using System;
using System.Net;
using System.Net.Http;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using StreamPlayer.Desktop.Models;

namespace StreamPlayer.Desktop.Services;

public sealed class DeviceRegistryService
{
    private static readonly HttpClient HttpClient = new(new HttpClientHandler
    {
        AutomaticDecompression = DecompressionMethods.All
    })
    {
        Timeout = TimeSpan.FromSeconds(20)
    };

    private readonly string _deviceId = CreateDeviceId();

    public async Task<DeviceStatus> SyncAsync(CancellationToken cancellationToken)
    {
        if (string.IsNullOrWhiteSpace(AppVersion.DeviceRegistryUrl))
        {
            return DeviceStatus.Allowed();
        }

        var payload = new
        {
            deviceId = _deviceId,
            deviceName = Environment.MachineName,
            model = RuntimeInformation.OSDescription,
            manufacturer = "Microsoft",
            osVersion = Environment.OSVersion.VersionString,
            appVersionName = AppVersion.VersionName,
            appVersionCode = AppVersion.VersionCode
        };

        string endpoint = $"{SanitizeBaseUrl(AppVersion.DeviceRegistryUrl)}/api/devices/register";
        var content = new StringContent(JsonSerializer.Serialize(payload), Encoding.UTF8, "application/json");
        using var request = new HttpRequestMessage(HttpMethod.Post, endpoint)
        {
            Content = content
        };
        using var response = await HttpClient.SendAsync(request, cancellationToken).ConfigureAwait(false);
        response.EnsureSuccessStatusCode();
        string body = await response.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
        using var document = JsonDocument.Parse(body);
        var root = document.RootElement;

        bool blocked = root.GetPropertyOrDefaultBool("blocked", false);
        string reason = root.GetPropertyOrDefault("message");
        if (root.TryGetProperty("device", out var deviceElement))
        {
            if (string.IsNullOrWhiteSpace(reason))
            {
                reason = deviceElement.GetPropertyOrDefault("notes");
            }
        }
        string tokenPart = string.Empty;
        if (root.TryGetProperty("verification", out var verificationElement))
        {
            bool verificationRequired = verificationElement.GetPropertyOrDefaultBool("required", false);
            blocked = blocked || verificationRequired;
            tokenPart = verificationElement.GetPropertyOrDefault("clientTokenPart");
        }

        return new DeviceStatus(blocked, reason, tokenPart);
    }

    private static string SanitizeBaseUrl(string value)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return string.Empty;
        }
        return value.EndsWith("/", StringComparison.Ordinal) ? value.TrimEnd('/') : value;
    }

    private static string CreateDeviceId()
    {
        string raw = $"{Environment.MachineName}|{Environment.UserName}|{RuntimeInformation.OSDescription}";
        byte[] hash = SHA256.HashData(Encoding.UTF8.GetBytes(raw));
        return Convert.ToHexString(hash)[..24].ToLowerInvariant();
    }
}