using System.Text;
using System.Text.Json;

namespace AmtScanner.Api.Services;

public interface IGuacamoleService
{
    Task<string?> GetAuthTokenAsync();
    Task<string?> CreateOrGetConnectionAsync(string token, string connectionName, string hostname, string username, string password);
    Task<string?> GetConnectionUrlAsync(string token, string connectionId);
}

public class GuacamoleService : IGuacamoleService
{
    private readonly HttpClient _httpClient;
    private readonly ILogger<GuacamoleService> _logger;
    private readonly IConfiguration _configuration;
    
    private string GuacamoleBaseUrl => _configuration["Guacamole:BaseUrl"] ?? "http://localhost:8080/guacamole";
    private string GuacamoleUsername => _configuration["Guacamole:Username"] ?? "guacadmin";
    private string GuacamolePassword => _configuration["Guacamole:Password"] ?? "guacadmin";

    public GuacamoleService(HttpClient httpClient, ILogger<GuacamoleService> logger, IConfiguration configuration)
    {
        _httpClient = httpClient;
        _logger = logger;
        _configuration = configuration;
    }

    /// <summary>
    /// 获取 Guacamole 认证 Token
    /// </summary>
    public async Task<string?> GetAuthTokenAsync()
    {
        try
        {
            var content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("username", GuacamoleUsername),
                new KeyValuePair<string, string>("password", GuacamolePassword)
            });

            var response = await _httpClient.PostAsync($"{GuacamoleBaseUrl}/api/tokens", content);
            
            if (!response.IsSuccessStatusCode)
            {
                _logger.LogError("Failed to get Guacamole token: {Status}", response.StatusCode);
                return null;
            }

            var json = await response.Content.ReadAsStringAsync();
            using var doc = JsonDocument.Parse(json);
            
            if (doc.RootElement.TryGetProperty("authToken", out var tokenElement))
            {
                return tokenElement.GetString();
            }

            return null;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting Guacamole token");
            return null;
        }
    }

    /// <summary>
    /// 创建或获取已存在的连接
    /// </summary>
    public async Task<string?> CreateOrGetConnectionAsync(string token, string connectionName, string hostname, string username, string password)
    {
        try
        {
            // 先查找是否已存在同名连接
            var existingId = await FindConnectionByNameAsync(token, connectionName);
            if (existingId != null)
            {
                // 更新连接参数
                await UpdateConnectionAsync(token, existingId, connectionName, hostname, username, password);
                return existingId;
            }

            // 创建新连接
            var connectionData = new Dictionary<string, object>
            {
                ["name"] = connectionName,
                ["parentIdentifier"] = "ROOT",
                ["protocol"] = "rdp",
                ["parameters"] = new Dictionary<string, string>
                {
                    ["hostname"] = hostname,
                    ["port"] = "3389",
                    ["username"] = username,
                    ["password"] = password,
                    ["security"] = "any",
                    ["ignore-cert"] = "true",
                    ["resize-method"] = "display-update",
                    ["enable-wallpaper"] = "true",
                    ["enable-theming"] = "true",
                    ["enable-font-smoothing"] = "true",
                    ["enable-full-window-drag"] = "true",
                    ["enable-desktop-composition"] = "true",
                    ["enable-menu-animations"] = "true",
                    ["disable-bitmap-caching"] = "false",
                    ["disable-offscreen-caching"] = "false",
                    ["disable-glyph-caching"] = "false"
                },
                ["attributes"] = new Dictionary<string, string>()
            };

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

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

            if (!response.IsSuccessStatusCode)
            {
                var error = await response.Content.ReadAsStringAsync();
                _logger.LogError("Failed to create connection: {Status} - {Error}", response.StatusCode, error);
                return null;
            }

            var responseJson = await response.Content.ReadAsStringAsync();
            using var doc = JsonDocument.Parse(responseJson);
            
            if (doc.RootElement.TryGetProperty("identifier", out var idElement))
            {
                return idElement.GetString();
            }

            return null;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error creating Guacamole connection");
            return null;
        }
    }


    /// <summary>
    /// 查找已存在的连接
    /// </summary>
    private async Task<string?> FindConnectionByNameAsync(string token, string connectionName)
    {
        try
        {
            var response = await _httpClient.GetAsync(
                $"{GuacamoleBaseUrl}/api/session/data/mysql/connections?token={token}");

            if (!response.IsSuccessStatusCode)
            {
                return null;
            }

            var json = await response.Content.ReadAsStringAsync();
            using var doc = JsonDocument.Parse(json);

            foreach (var prop in doc.RootElement.EnumerateObject())
            {
                if (prop.Value.TryGetProperty("name", out var nameElement) &&
                    nameElement.GetString() == connectionName)
                {
                    return prop.Name;
                }
            }

            return null;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error finding connection by name");
            return null;
        }
    }

    /// <summary>
    /// 更新连接参数
    /// </summary>
    private async Task UpdateConnectionAsync(string token, string connectionId, string connectionName, string hostname, string username, string password)
    {
        try
        {
            var connectionData = new Dictionary<string, object>
            {
                ["name"] = connectionName,
                ["parentIdentifier"] = "ROOT",
                ["protocol"] = "rdp",
                ["identifier"] = connectionId,
                ["parameters"] = new Dictionary<string, string>
                {
                    ["hostname"] = hostname,
                    ["port"] = "3389",
                    ["username"] = username,
                    ["password"] = password,
                    ["security"] = "any",
                    ["ignore-cert"] = "true",
                    ["resize-method"] = "display-update",
                    ["enable-wallpaper"] = "true",
                    ["enable-theming"] = "true",
                    ["enable-font-smoothing"] = "true",
                    ["enable-full-window-drag"] = "true",
                    ["enable-desktop-composition"] = "true",
                    ["enable-menu-animations"] = "true"
                },
                ["attributes"] = new Dictionary<string, string>()
            };

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

            var request = new HttpRequestMessage(HttpMethod.Put, 
                $"{GuacamoleBaseUrl}/api/session/data/mysql/connections/{connectionId}?token={token}")
            {
                Content = content
            };

            await _httpClient.SendAsync(request);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error updating connection");
        }
    }

    /// <summary>
    /// 获取连接 URL（用于 iframe 嵌入）
    /// </summary>
    public async Task<string?> GetConnectionUrlAsync(string token, string connectionId)
    {
        // Guacamole 客户端 URL 格式
        // 连接标识符需要 Base64 编码: connectionId + "\0" + "c" + "\0" + "mysql"
        var connectionIdentifier = $"{connectionId}\0c\0mysql";
        var encodedId = Convert.ToBase64String(Encoding.UTF8.GetBytes(connectionIdentifier));
        
        return $"{GuacamoleBaseUrl}/#/client/{encodedId}?token={token}";
    }
}