namespace GenshinAssistant.InputHelper;

internal enum NativeScannerInputGuardOutcome
{
    Ready,
    Stopped,
    Blocked,
}

internal readonly record struct NativeScannerInputGuardDecision(
    NativeScannerInputGuardOutcome Outcome,
    string Message)
{
    public bool CanContinue => Outcome == NativeScannerInputGuardOutcome.Ready;

    public static NativeScannerInputGuardDecision Ready()
        => new(NativeScannerInputGuardOutcome.Ready, "");

    public static NativeScannerInputGuardDecision Blocked(string message)
        => new(NativeScannerInputGuardOutcome.Blocked, message);
}

internal static class NativeScannerInputSafetyPolicy
{
    // The live inventory capacity is 2,400 Artifacts. A full visible page
    // contains 32 safe targets and the live-calibrated page transition uses 39
    // wheel events. 3,200 upward events therefore cover the complete inventory
    // with a deterministic safety margin while remaining explicitly bounded.
    internal const int MaximumArtifactInventoryCapacity = 2400;
    internal const int VisibleArtifactTargetsPerPage = 32;
    internal const int PageScrollWheelEvents = 39;
    internal const int InventoryTopResetWheelEvents = 3200;
    internal const int InventoryTopResetStabilizationMs = 300;
    internal const int PageScrollStabilizationMs = 120;
    internal const int WheelPacingBatchEvents = PageScrollWheelEvents;
    internal const int WheelPacingDelayMs = 1;

    internal static bool ShouldPauseAfterWheelEvent(int completedEventCount)
        => completedEventCount > 0 && completedEventCount % WheelPacingBatchEvents == 0;

    internal static NativeScannerInputGuardDecision Evaluate(
        bool stopRequested,
        bool escapePressed,
        bool enterPressed,
        bool f9Pressed,
        long expectedGenshinHwnd,
        long foregroundHwnd,
        string foregroundProcess,
        string action)
    {
        if (stopRequested)
        {
            return new NativeScannerInputGuardDecision(
                NativeScannerInputGuardOutcome.Stopped,
                $"stop requested before {action}");
        }
        if (escapePressed)
        {
            return new NativeScannerInputGuardDecision(
                NativeScannerInputGuardOutcome.Stopped,
                $"ESC held - native scan stopped before {action}");
        }
        if (enterPressed)
        {
            return new NativeScannerInputGuardDecision(
                NativeScannerInputGuardOutcome.Stopped,
                $"Enter held - native scan stopped before {action}");
        }
        if (f9Pressed)
        {
            return new NativeScannerInputGuardDecision(
                NativeScannerInputGuardOutcome.Stopped,
                $"F9 held - native scan stopped before {action}");
        }

        if (expectedGenshinHwnd == 0)
        {
            return NativeScannerInputGuardDecision.Blocked(
                $"Genshin target window is unavailable before {action}; native scan stopped without refocusing.");
        }
        if (foregroundHwnd != expectedGenshinHwnd)
        {
            var actual = string.IsNullOrWhiteSpace(foregroundProcess) ? "unknown" : foregroundProcess;
            return NativeScannerInputGuardDecision.Blocked(
                $"Genshin lost foreground before {action}; native scan stopped without refocusing (foreground: {actual}).");
        }

        return NativeScannerInputGuardDecision.Ready();
    }
}