using ClaudeDo.Ui.Services;
using ClaudeDo.Ui.ViewModels;
using ClaudeDo.Ui.ViewModels.MissionControl;
using Xunit;

namespace ClaudeDo.Ui.Tests.ViewModels.MissionControl;

public class ConPtyPaneViewModelTests
{
    private static ConPtyPaneViewModel NewTaskPane(
        Func<Task<TerminalLaunchDescriptor>> descriptorFactory,
        string taskId = "t1")
        => new(taskId, "Some Task", descriptorFactory);

    private static Task<TerminalLaunchDescriptor> NeverCompletes()
        => new TaskCompletionSource<TerminalLaunchDescriptor>().Task;

    private static Task<TerminalLaunchDescriptor> Failing(string message = "boom")
        => Task.FromException<TerminalLaunchDescriptor>(new InvalidOperationException(message));

    // ── CanSubmitForReview gating (fix: don't offer Submit for Review on a dead/starting pane) ──

    [Fact]
    public void CanSubmitForReview_False_WhileStarting()
    {
        using var pane = NewTaskPane(NeverCompletes);
        pane.Start();

        Assert.True(pane.Terminal.IsStarting);
        Assert.False(pane.SubmitForReviewCommand.CanExecute(null));
    }

    [Fact]
    public void CanSubmitForReview_False_AfterLaunchFailure()
    {
        using var pane = NewTaskPane(() => Failing());
        pane.Start();

        Assert.NotNull(pane.Terminal.StartError);
        Assert.True(pane.Terminal.HasExited);
        Assert.False(pane.SubmitForReviewCommand.CanExecute(null));
    }

    [Fact]
    public void CanSubmitForReview_True_WhenRunning()
    {
        using var pane = NewTaskPane(NeverCompletes);
        SetRunning(pane);

        Assert.True(pane.SubmitForReviewCommand.CanExecute(null));
    }

    [Fact]
    public void CanSubmitForReview_False_ForAdHocPane_EvenWhileRunning()
    {
        using var pane = new ConPtyPaneViewModel(null, "Ad hoc", NeverCompletes);
        SetRunning(pane);

        Assert.False(pane.IsTaskBased);
        Assert.False(pane.SubmitForReviewCommand.CanExecute(null));
    }

    [Fact]
    public void CanSubmitForReview_False_WhileSubmitPending()
    {
        using var pane = NewTaskPane(NeverCompletes);
        SetRunning(pane);
        Assert.True(pane.SubmitForReviewCommand.CanExecute(null));

        pane.IsSubmitPending = true;

        Assert.False(pane.SubmitForReviewCommand.CanExecute(null));

        pane.IsSubmitPending = false;

        Assert.True(pane.SubmitForReviewCommand.CanExecute(null));
    }

    // ── Retry (fix: a failed launch used to permanently occupy the TaskId dedupe slot) ──────────

    [Fact]
    public void RetryCommand_Disabled_BeforeAndWhileStarting()
    {
        using var pane = NewTaskPane(NeverCompletes);
        Assert.False(pane.RetryCommand.CanExecute(null));

        pane.Start();

        Assert.False(pane.RetryCommand.CanExecute(null)); // still starting, no failure yet
    }

    [Fact]
    public void RetryCommand_Enabled_AfterLaunchFailure()
    {
        using var pane = NewTaskPane(() => Failing());
        pane.Start();

        Assert.True(pane.RetryCommand.CanExecute(null));
    }

    [Fact]
    public void Retry_ReplacesTerminal_AndRefetchesDescriptor()
    {
        var callCount = 0;
        Func<Task<TerminalLaunchDescriptor>> factory = () =>
        {
            callCount++;
            return callCount == 1 ? Failing() : NeverCompletes();
        };

        using var pane = NewTaskPane(factory);
        pane.Start();
        Assert.True(pane.RetryCommand.CanExecute(null));
        var terminalBeforeRetry = pane.Terminal;

        pane.RetryCommand.Execute(null);

        Assert.Equal(2, callCount);
        Assert.NotSame(terminalBeforeRetry, pane.Terminal);
        Assert.Null(pane.Terminal.StartError);
        Assert.False(pane.Terminal.HasExited);
        Assert.False(pane.RetryCommand.CanExecute(null));
    }

    [Fact]
    public void Retry_FailsAgain_StillOffersRetry()
    {
        using var pane = NewTaskPane(() => Failing());
        pane.Start();
        Assert.True(pane.RetryCommand.CanExecute(null));

        pane.RetryCommand.Execute(null);

        Assert.NotNull(pane.Terminal.StartError);
        Assert.True(pane.RetryCommand.CanExecute(null));
    }

    // ── Died-at-startup (fix: an immediate ConPTY exit used to leave StartError null, so Retry
    //    never became reachable and the pane was stuck reusing the same persisted session id) ──

    [Fact]
    public void RetryCommand_Enabled_AfterProcessExitsNonzeroRightAfterLaunch()
    {
        using var pane = NewTaskPane(NeverCompletes);
        SetRunning(pane);
        Assert.False(pane.RetryCommand.CanExecute(null));

        pane.Terminal.OnSessionProcessExited(null, 1);

        Assert.NotNull(pane.Terminal.StartError);
        Assert.True(pane.RetryCommand.CanExecute(null));
    }

    // ── HasExitedAfterStartup banner (fix: a mid-run death used to leave a silent dead tile — no
    //    StartError, no signal at all) ─────────────────────────────────────────────────────────

    [Fact]
    public void RetryCommand_Enabled_AfterDeathAfterStartup()
    {
        using var pane = NewTaskPane(NeverCompletes);

        DieAfterRunning(pane, exitCode: 1);

        Assert.True(pane.Terminal.HasExitedAfterStartup);
        Assert.True(pane.RetryCommand.CanExecute(null));
    }

    [Fact]
    public void ExitedBannerText_IncludesExitCode()
    {
        using var pane = NewTaskPane(NeverCompletes);

        DieAfterRunning(pane, exitCode: 42);

        Assert.Contains("42", pane.ExitedBannerText);
    }

    // ── SessionDiedAfterStartup (feeds the worker's usage-limit auto-restart) ────────────────────

    [Fact]
    public void SessionDiedAfterStartup_TaskPane_RaisesWithTaskIdAndExitCode()
    {
        using var pane = NewTaskPane(NeverCompletes, taskId: "handler-1");
        (string TaskId, int ExitCode)? reported = null;
        pane.SessionDiedAfterStartup += (id, code) => reported = (id, code);

        DieAfterRunning(pane, exitCode: 1);

        Assert.Equal(("handler-1", 1), reported);
    }

    [Fact]
    public void SessionDiedAfterStartup_AdHocPane_NeverRaises()
    {
        using var pane = new ConPtyPaneViewModel(null, "Ad hoc", NeverCompletes);
        var raised = false;
        pane.SessionDiedAfterStartup += (_, _) => raised = true;

        DieAfterRunning(pane, exitCode: 1);

        Assert.False(raised);
    }

    // Retry swaps in a fresh terminal -- the death of the RETRIED session must still be reported.
    [Fact]
    public void SessionDiedAfterStartup_StillWiredAfterRetry()
    {
        var callCount = 0;
        using var pane = NewTaskPane(
            () => callCount++ == 0 ? Failing() : NeverCompletes(), taskId: "handler-1");
        pane.Start();
        pane.RetryCommand.Execute(null);

        var raised = false;
        pane.SessionDiedAfterStartup += (_, _) => raised = true;

        DieAfterRunning(pane, exitCode: 1);

        Assert.True(raised);
    }

    // ── Terminal.ErrorReported forwarding (fix: a failed paste/drop had no path to the footer
    //    error strip) ────────────────────────────────────────────────────────────────────────────

    [Fact]
    public void TerminalErrorReported_Forwards_ToPaneErrorReported()
    {
        using var pane = NewTaskPane(NeverCompletes);
        string? error = null;
        pane.ErrorReported += msg => error = msg;

        pane.Terminal.ReportSendFailed();

        Assert.NotNull(error);
    }

    [Fact]
    public void TerminalErrorReported_StillWiredAfterRetry()
    {
        using var pane = NewTaskPane(() => Failing());
        pane.Start();
        pane.RetryCommand.Execute(null);
        string? error = null;
        pane.ErrorReported += msg => error = msg;

        pane.Terminal.ReportSendFailed();

        Assert.NotNull(error);
    }

    private static void SetRunning(ConPtyPaneViewModel pane) => pane.Terminal.IsRunning = true;

    // Drives the terminal past its startup grace window, then kills it: IsRunning stamps the launch
    // time off the real clock, so a sleep-free "ran for a while" needs the exit routed through a
    // terminal whose clock has already moved on.
    private static void DieAfterRunning(ConPtyPaneViewModel pane, int exitCode)
    {
        var launchedAt = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        var callCount = 0;
        pane.Terminal = new InteractiveTerminalViewModel(
            () => callCount++ == 0 ? launchedAt : launchedAt.AddMinutes(90));
        pane.Terminal.IsRunning = true;
        pane.Terminal.OnSessionProcessExited(null, exitCode);
    }
}