using ADOFAIRenderer.Localization;
using ADOFAIRenderer.UI;
using UnityEngine;

namespace ADOFAIRenderer.Core;

/// <summary>
/// MonoBehaviour that runs before every other script's Update (execution order int.MinValue; scripts run from the
/// lowest order to the highest). Lives on a DontDestroyOnLoad object created by RenderMod.
/// It performs the start-up checks (FFmpeg libraries present, NVIDIA driver version) and then advances the render
/// frame counter through RenderManager.OnPreUpdate once per Unity frame, so every other script of that frame sees
/// the same render time.
/// Reference: https://docs.unity3d.com/ScriptReference/DefaultExecutionOrder.html
/// </summary>
[DefaultExecutionOrder(int.MinValue)]
internal class FirstUpdateHook : MonoBehaviour
{
    /// <summary>True once the FFmpeg libraries were found in UserLibs (after the download UI, if it was needed).</summary>
    private bool _checkedFFmpeg;

    /// <summary>True once the NVIDIA driver version check ran (it runs once per game session).</summary>
    private bool _checkedNvidiaDriver;

    /// <summary>
    /// Main thread, every frame. The checks are done in order and each one blocks the following steps while its dialog
    /// is open: the frame counter is not advanced until both checks are done.
    /// </summary>
    private void Update()
    {
        // 1. FFmpeg libraries: while the download UI is open, wait. When the libraries are missing, open the download UI.
        if (!_checkedFFmpeg)
        {
            if (FFmpegDownloadUI.Instance) return;

            if (!FFmpegDownloadUI.CheckFFmpegExists())
            {
                FFmpegDownloadUI.ShowDownloadUI();
                return;
            }
            _checkedFFmpeg = true;
        }

        // 2. NVIDIA driver version: waits until no other warning dialog is open, then runs once.
        if (!_checkedNvidiaDriver)
        {
            if (CommonWarningDialogUI.Instance) return;

            _checkedNvidiaDriver = true;
            CheckNvidiaDriverWarning();
        }

        // 3. Render frame counter (only counts while a render is in the OnScene stage or later).
        if (RenderManager.Instance)
        {
            RenderManager.Instance.OnPreUpdate();
        }
    }

    /// <summary>
    /// Shows a warning dialog when the active GPU is an NVIDIA GPU with a driver version below 610.00.
    /// No dialog is shown when the GPU is not NVIDIA or the version cannot be determined (GPUUtil returns null).
    /// Buttons: open the NVIDIA driver download page and quit the game, disable the render feature for this session
    /// (RenderMod.IsFeatureDisabled), or continue.
    /// </summary>
    private void CheckNvidiaDriverWarning()
    {
        var driverVer = Util.GPUUtil.GetNvidiaDriverVersion();
        if (driverVer is null or >= 610.00f) return;

        var currentVersion = driverVer.Value.ToString("F2");
            
        CommonWarningDialogUI.ShowDialog(
            LocalizationManager.Get("ui.driver_warning.title"),
            LocalizationManager.Get("ui.driver_warning.body", currentVersion),
            new DialogButton(LocalizationManager.Get("ui.driver_warning.btn_update"), () =>
            {
                Application.OpenURL("https://www.nvidia.com/Download/index.aspx");
                Application.Quit();
            }, new Color(0.0f, 0.8f, 1.0f, 1.0f)),
            new DialogButton(LocalizationManager.Get("ui.driver_warning.btn_disable"), () =>
            {
                RenderMod.IsFeatureDisabled = true;
            }),
            new DialogButton(LocalizationManager.Get("ui.driver_warning.btn_continue"), () =>
            {
                // ignored
            })
        );
    }
}