using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Text.RegularExpressions;
using ADOFAIRenderer.Util.FFmpeg;
using MelonLoader;

namespace ADOFAIRenderer.Util
{
    [SuppressMessage("ReSharper", "InconsistentNaming")]
    public enum GPUVendor
    {
        Unknown, NVIDIA, AMD, Intel
    }
    
    public static class GPUUtil
    {
        private const string NvidiaPattern = 
            @"^NVIDIA GeForce [RG]TX [0-9]+(?> SUPER| Ti(?> SUPER)?)?(?> [0-9]+GB)?(?> Laptop GPU)?/PCIe/SSE2$";

        private const string IntelPattern =
            @"^Intel(?>\(R\))? (?>U?HD Graphics [0-9]+$|Arc\(TM\) [A-C][0-9]+ Graphics)$";

        // ReSharper disable once InconsistentNaming
        private const string AMDPattern =
            @"^AMD Radeon RX [0-9]+(?> XT)?$";
        
        private static readonly Dictionary<Codec, List<(GPUVendor, string)>> CodecMap = new()
        {
            [Codec.H264] = new List<(GPUVendor, string)> { (GPUVendor.NVIDIA, "h264_nvenc"), (GPUVendor.Intel, "h264_qsv"), (GPUVendor.AMD, "h264_amf"), (GPUVendor.Unknown, "libx264") },
            [Codec.H265] = new List<(GPUVendor, string)> { (GPUVendor.NVIDIA, "hevc_nvenc"), (GPUVendor.Intel, "hevc_qsv"), (GPUVendor.AMD, "hevc_amf"), (GPUVendor.Unknown, "libx265") },
            [Codec.VP9] = new List<(GPUVendor, string)> { (GPUVendor.NVIDIA, "vp9_nvenc"), (GPUVendor.Intel, "vp9_qsv"), (GPUVendor.Unknown, "libvpx-vp9") },
            [Codec.AV1] = new List<(GPUVendor, string)> { (GPUVendor.NVIDIA, "av1_nvenc"), (GPUVendor.Intel, "av1_qsv"), (GPUVendor.AMD, "av1_amf"), (GPUVendor.Unknown, "libsvtav1"), (GPUVendor.Unknown, "libaom-av1") },
            [Codec.VVC] = new List<(GPUVendor, string)> { (GPUVendor.Unknown, "libvvenc") }
        };

        private static GPUVendor _cachedVendor = GPUVendor.Unknown;
        private static bool _hasCachedVendor = false;

        private static GPUVendor GetActiveGPUVendor()
        {
            if (_hasCachedVendor) return _cachedVendor;

            var gpuName = UnityEngine.SystemInfo.graphicsDeviceName;
            Melon<RenderMod>.Logger.Msg($"Active GPU: {gpuName}");
            
            _cachedVendor = GPUVendor.Unknown;
            foreach (Match unused in Regex.Matches(gpuName, NvidiaPattern))
            {
                _cachedVendor = GPUVendor.NVIDIA;
                break;
            }
            
            if (_cachedVendor == GPUVendor.Unknown)
            {
                foreach (Match unused in Regex.Matches(gpuName, IntelPattern))
                {
                    _cachedVendor = GPUVendor.Intel;
                    break;
                }
            }
            
            if (_cachedVendor == GPUVendor.Unknown)
            {
                foreach (Match unused in Regex.Matches(gpuName, AMDPattern))
                {
                    _cachedVendor = GPUVendor.AMD;
                    break;
                }
            }
            
            _hasCachedVendor = true;
            return _cachedVendor;
        }

        public static List<string> GetPrioritizedEncoderCandidates(Codec codec)
        {
            if (!CodecMap.TryGetValue(codec, out var list)) return new List<string>();

            var vendor = GetActiveGPUVendor();
            var prioritized = new List<string>();
            var others = new List<string>();

            foreach (var item in list)
            {
                if (item.Item1 == vendor) prioritized.Add(item.Item2);
                else others.Add(item.Item2);
            }

            prioritized.AddRange(others);
            return prioritized;
        }
    }
}