using System.Collections.Immutable;
using SVSim.BattleNode.Bridge;
using SVSim.BattleNode.Protocol;
using SVSim.BattleNode.Protocol.Bodies;

namespace SVSim.BattleNode.Lifecycle;

/// <summary>
/// v1 hand-rolled scripted opponent. Static frame builders for the five lifecycle uris
/// (Matched / BattleStart / Deal / Swap response / Ready) plus a trivial opponent TurnStart
/// the dispatch pushes after the player's TurnEnd. The values are templated from the TK2
/// captures at <c>data_dumps/captures/battle-traffic_tk2_regular.ndjson</c> — anything
/// hardcoded here came from a real prod frame, with names + provenance in
/// <see cref="ScriptedProfiles"/>. The player-half of Matched/BattleStart now reads from
/// <see cref="MatchContext"/> instead of <see cref="ScriptedProfiles"/>.
/// </summary>
public static class ScriptedLifecycle
{
    /// <summary>
    /// Viewer id we present as the opponent on every scripted push. Out-of-range vs. real
    /// viewer ids so it can't collide with a real account in the auth pipeline.
    /// </summary>
    public const long FakeOpponentViewerId = 999_999_999L;

    public static MsgEnvelope BuildMatched(MatchContext ctx, long playerViewerId, long opponentViewerId, string battleId) =>
        EnvelopeForPush(NetworkBattleUri.Matched,
            new MatchedBody(
                SelfInfo: new MatchedSelfInfo(
                    CountryCode: ctx.CountryCode,
                    UserName: ctx.UserName,
                    SleeveId: ctx.SleeveId,
                    EmblemId: ctx.EmblemId,
                    DegreeId: ctx.DegreeId,
                    FieldId: ctx.FieldId,
                    IsOfficial: ctx.IsOfficial,
                    OppoId: opponentViewerId,
                    Seed: ScriptedProfiles.BattleSeed),
                OppoInfo: ScriptedProfiles.OpponentMatchedProfile with { OppoId = playerViewerId },
                SelfDeck: BuildPlayerDeck(ctx.SelfDeckCardIds)),
            bid: battleId);

    public static MsgEnvelope BuildBattleStart(MatchContext ctx, long playerViewerId) =>
        EnvelopeForPush(NetworkBattleUri.BattleStart,
            new BattleStartBody(
                TurnState: 0,    // player goes first
                BattleType: ctx.BattleType,
                SelfInfo: new BattleStartSelfInfo(
                    Rank: ScriptedProfiles.PlayerRank,
                    BattlePoint: ScriptedProfiles.PlayerBattlePoint,
                    ClassId: ctx.ClassId,
                    CharaId: ctx.CharaId,
                    CardMasterName: ctx.CardMasterName),
                OppoInfo: ScriptedProfiles.OpponentBattleStartProfile));

    public static MsgEnvelope BuildDeal() =>
        EnvelopeForPush(NetworkBattleUri.Deal,
            new DealBody(
                Self: new[] { new PosIdx(0, 1), new PosIdx(1, 2), new PosIdx(2, 3) },
                Oppo: new[] { new PosIdx(0, 1), new PosIdx(1, 2), new PosIdx(2, 3) }));

    /// <summary>
    /// Initial 3-card hand idxs from <see cref="BuildDeal"/>. Each position in this array
    /// is one card; the value is the card's deck idx. <see cref="ImmutableArray{T}"/> enforces
    /// the "read-only constant" contract at the type level — callers cannot mutate it, even
    /// accidentally (the prior <c>long[]</c> allowed in-place modification by anyone with the
    /// field reference).
    /// </summary>
    private static readonly ImmutableArray<long> InitialHand = ImmutableArray.Create<long>(1, 2, 3);

    /// <summary>
    /// Compute the player's hand after a mulligan. For every idx in <paramref name="swapIndices"/>
    /// that is currently in the hand, replace it with the next unused deck idx (starting at 4,
    /// since 1..3 were dealt). Positions of kept cards are preserved.
    /// </summary>
    public static long[] ComputeHandAfterSwap(IReadOnlyList<long> swapIndices)
    {
        var hand = InitialHand.ToArray();
        var nextDeckIdx = 4L;
        for (var pos = 0; pos < hand.Length; pos++)
        {
            if (swapIndices.Contains(hand[pos]))
            {
                hand[pos] = nextDeckIdx++;
            }
        }
        return hand;
    }

    public static MsgEnvelope BuildSwapResponse(IReadOnlyList<long> hand) =>
        EnvelopeForPush(NetworkBattleUri.Swap,
            new SwapResponseBody(Self: BuildPosIdxList(hand)));

    public static MsgEnvelope BuildReady(IReadOnlyList<long> hand) =>
        EnvelopeForPush(NetworkBattleUri.Ready,
            new ReadyBody(
                Self: BuildPosIdxList(hand),
                Oppo: BuildPosIdxList(InitialHand),
                IdxChangeSeed: ScriptedProfiles.ReadyIdxChangeSeed,
                Spin: ScriptedProfiles.ReadySpin));

    /// <summary>
    /// First half of the v1.1 scripted opponent turn cycle: pushed after the player's
    /// TurnEnd, transitions the client into "Opponent's turn…" state. Paired with
    /// <see cref="BuildOpponentTurnEnd"/>, which immediately follows and hands control
    /// back to the player.
    /// </summary>
    public static MsgEnvelope BuildOpponentTurnStart() =>
        EnvelopeForPush(NetworkBattleUri.TurnStart,
            new OpponentTurnStartBody(Spin: ScriptedProfiles.OpponentTurnStartSpin));

    /// <summary>
    /// Server-pushed TurnEnd transition that closes the opponent's turn and hands control
    /// back to the player. Paired with <see cref="BuildOpponentTurnStart"/> in the v1.1 loop.
    /// Wire shape from prod capture battle-traffic_tk2_regular.ndjson L18:
    /// <c>{"uri":"TurnEnd","turnState":0,"resultCode":1,"playSeq":N}</c>.
    /// </summary>
    public static MsgEnvelope BuildOpponentTurnEnd() =>
        EnvelopeForPush(NetworkBattleUri.TurnEnd, new TurnEndBody(TurnState: 0));

    private static IReadOnlyList<PosIdx> BuildPosIdxList(IReadOnlyList<long> hand)
    {
        var list = new List<PosIdx>(hand.Count);
        for (var pos = 0; pos < hand.Count; pos++)
        {
            list.Add(new PosIdx(Pos: pos, Idx: (int)hand[pos]));
        }
        return list;
    }

    private static IReadOnlyList<DeckCardRef> BuildPlayerDeck(IReadOnlyList<long> cardIds)
    {
        var deck = new List<DeckCardRef>(cardIds.Count);
        for (var i = 0; i < cardIds.Count; i++)
        {
            deck.Add(new DeckCardRef(Idx: i + 1, CardId: cardIds[i]));
        }
        return deck;
    }

    private static MsgEnvelope EnvelopeForPush(NetworkBattleUri uri, IMsgBody body, string? bid = null) =>
        new(uri,
            ViewerId: FakeOpponentViewerId,
            Uuid: WireConstants.ServerUuid,
            Bid: bid,
            Try: 0,
            Cat: EmitCategory.Battle,
            PubSeq: null,
            PlaySeq: null,
            Body: body);
}