// ReSharper disable InconsistentNaming

using HarmonyLib;
using Manager;
using Manager.UserDatas;
using Monitor;
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Reflection.Emit;

namespace UnlockFrameRate;

[HarmonyPatch]
internal class PatchFrameTime
{
    private const float OriginalFrameRate = 60f;
    private const float OriginalFrameTime = 1000f / OriginalFrameRate;
    private const float OriginalFramePerMilliseconds = OriginalFrameRate / 1000;

    private static IEnumerable<MethodBase> TargetMethods()
    {
        // This shouldn't be patched, because they make the judgements
        // harder or easier depending on your frame rate.
        // var noteJudge = AccessTools.TypeByName("NoteJudge");
        // var juggeTiming = AccessTools.Inner(noteJudge, "JuggeTiming"); // lol

        // yield return AccessTools.Constructor(juggeTiming);

        // This changes the effect of judgement timing based on the set FPS,
        // so +2.0 at 120Hz will only add 17ms instead of 33ms.
        if (FrameRatePlugin.Instance.PatchJudgementTiming)
        {
            yield return AccessTools.Method(typeof(NoteJudge), nameof(NoteJudge.GetJudgeTiming));
            yield return AccessTools.Method(typeof(NoteJudge), nameof(NoteJudge.GetSlideJudgeTiming));
            yield return AccessTools.Method(typeof(UserOption), nameof(UserOption.GetAdjustMSec));
        }
        
        yield return AccessTools.Method(typeof(NoteBase), "IsNoteCheckTimeStart");
        yield return AccessTools.Method(typeof(TouchNoteB), "GetNoteYPosition");
        yield return AccessTools.Method(typeof(SlideRoot), "IsNoteCheckTimeStart");
        yield return AccessTools.Method(typeof(SlideJudge), nameof(SlideJudge.Initialize));
        yield return AccessTools.Method(typeof(JudgeGrade), nameof(JudgeGrade.Initialize));
        yield return AccessTools.Method(typeof(NotesManager), nameof(NotesManager.getPlayFirstMsec));
        yield return AccessTools.Method(typeof(NotesManager), nameof(NotesManager.getPlayFinalMsec));
        yield return AccessTools.Method(typeof(NotesManager), nameof(NotesManager.getCurrentDrawFrame));
        yield return AccessTools.Method(typeof(NotesReader), nameof(NotesReader.calcFrame));
        yield return AccessTools.Method(typeof(NotesReader), nameof(NotesReader.GetBPM_Frame));
        yield return AccessTools.Method(typeof(NotesReader), nameof(NotesReader.getMeter_Frame));
        yield return AccessTools.Method(typeof(NoteData), nameof(NoteData.getLengthFrame));
        yield return AccessTools.Method(typeof(GameManager), nameof(GameManager.UpdateGameTimer));
        yield return AccessTools.PropertyGetter(typeof(NotesTime), nameof(NotesTime.frame));
    }

    private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, MethodBase __originalMethod)
    {
        var targetFrameTime = 1000f / FrameRatePlugin.Instance.TargetFrameRate;
        var targetFramePerMs = (float)FrameRatePlugin.Instance.TargetFrameRate / 1000;
        var i = 0;

        foreach (var instruction in instructions)
        {
            if (instruction.opcode != OpCodes.Ldc_R4 || instruction.operand is not float operand)
            {
                yield return instruction;
                i++;
                continue;
            }

            var overridden = false;

            if (Math.Abs(operand - OriginalFrameTime) < float.Epsilon)
            {
                instruction.operand = targetFrameTime;
                overridden = true;
            }
            else if (Math.Abs(operand - OriginalFramePerMilliseconds) < float.Epsilon)
            {
                instruction.operand = targetFramePerMs;
                overridden = true;
            }

            if (overridden)
            {
                FrameRatePlugin.Logger.LogDebug(
                    "Overrode constant at opcode index {0} in {1}: {2} => {3}",
                    i,
                    __originalMethod.Name,
                    operand,
                    instruction.operand);
            }

            yield return instruction;
            i++;
        }
    }
}