using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Graph;
using Microsoft.Graph.Models;
using Microsoft.Graph.Models.ODataErrors;
using Microsoft.Kiota.Abstractions.Authentication;
using System.Collections.Concurrent;
using System.Text.Json;
using System.Text.Json.Serialization;
using JsonSerializer = System.Text.Json.JsonSerializer;

namespace OASystem.API.OAMethodLib.Hotmail
{
    public class HotmailService
    {
        private readonly IHttpClientFactory _httpClientFactory;
        private readonly IConfiguration _config;
        private readonly SqlSugarClient _sqlSugar;
        public const string RedisKeyPrefix = "MailAlchemy:Token:";

        public HotmailService(IHttpClientFactory httpClientFactory, IConfiguration config, SqlSugarClient sqlSugar)
        {
            _httpClientFactory = httpClientFactory;
            _config = config;
            _sqlSugar = sqlSugar;
        }

        /// <summary>
        /// 统一获取 Redis Key
        /// </summary>
        public static string GetRedisKey(string email) => $"{RedisKeyPrefix}{email.Trim().ToLower()}";

        /// <summary>
        /// hotmail 信息验证
        /// </summary>
        /// <param name="config"></param>
        /// <returns></returns>
        public (bool, string) ConfigVerify(HotmailConfig? config)
        {
            if (config == null) return (true, "当前用户未配置 hotmail 基础信息。");
            if (string.IsNullOrEmpty(config.UserName)) return (true, "当前用户未配置 hotmail 基础信息。");
            if (string.IsNullOrEmpty(config.ClientId)) return (true, "当前用户未配置 hotmail 租户标识符 (Guid)。");
            if (string.IsNullOrEmpty(config.TenantId)) return (true, "当前用户未配置 hotmail 应用程序的客户端标识。");
            if (string.IsNullOrEmpty(config.ClientSecret)) return (true, "当前用户未配置 hotmail 应用程序密钥。");
            if (string.IsNullOrEmpty(config.RedirectUri)) return (true, "当前用户未配置 hotmail OAuth2 回调重定向地址。");
            return (true, "");
        }

        /// <summary>
        /// Microsoft 鉴权预处理
        /// </summary>
        public async Task<(int status, string msg)> PrepareAuth(int userId)
        {
            // 1. 基础配置校验 (SqlSugar 优化)
            var userConfig = await GetUserMailConfig(userId);
            if (userConfig == null || string.IsNullOrWhiteSpace(userConfig.UserName))
                return (-1, "账号基础配置缺失");

            // 2. 状态检查 (Redis)
            var redisKey = GetRedisKey(userConfig.UserName);
            var repo = RedisRepository.RedisFactory.CreateRedisRepository();
            var cachedJson = await repo.StringGetAsync<string>(redisKey);

            if (!string.IsNullOrWhiteSpace(cachedJson))
                return (0, "已通过验证，无需重复操作");

            // 3. 参数净化与严谨性
            var clientId = userConfig.ClientId?.Trim();
            var redirectUri = userConfig.RedirectUri?.Trim().Split('\r', '\n')[0]; // 取第一行并修剪

            if (string.IsNullOrWhiteSpace(clientId) || string.IsNullOrWhiteSpace(redirectUri))
                return (-1, "ClientId 或 RedirectUri 配置无效");

            // 4. 构建长效授权 URL
            const string authEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/authorize";

            var queryParams = new Dictionary<string, string?>
            {
                { "client_id", clientId },
                { "response_type", "code" },
                { "redirect_uri", redirectUri },
                { "response_mode", "query" },
                // 核心：必须包含 offline_access 且建议加上 openid
                { "scope", "openid offline_access Mail.ReadWrite Mail.Send User.Read" },
                { "state", userId.ToString() }, // 简单场景使用 userId，安全场景建议使用加密 Hash
                { "prompt", "consent" } // 关键：确保触发长效令牌授权
            };

            var authUrl = QueryHelpers.AddQueryString(authEndpoint, queryParams);

            // 准则 4a: 直接返回结果
            return (1, authUrl);
        }

        public async Task<List<MailDto>> GetMergedMessagesAsync(List<string> emails, DateTime cstStart, DateTime cstEnd)
        {
            // 线程安全的合并容器
            var allMessages = new ConcurrentBag<MailDto>();

            // 转换过滤条件 (建议预先处理)
            string startFilter = CommonFun.ToGraphUtcString(cstStart);
            string endFilter = CommonFun.ToGraphUtcString(cstEnd);

            // 配置并发参数：限制最大并行度，防止被 Graph API 熔断
            var parallelOptions = new ParallelOptions
            {
                MaxDegreeOfParallelism = 5 // 根据服务器性能调整
            };

            await Parallel.ForEachAsync(emails, parallelOptions, async (email, ct) =>
            {
                try
                {
                    var client = await GetClientAsync(email);
                    var response = await client.Me.Messages.GetAsync(q =>
                    {
                        q.QueryParameters.Filter = $"receivedDateTime ge {startFilter} and receivedDateTime le {endFilter}";
                        q.QueryParameters.Select = new[] { "id", "subject", "from", "bodyPreview", "receivedDateTime" };
                        q.QueryParameters.Orderby = new[] { "receivedDateTime desc" };
                        q.QueryParameters.Top = 50; // 生产环境建议增加 Top 限制
                    }, ct);

                    if (response?.Value != null)
                    {
                        var chinaTimeZone = TimeZoneInfo.FindSystemTimeZoneById("China Standard Time");

                        foreach (var m in response.Value)
                        {
                            allMessages.Add(new MailDto
                            {
                                MessageId = m.Id,
                                Subject = m.Subject,
                                Content = m.BodyPreview,
                                From = m.From?.EmailAddress?.Address,
                                To = email,
                                ReceivedTime = m.ReceivedDateTime?.DateTime != null
                                ? TimeZoneInfo.ConvertTimeFromUtc(m.ReceivedDateTime.Value.DateTime, chinaTimeZone)
                                : DateTime.MinValue,
                                Source = email // 显式来源
                            });
                        }
                    }
                }
                catch (Exception ex)
                {
                    // 生产环境应接入 ILogger
                    //_logger.LogError(ex, "Failed to fetch mail for {Email}", email);
                }
            });

            // 最终排序并输出
            return allMessages.OrderByDescending(m => m.ReceivedTime).ToList();
        }

        /// <summary>
        /// 指定账户发送邮件
        /// </summary>
        public async Task<MailSendResult> SendMailAsync(string fromEmail, MailDto mail)
        {
            try
            {
                var client = await GetClientAsync(fromEmail);

                var requestBody = new Microsoft.Graph.Me.SendMail.SendMailPostRequestBody
                {
                    Message = new Message
                    {
                        Subject = mail.Subject,
                        Body = new ItemBody
                        {
                            Content = mail.Content,
                            ContentType = BodyType.Html
                        },
                        ToRecipients = new List<Recipient>
                {
                    new Recipient { EmailAddress = new EmailAddress { Address = mail.To } }
                }
                    }
                };

                // 执行发送
                await client.Me.SendMail.PostAsync(requestBody);

                return new MailSendResult { IsSuccess = true, Message = "邮件发送成功!" };
            }
            catch (ODataError odataError) // 捕获 Graph 特有异常
            {
                // 常见的错误：ErrorInvalidUser, ErrorQuotaExceeded, ErrorMessageSubmissionBlocked
                var code = odataError.Error?.Code ?? "Unknown";
                var msg = odataError.Error?.Message ?? "微软 API 调用异常";

                return new MailSendResult
                {
                    IsSuccess = false,
                    ErrorCode = code,
                    Message = $"发送失败: {msg}"
                };
            }
            catch (Exception ex)
            {
                return new MailSendResult
                {
                    IsSuccess = false,
                    ErrorCode = "InternalError",
                    Message = $"系统内部错误: {ex.Message}"
                };
            }
        }

        /// <summary>
        /// 获取邮箱配置信息 - single
        /// </summary>
        /// <returns></returns>
        public async Task<HotmailConfig?> GetUserMailConfig(int userId)
        {
            var allConfigs = await GetUserMailConfigListAsync();

            if (allConfigs == null || !allConfigs.Any()) return null;

            var userConfig = allConfigs.FirstOrDefault(x => x.UserId == userId);

            return userConfig;
        }

        /// <summary>
        /// 获取邮箱配置信息 - ALL
        /// </summary>
        /// <returns></returns>
        public async Task<List<HotmailConfig>?> GetUserMailConfigListAsync()
        {
            var remark = await _sqlSugar.Queryable<Sys_SetData>()
                .Where(x => x.IsDel == 0 && x.Id == 1555 && x.STid == 137)
                .Select(x => x.Remark)
                .FirstAsync();
            if (string.IsNullOrWhiteSpace(remark)) return null;

            try
            {
                var allConfigs = JsonConvert.DeserializeObject<List<HotmailConfig>>(remark);
                return allConfigs;
            }
            catch (Exception)
            {
                return null;
            }
        }

        /// <summary>
        /// 线程锁
        /// </summary>
        private static readonly ConcurrentDictionary<string, SemaphoreSlim> _userLocks = new ConcurrentDictionary<string, SemaphoreSlim>();

        /// <summary>
        /// 获取 Graph 客户端，处理 Token 自动刷新 (线程安全版)
        /// </summary>
        private async Task<GraphServiceClient> GetClientAsync(string email)
        {
            // 获取或创建针对该 Email 的独立信号量锁
            var userLock = _userLocks.GetOrAdd(email, _ => new SemaphoreSlim(1, 1));

            await userLock.WaitAsync();
            try
            {
                var redisKey = GetRedisKey(email);
                // 建议：每次获取 Repo 实例，避免单例 Repo 内部并发冲突
                var repo = RedisRepository.RedisFactory.CreateRedisRepository();
                var cachedJson = await repo.StringGetAsync<string>(redisKey);

                if (string.IsNullOrEmpty(cachedJson))
                    throw new UnauthorizedAccessException($"Account {email} not initialized in Redis.");

                var token = System.Text.Json.JsonSerializer.Deserialize<UserToken>(cachedJson!)!;

                // 令牌过期预校验 (带锁保护，防止并发刷新导致的 Token 失效)
                if (token.ExpiresAt < DateTime.UtcNow.AddMinutes(5))
                {
                    // 内部逻辑：调用 Graph 刷新接口 -> 更新 token 对象 -> 写入 Redis
                    token = await RefreshAndSaveTokenAsync(token);
                    // 调试建议：记录刷新日志
                    // _logger.LogInformation("Token refreshed for {Email}", email);
                }

                // 3. 构造认证提供者 (Scoped 局部化)
                // 使用 StaticTokenProvider 封装当前的 AccessToken
                var tokenProvider = new StaticTokenProvider(token.AccessToken);
                var authProvider = new BaseBearerTokenAuthenticationProvider(tokenProvider);

                // 4. 返回全新的客户端实例，确保 RequestAdapter 隔离
                return new GraphServiceClient(authProvider);
            }
            catch (Exception ex)
            {
                // _logger.LogError(ex, "GetClientAsync failed for {Email}", email);
                throw;
            }
            finally
            {
                userLock.Release(); // 必须在 finally 中释放锁
            }
        }

        public async Task<UserToken> RefreshAndSaveTokenAsync(UserToken oldToken)
        {
            // 1. 实时获取该用户对应的配置信息
            // 准则：不再信任全局 _config，而是根据 Email 溯源配置
            var allConfigs = await GetUserMailConfigListAsync();
            var currentConfig = allConfigs?.FirstOrDefault(x =>
                x.UserName.Equals(oldToken.Email, StringComparison.OrdinalIgnoreCase));

            if (currentConfig == null)
                throw new Exception($"刷新失败：未能在配置库中找到账号 {oldToken.Email} 的关联 Client 信息。");

            // 2. 使用该账号专属的凭据构造请求
            var httpClient = _httpClientFactory.CreateClient();
            var kvp = new Dictionary<string, string>
            {
                { "client_id", currentConfig.ClientId.Trim() },
                { "client_secret", currentConfig.ClientSecret.Trim() },
                { "grant_type", "refresh_token" },
                { "refresh_token", oldToken.RefreshToken },
                { "scope", "openid offline_access Mail.ReadWrite Mail.Send User.Read" } // 保持 Scope 一致性
            };

            var response = await httpClient.PostAsync("https://login.microsoftonline.com/common/oauth2/v2.0/token", new FormUrlEncodedContent(kvp));

            if (!response.IsSuccessStatusCode)
            {
                var error = await response.Content.ReadAsStringAsync();
                throw new Exception($"微软刷新接口拒绝请求: {error}");
            }

            using var doc = await JsonDocument.ParseAsync(await response.Content.ReadAsStreamAsync());
            var root = doc.RootElement;

            // 3. 构造新令牌 (注意：每次刷新都会返回新的 RefreshToken，必须覆盖旧的)
            var newToken = new UserToken
            {
                Email = oldToken.Email,
                AccessToken = root.GetProperty("access_token").GetString()!,
                // 关键：微软可能会滚动更新 RefreshToken，务必取回最新的
                RefreshToken = root.TryGetProperty("refresh_token", out var rt) ? rt.GetString()! : oldToken.RefreshToken,
                ExpiresAt = DateTime.UtcNow.AddSeconds(root.GetProperty("expires_in").GetInt32()),
                Source = "Microsoft_Graph_Refreshed"
            };

            // 4. 同步更新 Redis (保持 90 天长效)
            var redisKey = GetRedisKey(oldToken.Email);
            await RedisRepository.RedisFactory.CreateRedisRepository()
                .StringSetAsync(redisKey, JsonSerializer.Serialize(newToken), TimeSpan.FromDays(90));

            return newToken;
        }

        /// <summary>
        /// 静态 Token 提供者辅助类
        /// </summary>
        public class StaticTokenProvider : IAccessTokenProvider
        {
            private readonly string _token;
            public StaticTokenProvider(string token) => _token = token;
            public Task<string> GetAuthorizationTokenAsync(Uri uri, Dictionary<string, object>? context = null, CancellationToken ct = default) => Task.FromResult(_token);
            public AllowedHostsValidator AllowedHostsValidator { get; } = new();
        }

        #region 数据模型

        public class MailSendResult
        {
            public bool IsSuccess { get; set; }
            public string Message { get; set; } = string.Empty;
            public string? ErrorCode { get; set; } // Microsoft 提供的错误码
            public string Source => "Microsoft_Graph_API";
        }

        /// <summary>
        /// Hotmail 邮件服务 OAuth2 配置信息实体
        /// </summary>
        public class HotmailConfig
        {
            /// <summary>
            /// 用户唯一标识
            /// </summary>
            [JsonPropertyName("userId")]
            public int UserId { get; set; }

            /// <summary>
            /// 账号用户名
            /// </summary>
            [JsonPropertyName("userName")]
            public string UserName { get; set; }

            /// <summary>
            /// Azure AD 租户标识符 (Guid)
            /// </summary>
            [JsonPropertyName("tenantId")]
            public string TenantId { get; set; }

            /// <summary>
            /// 注册应用程序的客户端标识
            /// </summary>
            [JsonPropertyName("clientId")]
            public string ClientId { get; set; }

            /// <summary>
            /// 客户端密钥（敏感数据建议加密存储）
            /// </summary>
            [JsonPropertyName("clientSecret")]
            public string ClientSecret { get; set; }

            /// <summary>
            /// 租户类型（如 common, organizations 或具体域名）
            /// </summary>
            [JsonPropertyName("tenant")]
            public string Tenant { get; set; } = "common";

            /// <summary>
            /// OAuth2 回调重定向地址
            /// </summary>
            [JsonPropertyName("redirectUri")]
            public string RedirectUri { get; set; }
        }

        public class UserToken
        {
            public string Email { get; set; }
            public string AccessToken { get; set; }
            public string RefreshToken { get; set; }
            public DateTime ExpiresAt { get; set; }

            public string Source { get; set; }
        }

        /// <summary>
        /// 邮件请求对象
        /// </summary>
        public class MailDto
        {
            /// <summary>
            /// 邮件唯一标识符 (UID/Message-ID)
            /// </summary>
            [JsonPropertyName("messageId")]
            public string? MessageId { get; set; }

            /// <summary>
            /// 邮件主题
            /// </summary>
            [JsonPropertyName("subject")]
            public string? Subject { get; set; }

            /// <summary>
            /// 发件人地址 (e.g. "sender@example.com")
            /// </summary>
            [JsonPropertyName("from")]
            public string? From { get; set; }

            /// <summary>
            /// 收件人地址
            /// </summary>
            [JsonPropertyName("to")]
            public string? To { get; set; }

            /// <summary>
            /// 邮件正文内容 (HTML 或纯文本)
            /// </summary>
            [JsonPropertyName("content")]
            public string? Content { get; set; }

            /// <summary>
            /// 接收时间 - 使用 DateTimeOffset 以确保跨时区准确性
            /// </summary>
            [JsonPropertyName("receivedTime")]
            public DateTimeOffset? ReceivedTime { get; set; }

            /// <summary>
            /// 数据来源标识 (用于区分不同配置源或采集渠道，如 "Hotmail", "Gmail", "Sys_SetData")
            /// </summary>
            [JsonPropertyName("source")]
            public string? Source { get; set; } = "Hotmail";
        }
        #endregion
    }
}