using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.IO;
using System.Text;

namespace AnotherReplayReader.ReplayFile
{
    internal static class RA3Commands
    {
        private interface IArgumentReader
        {
            object Read(BinaryReader reader, int count);
        }
        private sealed class ArgumentReader<T> : IArgumentReader
        {
            private readonly Func<BinaryReader, T> _reader;

            public ArgumentReader(Func<BinaryReader, T> reader) => _reader = reader;

            public object Read(BinaryReader reader, int count)
            {
                if (count == 1)
                {
                    return _reader(reader)!;
                }

                var result = new T[count];
                for (int i = 0; i < count; i++)
                {
                    result[i] = _reader(reader);
                }
                return result;
            }
        }
        private static readonly Dictionary<CommandArgumentType, IArgumentReader> _readers = new()
        {
            [CommandArgumentType.Int32] = new ArgumentReader<int>(r => r.ReadInt32()),
            [CommandArgumentType.Float32] = new ArgumentReader<float>(r => r.ReadSingle()),
            [CommandArgumentType.Bool] = new ArgumentReader<bool>(r => r.ReadByte() != 0),
            [CommandArgumentType.UInt16] = new ArgumentReader<ushort>(r => r.ReadUInt16()),
            [CommandArgumentType.UInt32] = new ArgumentReader<uint>(r => r.ReadUInt32()),
            [CommandArgumentType.UInt32_2] = new ArgumentReader<uint>(r => r.ReadUInt32()),
            [CommandArgumentType.ObjectId] = new ArgumentReader<uint>(r => r.ReadUInt32()),
            [CommandArgumentType.ObjectId_2] = new ArgumentReader<uint>(r => r.ReadUInt32()),
            [CommandArgumentType.Vector3] = new ArgumentReader<Vector3>(ReadVector3),
            [CommandArgumentType.AssetId] = new ArgumentReader<AssetId>(ReadAssetId),
            [CommandArgumentType.AsciiString] = new ArgumentReader<string>(r => ReadString(r, CommandArgumentType.AsciiString)),
            [CommandArgumentType.UnicodeString] = new ArgumentReader<string>(r => ReadString(r, CommandArgumentType.UnicodeString)),
        };

        private static readonly Dictionary<int, string> _commandNames;


        public static ImmutableArray<int> UnknownCommands { get; } = new[]
        {
            0x1FD, // unk
            0x25F, // unk
        }.ToImmutableArray();

        public static ImmutableArray<int> AutoCommands { get; } = new[]
        {
            0x1,
            0x221, // 3 seconds heartbeat
            0x233, // uuid
            0x234, // uuid
            0x235, // player info
            0x237, // indeterminate autogen
            0x247, // 5th frame auto gen
            0x252, // another player quits
        }.ToImmutableArray();


        static RA3Commands()
        {
            _commandNames = new()
            {
                [0x1] = "[游戏结束]", // 1

                [0x1F5] = "选择单位", // 501
                [0x1F6] = "选择相同单位（W）", // 502
                [0x1F8] = "取消选择", // 504
                [0x1F9] = "从选择中移除单位", // 505
                [0x1FA] = "创建编队", // 506
                [0x1FB] = "选择编队", // 507
                [0x1FC] = "将编队加入选择", // 508
                [0x1FD] = "（未知指令 0x1FD）", // 509
                [0x1FE] = "释放特殊能力（无目标）", // 510
                [0x1FF] = "释放特殊能力（指定位置）", // 511
                [0x200] = "释放特殊能力（指定位置和角度）", // 512
                [0x201] = "释放特殊能力（指定目标）", // 513
                [0x202] = "设置集结点", // 514
                [0x203] = "开始升级", // 515
                [0x204] = "暂停/中止升级", // 516
                [0x205] = "开始出兵", // 517
                [0x206] = "暂停/取消出兵", // 518
                [0x207] = "开始建造", // 519
                [0x208] = "暂停/取消建造", // 520
                [0x209] = "摆放建筑", // 521

                [0x20A] = "出售建筑", // 522
                // 523
                [0x20C] = "从进驻的建筑撤出（？）", // 524
                [0x20D] = "集火攻击", // 525
                [0x20E] = "强制攻击单位（Ctrl）", // 526
                [0x20F] = "强制攻击地板（Ctrl）", // 527
                [0x210] = "进驻建筑", // 528
                // 529
                [0x212] = "命令矿车交矿", // 530
                // 531
                [0x214] = "移动", // 532
                [0x215] = "行进攻击（A）", // 533
                [0x216] = "强制移动/碾压（G）", // 534
                // 535
                // 536
                // 537
                [0x21A] = "停止（S）", // 538
                [0x21B] = "散开（X）", // 539

                // 0x21E 542 有可能是 AI 信标相关的？

                [0x221] = "[游戏每3秒自动产生的检测不同步指令]", // 545

                [0x228] = "开始维修建筑", // 552
                [0x229] = "停止维修建筑", // 553
                [0x22A] = "选择所有单位（Q）", // 554
                // 555
                [0x22C] = "队形操作（左右键）", // 556
                // 557
                [0x22E] = "切换姿态（警戒/侵略/固守/停火模式）", // 558
                [0x22F] = "路径点模式/计划模式（Alt）", // 559
                // 560
                // 561
                [0x232] = "释放特殊能力（一个或多个目标）", // 562
                [0x233] = "[游戏自动生成的UUID指令]", // 563
                [0x234] = "[游戏自动产生的UUID]", // 564
                [0x235] = "[玩家信息（？）]", // 565
                [0x236] = "倒车（D）", // 566
                [0x237] = "[游戏不定期自动产生的指令]", // 567

                [0x247] = "[游戏在第五帧自动产生的指令]", // 583
                [0x248] = "让矿车去采矿", // 584

                [0x24B] = "信标", // 587
                [0x24C] = "删除信标", // 588
                [0x24D] = "在信标里输入文字", // 589
                [0x24E] = "选择协议", // 590

                [0x252] = "[其他玩家主动退出游戏]", // 594

                [0x25F] = "（未知指令 0x25F）", // 607
            };
        }

        public static List<CommandArgumentEntry> ReadCommandData(this BinaryReader reader)
        {
            var list = new List<CommandArgumentEntry>();

            while (true)
            {
                byte head = reader.ReadByte();

                if (head == 0xFF)
                    break;

                int count = (head >> 4) + 1;
                var type = (CommandArgumentType)(head & 0xF);

                var value = _readers[type].Read(reader, count);

                list.Add(new CommandArgumentEntry(type, value, count));
            }

            return list;
        }

        public static bool IsUnknownCommand(int commandId)
        {
            return !_commandNames.ContainsKey(commandId);
        }

        public static string GetCommandName(int commandId)
        {
            return _commandNames.TryGetValue(commandId, out var storedName)
                ? storedName
                : $"（未知指令 0x{commandId:X2}）";
        }

        private static AssetId ReadAssetId(BinaryReader reader)
        {
            var version = reader.ReadByte();
            var typeId = reader.ReadUInt32();
            var instanceId = reader.ReadUInt32();
            return new(TypeId: typeId, InstanceId: instanceId);
        }
        private static Vector3 ReadVector3(BinaryReader reader)
        {
            var x = reader.ReadSingle();
            var y = reader.ReadSingle();
            var z = reader.ReadSingle();
            return new(X: x, Y: y, Z: z);
        }
        private static string ReadString(BinaryReader current, CommandArgumentType type)
        {
            var length = (int)current.ReadByte();
            if (length == 0xFF)
            {
                length = current.ReadInt32();
            }
            // read byte string or wchar_t string based on T type
            switch (type)
            {
                case CommandArgumentType.AsciiString:
                    return Encoding.UTF8.GetString(current.ReadBytes(length));
                case CommandArgumentType.UnicodeString:
                    return Encoding.Unicode.GetString(current.ReadBytes(length * 2));
            }
            throw new InvalidDataException($"Invalid string type {type}");
        }
    }
}