using ClaudeDo.Data.Models;
using ClaudeDo.Data.Repositories;
using ClaudeDo.Worker.External;
using ClaudeDo.Worker.Hub;
using ClaudeDo.Worker.Runner;
using ClaudeDo.Worker.Tests.Infrastructure;
using ClaudeDo.Worker.Usage;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;

namespace ClaudeDo.Worker.Tests.Runner;

/// Auto-restart of a list-handler ConPTY session that died at the usage limit. The UI half (the
/// exit code reaching the worker at all) lives in Ui.Tests' InteractiveTerminalViewModel /
/// MissionControlViewModel tests.
public sealed class HandlerRestartCoordinatorTests : IDisposable
{
    private readonly DbFixture _db = new();
    private readonly string _tempDir;
    private readonly CapturingHubContext _hub = new();
    private readonly HandlerRoundState _rounds;

    private static readonly DateTimeOffset ResetsAt = new(2026, 9, 3, 2, 0, 0, TimeSpan.Zero);

    public HandlerRestartCoordinatorTests()
    {
        _tempDir = Path.Combine(Path.GetTempPath(), $"cd_handlerrestart_{Guid.NewGuid():N}");
        Directory.CreateDirectory(_tempDir);
        _rounds = new HandlerRoundState(Path.Combine(_tempDir, "handler-rounds.json"));
    }

    public void Dispose() { _db.Dispose(); try { Directory.Delete(_tempDir, true); } catch { } }

    private static readonly DateTimeOffset DueAt = ResetsAt + HandlerUsageGuard.ResetGrace;

    private HandlerRestartCoordinator BuildCoordinator(UsageState usage) =>
        new(_db.CreateFactory(), usage, _rounds, new HubBroadcaster(_hub),
            NullLogger<HandlerRestartCoordinator>.Instance);

    /// The coordinator only parks the restart; this is what actually fires it. `now` decides whether
    /// the parked handoff is already due, so a 5h wait costs a test nothing.
    private HandlerUsageGuard BuildGuard(UsageState usage, DateTimeOffset now) =>
        new(_db.CreateFactory(), usage, _rounds, new HandoffRoundTracker(), new HubBroadcaster(_hub),
            NullLogger<HandlerUsageGuard>.Instance)
        { NowUtc = () => now };

    /// The one signal a ConPTY death gives the worker: the 5h window pinned at the limit.
    private static UsageState AtUsageLimit(double percent = 100) =>
        Snapshot(new UsageBucket(percent, ResetsAt));

    private static UsageState Snapshot(UsageBucket? fiveHour)
    {
        var state = new UsageState();
        state.ReportSuccess(new UsageSnapshot(fiveHour, null, Array.Empty<UsageLimitRow>(), DateTime.UtcNow));
        return state;
    }

    private int _nextNumber = 1;

    private async Task<string> SeedHandlerTaskAsync(bool powerUseEnabled = true, bool powerUseAllowed = true)
    {
        var listId = Guid.NewGuid().ToString();
        var taskId = Guid.NewGuid().ToString();
        using (var ctx = _db.CreateContext())
        {
            ctx.Lists.Add(new ListEntity { Id = listId, Name = "L", WorkingDir = _tempDir, CreatedAt = DateTime.UtcNow });
            ctx.ListConfigs.Add(new ListConfigEntity { ListId = listId, PowerUseAllowed = powerUseAllowed });
            ctx.Tasks.Add(new TaskEntity
            {
                Id = taskId, ListId = listId, Title = "Handler", Number = _nextNumber++,
                IsManual = true, CreatedAt = DateTime.UtcNow,
            });
            await ctx.SaveChangesAsync();

            // Written straight to the row: AppSettingsRepository.UpdateAsync deliberately doesn't
            // copy PowerUseEnabled (the usage monitor owns that toggle, not the settings modal).
            await new AppSettingsRepository(ctx).GetAsync(); // materializes the singleton row
            var settings = await ctx.AppSettings.FirstAsync(s => s.Id == AppSettingsEntity.SingletonId);
            settings.PowerUseEnabled = powerUseEnabled;
            await ctx.SaveChangesAsync();
        }
        return taskId;
    }

    private IReadOnlyList<CapturedHubCall> HandoffCalls =>
        _hub.Proxy.Calls.Where(c => c.Method == "HandoffRequested").ToList();

    // ── acceptance 1: same phase, same task set, after the reset ────────────────────────────────

    [Fact]
    public async Task UsageLimitDeath_ReopensSamePhaseWithSameTaskSet_AfterTheReset()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a", "b" }, DateTime.UtcNow));

        Assert.True(await BuildCoordinator(AtUsageLimit()).OnSessionExitedAsync(taskId, 1));

        // Parked, not relaunched straight into the same exhausted window.
        Assert.Empty(HandoffCalls);
        Assert.Equal(DueAt, _rounds.Get(taskId)!.DeferredHandoffAt);

        await BuildGuard(AtUsageLimit(), DueAt).TickAsync(default);

        var call = Assert.Single(HandoffCalls);
        Assert.Equal(taskId, call.Args[0]);
        Assert.Equal(new[] { "a", "b" }, (IReadOnlyList<string>)call.Args[1]!);
        Assert.Equal(MergeHelperPhase.Merge, call.Args[2]);
    }

    // The #272 review finding: the restart budget used to be spent when the wait STARTED, so a
    // worker that died during the hours-long wait left the round marked "restart used" without one
    // ever having happened -- and the session stayed dead forever.
    [Fact]
    public async Task ParkedRestart_SurvivesAWorkerRestart_AndOnlySpendsTheBudgetOnceItFires()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));
        Assert.True(await BuildCoordinator(AtUsageLimit()).OnSessionExitedAsync(taskId, 1));

        // Worker restart: a fresh state object re-reads the same file, nothing else carries over.
        var afterRestart = new HandlerRoundState(Path.Combine(_tempDir, "handler-rounds.json"));
        Assert.False(afterRestart.Get(taskId)!.AutoRestartUsed);
        Assert.Equal(DueAt, afterRestart.Get(taskId)!.DeferredHandoffAt);

        // Still parked while the window is open...
        await BuildGuard(AtUsageLimit(), DueAt.AddMinutes(-5)).TickAsync(default);
        Assert.Empty(HandoffCalls);

        // ...and sent as soon as it is due, which is also when the budget is spent.
        await BuildGuard(AtUsageLimit(), DueAt).TickAsync(default);
        Assert.Single(HandoffCalls);
        Assert.True(_rounds.Get(taskId)!.AutoRestartUsed);
        Assert.Null(_rounds.Get(taskId)!.DeferredHandoffAt);
    }

    // ── acceptance 2: at most one auto-restart per round ───────────────────────────────────────

    [Fact]
    public async Task SecondDeathInTheSameRound_DoesNotRestartAgain()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));
        var coordinator = BuildCoordinator(AtUsageLimit());

        Assert.True(await coordinator.OnSessionExitedAsync(taskId, 1));
        await BuildGuard(AtUsageLimit(), DueAt).TickAsync(default);

        Assert.False(await coordinator.OnSessionExitedAsync(taskId, 1));
        Assert.Single(HandoffCalls);
    }

    // A second death while the first restart is still parked must not overwrite or duplicate it.
    [Fact]
    public async Task SecondDeathWhileTheRestartIsStillParked_ChangesNothing()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));
        var coordinator = BuildCoordinator(AtUsageLimit());

        Assert.True(await coordinator.OnSessionExitedAsync(taskId, 1));
        Assert.False(await coordinator.OnSessionExitedAsync(taskId, 1));

        await BuildGuard(AtUsageLimit(), DueAt).TickAsync(default);
        Assert.Single(HandoffCalls);
    }

    // The restart relaunches the SAME phase, which writes the round again through
    // InteractiveLaunchSpecService -- that re-save must not hand the round a fresh restart budget.
    [Fact]
    public async Task RestartRebuildingTheSamePhase_DoesNotRefreshTheRestartBudget()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));
        var coordinator = BuildCoordinator(AtUsageLimit());

        Assert.True(await coordinator.OnSessionExitedAsync(taskId, 1));
        await BuildGuard(AtUsageLimit(), DueAt).TickAsync(default);
        // The relaunched session's launch spec writes the round again, same phase.
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));

        Assert.False(await coordinator.OnSessionExitedAsync(taskId, 1));
        Assert.Single(HandoffCalls);
    }

    // ── acceptance 3: PowerUse gates it ────────────────────────────────────────────────────────

    [Fact]
    public async Task ListWithoutPowerUseOptIn_NoRestart()
    {
        var taskId = await SeedHandlerTaskAsync(powerUseAllowed: false);
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));
        var coordinator = BuildCoordinator(AtUsageLimit());

        Assert.False(await coordinator.OnSessionExitedAsync(taskId, 1));

        Assert.Empty(HandoffCalls);
    }

    [Fact]
    public async Task PowerUseGloballyOff_NoRestart()
    {
        var taskId = await SeedHandlerTaskAsync(powerUseEnabled: false);
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));
        var coordinator = BuildCoordinator(AtUsageLimit());

        Assert.False(await coordinator.OnSessionExitedAsync(taskId, 1));

        Assert.Empty(HandoffCalls);
    }

    // ── acceptance 4: a restart spends no handoff budget ───────────────────────────────────────

    // handoff_list_handler is the only caller of HandoffRoundTracker.Register, and the restart never
    // goes through it -- so a run interrupted by the usage limit does not lose a round of its
    // wait/merge chain. Asserted against the tool the handler session itself reads the budget from.
    [Fact]
    public async Task Restart_DoesNotConsumeHandoffBudget()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));

        var tracker = new HandoffRoundTracker();
        tracker.Register(taskId, MergeHelperPhase.Merge, 4); // the run's real handoff into this phase

        using var ctx = _db.CreateContext();
        var usage = AtUsageLimit();
        var tools = new HandoffMcpTools(
            new TaskRepository(ctx), new HubBroadcaster(_hub), tracker, _db.CreateFactory(),
            BuildGuard(usage, ResetsAt));
        var before = await tools.GetHandoffStatus(taskId);

        Assert.True(await BuildCoordinator(usage).OnSessionExitedAsync(taskId, 1));
        await BuildGuard(usage, DueAt).TickAsync(default);

        var after = await tools.GetHandoffStatus(taskId);
        Assert.Equal(before.Round, after.Round);
        Assert.Equal(before.Remaining, after.Remaining);
        Assert.False(after.Final);
    }

    // ── proof requirement: a non-zero exit alone is not enough ─────────────────────────────────

    // The user closed the session -- exit 0 even sitting at the usage limit.
    [Fact]
    public async Task CleanExit_NoRestart()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));

        Assert.False(await BuildCoordinator(AtUsageLimit()).OnSessionExitedAsync(taskId, 0));
        Assert.Empty(HandoffCalls);
    }

    [Fact]
    public async Task NonZeroExit_WellBelowTheLimit_IsTreatedAsACrash_NoRestart()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));

        Assert.False(await BuildCoordinator(AtUsageLimit(percent: 40)).OnSessionExitedAsync(taskId, 1));
        Assert.Empty(HandoffCalls);
    }

    [Fact]
    public async Task NoUsageSnapshot_FailsClosed_NoRestart()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(taskId, MergeHelperPhase.Merge, new[] { "a" }, DateTime.UtcNow));

        Assert.False(await BuildCoordinator(new UsageState()).OnSessionExitedAsync(taskId, 1));
        Assert.Empty(HandoffCalls);
    }

    // ── not a handler round at all ─────────────────────────────────────────────────────────────

    [Fact]
    public async Task PlainInteractiveSession_HasNoRound_NoRestart()
    {
        var taskId = await SeedHandlerTaskAsync();

        Assert.False(await BuildCoordinator(AtUsageLimit()).OnSessionExitedAsync(taskId, 1));
        Assert.Empty(HandoffCalls);
    }

    // The triage round has no handoff launch spec, so there is nothing to reopen it with.
    [Fact]
    public async Task TriageRound_IsNotReopened()
    {
        var taskId = await SeedHandlerTaskAsync();
        _rounds.Save(new HandlerRound(
            taskId, InteractiveLaunchSpecService.TriagePhase, new[] { "a" }, DateTime.UtcNow));

        Assert.False(await BuildCoordinator(AtUsageLimit()).OnSessionExitedAsync(taskId, 1));
        Assert.Empty(HandoffCalls);
    }
}