using System;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;

namespace KSTools.Licensing
{
    /// <summary>
    /// KSTools 授權 API 客戶端
    /// 負責與授權管理系統的 API 通信
    /// </summary>
    public class ApiClient
    {
        private static readonly string DEFAULT_API_BASE = "https://your-space.hf.space/api";
        private static readonly HttpClient httpClient = new HttpClient() { Timeout = TimeSpan.FromSeconds(30) };
        
        private readonly string _apiBase;
        
        /// <summary>
        /// 初始化 API 客戶端
        /// </summary>
        /// <param name="apiBase">API 基礎 URL，如果為空則使用預設值</param>
        public ApiClient(string apiBase = null)
        {
            _apiBase = string.IsNullOrEmpty(apiBase) ? DEFAULT_API_BASE : apiBase.TrimEnd('/');
            
            // 設定 HTTP 客戶端標頭
            httpClient.DefaultRequestHeaders.Clear();
            httpClient.DefaultRequestHeaders.Add("User-Agent", "KSTools-Revit-Plugin/1.0");
        }
        
        /// <summary>
        /// 啟用授權
        /// </summary>
        /// <param name="licenseCode">授權碼</param>
        /// <param name="hardwareId">硬體指紋ID，如果為空則自動生成</param>
        /// <returns>啟用結果</returns>
        public async Task<ActivationResult> ActivateLicenseAsync(string licenseCode, string hardwareId = null)
        {
            try
            {
                if (string.IsNullOrEmpty(licenseCode))
                {
                    return new ActivationResult
                    {
                        Success = false,
                        Message = "授權碼不能為空"
                    };
                }
                
                // 如果沒有提供硬體ID，自動生成
                if (string.IsNullOrEmpty(hardwareId))
                {
                    hardwareId = HardwareFingerprint.GetHardwareId();
                }
                
                var request = new
                {
                    license_code = licenseCode,
                    hardware_id = hardwareId,
                    machine_name = Environment.MachineName
                };
                
                var json = JsonSerializer.Serialize(request, new JsonSerializerOptions 
                { 
                    PropertyNamingPolicy = JsonNamingPolicy.CamelCase 
                });
                var content = new StringContent(json, Encoding.UTF8, "application/json");
                
                var response = await httpClient.PostAsync($"{_apiBase}/license/activate", content);
                var resultJson = await response.Content.ReadAsStringAsync();
                
                if (response.IsSuccessStatusCode)
                {
                    var apiResponse = JsonSerializer.Deserialize<ApiActivationResponse>(resultJson, new JsonSerializerOptions 
                    { 
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase 
                    });
                    
                    return new ActivationResult
                    {
                        Success = apiResponse.Success,
                        Message = apiResponse.Message,
                        ExpiresAt = apiResponse.ExpiresAt,
                        UserName = apiResponse.UserName,
                        HardwareId = apiResponse.HardwareId
                    };
                }
                else
                {
                    return new ActivationResult
                    {
                        Success = false,
                        Message = $"HTTP 錯誤 {response.StatusCode}: {resultJson}"
                    };
                }
            }
            catch (HttpRequestException ex)
            {
                return new ActivationResult
                {
                    Success = false,
                    Message = $"網路連接錯誤: {ex.Message}"
                };
            }
            catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
            {
                return new ActivationResult
                {
                    Success = false,
                    Message = "請求超時，請檢查網路連接"
                };
            }
            catch (Exception ex)
            {
                return new ActivationResult
                {
                    Success = false,
                    Message = $"未知錯誤: {ex.Message}"
                };
            }
        }
        
        /// <summary>
        /// 驗證授權
        /// </summary>
        /// <param name="licenseCode">授權碼</param>
        /// <param name="hardwareId">硬體指紋ID，如果為空則自動生成</param>
        /// <returns>驗證結果</returns>
        public async Task<ValidationResult> ValidateLicenseAsync(string licenseCode, string hardwareId = null)
        {
            try
            {
                if (string.IsNullOrEmpty(licenseCode))
                {
                    return new ValidationResult
                    {
                        Valid = false,
                        Message = "授權碼不能為空"
                    };
                }
                
                // 如果沒有提供硬體ID，自動生成
                if (string.IsNullOrEmpty(hardwareId))
                {
                    hardwareId = HardwareFingerprint.GetHardwareId();
                }
                
                var request = new
                {
                    license_code = licenseCode,
                    hardware_id = hardwareId,
                    machine_name = Environment.MachineName
                };
                
                var json = JsonSerializer.Serialize(request, new JsonSerializerOptions 
                { 
                    PropertyNamingPolicy = JsonNamingPolicy.CamelCase 
                });
                var content = new StringContent(json, Encoding.UTF8, "application/json");
                
                var response = await httpClient.PostAsync($"{_apiBase}/license/validate", content);
                var resultJson = await response.Content.ReadAsStringAsync();
                
                if (response.IsSuccessStatusCode)
                {
                    var apiResponse = JsonSerializer.Deserialize<ApiValidationResponse>(resultJson, new JsonSerializerOptions 
                    { 
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase 
                    });
                    
                    return new ValidationResult
                    {
                        Valid = apiResponse.Valid,
                        Message = apiResponse.Message,
                        ExpiresAt = apiResponse.ExpiresAt,
                        UserName = apiResponse.UserName,
                        HardwareId = apiResponse.HardwareId
                    };
                }
                else
                {
                    return new ValidationResult
                    {
                        Valid = false,
                        Message = $"HTTP 錯誤 {response.StatusCode}: {resultJson}"
                    };
                }
            }
            catch (HttpRequestException ex)
            {
                return new ValidationResult
                {
                    Valid = false,
                    Message = $"網路連接錯誤: {ex.Message}"
                };
            }
            catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
            {
                return new ValidationResult
                {
                    Valid = false,
                    Message = "請求超時，請檢查網路連接"
                };
            }
            catch (Exception ex)
            {
                return new ValidationResult
                {
                    Valid = false,
                    Message = $"未知錯誤: {ex.Message}"
                };
            }
        }
        
        /// <summary>
        /// 測試 API 連接
        /// </summary>
        /// <returns>是否連接成功</returns>
        public async Task<bool> TestConnectionAsync()
        {
            try
            {
                var response = await httpClient.GetAsync($"{_apiBase.Replace("/api", "")}/health");
                return response.IsSuccessStatusCode;
            }
            catch
            {
                return false;
            }
        }
    }
    
    #region API 回應模型
    
    /// <summary>
    /// API 啟用回應模型
    /// </summary>
    internal class ApiActivationResponse
    {
        public bool Success { get; set; }
        public string Message { get; set; }
        public DateTime? ExpiresAt { get; set; }
        public string UserName { get; set; }
        public string HardwareId { get; set; }
    }
    
    /// <summary>
    /// API 驗證回應模型
    /// </summary>
    internal class ApiValidationResponse
    {
        public bool Valid { get; set; }
        public string Message { get; set; }
        public DateTime? ExpiresAt { get; set; }
        public string UserName { get; set; }
        public string HardwareId { get; set; }
    }
    
    #endregion
    
    #region 公開結果模型
    
    /// <summary>
    /// 授權啟用結果
    /// </summary>
    public class ActivationResult
    {
        /// <summary>
        /// 啟用是否成功
        /// </summary>
        public bool Success { get; set; }
        
        /// <summary>
        /// 狀態訊息
        /// </summary>
        public string Message { get; set; }
        
        /// <summary>
        /// 授權到期時間
        /// </summary>
        public DateTime? ExpiresAt { get; set; }
        
        /// <summary>
        /// 授權用戶名稱
        /// </summary>
        public string UserName { get; set; }
        
        /// <summary>
        /// 硬體指紋ID
        /// </summary>
        public string HardwareId { get; set; }
    }
    
    /// <summary>
    /// 授權驗證結果
    /// </summary>
    public class ValidationResult
    {
        /// <summary>
        /// 授權是否有效
        /// </summary>
        public bool Valid { get; set; }
        
        /// <summary>
        /// 狀態訊息
        /// </summary>
        public string Message { get; set; }
        
        /// <summary>
        /// 授權到期時間
        /// </summary>
        public DateTime? ExpiresAt { get; set; }
        
        /// <summary>
        /// 授權用戶名稱
        /// </summary>
        public string UserName { get; set; }
        
        /// <summary>
        /// 硬體指紋ID
        /// </summary>
        public string HardwareId { get; set; }
    }
    
    #endregion
}