ())

    [<TestMethod>]
    member _.SimulationClockSupportsPauseAndRequestedSpeeds () =
        let initial = SimulationControl.initial
        Assert.AreEqual<int>(1, SimulationControl.stepsPerFrame initial)
        Assert.AreEqual<int>(2, SimulationControl.stepsPerFrame (SimulationControl.setSpeed TwoX initial))
        Assert.AreEqual<int>(5, SimulationControl.stepsPerFrame (SimulationControl.setSpeed FiveX initial))
        let paused = SimulationControl.togglePause initial
        Assert.IsTrue(paused.Paused)
        Assert.AreEqual<int>(0, SimulationControl.stepsPerFrame paused)
        let resumed = SimulationControl.togglePause paused
        Assert.IsFalse(resumed.Paused)
        Assert.AreEqual<SimulationSpeed>(OneX, resumed.Speed)

    [<TestMethod>]
    member _.BoundsAreParameterizableAndClampMovementAtLargeMapEdge () =
        Sim.configureBounds 512 384
        try
            let world = Sim.initialWorld (uint64 42)
            let stepped = Sim.step { Input = { MoveX = 1.0f; MoveY = 1.0f } } world
            // Legacy maps clamp within 64x48; at 512x384 the avatar is free to wander
            // well past the old tile limits.
            let maxX = float32 (Sim.mapWidthTiles * Sim.tilePixels - Sim.tilePixels)
            let maxY = float32 (Sim.mapHeightTiles * Sim.tilePixels - Sim.tilePixels)
            Assert.IsTrue(stepped.Avatar.Pos.X <= maxX)
            Assert.IsTrue(stepped.Avatar.Pos.Y <= maxY)
            Assert.AreEqual<int>(512, Sim.mapWidthTiles)
        finally
            Sim.configureBounds 64 48

    [<TestMethod>]
    member _.SaveV1LegacyStillReadable () =
        let world = Sim.initialWorld (uint64 42)
        WorldSave.saveToFile "p7-legacy-src.save" world
        let modern = System.IO.File.ReadAllText "p7-legacy-src.save"
        // v2 = version|w|h|body...; strip the two bounds integers and roll the header back to v1.
        let firstPipe = modern.IndexOf('|')
        let secondPipe = modern.IndexOf('|', firstPipe + 1)
        let thirdPipe = modern.IndexOf('|', secondPipe + 1)
        System.IO.File.WriteAllText("p7-legacy.save", ("LV_WORLD_SAVE_V1" + modern.Substring(thirdPipe)))
        let text = System.IO.File.ReadAllText "p7-legacy.save"
        Sim.configureBounds 512 384
        try
            Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V1"), "legacy header must be v1")
            match WorldSave.loadFromFile "p7-legacy.save" with
            | Ok loaded ->
                Assert.AreEqual<int>(64, Sim.mapWidthTiles)
                Assert.AreEqual<int>(48, Sim.mapHeightTiles)
            | Error message ->
                Assert.Fail(sprintf "legacy v1 load failed: %s" message)
        finally
            Sim.configureBounds 64 48

    [<TestMethod>]
    member _.SaveV2RecordsBoundsAndStaysDeterministic () =
        Sim.configureBounds 512 384
        try
            let world = Sim.initialWorld (uint64 7)
            WorldSave.saveToFile "p7-v2.save" world
            let text = System.IO.File.ReadAllText "p7-v2.save"
            Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V2"), "v2 save must carry bounds")
            Sim.configureBounds 64 48
            match WorldSave.loadFromFile "p7-v2.save" with
            | Ok loaded ->
                Assert.AreEqual<int>(512, Sim.mapWidthTiles)
                Assert.AreEqual<int>(384, Sim.mapHeightTiles)
                Assert.AreEqual<int64>(loaded.Tick, world.Tick)
            | Error message ->
                Assert.Fail(sprintf "v2 load failed: %s" message)
        finally
            Sim.configureBounds 64 48

    [<TestMethod>]
    member _.ConfiguredLegacyStepCountsRemainExactUntilManualSpeedSelection () =
        let control, legacySteps = SimulationControl.initialForConfiguredSteps 7
        Assert.AreEqual<int option>(Some 7, legacySteps)
        Assert.AreEqual<int>(7, SimulationControl.stepsPerFrameWithLegacy legacySteps control)
        Assert.AreEqual<int>(0, SimulationControl.stepsPerFrameWithLegacy legacySteps (SimulationControl.togglePause control))
        let manuallySelected = SimulationControl.setSpeed TwoX control
        Assert.AreEqual<int>(2, SimulationControl.stepsPerFrameWithLegacy None manuallySelected)

    [<TestMethod>]
    member _.OccupationProfilesMatchTheDesignTable () =
        let farmer = LivingVillage.Kernel.Occupation.profileOf Occupation.Farmer
        Assert.AreEqual<int>(60, farmer.InitialMoney)
        Assert.AreEqual<float32>(100.0f, farmer.InitialEnergy)
        Assert.AreEqual<int>(12, snd (List.head farmer.InitialInventory))
        let fisher = Occupation.profileOf Occupation.Fisher
        Assert.AreEqual<int>(45, fisher.InitialMoney)
        Assert.AreEqual<float32>(95.0f, fisher.InitialEnergy)
        Assert.AreEqual<int>(8, snd (List.head fisher.InitialInventory))
        Assert.AreEqual<int>(3, snd (List.item 1 fisher.InitialInventory))
        let peddler = Occupation.profileOf Occupation.Peddler
        Assert.AreEqual<int>(90, peddler.InitialMoney)
        Assert.AreEqual<int>(6, snd (List.head peddler.InitialInventory))
        Assert.AreEqual<int>(4, snd (List.item 1 peddler.InitialInventory))
        let scholar = Occupation.profileOf Occupation.Scholar
        Assert.AreEqual<int>(70, scholar.InitialMoney)
        Assert.AreEqual<int>(10, snd (List.head scholar.InitialInventory))
        Assert.AreEqual<int>(2, snd (List.item 1 scholar.InitialInventory))

    [<TestMethod>]
    member _.WorldSaveV3RoundTripsOccupation () =
        let world = Sim.initialWorld (uint64 11)
        let state = Occupation.stateOf Occupation.Fisher
        WorldSave.saveToFileWith (Some state) "p10-v3.save" world
        let text = System.IO.File.ReadAllText "p10-v3.save"
        Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V3"), "v3 header expected")
        match WorldSave.loadFromFileWith "p10-v3.save" with
        | Ok (_loaded, restored) ->
            match restored with
            | Some st ->
                Assert.AreEqual<int>(45, st.Profile.InitialMoney)
                Assert.AreEqual<int>(0, st.TaskToken)
                Assert.AreEqual<int>(0, st.StoryStage)
            | None -> Assert.Fail("v3 round trip lost the occupation")
        | Error message -> Assert.Fail(sprintf "v3 round trip failed: %s" message)

    [<TestMethod>]
    member _.WorldSaveLegacySavesStillReadWithoutOccupation () =
        let world = Sim.initialWorld (uint64 42)
        WorldSave.saveToFile "p10-v2.save" world
        Assert.IsTrue((System.IO.File.ReadAllText "p10-v2.save").StartsWith("LV_WORLD_SAVE_V2"))
        match WorldSave.loadFromFileWith "p10-v2.save" with
        | Ok (_w, occ) -> Assert.AreEqual<obj>(null, occ |> Option.map (fun _ -> box 1) |> Option.defaultValue null)
        | Error message -> Assert.Fail(sprintf "v2 read failed: %s" message)
        Sim.configureBounds 64 48

    [<TestMethod>]
    member _.OccupationBootstrapSavesAreByteIdenticalForSameSeed () =
        let seed = uint64 4242
        let state1 = Some (Occupation.stateOf Occupation.Peddler)
        let state2 = Some (Occupation.stateOf Occupation.Peddler)
        let world1 = WorldBootstrap.initialWorldWithOccupation false seed 4 state1
        let world2 = WorldBootstrap.initialWorldWithOccupation false seed 4 state2
        let text1 = WorldSave.saveWith state1 world1
        let text2 = WorldSave.saveWith state2 world2
        Assert.AreEqual<string>(text1, text2)

    [<TestMethod>]
    member _.OccupationChineseNamesAreKernelSideConstants () =
        Assert.AreEqual<string>("农夫", Occupation.nameOf Occupation.Farmer)
        Assert.AreEqual<string>("渔夫", Occupation.nameOf Occupation.Fisher)
        Assert.AreEqual<string>("货郎", Occupation.nameOf Occupation.Peddler)
        Assert.AreEqual<string>("书生", Occupation.nameOf Occupation.Scholar)

    /// P20：存档 v2 的边界字段在非默认尺寸下必须 round-trip，读回后
    /// mapWidthTiles/mapHeightTiles 恢复且再次保存与原文逐字节一致。
    /// 旧 64x48 存档的 Round-trip 保持不变由既有 v1/v2 用例覆盖。
    [<TestMethod>]
    member _.SaveRoundTripsParameterizedMapBounds () =
        let path = "p20-bounds-v2.save"
        try
            Sim.configureBounds 256 192
            let world = Sim.initialWorld (uint64 4242)
            WorldSave.saveToFile path world
            let text = File.ReadAllText path
            Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V2"), "bounds save must stay v2")
            match WorldSave.loadFromFile path with
            | Error failure -> Assert.Fail(sprintf "bounds save should load: %s" failure)
            | Ok restored ->
                Assert.AreEqual<int>(256, Sim.mapWidthTiles)
                Assert.AreEqual<int>(192, Sim.mapHeightTiles)
                Assert.AreEqual<string>(text, WorldSave.save restored)
        finally
            Sim.configureBounds 64 48
            if File.Exists path then File.Delete path

    /// P23：512x384 参数化边界在存档 v2 中 round-trip；同 world 两次保存逐字节一致，
    /// 读回后再次保存仍与原文一致（v1 的 64x48 兼容由 SaveV1LegacyStillReadable 覆盖）。
    [<TestMethod>]
    member _.SaveRoundTrips512x384BoundsAndIsByteStable () =
        let path = "p23-bounds-512-v2.save"
        let path2 = path + ".2"
        try
            Sim.configureBounds 512 384
            let world = Sim.initialWorld (uint64 4242)
            WorldSave.saveToFile path world
            WorldSave.saveToFile path2 world
            let text = File.ReadAllText path
            Assert.IsTrue(text.StartsWith("LV_WORLD_SAVE_V2"), "bounds save must stay v2")
            Assert.AreEqual<string>(text, File.ReadAllText path2)
            Sim.configureBounds 64 48
            match WorldSave.loadFromFile path with
            | Error failure -> Assert.Fail(sprintf "512x384 bounds save should load: %s" failure)
            | Ok restored ->
                Assert.AreEqual<int>(512, Sim.mapWidthTiles)
                Assert.AreEqual<int>(384, Sim.mapHeightTiles)
                Assert.AreEqual<string>(text, WorldSave.save restored)
        finally
            Sim.configureBounds 64 48
            if File.Exists path then File.Delete path
            if File.Exists path2 then File.Delete path2