using System.Management;
using System.Net.Http.Json;
using System.Net.NetworkInformation;
using System.Runtime.Versioning;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace ShopDbAdoptionTool;

// ShopDB adoption tool (SPIKE). A one-shot, agentless enrollment client: it uses
// only the endpoints collector key to create a ShopDB PC (Computer) + Endpoint
// entry via the existing collector adopt path, then exits. It is NOT the endpoint
// agent - it installs nothing, runs no service, and reports no ongoing telemetry.
// For sites that want an inventory entry without running the full agent.
//
// Configuration comes from adopt.config.json beside the exe, or from
// --baseurl / --collectorkey / --hostname arguments (arguments win). The
// collector key is never written to disk by this tool; it is read from the
// config the operator generated and placed next to the exe.
[SupportedOSPlatform("windows")]
internal static class Program
{
    private const string ReportPath = "/api/collector/endpoints";

    private static async Task<int> Main(string[] args)
    {
        try
        {
            var config = LoadConfig(args);
            if (string.IsNullOrWhiteSpace(config.BaseUrl) ||
                string.IsNullOrWhiteSpace(config.CollectorKey))
            {
                Console.Error.WriteLine(
                    "Missing baseurl or collectorkey. Provide adopt.config.json next to the "
                    + "exe or pass --baseurl and --collectorkey.");
                return 2;
            }

            // The app manifest forces UAC elevation, so this is a belt-and-braces
            // guard for edge cases (for example a stripped manifest). Full WMI and
            // the machine Uninstall hives need admin, or collection is partial.
            if (!IsElevated())
            {
                Console.Error.WriteLine(
                    "This tool must run as administrator so hardware and installed-"
                    + "software collection succeeds. Right-click and Run as administrator.");
                return 3;
            }

            var payload = BuildPayload(config);
            Console.WriteLine($"Adopting '{payload.Hostname}' into {config.BaseUrl} ...");
            Console.WriteLine(
                $"Collected {payload.Applications?.Length ?? 0} installed applications.");

            using var client = new HttpClient { Timeout = TimeSpan.FromSeconds(60) };
            client.DefaultRequestHeaders.Add("X-API-Key", config.CollectorKey);

            var url = config.BaseUrl!.TrimEnd('/') + ReportPath;
            using var response = await client.PostAsJsonAsync(url, payload);
            var body = await response.Content.ReadAsStringAsync();

            if (!response.IsSuccessStatusCode)
            {
                Console.Error.WriteLine(
                    $"Adoption failed: HTTP {(int)response.StatusCode}. {body}");
                return 1;
            }

            Console.WriteLine("Adoption succeeded.");
            Console.WriteLine(body);
            return 0;
        }
        catch (Exception error)
        {
            Console.Error.WriteLine($"Adoption error: {error.Message}");
            return 1;
        }
    }

    private static AdoptConfig LoadConfig(string[] args)
    {
        var config = new AdoptConfig();

        var configPath = Path.Combine(AppContext.BaseDirectory, "adopt.config.json");
        if (File.Exists(configPath))
        {
            var fromFile = JsonSerializer.Deserialize<AdoptConfig>(
                File.ReadAllText(configPath),
                new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
            if (fromFile is not null)
                config = fromFile;
        }

        for (var i = 0; i < args.Length - 1; i++)
        {
            var value = args[i + 1];
            switch (args[i].ToLowerInvariant())
            {
                case "--baseurl":
                    config.BaseUrl = value;
                    break;
                case "--collectorkey":
                    config.CollectorKey = value;
                    break;
                case "--hostname":
                    config.Hostname = value;
                    break;
            }
        }

        return config;
    }

    private static AdoptPayload BuildPayload(AdoptConfig config)
    {
        var hostname = !string.IsNullOrWhiteSpace(config.Hostname)
            ? config.Hostname!
            : Environment.MachineName;

        return new AdoptPayload
        {
            Hostname = hostname,
            Adopt = true,
            LoggedInUser = GetLoggedInUser(),
            SerialNumber = WmiFirst("SELECT SerialNumber FROM Win32_BIOS", "SerialNumber"),
            PcType = WmiFirst("SELECT Model FROM Win32_ComputerSystem", "Model"),
            VendorName = WmiFirst("SELECT Manufacturer FROM Win32_ComputerSystem", "Manufacturer"),
            ModelNumber = GetModelNumber(),
            OsName = WmiFirst("SELECT Caption FROM Win32_OperatingSystem", "Caption"),
            IpAddress = ResolveIpAddress(),
            LastBootTime = GetLastBootTime(),
            Applications = GetApplications(),
            AgentVersion = "adopt-0.1.0",
        };
    }

    // Mirrors the endpoint agent: prefer the WMI logged-on user, fall back to
    // the process identity so the field is never blank.
    private static string GetLoggedInUser()
    {
        var user = WmiFirst("SELECT UserName FROM Win32_ComputerSystem", "UserName");
        return string.IsNullOrWhiteSpace(user)
            ? $"{Environment.UserDomainName}\\{Environment.UserName}"
            : user;
    }

    // Human-readable model first (what pctype classifies on); SystemSKUNumber is
    // an OEM SKU code, used only when Model is blank. Matches EndpointCollector.
    private static string? GetModelNumber()
    {
        var model = WmiFirst("SELECT Model FROM Win32_ComputerSystem", "Model");
        if (!string.IsNullOrWhiteSpace(model))
            return model;
        return WmiFirst("SELECT SystemSKUNumber FROM Win32_ComputerSystem",
            "SystemSKUNumber");
    }

    private static DateTimeOffset? GetLastBootTime()
    {
        var raw = WmiFirst("SELECT LastBootUpTime FROM Win32_OperatingSystem",
            "LastBootUpTime");
        if (string.IsNullOrWhiteSpace(raw))
            return null;
        try
        {
            return ManagementDateTimeConverter.ToDateTime(raw).ToUniversalTime();
        }
        catch
        {
            return null;
        }
    }

    // Run one WMI query and return the first row's column as a trimmed string,
    // or null. Best-effort: WMI failures never abort adoption.
    private static string? WmiFirst(string query, string column)
    {
        try
        {
            using var searcher = new ManagementObjectSearcher(query);
            foreach (var item in searcher.Get())
            {
                var value = item[column]?.ToString()?.Trim();
                if (!string.IsNullOrWhiteSpace(value))
                    return value;
            }
        }
        catch
        {
            // Best-effort: the server treats every hardware field as optional.
        }
        return null;
    }

    // Installed-software SBOM. Mirrors the endpoint agent exactly: enumerate both
    // Uninstall registry hives (64-bit and WOW6432Node), keep entries with a
    // DisplayName, de-dupe on name+version, and emit {displayname, displayversion,
    // publisher}. Requires admin to read the machine hives reliably (see the
    // app manifest). Never throws out to the caller.
    private static object[] GetApplications()
    {
        const string uninstall64 =
            @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
        const string uninstall32 =
            @"SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall";

        var result = new List<object>();
        var seen = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
        CollectUninstallHive(uninstall64, result, seen);
        CollectUninstallHive(uninstall32, result, seen);
        return result.ToArray();
    }

    private static void CollectUninstallHive(string subKey, List<object> result,
        HashSet<string> seen)
    {
        try
        {
            using var machine = Microsoft.Win32.RegistryKey.OpenBaseKey(
                Microsoft.Win32.RegistryHive.LocalMachine,
                Microsoft.Win32.RegistryView.Default);
            using var uninstall = machine.OpenSubKey(subKey);
            if (uninstall is null)
                return;

            foreach (var name in uninstall.GetSubKeyNames())
            {
                try
                {
                    using var entry = uninstall.OpenSubKey(name);
                    var displayName = entry?.GetValue("DisplayName")?.ToString()?.Trim();
                    if (string.IsNullOrWhiteSpace(displayName))
                        continue;

                    var displayVersion =
                        entry?.GetValue("DisplayVersion")?.ToString()?.Trim() ?? "";
                    var publisher =
                        entry?.GetValue("Publisher")?.ToString()?.Trim() ?? "";

                    if (!seen.Add(displayName + "\u0000" + displayVersion))
                        continue;

                    result.Add(new
                    {
                        displayname = displayName,
                        displayversion = displayVersion,
                        publisher,
                    });
                }
                catch
                {
                    // Skip unreadable entries; keep collecting the rest.
                }
            }
        }
        catch
        {
            // Skip an unreadable hive; the other hive may still return data.
        }
    }

    private static string? ResolveIpAddress()
    {
        try
        {
            foreach (var network in NetworkInterface.GetAllNetworkInterfaces())
            {
                if (network.OperationalStatus != OperationalStatus.Up)
                    continue;
                if (network.NetworkInterfaceType == NetworkInterfaceType.Loopback)
                    continue;
                foreach (var address in network.GetIPProperties().UnicastAddresses)
                {
                    if (address.Address.AddressFamily ==
                        System.Net.Sockets.AddressFamily.InterNetwork)
                        return address.Address.ToString();
                }
            }
        }
        catch
        {
            // Best-effort: the server treats ipaddress as optional.
        }
        return null;
    }

    // True when the process runs with the Administrators group in its token.
    private static bool IsElevated()
    {
        try
        {
            using var identity = System.Security.Principal.WindowsIdentity.GetCurrent();
            var principal = new System.Security.Principal.WindowsPrincipal(identity);
            return principal.IsInRole(
                System.Security.Principal.WindowsBuiltInRole.Administrator);
        }
        catch
        {
            return false;
        }
    }
}

internal sealed class AdoptConfig
{
    [JsonPropertyName("baseurl")]
    public string? BaseUrl { get; set; }

    [JsonPropertyName("collectorkey")]
    public string? CollectorKey { get; set; }

    [JsonPropertyName("hostname")]
    public string? Hostname { get; set; }
}

// Payload keys mirror the endpoints collector adopt schema exactly (lowercase,
// concatenated) so the server stores them without translation. This tool sends
// the adopt identity plus the hardware and SBOM subset the endpoint agent
// collects; ongoing health telemetry (cpu, services, events) is intentionally
// absent because this is agentless enrollment, not the agent.
internal sealed class AdoptPayload
{
    [JsonPropertyName("hostname")]
    public string Hostname { get; set; } = "";

    [JsonPropertyName("adopt")]
    public bool Adopt { get; set; }

    [JsonPropertyName("loggedinuser")]
    public string? LoggedInUser { get; set; }

    [JsonPropertyName("serialnumber")]
    public string? SerialNumber { get; set; }

    [JsonPropertyName("pctype")]
    public string? PcType { get; set; }

    [JsonPropertyName("vendorname")]
    public string? VendorName { get; set; }

    [JsonPropertyName("modelnumber")]
    public string? ModelNumber { get; set; }

    [JsonPropertyName("osname")]
    public string? OsName { get; set; }

    [JsonPropertyName("ipaddress")]
    public string? IpAddress { get; set; }

    [JsonPropertyName("lastboottime")]
    public DateTimeOffset? LastBootTime { get; set; }

    [JsonPropertyName("applications")]
    public object[]? Applications { get; set; }

    [JsonPropertyName("agentversion")]
    public string? AgentVersion { get; set; }
}