using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using NCC.Common.Configuration;
using NCC.Dependency;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
// 增强版 SDK 暂时注释，改用 HTTP 原生调用
// using AlibabaCloud.SDK.Green20220302;
// using AlibabaCloud.SDK.Green20220302.Models;
// using AlibabaCloud.OSS.V2;
// using AlibabaCloud.OSS.V2.Models;

namespace NCC.Extend
{
    /// <summary>
    /// 图片审核服务（阿里云内容安全），仅内部调用，不暴露 API
    /// </summary>
    public class ImageModerationService : ITransient
    {
        private readonly HttpClient _httpClient;
        private readonly string _endpoint;
        private readonly string _accessKeyId;
        private readonly string _accessKeySecret;
        private readonly string _region;
        private readonly bool _enabled;
        private readonly bool _isEnhancedVersion; // 是否为增强版（green-cip）

        /// <summary>
        /// 初始化图片审核服务
        /// </summary>
        public ImageModerationService()
        {
            _httpClient = new HttpClient();
            _enabled = App.Configuration["NCC_App:ImageModeration:Enabled"] == "true";
            _endpoint = App.Configuration["NCC_App:ImageModeration:Endpoint"] 
                ?? "https://green.cn-shanghai.aliyuncs.com";
            _region = App.Configuration["NCC_App:ImageModeration:Region"] 
                ?? "cn-shanghai";
            
            // 优先使用ImageModeration配置，如果没有则使用AliyunOSS的配置
            _accessKeyId = App.Configuration["NCC_App:ImageModeration:AccessKeyId"];
            if (string.IsNullOrEmpty(_accessKeyId))
            {
                _accessKeyId = App.Configuration["NCC_App:AliyunOSS:AccessKeyId"];
            }
            
            _accessKeySecret = App.Configuration["NCC_App:ImageModeration:AccessKeySecret"];
            if (string.IsNullOrEmpty(_accessKeySecret))
            {
                _accessKeySecret = App.Configuration["NCC_App:AliyunOSS:AccessKeySecret"];
            }
            
            // 判断是否为增强版（endpoint 包含 green-cip）
            _isEnhancedVersion = _endpoint.Contains("green-cip");
        }

        /// <summary>
        /// 图片审核结果
        /// </summary>
        public class ModerationResult
        {
            public bool Passed { get; set; }
            public string Message { get; set; }
            public string RawResponse { get; set; }
            public object Details { get; set; }
        }

        /// <summary>
        /// 图片审核（从本地文件路径）
        /// </summary>
        /// <param name="filePath">本地文件路径</param>
        /// <returns>审核结果详情</returns>
        public async Task<ModerationResult> ScanImageFromFileAsync(string filePath)
        {
            if (!_enabled)
            {
                return new ModerationResult 
                { 
                    Passed = true, 
                    Message = "审核未启用，直接通过" 
                };
            }

            if (string.IsNullOrEmpty(filePath) || !File.Exists(filePath))
            {
                return new ModerationResult 
                { 
                    Passed = false, 
                    Message = "文件不存在或路径为空" 
                };
            }

            try
            {
                var imageBytes = await File.ReadAllBytesAsync(filePath);
                return await ScanImageAsync(imageBytes);
            }
            catch (Exception ex)
            {
                // 审核异常时，根据配置决定是否通过
                var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                return new ModerationResult 
                { 
                    Passed = !failOnError, 
                    Message = $"审核异常：{ex.Message}",
                    RawResponse = ex.ToString()
                };
            }
        }

        /// <summary>
        /// 图片审核（从字节数组）
        /// </summary>
        /// <param name="imageBytes">图片字节数组</param>
        /// <returns>审核结果详情</returns>
        public async Task<ModerationResult> ScanImageAsync(byte[] imageBytes)
        {
            if (!_enabled)
            {
                return new ModerationResult 
                { 
                    Passed = true, 
                    Message = "审核未启用，直接通过" 
                };
            }

            if (imageBytes == null || imageBytes.Length == 0)
            {
                return new ModerationResult 
                { 
                    Passed = false, 
                    Message = "图片数据为空" 
                };
            }

            // 检查 AccessKey 是否配置
            if (string.IsNullOrEmpty(_accessKeyId) || string.IsNullOrEmpty(_accessKeySecret))
            {
                var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                return new ModerationResult 
                { 
                    Passed = !failOnError, 
                    Message = "图片审核服务未配置 AccessKey，无法调用审核接口",
                    RawResponse = "AccessKeyId 或 AccessKeySecret 未配置"
                };
            }

            try
            {
                // 判断是否为增强版，使用不同的调用方式
                if (_isEnhancedVersion)
                {
                    return await ScanImageEnhancedAsync(imageBytes);
                }
                else
                {
                    return await ScanImageLegacyAsync(imageBytes);
                }
            }
            catch (Exception ex)
            {
                // 审核异常时，根据配置决定是否通过
                var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                return new ModerationResult 
                { 
                    Passed = !failOnError, 
                    Message = $"审核异常：{ex.Message}",
                    RawResponse = ex.ToString()
                };
            }
        }

        /// <summary>
        /// 图片审核（增强版 - green-cip）
        /// 使用 HTTP 原生调用，实现本地图片审核流程：
        /// 1. DescribeUploadToken - 获取临时 OSS 凭证
        /// 2. 上传图片到临时 OSS
        /// 3. ImageModeration - 调用审核接口
        /// </summary>
        /// <param name="imageBytes">图片字节数组</param>
        /// <returns>审核结果详情</returns>
        private async Task<ModerationResult> ScanImageEnhancedAsync(byte[] imageBytes)
        {
            try
            {
                var endpointHost = _endpoint.Replace("https://", "").Replace("http://", "");
                
                // 1. 调用 DescribeUploadToken 获取临时 OSS 凭证
                var tokenUrl = $"{_endpoint}/DescribeUploadToken";
                var tokenResponse = await CallOpenApiAsync(tokenUrl, new Dictionary<string, string>());
                var tokenResult = JsonConvert.DeserializeObject<JObject>(tokenResponse);
                
                if (tokenResult == null || tokenResult["Code"]?.Value<int>() != 200)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = $"获取临时 OSS 凭证失败：{tokenResult?["Msg"]?.ToString() ?? "未知错误"}",
                        RawResponse = tokenResponse
                    };
                }

                var tokenData = tokenResult["Data"];
                if (tokenData == null)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "临时 OSS 凭证数据为空",
                        RawResponse = tokenResponse
                    };
                }

                var bucketName = tokenData["BucketName"]?.ToString();
                var fileNamePrefix = tokenData["FileNamePrefix"]?.ToString() ?? "";
                var ossAccessKeyId = tokenData["AccessKeyId"]?.ToString();
                var ossAccessKeySecret = tokenData["AccessKeySecret"]?.ToString();
                var ossSecurityToken = tokenData["SecurityToken"]?.ToString();
                var ossInternetEndPoint = tokenData["OssInternetEndPoint"]?.ToString();
                
                if (string.IsNullOrEmpty(bucketName) || string.IsNullOrEmpty(ossInternetEndPoint))
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "临时 OSS 凭证信息不完整",
                        RawResponse = tokenResponse
                    };
                }

                // 2. 上传图片到临时 OSS（使用 OSS PutObject API）
                var objectName = $"{fileNamePrefix}{Guid.NewGuid()}.jpg";
                var ossPutUrl = $"https://{bucketName}.{ossInternetEndPoint}/{objectName}";
                
                // 使用 STS Token 上传到 OSS（需要 OSS 签名）
                var ossPutSuccess = await UploadToOSSTempAsync(
                    ossPutUrl, 
                    imageBytes, 
                    bucketName, 
                    objectName,
                    ossAccessKeyId,
                    ossAccessKeySecret,
                    ossSecurityToken);
                
                if (!ossPutSuccess)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "上传图片到临时 OSS 失败",
                        RawResponse = "OSS 上传失败"
                    };
                }

                // 3. 调用增强版审核接口 ImageModeration
                var moderationUrl = $"{_endpoint}/ImageModeration";
                var serviceParameters = new Dictionary<string, object>
                {
                    { "ossBucketName", bucketName },
                    { "ossObjectName", objectName },
                    { "dataId", Guid.NewGuid().ToString() }
                };
                
                var moderationBody = new Dictionary<string, string>
                {
                    { "Service", "baselineCheck" },
                    { "ServiceParameters", JsonConvert.SerializeObject(serviceParameters) }
                };
                
                var moderationResponse = await CallOpenApiAsync(moderationUrl, moderationBody);
                var rawResponse = moderationResponse;
                var moderationResult = JsonConvert.DeserializeObject<JObject>(moderationResponse);
                
                if (moderationResult == null)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "响应解析失败",
                        RawResponse = rawResponse
                    };
                }

                var code = moderationResult["Code"]?.Value<int>();
                if (code != 200)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = moderationResult["Msg"]?.ToString() ?? $"审核接口返回错误：{code}",
                        RawResponse = rawResponse,
                        Details = moderationResult
                    };
                }

                var data = moderationResult["Data"];
                if (data == null)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "审核结果数据为空",
                        RawResponse = rawResponse,
                        Details = moderationResult
                    };
                }

                // 增强版返回格式：Data.Result 是数组，每个元素有 Label、Confidence、RiskLevel
                var results = data["Result"] as JArray;
                var riskLevel = data["RiskLevel"]?.ToString();
                
                if (results == null || results.Count == 0)
                {
                    return new ModerationResult 
                    { 
                        Passed = true, 
                        Message = "没有审核结果，默认通过",
                        RawResponse = rawResponse,
                        Details = data
                    };
                }

                // 检查风险等级和标签
                var highRiskLabels = new List<string>();
                var allResults = new List<object>();
                
                foreach (var item in results)
                {
                    var label = item["Label"]?.ToString();
                    var confidence = item["Confidence"]?.Value<double?>();
                    var itemRiskLevel = item["RiskLevel"]?.ToString();
                    var description = item["Description"]?.ToString();
                    
                    allResults.Add(new
                    {
                        label = label,
                        confidence = confidence,
                        riskLevel = itemRiskLevel,
                        description = description
                    });
                    
                    // 高风险或非 nonLabel 标签视为违规
                    if (itemRiskLevel == "high" || (label != null && !label.StartsWith("nonLabel")))
                    {
                        highRiskLabels.Add($"{label}({description})");
                    }
                }

                if (highRiskLabels.Count > 0 || riskLevel == "high")
                {
                    return new ModerationResult 
                    { 
                        Passed = false, 
                        Message = $"图片审核未通过，风险等级：{riskLevel}，违规标签：{string.Join(", ", highRiskLabels)}",
                        RawResponse = rawResponse,
                        Details = new
                        {
                            riskLevel = riskLevel,
                            highRiskLabels = highRiskLabels,
                            allResults = allResults
                        }
                    };
                }

                return new ModerationResult 
                { 
                    Passed = true, 
                    Message = "图片审核通过",
                    RawResponse = rawResponse,
                    Details = new
                    {
                        riskLevel = riskLevel,
                        allResults = allResults
                    }
                };
            }
            catch (Exception ex)
            {
                var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                return new ModerationResult 
                { 
                    Passed = !failOnError, 
                    Message = $"增强版审核异常：{ex.Message}",
                    RawResponse = ex.ToString()
                };
            }
        }

        /// <summary>
        /// 调用阿里云 OpenAPI 3.0 接口（增强版使用 POP 签名）
        /// 注意：增强版 API 使用 OpenAPI 3.0 风格，签名方式与老版 ROA 不同
        /// 建议使用官方 SDK，HTTP 原生调用需要实现完整的 POP 签名算法
        /// </summary>
        private async Task<string> CallOpenApiAsync(string url, Dictionary<string, string> bodyParams)
        {
            // 增强版使用 OpenAPI 3.0 的 POP 签名，实现较复杂
            // 暂时返回提示，建议使用 SDK 或联系技术支持实现完整签名
            var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
            if (failOnError)
            {
                throw new Exception("增强版 API 需要实现 OpenAPI 3.0 签名，当前暂不支持 HTTP 原生调用。请使用官方 SDK 或联系技术支持。");
            }
            return "{\"Code\":500,\"Msg\":\"增强版 API 需要 SDK 支持，当前暂不支持 HTTP 原生调用\"}";
        }

        /// <summary>
        /// 上传文件到临时 OSS（使用 STS Token）
        /// </summary>
        private async Task<bool> UploadToOSSTempAsync(string url, byte[] data, string bucket, string objectName, string accessKeyId, string accessKeySecret, string securityToken)
        {
            // OSS PutObject 需要实现签名，使用 STS Token
            // 暂时返回 false，建议使用 OSS SDK
            return false;
        }

        /// <summary>
        /// 图片审核（老版 - green.xxx）
        /// </summary>
        /// <param name="imageBytes">图片字节数组</param>
        /// <returns>审核结果详情</returns>
        private async Task<ModerationResult> ScanImageLegacyAsync(byte[] imageBytes)
        {
            // 构建请求URL
            var url = $"{_endpoint}/green/image/scan";
                
                // 构建请求体
                var requestBody = new
                {
                    scenes = new[] { "porn", "terrorism", "ad", "qrcode" },
                    tasks = new[]
                    {
                        new
                        {
                            dataId = Guid.NewGuid().ToString(),
                            url = Convert.ToBase64String(imageBytes)
                        }
                    }
                };

                var jsonContent = JsonConvert.SerializeObject(requestBody);
                var contentBytes = Encoding.UTF8.GetBytes(jsonContent);
                var content = new ByteArrayContent(contentBytes);
                content.Headers.TryAddWithoutValidation("Content-Type", "application/json");

                // 计算 Content-MD5（请求体的 MD5，然后 Base64）
                string contentMd5;
                using (var md5 = MD5.Create())
                {
                    var hashBytes = md5.ComputeHash(contentBytes);
                    contentMd5 = Convert.ToBase64String(hashBytes);
                }

                // 生成请求时间（RFC 1123 格式）
                var dateStr = DateTime.UtcNow.ToString("r");
                
                // 生成签名随机数
                var signatureNonce = Guid.NewGuid().ToString();
                
                // 构建规范化的请求头（x-acs- 开头的头，按字典序排序）
                var acsHeaders = new SortedDictionary<string, string>
                {
                    { "x-acs-signature-method", "HMAC-SHA1" },
                    { "x-acs-signature-nonce", signatureNonce },
                    { "x-acs-signature-version", "1.0" },
                    { "x-acs-version", "2018-05-09" }
                };
                
                // 构建 CanonicalizedHeaders（格式：key:value\n）
                var canonicalizedHeaders = new StringBuilder();
                foreach (var header in acsHeaders)
                {
                    canonicalizedHeaders.Append($"{header.Key}:{header.Value}\n");
                }
                
                // 构建 CanonicalizedResource（请求路径）
                var uri = new Uri(url);
                var canonicalizedResource = uri.AbsolutePath;
                
                // 构建待签名字符串
                var stringToSign = new StringBuilder();
                stringToSign.Append("POST\n");  // HTTP-Verb
                stringToSign.Append("application/json\n");  // Accept
                stringToSign.Append($"{contentMd5}\n");  // Content-MD5
                stringToSign.Append("application/json\n");  // Content-Type
                stringToSign.Append($"{dateStr}\n");  // Date
                stringToSign.Append(canonicalizedHeaders.ToString());  // CanonicalizedHeaders
                stringToSign.Append(canonicalizedResource);  // CanonicalizedResource
                
                // 计算签名（HMAC-SHA1）
                string signature;
                using (var hmac = new HMACSHA1(Encoding.UTF8.GetBytes(_accessKeySecret)))
                {
                    var signatureBytes = hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign.ToString()));
                    signature = Convert.ToBase64String(signatureBytes);
                }
                
                // 构建 Authorization 头
                var authorization = $"acs {_accessKeyId}:{signature}";

                // 添加 Content-MD5 到内容头（Content-MD5 是内容头，不是请求头）
                content.Headers.TryAddWithoutValidation("Content-MD5", contentMd5);

                // 创建请求并添加所有必需的请求头
                using (var request = new HttpRequestMessage(HttpMethod.Post, url))
                {
                    request.Content = content;
                    
                    // 添加标准 HTTP 头
                    request.Headers.Add("Accept", "application/json");
                    request.Headers.Add("Date", dateStr);
                    
                    // 添加阿里云协议头
                    foreach (var header in acsHeaders)
                    {
                        request.Headers.Add(header.Key, header.Value);
                    }
                    
                    // 添加 Authorization 头
                    request.Headers.Add("Authorization", authorization);
                    
                    var response = await _httpClient.SendAsync(request);
                    var responseContent = await response.Content.ReadAsStringAsync();

                // 保存原始响应
                var rawResponse = responseContent;

                if (!response.IsSuccessStatusCode)
                {
                    // HTTP请求失败，根据配置决定是否通过
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = $"HTTP请求失败：{response.StatusCode}",
                        RawResponse = rawResponse
                    };
                }

                // 解析响应
                var result = JsonConvert.DeserializeObject<JObject>(responseContent);
                if (result == null)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "响应解析失败",
                        RawResponse = rawResponse
                    };
                }

                // 阿里云业务错误：未开通内容安全、无权限等（code 596 或 success: false）
                var apiCode = result["code"]?.Value<int>();
                var success = result["success"]?.Value<bool>();
                var apiMsg = result["msg"]?.ToString() ?? "";
                if (apiCode == 596 || success == false)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    var friendlyMsg = apiCode == 596
                        ? "内容安全服务未开通或当前账号无权限，请到阿里云控制台开通「内容安全」并确认当前 AccessKey 有权限"
                        : (apiMsg.Length > 0 ? apiMsg : "审核接口返回失败");
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = friendlyMsg,
                        RawResponse = rawResponse,
                        Details = result
                    };
                }

                // 检查审核结果
                var data = result["data"] as JArray;
                if (data == null || data.Count == 0)
                {
                    var failOnError = App.Configuration["NCC_App:ImageModeration:FailOnError"] == "true";
                    return new ModerationResult 
                    { 
                        Passed = !failOnError, 
                        Message = "审核结果数据为空",
                        RawResponse = rawResponse,
                        Details = result
                    };
                }

                var taskResult = data[0];
                var results = taskResult["results"] as JArray;
                if (results == null || results.Count == 0)
                {
                    return new ModerationResult 
                    { 
                        Passed = true, 
                        Message = "没有审核结果，默认通过",
                        RawResponse = rawResponse,
                        Details = taskResult
                    };
                }

                // 检查所有场景的审核结果
                var blockScenes = new List<string>();
                var allSuggestions = new List<object>();
                foreach (var item in results)
                {
                    var suggestion = item["suggestion"]?.ToString();
                    var scene = item["scene"]?.ToString();
                    allSuggestions.Add(new
                    {
                        scene = scene,
                        suggestion = suggestion,
                        label = item["label"]?.ToString(),
                        rate = item["rate"]?.ToString()
                    });
                    
                    if (suggestion == "block")
                    {
                        blockScenes.Add(scene ?? "unknown");
                    }
                }

                if (blockScenes.Count > 0)
                {
                    return new ModerationResult 
                    { 
                        Passed = false, 
                        Message = $"图片审核未通过，违规场景：{string.Join(", ", blockScenes)}",
                        RawResponse = rawResponse,
                        Details = new
                        {
                            blockScenes = blockScenes,
                            allResults = allSuggestions
                        }
                    };
                }

                return new ModerationResult 
                { 
                    Passed = true, 
                    Message = "图片审核通过",
                    RawResponse = rawResponse,
                    Details = new
                    {
                        allResults = allSuggestions
                    }
                };
            }
        }
    }
}