using Common.Notify;
using Microsoft.Extensions.Logging;
using Service.Interface;
using System;
using System.Collections.Concurrent;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace Service.Implement
{
    /// <summary>
    /// 飞书通讯录服务实现：手机号 → open_id
    /// 依赖飞书自建应用凭证(FeishuConfig)；tenant_access_token 与 open_id 结果均做进程级内存缓存，
    /// 避免每条告警都调用飞书 API（token 有效期约 7200s，open_id 基本不变）。
    /// </summary>
    public class FeishuContactService : IFeishuContactService
    {
        private const string TokenUrl = "https://open.feishu.cn/open-apis/auth/v3/tenant_access_token/internal";
        private const string BatchGetIdUrl = "https://open.feishu.cn/open-apis/contact/v3/users/batch_get_id?user_id_type=open_id";

        private readonly IHttpClientFactory _httpClientFactory;
        private readonly ILogger<FeishuContactService> _logger;

        // tenant_access_token 进程级缓存（提前 5 分钟刷新，避免边界失效）
        private static string? _token;
        private static DateTime _tokenExpireAt = DateTime.MinValue;
        private static readonly SemaphoreSlim _tokenLock = new(1, 1);

        // 手机号 → open_id 结果缓存（换不到的也缓存 null 避免反复调用；重启进程可重置）
        private static readonly ConcurrentDictionary<string, string?> _openIdCache = new();

        public FeishuContactService(IHttpClientFactory httpClientFactory, ILogger<FeishuContactService> logger)
        {
            _httpClientFactory = httpClientFactory;
            _logger = logger;
        }

        /// <summary>
        /// 用手机号换取飞书 open_id；未配置凭证、查无此人或无权限时返回 null
        /// </summary>
        public async Task<string?> GetOpenIdByMobileAsync(string mobile)
        {
            if (string.IsNullOrWhiteSpace(mobile)) return null;
            mobile = mobile.Trim();

            if (_openIdCache.TryGetValue(mobile, out var cached)) return cached;

            if (!FeishuConfig.IsConfigured)
            {
                _logger.LogWarning("飞书应用凭证未配置(AppId/AppSecret)，无法把手机号 {Mobile} 转 open_id；请在 appsettings.json 的 Feishu 节配置", mobile);
                return null;
            }

            try
            {
                var token = await GetTenantAccessTokenAsync();
                if (string.IsNullOrEmpty(token)) return null;

                var http = _httpClientFactory.CreateClient();
                string body = JsonSerializer.Serialize(new { mobiles = new[] { mobile } });
                using var req = new HttpRequestMessage(HttpMethod.Post, BatchGetIdUrl);
                req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
                req.Content = new StringContent(body, Encoding.UTF8, "application/json");
                using var resp = await http.SendAsync(req);
                string respText = await resp.Content.ReadAsStringAsync();

                using var doc = JsonDocument.Parse(respText);
                var root = doc.RootElement;
                int code = root.TryGetProperty("code", out var c) ? c.GetInt32() : -1;
                if (code != 0)
                {
                    string msg = root.TryGetProperty("msg", out var m) ? m.GetString() ?? "" : "";
                    _logger.LogWarning("飞书手机号换 open_id 失败 mobile={Mobile} code={Code} msg={Msg}（多为权限未开通或通讯录范围不含该成员）", mobile, code, msg);
                    _openIdCache[mobile] = null;
                    return null;
                }

                string? openId = null;
                if (root.TryGetProperty("data", out var data) &&
                    data.TryGetProperty("user_list", out var list) &&
                    list.ValueKind == JsonValueKind.Array && list.GetArrayLength() > 0 &&
                    list[0].TryGetProperty("user_id", out var uid))
                {
                    openId = uid.GetString();
                }

                if (string.IsNullOrEmpty(openId))
                    _logger.LogWarning("飞书手机号 {Mobile} 未查到 open_id（该手机号可能不在应用通讯录范围内）", mobile);

                _openIdCache[mobile] = openId;
                return openId;
            }
            catch (Exception ex)
            {
                _logger.LogError("飞书手机号换 open_id 异常 mobile={Mobile}: {Err}", mobile, NotifyError.Describe(ex));
                return null;
            }
        }

        /// <summary>
        /// 获取 tenant_access_token（进程级缓存，提前 5 分钟刷新）
        /// </summary>
        private async Task<string?> GetTenantAccessTokenAsync()
        {
            if (!string.IsNullOrEmpty(_token) && DateTime.Now < _tokenExpireAt) return _token;
            await _tokenLock.WaitAsync();
            try
            {
                if (!string.IsNullOrEmpty(_token) && DateTime.Now < _tokenExpireAt) return _token;

                var http = _httpClientFactory.CreateClient();
                string body = JsonSerializer.Serialize(new { app_id = FeishuConfig.AppId, app_secret = FeishuConfig.AppSecret });
                using var content = new StringContent(body, Encoding.UTF8, "application/json");
                using var resp = await http.PostAsync(TokenUrl, content);
                string respText = await resp.Content.ReadAsStringAsync();

                using var doc = JsonDocument.Parse(respText);
                var root = doc.RootElement;
                int code = root.TryGetProperty("code", out var c) ? c.GetInt32() : -1;
                if (code != 0)
                {
                    string msg = root.TryGetProperty("msg", out var m) ? m.GetString() ?? "" : "";
                    _logger.LogError("飞书获取 tenant_access_token 失败 code={Code} msg={Msg}（检查 AppId/AppSecret）", code, msg);
                    return null;
                }

                _token = root.TryGetProperty("tenant_access_token", out var t) ? t.GetString() : null;
                int expire = root.TryGetProperty("expire", out var e) ? e.GetInt32() : 7200;
                _tokenExpireAt = DateTime.Now.AddSeconds(Math.Max(60, expire - 300));
                return _token;
            }
            catch (Exception ex)
            {
                _logger.LogError("飞书获取 tenant_access_token 异常: {Err}", NotifyError.Describe(ex));
                return null;
            }
            finally
            {
                _tokenLock.Release();
            }
        }
    }
}