// <copyright file="CastleSiegeContextTest.cs" company="MUnique">
// Licensed under the MIT License. See LICENSE file in the project root for full license information.
// </copyright>

namespace MUnique.OpenMU.Tests.CastleSiege;

using MUnique.OpenMU.GameLogic.CastleSiege;

/// <summary>
/// Tests for the Castle Siege phase state machine (time-driven, injected clock).
/// </summary>
[TestFixture]
public class CastleSiegeContextTest
{
    private static readonly DateTime T0 = new(2026, 1, 1, 12, 0, 0, DateTimeKind.Utc);

    /// <summary>Tests that a fresh context starts in the ownership (resting) phase.</summary>
    [Test]
    public void StartsInOwnership()
    {
        var ctx = new CastleSiegeContext(Config());
        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Ownership));
    }

    /// <summary>Tests that force-starting moves the state machine into registration.</summary>
    [Test]
    public async Task ForceStartMovesToRegistrationAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        await ctx.ForceStartRegistrationAsync(T0);
        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Registration));
    }

    /// <summary>Tests that registration advances to preparation once its duration elapses.</summary>
    [Test]
    public async Task RegistrationAdvancesToPreparationAfterDurationAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        await ctx.ForceStartRegistrationAsync(T0);
        await ctx.TickAsync(T0.AddMinutes(4)); // still within registration
        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Registration));
        await ctx.TickAsync(T0.AddMinutes(5)); // registration duration elapsed
        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Preparation));
    }

    /// <summary>Tests a full cycle: registration -> preparation -> siege -> settlement -> ownership.</summary>
    [Test]
    public async Task FullCycleReturnsToOwnershipAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        await ctx.ForceStartRegistrationAsync(T0);
        await ctx.TickAsync(T0.AddMinutes(5));  // -> Preparation
        await ctx.TickAsync(T0.AddMinutes(7));  // +2 prep -> Siege
        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Siege));
        await ctx.TickAsync(T0.AddMinutes(17)); // +10 siege -> Settlement
        await ctx.TickAsync(T0.AddMinutes(17)); // Settlement -> Ownership
        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Ownership));
    }

    /// <summary>Tests that guilds can be registered (by name) during the registration phase.</summary>
    [Test]
    public async Task RegisterGuildCollectsNamesDuringRegistrationAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        await ctx.ForceStartRegistrationAsync(T0);
        ctx.RegisterGuild("Attackers");
        Assert.That(ctx.RegisteredGuilds, Does.Contain("Attackers"));
    }

    /// <summary>Tests the full siege objective chain: destroy defenses, then hold both switches to capture the throne.</summary>
    [Test]
    public async Task FullSiegeObjectiveChainToOwnershipAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        await ctx.ForceStartRegistrationAsync(T0);
        await ctx.ForcePhaseAsync(CastleSiegePhase.Siege, T0);
        ctx.SetDefenseCount(2);

        // Both switches held but defenses still up -> no capture.
        ctx.SetSwitchHolder(217, "Attackers");
        ctx.SetSwitchHolder(218, "Attackers");
        Assert.That(ctx.TryCaptureThrone("Attackers").Success, Is.False);

        ctx.NotifyDefenseDestroyed();
        ctx.NotifyDefenseDestroyed();

        // Only one switch held -> still no capture.
        ctx.SetSwitchHolder(218, null);
        Assert.That(ctx.TryCaptureThrone("Attackers").Success, Is.False);

        // Both switches held by the same guild + defenses down -> capture at the Sinior/Crown.
        ctx.SetSwitchHolder(218, "Attackers");
        Assert.That(ctx.TryCaptureThrone("Attackers").Success, Is.True);
        Assert.That(ctx.OccupierGuildName, Is.EqualTo("Attackers"));

        await ctx.TickAsync(T0.AddMinutes(20)); // Siege -> Settlement
        await ctx.TickAsync(T0.AddMinutes(20)); // Settlement -> Ownership
        Assert.That(ctx.OwnerGuildName, Is.EqualTo("Attackers"));
    }

    /// <summary>Tests that two different guilds each holding one switch cannot capture the throne.</summary>
    [Test]
    public async Task ThroneRequiresBothSwitchesBySameGuildAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        await ctx.ForceStartRegistrationAsync(T0);
        await ctx.ForcePhaseAsync(CastleSiegePhase.Siege, T0);
        ctx.SetDefenseCount(0);
        ctx.SetSwitchHolder(217, "A");
        ctx.SetSwitchHolder(218, "B");
        Assert.That(ctx.TryCaptureThrone("A").Success, Is.False);
        Assert.That(ctx.TryCaptureThrone("B").Success, Is.False);
    }

    /// <summary>Tests that capturing the throne outside the siege phase is a no-op.</summary>
    [Test]
    public void ThroneCaptureOutsideSiegeIsNoOp()
    {
        var ctx = new CastleSiegeContext(Config());
        ctx.SetSwitchHolder(217, "A");
        ctx.SetSwitchHolder(218, "A");
        Assert.That(ctx.TryCaptureThrone("A").Success, Is.False);
        Assert.That(ctx.OccupierGuildName, Is.Null);
    }

    /// <summary>Tests that restoring persisted state sets phase/owner/registrations without raising PhaseChanged.</summary>
    [Test]
    public void RestoreStateSetsStateWithoutFiringPhaseChanged()
    {
        var ctx = new CastleSiegeContext(Config());
        var phaseChangedFired = false;
        ctx.PhaseChanged += _ => phaseChangedFired = true;

        ctx.RestoreState("Winners", CastleSiegePhase.Ownership, T0, new[] { "Winners", "Losers" });

        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Ownership));
        Assert.That(ctx.OwnerGuildName, Is.EqualTo("Winners"));
        Assert.That(ctx.RegisteredGuilds, Is.EquivalentTo(new[] { "Winners", "Losers" }));
        Assert.That(phaseChangedFired, Is.False);
        Assert.That(ctx.ConsumeDirty(), Is.False, "restore must not mark the state dirty");
    }

    /// <summary>Tests that state-changing operations flip the dirty flag, which ConsumeDirty reads-and-resets.</summary>
    [Test]
    public async Task DirtyFlagTracksPersistableChangesAsync()
    {
        var ctx = new CastleSiegeContext(Config());
        Assert.That(ctx.ConsumeDirty(), Is.False, "a fresh context has nothing to persist");

        await ctx.ForceStartRegistrationAsync(T0); // phase transition -> dirty
        Assert.That(ctx.ConsumeDirty(), Is.True);
        Assert.That(ctx.ConsumeDirty(), Is.False, "ConsumeDirty resets the flag");

        ctx.RegisterGuild("Attackers"); // registration -> dirty
        Assert.That(ctx.ConsumeDirty(), Is.True);

        ctx.SetOwner("Attackers"); // owner change -> dirty
        Assert.That(ctx.ConsumeDirty(), Is.True);
    }

    private static CastleSiegeConfiguration Config() => new()
    {
        RegistrationDuration = TimeSpan.FromMinutes(5),
        PreparationDuration = TimeSpan.FromMinutes(2),
        SiegeDuration = TimeSpan.FromMinutes(10),
    };
}