using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;

namespace AmtScanner.Api.Services;

/// <summary>
/// Guacamole 远程桌面服务
/// </summary>
public class GuacamoleService
{
    private readonly ILogger<GuacamoleService> _logger;
    private readonly HttpClient _httpClient;
    private readonly IConfiguration _config;
    
    private string? _authToken;
    private DateTime _tokenExpiry = DateTime.MinValue;

    public GuacamoleService(ILogger<GuacamoleService> logger, IHttpClientFactory httpClientFactory, IConfiguration config)
    {
        _logger = logger;
        _httpClient = httpClientFactory.CreateClient("Guacamole");
        _config = config;
    }

    /// <summary>
    /// 获取 Guacamole 认证 Token
    /// </summary>
    public async Task<string?> GetAuthTokenAsync()
    {
        // 如果 token 还有效，直接返回
        if (!string.IsNullOrEmpty(_authToken) && DateTime.Now < _tokenExpiry)
        {
            return _authToken;
        }

        try
        {
            var baseUrl = _config["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
            var username = _config["Guacamole:Username"] ?? "guacadmin";
            var password = _config["Guacamole:Password"] ?? "guacadmin";

            var content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("username", username),
                new KeyValuePair<string, string>("password", password)
            });

            var response = await _httpClient.PostAsync($"{baseUrl}/api/tokens", content);
            
            if (response.IsSuccessStatusCode)
            {
                var json = await response.Content.ReadAsStringAsync();
                var result = JsonSerializer.Deserialize<JsonElement>(json);
                
                _authToken = result.GetProperty("authToken").GetString();
                _tokenExpiry = DateTime.Now.AddMinutes(30); // Token 有效期约 30 分钟
                
                _logger.LogInformation("Guacamole 认证成功");
                return _authToken;
            }
            else
            {
                _logger.LogError("Guacamole 认证失败: {Status}", response.StatusCode);
                return null;
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "获取 Guacamole Token 失败");
            return null;
        }
    }

    /// <summary>
    /// 创建 RDP 连接
    /// </summary>
    public async Task<string?> CreateRdpConnectionAsync(string name, string hostname, string username, string password, int port = 3389)
    {
        var token = await GetAuthTokenAsync();
        if (string.IsNullOrEmpty(token)) return null;

        try
        {
            var baseUrl = _config["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
            var dataSource = _config["Guacamole:DataSource"] ?? "mysql";

            var connection = new
            {
                parentIdentifier = "ROOT",
                name = name,
                protocol = "rdp",
                parameters = new
                {
                    hostname = hostname,
                    port = port.ToString(),
                    username = username,
                    password = password,
                    security = "any",
                    ignoreCert = "true",
                    enableDrive = "true",
                    createDrivePath = "true"
                },
                attributes = new
                {
                    maxConnections = "",
                    maxConnectionsPerUser = ""
                }
            };

            var json = JsonSerializer.Serialize(connection);
            var content = new StringContent(json, Encoding.UTF8, "application/json");

            var response = await _httpClient.PostAsync(
                $"{baseUrl}/api/session/data/{dataSource}/connections?token={token}",
                content);

            if (response.IsSuccessStatusCode)
            {
                var resultJson = await response.Content.ReadAsStringAsync();
                var result = JsonSerializer.Deserialize<JsonElement>(resultJson);
                var connectionId = result.GetProperty("identifier").GetString();
                
                _logger.LogInformation("创建 RDP 连接成功: {Id}", connectionId);
                return connectionId;
            }
            else
            {
                var error = await response.Content.ReadAsStringAsync();
                _logger.LogError("创建 RDP 连接失败: {Status} - {Error}", response.StatusCode, error);
                return null;
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "创建 RDP 连接异常");
            return null;
        }
    }

    /// <summary>
    /// 创建 VNC 连接
    /// </summary>
    public async Task<string?> CreateVncConnectionAsync(string name, string hostname, string password, int port = 5900)
    {
        var token = await GetAuthTokenAsync();
        if (string.IsNullOrEmpty(token)) return null;

        try
        {
            var baseUrl = _config["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
            var dataSource = _config["Guacamole:DataSource"] ?? "mysql";

            var connection = new
            {
                parentIdentifier = "ROOT",
                name = name,
                protocol = "vnc",
                parameters = new
                {
                    hostname = hostname,
                    port = port.ToString(),
                    password = password
                },
                attributes = new
                {
                    maxConnections = "",
                    maxConnectionsPerUser = ""
                }
            };

            var json = JsonSerializer.Serialize(connection);
            var content = new StringContent(json, Encoding.UTF8, "application/json");

            var response = await _httpClient.PostAsync(
                $"{baseUrl}/api/session/data/{dataSource}/connections?token={token}",
                content);

            if (response.IsSuccessStatusCode)
            {
                var resultJson = await response.Content.ReadAsStringAsync();
                var result = JsonSerializer.Deserialize<JsonElement>(resultJson);
                var connectionId = result.GetProperty("identifier").GetString();
                
                _logger.LogInformation("创建 VNC 连接成功: {Id}", connectionId);
                return connectionId;
            }
            else
            {
                var error = await response.Content.ReadAsStringAsync();
                _logger.LogError("创建 VNC 连接失败: {Status} - {Error}", response.StatusCode, error);
                return null;
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "创建 VNC 连接异常");
            return null;
        }
    }

    /// <summary>
    /// 删除连接
    /// </summary>
    public async Task<bool> DeleteConnectionAsync(string connectionId)
    {
        var token = await GetAuthTokenAsync();
        if (string.IsNullOrEmpty(token)) return false;

        try
        {
            var baseUrl = _config["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
            var dataSource = _config["Guacamole:DataSource"] ?? "mysql";

            var response = await _httpClient.DeleteAsync(
                $"{baseUrl}/api/session/data/{dataSource}/connections/{connectionId}?token={token}");

            if (response.IsSuccessStatusCode)
            {
                _logger.LogInformation("删除连接成功: {Id}", connectionId);
                return true;
            }
            else
            {
                _logger.LogError("删除连接失败: {Status}", response.StatusCode);
                return false;
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "删除连接异常");
            return false;
        }
    }

    /// <summary>
    /// 获取连接 URL（用于 iframe 嵌入）
    /// </summary>
    public async Task<string?> GetConnectionUrlAsync(string connectionId)
    {
        var token = await GetAuthTokenAsync();
        if (string.IsNullOrEmpty(token)) return null;

        var baseUrl = _config["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
        var dataSource = _config["Guacamole:DataSource"] ?? "mysql";

        // 构建客户端连接 URL
        // 格式: BASE_URL/#/client/BASE64(connectionId + '\0' + 'c' + '\0' + dataSource)
        var clientId = $"{connectionId}\0c\0{dataSource}";
        var encodedClientId = Convert.ToBase64String(Encoding.UTF8.GetBytes(clientId));

        return $"{baseUrl}/#/client/{encodedClientId}?token={token}";
    }

    /// <summary>
    /// 获取所有连接
    /// </summary>
    public async Task<List<GuacamoleConnection>> GetConnectionsAsync()
    {
        var token = await GetAuthTokenAsync();
        if (string.IsNullOrEmpty(token)) return new List<GuacamoleConnection>();

        try
        {
            var baseUrl = _config["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
            var dataSource = _config["Guacamole:DataSource"] ?? "mysql";

            var response = await _httpClient.GetAsync(
                $"{baseUrl}/api/session/data/{dataSource}/connections?token={token}");

            if (response.IsSuccessStatusCode)
            {
                var json = await response.Content.ReadAsStringAsync();
                var connections = JsonSerializer.Deserialize<Dictionary<string, GuacamoleConnection>>(json,
                    new JsonSerializerOptions { PropertyNameCaseInsensitive = true });

                return connections?.Values.ToList() ?? new List<GuacamoleConnection>();
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "获取连接列表失败");
        }

        return new List<GuacamoleConnection>();
    }
}

public class GuacamoleConnection
{
    public string Identifier { get; set; } = "";
    public string Name { get; set; } = "";
    public string Protocol { get; set; } = "";
    public string ParentIdentifier { get; set; } = "";
}