using System;
using System.Collections.Generic;
using System.Management;
using System.Windows.Forms;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;

public static class DisplayFusionFunction
{
    // =========================
    // 常量参数 - 要关闭的显示器名称
    // =========================
    private const string TARGET_MONITOR_NAME = "DP1";

    // 存储显示器真名到硬件ID的映射
    private static Dictionary<string, string> monitorHardwareIdMap = new Dictionary<string, string>();

    // =========================
    // DDC/CI 相关 Win32 API
    // =========================
    private const byte VCP_POWER_MODE = 0xD6;
    private const uint POWER_OFF = 0x05;

    [StructLayout(LayoutKind.Sequential)]
    struct PHYSICAL_MONITOR
    {
        public IntPtr hPhysicalMonitor;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string szPhysicalMonitorDescription;
    }

    [DllImport("dxva2.dll", SetLastError = true)]
    static extern bool GetNumberOfPhysicalMonitorsFromHMONITOR(
        IntPtr hMonitor,
        out uint pdwNumberOfPhysicalMonitors);

    [DllImport("dxva2.dll", SetLastError = true)]
    static extern bool GetPhysicalMonitorsFromHMONITOR(
        IntPtr hMonitor,
        uint dwPhysicalMonitorArraySize,
        [Out] PHYSICAL_MONITOR[] pPhysicalMonitorArray);

    [DllImport("dxva2.dll", SetLastError = true)]
    static extern bool SetVCPFeature(
        IntPtr hMonitor,
        byte bVCPCode,
        uint dwNewValue);

    [DllImport("dxva2.dll", SetLastError = true)]
    static extern bool DestroyPhysicalMonitors(
        uint dwPhysicalMonitorArraySize,
        PHYSICAL_MONITOR[] pPhysicalMonitorArray);

    [DllImport("user32.dll")]
    static extern IntPtr MonitorFromPoint(Point pt, uint dwFlags);

    // =========================
    // 枚举显示设备（用于获取设备描述和设备ID）
    // =========================
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    static extern bool EnumDisplayDevices(string lpDevice, uint iDevNum, ref DISPLAY_DEVICE lpDisplayDevice, uint dwFlags);

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    struct DISPLAY_DEVICE
    {
        public int cb;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
        public string DeviceName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string DeviceString;
        public uint StateFlags;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string DeviceID;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string DeviceKey;
    }

    // =========================
    // 主逻辑
    // =========================
    public static void Run()
    {
        List<string> monitorNames = new List<string>();
        bool hasTargetMonitor = false;
        monitorHardwareIdMap.Clear();

        try
        {
            using (var searcher = new ManagementObjectSearcher(@"Root\WMI", "SELECT * FROM WmiMonitorID"))
            {
                foreach (ManagementObject mo in searcher.Get())
                {
                    // 获取显示器真名
                    ushort[] nameArray = (ushort[])mo["UserFriendlyName"];
                    string displayName = null;
                    if (nameArray != null)
                    {
                        char[] chars = new char[nameArray.Length];
                        for (int i = 0; i < nameArray.Length; i++)
                            chars[i] = (char)nameArray[i];
                        displayName = new string(chars).Trim('\0', ' ', '\n', '\r');
                    }

                    // 获取实例名称（包含硬件ID）
                    string instanceName = mo["InstanceName"]?.ToString();
                    string hardwareId = null;
                    if (!string.IsNullOrEmpty(instanceName))
                    {
                        // 解析硬件ID：从 InstanceName 中提取第二个字段
                        int firstSlash = instanceName.IndexOf('\\');
                        if (firstSlash >= 0)
                        {
                            int secondSlash = instanceName.IndexOf('\\', firstSlash + 1);
                            if (secondSlash >= 0)
                                hardwareId = instanceName.Substring(firstSlash + 1, secondSlash - firstSlash - 1);
                            else
                                hardwareId = instanceName.Substring(firstSlash + 1);
                        }
                    }

                    if (!string.IsNullOrEmpty(displayName))
                    {
                        monitorNames.Add(displayName);

                        if (displayName == TARGET_MONITOR_NAME)
                            hasTargetMonitor = true;

                        if (!string.IsNullOrEmpty(hardwareId))
                            monitorHardwareIdMap[displayName] = hardwareId;
                    }
                }
            }

            int monitorCount = monitorNames.Count;

            // =========================
            // 条件判断
            // =========================
            if (monitorCount > 1 && hasTargetMonitor)
            {
                try
                {
                    TurnOffMonitorByName(TARGET_MONITOR_NAME);
                }
                catch
                {
                    // 静默失败
                }
            }
        }
        catch
        {
            // 静默失败
        }
    }

    // =========================
    // 根据显示器名称（真名）关闭对应的物理显示器（通过硬件ID匹配）
    // =========================
    static void TurnOffMonitorByName(string targetName)
    {
        if (!monitorHardwareIdMap.TryGetValue(targetName, out string targetHwId))
            return;

        foreach (Screen screen in Screen.AllScreens)
        {
            IntPtr hMonitor = MonitorFromPoint(
                new Point(screen.Bounds.Left + 1, screen.Bounds.Top + 1),
                2); // MONITOR_DEFAULTTONEAREST

            if (hMonitor == IntPtr.Zero)
                continue;

            DISPLAY_DEVICE dd = new DISPLAY_DEVICE();
            dd.cb = Marshal.SizeOf(dd);
            if (!EnumDisplayDevices(screen.DeviceName, 0, ref dd, 0))
                continue;

            // 从 DeviceID 中提取硬件ID
            string screenHwId = ExtractHardwareIdFromDeviceID(dd.DeviceID);

            if (!string.IsNullOrEmpty(screenHwId) && screenHwId.Equals(targetHwId, StringComparison.OrdinalIgnoreCase))
            {
                // 获取物理监视器数量
                if (!GetNumberOfPhysicalMonitorsFromHMONITOR(hMonitor, out uint count) || count == 0)
                    return;

                PHYSICAL_MONITOR[] monitors = new PHYSICAL_MONITOR[count];
                if (!GetPhysicalMonitorsFromHMONITOR(hMonitor, count, monitors))
                    return;

                // 遍历并发送关机指令
                for (int i = 0; i < monitors.Length; i++)
                {
                    SetVCPFeature(monitors[i].hPhysicalMonitor, VCP_POWER_MODE, POWER_OFF);
                }

                // 释放资源
                DestroyPhysicalMonitors(count, monitors);
                break;
            }
        }
    }

    // 从 DeviceID 中提取硬件ID（例如：从 "MONITOR\DELA0D2\{...}" 提取 "DELA0D2"）
    private static string ExtractHardwareIdFromDeviceID(string deviceID)
    {
        if (string.IsNullOrEmpty(deviceID)) return null;
        int firstSlash = deviceID.IndexOf('\\');
        if (firstSlash >= 0)
        {
            int secondSlash = deviceID.IndexOf('\\', firstSlash + 1);
            if (secondSlash >= 0)
                return deviceID.Substring(firstSlash + 1, secondSlash - firstSlash - 1);
            else
                return deviceID.Substring(firstSlash + 1);
        }
        return null;
    }
}