using CapMachine.Wpf.CanDrive;
using CapMachine.Wpf.Services;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;

namespace CapMachine.Wpf.CanDrive.ZlgCan
{
    /// <summary>
    /// 基于周立功 ZDBC（zdbc.dll）的 DBC 数据库封装。
    /// </summary>
    /// <remarks>
    /// 设计要点：
    /// - zdbc.dll 为原生依赖，必须放置在程序输出目录（AppContext.BaseDirectory）。
    /// - 本类封装 DBC 文件加载、消息/信号枚举、以及基于 DBCMessage 的编码/解码能力。
    /// - 运行稳定性：实现 IDisposable，确保 ZDBC_Release 与相关非托管内存释放。
    /// </remarks>
    public sealed class ZlgDbcDatabase : IDisposable
    {
        private readonly ILogService _log;
        private readonly object _sync = new object();

        private uint _dbcHandle;
        private bool _disposed;

        // 复用非托管缓冲，避免高频 Allocate/Free
        private IntPtr _msgPtr = IntPtr.Zero;
        private IntPtr _countPtr = IntPtr.Zero;
        private IntPtr _canFramePtr = IntPtr.Zero;
        private IntPtr _canFdFramePtr = IntPtr.Zero;

        private readonly Dictionary<string, ZDBC.DBCMessage> _messageByName = new Dictionary<string, ZDBC.DBCMessage>(StringComparer.Ordinal);
        private readonly Dictionary<string, uint> _messageIdByName = new Dictionary<string, uint>(StringComparer.Ordinal);

        /// <summary>
        /// 构造函数。
        /// </summary>
        /// <param name="logService">日志服务。</param>
        public ZlgDbcDatabase(ILogService logService)
        {
            _log = logService;
        }

        /// <summary>
        /// 是否已加载。
        /// </summary>
        public bool IsLoaded
        {
            get
            {
                return _dbcHandle != 0 && _dbcHandle != ZDBC.INVALID_DBC_HANDLE;
            }
        }

        /// <summary>
        /// 加载 DBC 文件。
        /// </summary>
        /// <param name="dbcPath">DBC 文件路径。</param>
        /// <param name="enableAsyncAnalyse">是否启用异步解析（库内部线程）。</param>
        /// <param name="merge">是否合并到当前数据库（支持加载多个文件）。</param>
        /// <param name="protocolType">协议类型：J1939=0，其他=1。</param>
        public void Load(string dbcPath, bool enableAsyncAnalyse = true, bool merge = false, byte protocolType = ZDBC.PROTOCOL_OTHER)
        {
            ThrowIfDisposed();

            if (string.IsNullOrWhiteSpace(dbcPath))
            {
                throw new ArgumentException("dbcPath 不能为空。", nameof(dbcPath));
            }

            EnsureNativeDllExists("zdbc.dll");

            if (!File.Exists(dbcPath))
            {
                throw new FileNotFoundException("DBC 文件不存在。", dbcPath);
            }

            var fileSize = 0L;
            try
            {
                fileSize = new FileInfo(dbcPath).Length;
            }
            catch
            {
            }

            var fullPath = dbcPath;
            try
            {
                fullPath = Path.GetFullPath(dbcPath);
            }
            catch
            {
            }

            var shortPath = TryGetShortPath(fullPath);
            var candidatePaths = new List<string>();
            if (!string.IsNullOrWhiteSpace(fullPath)) candidatePaths.Add(fullPath);
            if (!string.IsNullOrWhiteSpace(shortPath)
                && !string.Equals(shortPath, fullPath, StringComparison.OrdinalIgnoreCase))
            {
                candidatePaths.Add(shortPath);
            }

            lock (_sync)
            {
                if (_dbcHandle == 0 || _dbcHandle == ZDBC.INVALID_DBC_HANDLE)
                {
                    _dbcHandle = ZDBC.ZDBC_Init(0, enableAsyncAnalyse ? (byte)1 : (byte)0);
                    if (_dbcHandle == ZDBC.INVALID_DBC_HANDLE)
                    {
                        _dbcHandle = 0;
                        throw new InvalidOperationException("ZDBC_Init 初始化失败。");
                    }
                }

                var loadOk = false;
                foreach (var path in candidatePaths)
                {
                    var fileInfo = new ZDBC.FileInfo
                    {
                        strFilePath = BuildFixedPathBytes(path, ZDBC._MAX_FILE_PATH_ + 1),
                        type = protocolType,
                        merge = (byte)(merge ? 1 : 0)
                    };

                    IntPtr pFile = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ZDBC.FileInfo)));
                    try
                    {
                        Marshal.StructureToPtr(fileInfo, pFile, false);
                        loadOk = ZDBC.ZDBC_LoadFile(_dbcHandle, pFile);
                        if (loadOk)
                        {
                            break;
                        }
                    }
                    finally
                    {
                        Marshal.FreeHGlobal(pFile);
                    }
                }

                if (!loadOk)
                {
                    // fallback：直接按内容加载，绕开路径编码问题；同时尝试多种编码以提升兼容性。
                    loadOk = TryLoadContentFallback_NoLock(fullPath, merge);
                }

                if (!loadOk)
                {
                    var msg = $"ZDBC_LoadFile 失败。DbcPath={fullPath}，ShortPath={shortPath ?? string.Empty}，Size={fileSize}。请检查 DBC 文件格式，或将 DBC 放到纯英文路径后重试。";
                    throw new InvalidOperationException(msg);
                }

                RefreshMessageCache_NoLock();
            }
        }

        /// <summary>
        /// 枚举 DBC 内全部 Message/Signal 元信息，并转换为 UI 使用的 CanDbcModel 集合。
        /// </summary>
        /// <returns>信号集合。</returns>
        public ObservableCollection<CanDbcModel> BuildCanDbcModels()
        {
            ThrowIfDisposed();

            if (!IsLoaded)
            {
                return new ObservableCollection<CanDbcModel>();
            }

            lock (_sync)
            {
                var list = new List<CanDbcModel>();

                foreach (var kv in _messageByName)
                {
                    var msg = kv.Value;
                    var msgName = ByteArrayToAsciiString(msg.strName);
                    var msgIdStr = "0x" + msg.nID.ToString("X8");

                    var signals = msg.vSignals;
                    if (signals == null || signals.Length == 0)
                    {
                        continue;
                    }

                    var signalCount = (int)Math.Min(msg.nSignalCount, (uint)signals.Length);
                    for (int i = 0; i < signalCount; i++)
                    {
                        var s = signals[i];
                        var sigName = ByteArrayToAsciiString(s.strName);
                        if (string.IsNullOrWhiteSpace(sigName))
                        {
                            continue;
                        }

                        list.Add(new CanDbcModel
                        {
                            MsgName = msgName,
                            MsgId = msgIdStr,
                            SignalName = sigName,
                            SignalDesc = ByteArrayToAsciiString(s.strComment),
                            SignalUnit = ByteArrayToAsciiString(s.unit),
                            SignalRtValue = "--",
                            Publisher = string.Empty
                        });
                    }
                }

                return new ObservableCollection<CanDbcModel>(list);
            }
        }

        /// <summary>
        /// 根据 MsgName 获取 Message ID。
        /// </summary>
        /// <param name="msgName">消息名称。</param>
        /// <returns>Message ID。</returns>
        public uint GetMessageIdByName(string msgName)
        {
            ThrowIfDisposed();
            if (string.IsNullOrWhiteSpace(msgName)) return 0;

            lock (_sync)
            {
                return _messageIdByName.TryGetValue(msgName, out var id) ? id : 0;
            }
        }

        /// <summary>
        /// 根据 MsgName + 信号值集合编码为 CAN/CANFD 原始帧。
        /// </summary>
        /// <param name="msgName">消息名称。</param>
        /// <param name="signals">信号值（SignalName -> 实际值）。</param>
        /// <param name="frameType">帧类型：FT_CAN=0，FT_CANFD=1。</param>
        /// <returns>编码后的 can_id 与数据。</returns>
        public (uint CanId, byte[] Data, int DataLen) EncodeToRawFrame(string msgName, IDictionary<string, double> signals, byte frameType)
        {
            ThrowIfDisposed();

            if (!IsLoaded)
            {
                throw new InvalidOperationException("DBC 未加载。");
            }

            if (string.IsNullOrWhiteSpace(msgName))
            {
                throw new ArgumentException("msgName 不能为空。", nameof(msgName));
            }

            lock (_sync)
            {
                if (!_messageByName.TryGetValue(msgName, out var msg))
                {
                    throw new InvalidOperationException($"DBC 中未找到消息：{msgName}");
                }

                // 在副本上修改信号，避免污染缓存
                var workingMsg = msg;
                if (workingMsg.vSignals == null)
                {
                    workingMsg.vSignals = new ZDBC.DBCSignal[ZDBC._DBC_SIGNAL_MAX_COUNT_];
                }

                if (signals != null)
                {
                    foreach (var kv in signals)
                    {
                        SetSignalActualValue(ref workingMsg, kv.Key, kv.Value);
                    }
                }

                EnsureMarshalBuffers_NoLock();

                // 写入 msg 到非托管
                Marshal.StructureToPtr(workingMsg, _msgPtr, false);

                // nCount 输入输出参数，准备 1 帧
                Marshal.WriteInt32(_countPtr, 1);

                if (frameType == ZDBC.FT_CAN)
                {
                    var ok = ZDBC.ZDBC_Encode(_dbcHandle, _canFramePtr, _countPtr, _msgPtr, frameType);
                    if (!ok)
                    {
                        throw new InvalidOperationException("ZDBC_Encode(CAN) 失败。");
                    }

                    var frame = (ZlgNativeCanFrame)Marshal.PtrToStructure(_canFramePtr, typeof(ZlgNativeCanFrame));
                    var len = Math.Min(8, (int)frame.can_dlc);
                    var data = new byte[len];
                    if (len > 0 && frame.data != null)
                    {
                        Array.Copy(frame.data, data, len);
                    }

                    return (frame.can_id, data, len);
                }

                if (frameType == ZDBC.FT_CANFD)
                {
                    var ok = ZDBC.ZDBC_Encode(_dbcHandle, _canFdFramePtr, _countPtr, _msgPtr, frameType);
                    if (!ok)
                    {
                        throw new InvalidOperationException("ZDBC_Encode(CANFD) 失败。");
                    }

                    var frame = (ZlgNativeCanFdFrame)Marshal.PtrToStructure(_canFdFramePtr, typeof(ZlgNativeCanFdFrame));
                    var len = Math.Min(64, (int)frame.len);
                    var data = new byte[len];
                    if (len > 0 && frame.data != null)
                    {
                        Array.Copy(frame.data, data, len);
                    }

                    return (frame.can_id, data, len);
                }

                throw new ArgumentOutOfRangeException(nameof(frameType), "frameType 仅支持 FT_CAN=0 或 FT_CANFD=1。");
            }
        }

        /// <summary>
        /// 将原始 CAN/CANFD 帧解码为 DBCMessage，并返回消息名称与信号实际值。
        /// </summary>
        /// <param name="canId">can_id。</param>
        /// <param name="data">payload。</param>
        /// <param name="frameType">帧类型：FT_CAN=0，FT_CANFD=1。</param>
        /// <returns>解码结果。</returns>
        public (string MsgName, Dictionary<string, double> Signals) DecodeRawFrame(uint canId, byte[] data, byte frameType)
        {
            ThrowIfDisposed();

            if (!IsLoaded)
            {
                throw new InvalidOperationException("DBC 未加载。");
            }

            lock (_sync)
            {
                EnsureMarshalBuffers_NoLock();

                if (frameType == ZDBC.FT_CAN)
                {
                    var frame = ZlgNativeCanFrame.Create(canId, data ?? Array.Empty<byte>(), requestTxEcho: false);
                    Marshal.StructureToPtr(frame, _canFramePtr, false);

                    var ok = ZDBC.ZDBC_Decode(_dbcHandle, _msgPtr, _canFramePtr, 1, frameType);
                    if (!ok)
                    {
                        return (string.Empty, new Dictionary<string, double>());
                    }

                    var msg = Marshal.PtrToStructure<ZDBC.DBCMessage>(_msgPtr);
                    return ExtractActualSignals(msg);
                }

                if (frameType == ZDBC.FT_CANFD)
                {
                    var frame = ZlgNativeCanFdFrame.Create(canId, data ?? Array.Empty<byte>(), requestTxEcho: false);
                    Marshal.StructureToPtr(frame, _canFdFramePtr, false);

                    var ok = ZDBC.ZDBC_Decode(_dbcHandle, _msgPtr, _canFdFramePtr, 1, frameType);
                    if (!ok)
                    {
                        return (string.Empty, new Dictionary<string, double>());
                    }

                    var msg = Marshal.PtrToStructure<ZDBC.DBCMessage>(_msgPtr);
                    return ExtractActualSignals(msg);
                }

                throw new ArgumentOutOfRangeException(nameof(frameType), "frameType 仅支持 FT_CAN=0 或 FT_CANFD=1。");
            }
        }

        /// <inheritdoc />
        public void Dispose()
        {
            if (_disposed) return;
            _disposed = true;

            lock (_sync)
            {
                try
                {
                    if (_dbcHandle != 0 && _dbcHandle != ZDBC.INVALID_DBC_HANDLE)
                    {
                        ZDBC.ZDBC_Release(_dbcHandle);
                    }
                }
                catch (Exception ex)
                {
                    _log.Warn($"ZDBC_Release 异常：{ex.Message}");
                }
                finally
                {
                    _dbcHandle = 0;
                }

                FreeMarshalBuffers_NoLock();
                _messageByName.Clear();
                _messageIdByName.Clear();
            }
        }

        private void RefreshMessageCache_NoLock()
        {
            _messageByName.Clear();
            _messageIdByName.Clear();

            if (!IsLoaded)
            {
                return;
            }

            EnsureMarshalBuffers_NoLock();

            // 遍历消息
            var msg = new ZDBC.DBCMessage
            {
                vSignals = new ZDBC.DBCSignal[ZDBC._DBC_SIGNAL_MAX_COUNT_],
                strName = new byte[ZDBC._DBC_NAME_LENGTH_ + 1],
                strComment = new byte[ZDBC._DBC_COMMENT_MAX_LENGTH_ + 1]
            };

            Marshal.StructureToPtr(msg, _msgPtr, false);
            var ok = ZDBC.ZDBC_GetFirstMessage(_dbcHandle, _msgPtr);
            while (ok)
            {
                var m = Marshal.PtrToStructure<ZDBC.DBCMessage>(_msgPtr);
                var name = ByteArrayToAsciiString(m.strName);
                if (!string.IsNullOrWhiteSpace(name))
                {
                    _messageByName[name] = m;
                    _messageIdByName[name] = m.nID;
                }

                Marshal.StructureToPtr(msg, _msgPtr, false);
                ok = ZDBC.ZDBC_GetNextMessage(_dbcHandle, _msgPtr);
            }
        }

        private void EnsureMarshalBuffers_NoLock()
        {
            if (_msgPtr == IntPtr.Zero)
            {
                _msgPtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ZDBC.DBCMessage)));
            }

            if (_countPtr == IntPtr.Zero)
            {
                _countPtr = Marshal.AllocHGlobal(sizeof(int));
            }

            if (_canFramePtr == IntPtr.Zero)
            {
                _canFramePtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ZlgNativeCanFrame)));
            }

            if (_canFdFramePtr == IntPtr.Zero)
            {
                _canFdFramePtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ZlgNativeCanFdFrame)));
            }
        }

        private void FreeMarshalBuffers_NoLock()
        {
            if (_canFdFramePtr != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(_canFdFramePtr);
                _canFdFramePtr = IntPtr.Zero;
            }

            if (_canFramePtr != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(_canFramePtr);
                _canFramePtr = IntPtr.Zero;
            }

            if (_countPtr != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(_countPtr);
                _countPtr = IntPtr.Zero;
            }

            if (_msgPtr != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(_msgPtr);
                _msgPtr = IntPtr.Zero;
            }
        }

        private static void EnsureNativeDllExists(string dllName)
        {
            var baseDir = AppContext.BaseDirectory;
            var full = Path.Combine(baseDir, dllName);
            if (!File.Exists(full))
            {
                throw new FileNotFoundException($"未找到 {dllName}，请将其复制到程序输出目录：{baseDir}", full);
            }
        }

        private void SetSignalActualValue(ref ZDBC.DBCMessage msg, string signalName, double actualValue)
        {
            if (msg.vSignals == null || msg.vSignals.Length == 0)
            {
                return;
            }

            var count = (int)Math.Min(msg.nSignalCount, (uint)msg.vSignals.Length);
            for (int i = 0; i < count; i++)
            {
                var s = msg.vSignals[i];
                var name = ByteArrayToAsciiString(s.strName);
                if (!string.Equals(name, signalName, StringComparison.Ordinal))
                {
                    continue;
                }

                // 使用 ZDBC_CalcRawValue 做实际值->原始值转换
                IntPtr pSgl = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ZDBC.DBCSignal)));
                IntPtr pVal = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(double)));
                try
                {
                    Marshal.StructureToPtr(s, pSgl, false);
                    Marshal.StructureToPtr(actualValue, pVal, false);
                    var raw = ZDBC.ZDBC_CalcRawValue(pSgl, pVal);
                    msg.vSignals[i].nRawvalue = raw;
                }
                finally
                {
                    Marshal.FreeHGlobal(pVal);
                    Marshal.FreeHGlobal(pSgl);
                }

                return;
            }
        }

        private (string MsgName, Dictionary<string, double> Signals) ExtractActualSignals(ZDBC.DBCMessage msg)
        {
            var msgName = ByteArrayToAsciiString(msg.strName);
            var dict = new Dictionary<string, double>(StringComparer.Ordinal);

            if (msg.vSignals == null)
            {
                return (msgName, dict);
            }

            var count = (int)Math.Min(msg.nSignalCount, (uint)msg.vSignals.Length);
            for (int i = 0; i < count; i++)
            {
                var s = msg.vSignals[i];
                var name = ByteArrayToAsciiString(s.strName);
                if (string.IsNullOrWhiteSpace(name))
                {
                    continue;
                }

                // 使用 ZDBC_CalcActualValue 做原始值->实际值转换
                IntPtr pSgl = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ZDBC.DBCSignal)));
                IntPtr pRaw = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(ulong)));
                try
                {
                    Marshal.StructureToPtr(s, pSgl, false);
                    Marshal.StructureToPtr(s.nRawvalue, pRaw, false);
                    var actual = ZDBC.ZDBC_CalcActualValue(pSgl, pRaw);
                    dict[name] = actual;
                }
                finally
                {
                    Marshal.FreeHGlobal(pRaw);
                    Marshal.FreeHGlobal(pSgl);
                }
            }

            return (msgName, dict);
        }

        private static byte[] BuildFixedPathBytes(string path, int fixedLen)
        {
            var bytes = Encoding.Default.GetBytes(path);
            var dst = new byte[fixedLen];
            Array.Clear(dst, 0, dst.Length);
            Array.Copy(bytes, 0, dst, 0, Math.Min(bytes.Length, fixedLen - 1));
            return dst;
        }

        /// <summary>
        /// 当 ZDBC_LoadFile 失败时的兜底加载策略：读取文件内容并调用 ZDBC_LoadContent。
        /// </summary>
        /// <param name="fullPath">DBC 完整路径。</param>
        /// <param name="merge">是否合并。</param>
        /// <returns>加载成功返回 true。</returns>
        private bool TryLoadContentFallback_NoLock(string fullPath, bool merge)
        {
            // zdbc.dll 入口为 ANSI 字符串，因此这里优先使用 ASCII（将非 ASCII 字符替换为 ?），
            // 避免中文注释/特殊字符导致原生库解析失败；同时需要兼容 UTF-16 BOM，否则用 ASCII 读会出现大量 \0 造成内容截断。

            var encodings = new List<Encoding>();

            try
            {
                var bytes = File.ReadAllBytes(fullPath);
                if (bytes.Length >= 2)
                {
                    // UTF-16 LE BOM: FF FE
                    if (bytes[0] == 0xFF && bytes[1] == 0xFE)
                    {
                        encodings.Add(Encoding.Unicode);
                    }
                    // UTF-16 BE BOM: FE FF
                    else if (bytes[0] == 0xFE && bytes[1] == 0xFF)
                    {
                        encodings.Add(Encoding.BigEndianUnicode);
                    }
                }

                if (bytes.Length >= 3)
                {
                    // UTF-8 BOM: EF BB BF
                    if (bytes[0] == 0xEF && bytes[1] == 0xBB && bytes[2] == 0xBF)
                    {
                        encodings.Add(Encoding.UTF8);
                    }
                }
            }
            catch
            {
            }

            // 常规兜底编码序列
            encodings.Add(new UTF8Encoding(false, true));
            encodings.Add(Encoding.UTF8);
            encodings.Add(Encoding.Default);
            encodings.Add(Encoding.ASCII);

            foreach (var enc in encodings.Distinct())
            {
                IntPtr pContent = IntPtr.Zero;
                try
                {
                    var content = File.ReadAllText(fullPath, enc);
                    pContent = Marshal.StringToHGlobalAnsi(content);
                    var ok = ZDBC.ZDBC_LoadContent(_dbcHandle, pContent, merge ? 1u : 0u);
                    if (ok)
                    {
                        return true;
                    }
                }
                catch
                {
                }
                finally
                {
                    if (pContent != IntPtr.Zero)
                    {
                        Marshal.FreeHGlobal(pContent);
                    }
                }
            }

            return false;
        }

        /// <summary>
        /// 获取 Windows 8.3 短路径。
        /// </summary>
        /// <param name="lpszLongPath">长路径。</param>
        /// <param name="lpszShortPath">短路径缓冲。</param>
        /// <param name="cchBuffer">缓冲区大小。</param>
        /// <returns>返回写入的字符数量；0 表示失败。</returns>
        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        private static extern uint GetShortPathName(string lpszLongPath, StringBuilder lpszShortPath, uint cchBuffer);

        /// <summary>
        /// 尝试将长路径转换为短路径（8.3），用于兼容部分原生库对中文/特殊字符路径处理不完整的问题。
        /// </summary>
        /// <param name="fullPath">长路径。</param>
        /// <returns>短路径；失败返回 null。</returns>
        private static string? TryGetShortPath(string fullPath)
        {
            try
            {
                if (string.IsNullOrWhiteSpace(fullPath))
                {
                    return null;
                }

                var sb = new StringBuilder(1024);
                var ret = GetShortPathName(fullPath, sb, (uint)sb.Capacity);
                if (ret == 0)
                {
                    return null;
                }
                return sb.ToString();
            }
            catch
            {
                return null;
            }
        }

        private static string ByteArrayToAsciiString(byte[]? bytes)
        {
            if (bytes == null || bytes.Length == 0) return string.Empty;

            int len = Array.IndexOf(bytes, (byte)0);
            if (len < 0) len = bytes.Length;

            return Encoding.Default.GetString(bytes, 0, len).Trim();
        }

        private void ThrowIfDisposed()
        {
            if (_disposed)
            {
                throw new ObjectDisposedException(nameof(ZlgDbcDatabase));
            }
        }
    }
}