using System.Diagnostics.CodeAnalysis;
using HarmonyLib;

namespace ADOFAIRenderer.Patch.Game;

/// <summary>
/// Protects the camera render texture <c>scrCamera.camRT</c> when the custom frame rate effect is turned off while it is
/// already off.
/// <para>
/// Patched member: <c>scrCamera.SetCustomFrameRate(bool enable, float frame)</c> (level effect that updates the screen at a
/// lower frame rate). Enabling assigns a new RenderTexture to the camera quad material and refreshes it at <c>frame</c> fps.
/// Disabling calls <c>Release()</c> on the quad material's current <c>mainTexture</c> and assigns <c>camRT</c> back. When
/// the effect was never enabled, <c>mainTexture</c> is <c>camRT</c> itself, so the original releases the live camera
/// render texture.
/// </para>
/// <para>Always active (independent of the render stage).</para>
/// </summary>
[HarmonyPatch(typeof(scrCamera))]
// ReSharper disable once InconsistentNaming
public class scrCameraPatch
{
    /// <summary>
    /// Prefix of <c>scrCamera.SetCustomFrameRate</c>. For a disable request while <c>enableCustomFPS</c> is already false,
    /// stores the arguments in <c>enableCustomFPS</c> / <c>frameRate</c> and skips the original (no texture is released).
    /// Enable requests and disable requests while the effect is on run the original.
    /// </summary>
    /// <param name="__instance">The camera.</param>
    /// <param name="enable">True to turn the custom frame rate on, false to turn it off.</param>
    /// <param name="frame">Custom frame rate in frames per second.</param>
    /// <returns>True to run the original method; false to skip it.</returns>
    [HarmonyPrefix]
    [HarmonyPatch("SetCustomFrameRate")]
    [SuppressMessage("ReSharper", "InconsistentNaming")]
    private static bool FixCamRT(scrCamera __instance, bool enable, float frame)
    {
        // Disable request while the effect is off: the quad material's mainTexture is camRT, which the original would Release().
        if (enable || __instance.enableCustomFPS != enable) return true;
            
        __instance.enableCustomFPS = enable;
        __instance.frameRate = frame;
        return false;
    }
}