using System.Linq;
using SVSim.BattleNode.Bridge;
using SVSim.BattleNode.Lifecycle;
using SVSim.BattleNode.Protocol;

namespace SVSim.BattleNode.Sessions.Participants;

/// <summary>
/// Server-scripted opponent (today's v1.2 testing-harness behavior, repackaged).
/// On <see cref="PushAsync"/> with <c>TurnEnd</c> or <c>TurnEndFinal</c>, fires
/// <see cref="FrameEmitted"/> three times: <c>OpponentTurnStart</c>,
/// <c>OpponentTurnEnd</c>, <c>OpponentJudge</c>. All other URIs are swallowed
/// (no opponent reaction needed for v1.2 behavior).
/// </summary>
/// <remarks>
/// ViewerId, Context are fixtures matching <see cref="ScriptedLifecycle.FakeOpponentViewerId"/>
/// and a scripted opponent profile. The Context fixture is the source of truth for the
/// scripted opponent's half of Matched and BattleStart (cosmetics, deck count, class/chara) —
/// <see cref="BattleSession.ComputeFrames"/> reads <c>other.Context</c> for those frames.
/// Deal still uses fixed scripted frames that ignore Context.
/// </remarks>
public sealed class ScriptedBotParticipant : IBattleParticipant
{
    public long ViewerId => ScriptedLifecycle.FakeOpponentViewerId;
    public MatchContext Context { get; } = new(
        // 30 dummy card ids so oppoCtx.SelfDeckCardIds.Count == 30 — prod frame[2] (Matched)
        // shipped OppoDeckCount: 30.
        SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 0L).ToList(),
        // BattleStart opponent half (frame[5]): ClassId/CharaId both "8" (neutral test class).
        ClassId: "8", CharaId: "8", CardMasterName: "card_master_node_10015",
        // Matched opponent half (frame[2]): cosmetic fields from the prod capture.
        CountryCode: "JPN", UserName: "Opponent", SleeveId: "704141010",
        EmblemId: "400001100", DegreeId: "120027", FieldId: 5, IsOfficial: 0,
        BattleType: 0);

    public event Func<MsgEnvelope, CancellationToken, Task>? FrameEmitted;

    public async Task PushAsync(MsgEnvelope envelope, bool noStock, CancellationToken ct)
    {
        // React to the player's TurnEnd with the three-frame burst (TurnStart / TurnEnd /
        // Judge) — that's the v1.2 "scripted bot takes its turn" behavior. Everything else
        // (including TurnEndFinal) is silently swallowed: TurnEndFinal is the player's
        // game-end signal and is handled directly by the BattleSession dispatch arm, which
        // pushes BattleFinish per-side; the bot doesn't need to react.
        if (envelope.Uri is NetworkBattleUri.TurnEnd)
        {
            await EmitAsync(ScriptedLifecycle.BuildOpponentTurnStart(), ct).ConfigureAwait(false);
            await EmitAsync(ScriptedLifecycle.BuildOpponentTurnEnd(), ct).ConfigureAwait(false);
            await EmitAsync(ScriptedLifecycle.BuildOpponentJudge(), ct).ConfigureAwait(false);
        }
    }

    public Task RunAsync(CancellationToken ct) => Task.CompletedTask;
    public Task TerminateAsync(BattleFinishReason reason) => Task.CompletedTask;
    public ValueTask DisposeAsync() => ValueTask.CompletedTask;

    private Task EmitAsync(MsgEnvelope env, CancellationToken ct) =>
        FrameEmitted?.Invoke(env, ct) ?? Task.CompletedTask;
}