using System.Collections.Generic;
using NUnit.Framework;
using SVSim.BattleNode.Protocol;

namespace SVSim.UnitTests.BattleNode.Integration;

/// <summary>
/// Headless-Conductor milestone tests (M-HC-*). The oracle is a node-native battle:
/// a FIXED master seed + FIXED decks drive the engine's receive path headless, and we
/// assert on engine board-state. By construction the node assigns idx = position in the
/// shuffled order, so the engine's headless draw reproduces the node's draw order.
///
/// Task 1 (M-HC-0a) exit criterion: the engine seats headless (IsReady) in the
/// SVSim.UnitTests process.
///
/// Task 2 (M-HC-0b) exit criterion: a node-generated <c>Deal</c> seats the 3-card hand and a
/// vanilla hand-card <c>Play</c> resolves on ENGINE board state (card left hand, PP dropped
/// by cost, board reflects the play) — driven through the receive CONDUCTOR, not the
/// direct ActionProcessor path the M2-M12 oracles use.
///
/// Task 3 (M-HC-1) exit criterion: the mulligan ops (<c>Swap</c> seats the post-mulligan hand —
/// idx-3 swapped for the next unused deck idx-4) and turn ops (<c>Ready</c>/<c>TurnStart</c>/
/// <c>TurnEnd</c>) resolve headless, so two full turns of a node-native battle track on engine
/// state (hand/board/PP/deck/turn/leader-life on both seats match the deterministic progression
/// at each boundary). All driven through the same receive conductor.
/// </summary>
[TestFixture]
[NonParallelizable]
public class HeadlessConductorTests
{
    [Test]
    public void Harness_seats_engine_headless_and_is_ready()
    {
        using var harness = NodeNativeBattleHarness.Create();

        Assert.That(harness.IsReady, Is.True,
            "Engine must seat headless: EngineGlobalInit ran + both decks seeded. " +
            "If false, the most likely cause is a missing cards.json content link in " +
            "SVSim.UnitTests.csproj (EngineGlobalInit reads AppContext.BaseDirectory/Data/cards.json).");

        // Non-vacuous: a seated engine has live board state for BOTH seats. Reading these off a
        // not-really-set-up engine would throw (Seat() guards on _mgr). Leader life is the headless
        // default (20) before any frame is ingested.
        Assert.That(harness.LeaderLife(playerSeat: true), Is.EqualTo(20), "seat A leader life");
        Assert.That(harness.LeaderLife(playerSeat: false), Is.EqualTo(20), "seat B leader life");
    }

    // The node's BuildDeal opening hand: pos->idx (0,1),(1,2),(2,3). hand == deck idx 1,2,3, i.e.
    // the top 3 of the node-native shuffled deck. Both seats deal the same idx triple.
    private static Dictionary<string, object?> DealBody() => new()
    {
        ["self"] = new List<object?>
        {
            new Dictionary<string, object?> { ["pos"] = 0, ["idx"] = 1 },
            new Dictionary<string, object?> { ["pos"] = 1, ["idx"] = 2 },
            new Dictionary<string, object?> { ["pos"] = 2, ["idx"] = 3 },
        },
        ["oppo"] = new List<object?>
        {
            new Dictionary<string, object?> { ["pos"] = 0, ["idx"] = 1 },
            new Dictionary<string, object?> { ["pos"] = 1, ["idx"] = 2 },
            new Dictionary<string, object?> { ["pos"] = 2, ["idx"] = 3 },
        },
    };

    // A minimal vanilla hand-card play: type 30 == PLAY_HAND; playIdx is the played card's index.
    // No targetList/orderList — a vanilla follower auto-resolves with no selection.
    private static Dictionary<string, object?> PlayBody(int playIdx) => new()
    {
        ["playIdx"] = playIdx,
        ["type"] = 30,
    };

    // A pos->idx list (the wire shape NetworkParameter.self/oppo carry: an ordered list of
    // {pos, idx} dicts). The receiver re-sorts by pos into the seat's idx list.
    private static List<object?> PosIdxList(params (int pos, int idx)[] entries)
    {
        var list = new List<object?>(entries.Length);
        foreach (var (pos, idx) in entries)
            list.Add(new Dictionary<string, object?> { ["pos"] = pos, ["idx"] = idx });
        return list;
    }

    // Server-authored Swap RESPONSE frame (the shadow ingests this, NOT the client's {idxList}
    // Submit). It carries the POST-mulligan self hand as pos->idx. Swapping the pos-2 card (deck
    // idx 3) pulls the next unused deck idx (4) — exactly battle_test_cl1's Swap receive frame.
    private static Dictionary<string, object?> SwapBody() => new()
    {
        ["self"] = PosIdxList((0, 1), (1, 2), (2, 4)),
    };

    // Server-authored Ready frame: both hands known + the idxChangeSeed/spin the receiver
    // consumes to seal the mulligan and start turn 1. Mirrors battle_test_cl1's Ready receive.
    private static Dictionary<string, object?> ReadyBody() => new()
    {
        ["self"] = PosIdxList((0, 1), (1, 2), (2, 4)),
        ["oppo"] = PosIdxList((0, 1), (1, 2), (2, 3)),
        ["idxChangeSeed"] = 857671914,
        ["spin"] = 0,
    };

    private static Dictionary<string, object?> TurnStartBody() => new() { ["spin"] = 0 };
    private static Dictionary<string, object?> TurnEndBody() => new() { ["turnState"] = 0 };

    [Test]
    public void Swap_seats_post_mulligan_hand_headless()
    {
        using var harness = NodeNativeBattleHarness.Create();

        var deal = harness.Push(NetworkBattleUri.Deal, DealBody(), isPlayerSeat: true);
        Assert.That(deal.Accepted, Is.True, $"Deal rejected: {deal.RejectReason}");
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(3), "post-Deal hand");

        var swap = harness.Push(NetworkBattleUri.Swap, SwapBody(), isPlayerSeat: true);
        Assert.That(swap.Accepted, Is.True, $"Swap rejected: {swap.RejectReason}");
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(3),
            "the swapped slot is replaced, not removed — hand stays at 3");

        // The pos-2 card was the deck-idx-3 card; the swap replaces it with the deck-idx-4 card.
        // The kept cards (idx 1, 2) stay put. Assert the engine hand holds idx {1,2,4}.
        var handIdxs = new[]
        {
            harness.PlayerHandCardIndex(0),
            harness.PlayerHandCardIndex(1),
            harness.PlayerHandCardIndex(2),
        };
        Assert.That(handIdxs, Is.EquivalentTo(new[] { 1, 2, 4 }),
            "post-mulligan hand must hold deck idx 1,2,4 (idx-3 swapped for the next unused idx-4)");
    }

    [Test]
    public void Two_turns_track_on_engine_state_headless()
    {
        // The oracle is the engine's OWN deterministic node-native progression off the fixed seed:
        // every value below is the engine-resolved state, reproducible by construction. The shadow
        // ingests the same server-authored frame stream the live node emits (Deal/Swap/Ready then
        // per-turn TurnStart/TurnEnd — the exact receive frames captured in battle_test_cl1.ndjson).
        using var harness = NodeNativeBattleHarness.Create();

        // --- mulligan barrier: Deal, Swap, Ready -------------------------------------------------
        Assert.That(harness.Push(NetworkBattleUri.Deal, DealBody(), isPlayerSeat: true).Accepted,
            Is.True, "Deal");
        Assert.That(harness.Push(NetworkBattleUri.Swap, SwapBody(), isPlayerSeat: true).Accepted,
            Is.True, "Swap");
        var ready = harness.Push(NetworkBattleUri.Ready, ReadyBody(), isPlayerSeat: true);
        Assert.That(ready.Accepted, Is.True, $"Ready rejected: {ready.RejectReason}");

        // After Ready the mulligan is sealed and the main phase is entered, but no turn has been
        // opened yet (TurnStart does the ramp + draw). Seat A holds its post-mulligan 3-card hand;
        // the opponent's hand stays hidden until its reveal frames land (Task 4) — node-native, the
        // opponent's opening hand is never disclosed to the relay before its own turn.
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(3), "seat A hand after Ready");
        Assert.That(harness.Turn(playerSeat: true), Is.EqualTo(0), "no turn opened yet after Ready");

        // --- turn 1 (seat A active) -------------------------------------------------------------
        // Seat A is the engine's player seat and is NOT game-first here, so turn-1 draws TWO cards
        // (the standard second-player turn-1 draw). PP ramps to 1.
        var t1 = harness.Push(NetworkBattleUri.TurnStart, TurnStartBody(), isPlayerSeat: true);
        Assert.That(t1.Accepted, Is.True, $"turn1 TurnStart rejected: {t1.RejectReason}");
        Assert.That(harness.Turn(playerSeat: true), Is.EqualTo(1), "seat A turn counter");
        Assert.That(harness.Pp(playerSeat: true), Is.EqualTo(1), "turn 1 ramps seat A max PP to 1");
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(5),
            "turn-1 second-player draw is 2 cards (3 -> 5)");
        Assert.That(harness.DeckCount(playerSeat: true), Is.EqualTo(25), "seat A deck after draw");

        // End seat A's turn.
        var t1End = harness.Push(NetworkBattleUri.TurnEnd, TurnEndBody(), isPlayerSeat: true);
        Assert.That(t1End.Accepted, Is.True, $"turn1 TurnEnd rejected: {t1End.RejectReason}");

        // --- turn 2 (seat B active) -------------------------------------------------------------
        // Seat B opens its first turn: PP ramps to 1 and it draws its turn-1 card. (Seat B's deck
        // started full at 30 because its opening hand is dealt into hidden zones, not its
        // HandCardList, until reveal — so its first visible draw moves deck 30 -> 29, hand 0 -> 1.)
        var t2 = harness.Push(NetworkBattleUri.TurnStart, TurnStartBody(), isPlayerSeat: false);
        Assert.That(t2.Accepted, Is.True, $"turn2 TurnStart rejected: {t2.RejectReason}");
        Assert.That(harness.Turn(playerSeat: false), Is.EqualTo(1), "seat B turn counter");
        Assert.That(harness.Pp(playerSeat: false), Is.EqualTo(1), "turn 2 ramps seat B max PP to 1");
        Assert.That(harness.HandCount(playerSeat: false), Is.EqualTo(1), "seat B turn-1 draw");

        // Both leaders untouched (no damage dealt across the two opening turns) — state tracks
        // cleanly on BOTH seats at the turn boundary.
        Assert.That(harness.LeaderLife(playerSeat: true), Is.EqualTo(20), "seat A leader life");
        Assert.That(harness.LeaderLife(playerSeat: false), Is.EqualTo(20), "seat B leader life");
    }

    [Test]
    public void Deal_seats_three_card_hand_headless()
    {
        using var harness = NodeNativeBattleHarness.Create();

        var result = harness.Push(NetworkBattleUri.Deal, DealBody(), isPlayerSeat: true);

        Assert.That(result.Accepted, Is.True, $"Deal rejected: {result.RejectReason}");
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(3),
            "Deal must seat the 3-card opening hand on the player seat.");
    }

    [Test]
    public void Vanilla_play_resolves_on_engine_state_headless()
    {
        // Deck idx 1/2/3 are the top three of the shuffled deck; arrange idx-1 to be a known vanilla
        // follower so the Play assertion is decisive. Put the vanilla follower first; the rest of the
        // default deck (spellboost + vanillas) follows.
        var deck = new List<long> { NodeNativeBattleHarness.VanillaFollowerId };
        deck.AddRange(NodeNativeBattleHarness.DefaultDeck());
        deck = deck.GetRange(0, 30);

        using var harness = NodeNativeBattleHarness.Create(seatADeck: deck);

        var deal = harness.Push(NetworkBattleUri.Deal, DealBody(), isPlayerSeat: true);
        Assert.That(deal.Accepted, Is.True, $"Deal rejected: {deal.RejectReason}");
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(3), "post-Deal hand");

        var ppBefore = harness.Pp(playerSeat: true);
        var handBefore = harness.HandCount(playerSeat: true);
        var boardBefore = harness.BoardCount(playerSeat: true);

        // The played card is at hand index 1 (deck idx 1 -> the first dealt card; engine card Index
        // mirrors deck position+1). The shuffle determines which deck idx-1 maps to; we only need a
        // vanilla follower in the opening hand. Use the first dealt idx.
        var playIdx = harness.PlayerHandCardIndex(0);
        var play = harness.Push(NetworkBattleUri.PlayActions, PlayBody(playIdx), isPlayerSeat: true);

        Assert.That(play.Accepted, Is.True, $"Play rejected: {play.RejectReason}");
        Assert.That(harness.HandCount(playerSeat: true), Is.EqualTo(handBefore - 1),
            "the played card must leave the hand");
        Assert.That(harness.BoardCount(playerSeat: true), Is.EqualTo(boardBefore + 1),
            "a follower play must add one to the board");
        Assert.That(harness.Pp(playerSeat: true), Is.LessThan(ppBefore),
            "PP must drop by the played card's cost");
    }
}