using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Security.Cryptography;
using System.Text;
using System.Web.Http;

using HH.WCS.Mobox3.DSZSH.core;

using Newtonsoft.Json;

using static HH.WCS.Mobox3.DSZSH.api.ApiModel;
using static HH.WCS.Mobox3.DSZSH.dispatch.NDC;

namespace HH.WCS.Mobox3.DSZSH.api {
    /// <summary>
    /// 设备信息上报（HostToAGV上报、杭奥堆垛机、国自AGV）
    /// </summary>
    [RoutePrefix("agv")]
    public class AgvController : ApiController
    {
        /// <summary>
        /// NDC HostToAGV 任务状态回报
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        [HttpPost]
        [Route("AGVCallbackState")]
        public ReturnResult AGVCallbackState(AgvTaskState model){
            LogHelper.InfoHostToAGV("NDC任务状态回报", model);
            return WCSCore.OperateAgvTaskStatus(model);
        }

        /// <summary>
        /// AGV 与产线进行安全交互
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        [HttpPost]
        [Route("SafetyInteraction")]
        public ReturnResult SafetyInteraction(SafetyInteractionInfo model) {
            LogHelper.InfoHostToAGV("AGV与产线进行安全交互", model);
            return WCSCore.SafetyInteraction(model);
        }

        // 备用：Request 请求授权 ---------------------------------------------

        // 模拟存储的AppKey和AppSecret（实际应存储在数据库或配置中）
        private static readonly Dictionary<string, string> AppSecrets = new Dictionary<string, string> {
            { "testAppKey", "7a8f9b3d2e1c6a5b4c8d7e6f" }
        };

        // 允许的时间差（秒），用于验证时间戳
        private const int AllowedTimeDiff = 300; // 5分钟

        private CheckHeadersResult CheckHeaders(System.Net.Http.Headers.HttpRequestHeaders headers) {
            // 必须字段验证
            if (!headers.Contains("AppKey") || !headers.Contains("ReqVerify") || !headers.Contains("ReqTime")) {
                return CreateCheckHeadersResult(false, HttpStatusCode.BadRequest, "缺少必要请求头参数");
            }

            var headerModel = new SecureRequest {
                AppKey = headers.GetValues("AppKey").First(),
                ReqVerify = headers.GetValues("ReqVerify").First(),
                ReqTime = long.Parse(headers.GetValues("ReqTime").First()),
            };

            // 验证Header
            var validationResult = ValidateHeaders(headerModel);
            if (validationResult != null) {
                return validationResult;
            }

            return CreateCheckHeadersResult(true);
        }

        private CheckHeadersResult ValidateHeaders(SecureRequest request) {
            // 实现所有Header验证逻辑

            // 验证AppKey是否存在
            if (!AppSecrets.TryGetValue(request.AppKey, out var appSecret)) {
                return CreateCheckHeadersResult(false, HttpStatusCode.Unauthorized, "无效的AppKey");
            }

            // 验证时间戳是否在允许范围内
            var currentTime = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
            if (Math.Abs(currentTime - request.ReqTime) > AllowedTimeDiff) {
                return CreateCheckHeadersResult(false, HttpStatusCode.Unauthorized, "请求已过期");
            }

            // 计算验证串
            var expectedVerify = CalculateRequestVerify(request.AppKey, appSecret, request.ReqTime);

            // 验证请求签名
            if (!string.Equals(expectedVerify, request.ReqVerify, StringComparison.OrdinalIgnoreCase)) {
                return CreateCheckHeadersResult(false, HttpStatusCode.Unauthorized, "验证失败");
            }

            return null;
        }

        /// <summary>
        /// 构造一个成功结果的ResponseMessage
        /// </summary>
        /// <example><code><![CDATA[
        /// var res = ApiHelper.OperateAgvTaskStatus(model);
        /// return CreateSuccessResponse(res);
        /// ]]></code></example>
        /// <param name="code"></param>
        /// <param name="data"></param>
        /// <returns></returns>
        private IHttpActionResult CreateSuccessResponse(HttpStatusCode code, object data) {
            return ResponseMessage(new HttpResponseMessage(code) {
                Headers = { },
                Content = new StringContent(JsonConvert.SerializeObject(data), Encoding.UTF8, "application/json")
            });
        }

        /// <summary>
        /// 构造一个失败结果的ResponseMessage
        /// </summary>
        /// <example><code><![CDATA[
        /// var headers = Request.Headers;
        /// var checkRes = CheckHeaders(headers);
        /// if (!checkRes.isSuccess) {
        ///     return CreateErrorResponse(checkRes.code, checkRes.message);
        /// }
        /// ]]></code></example>
        /// <param name="code"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        private IHttpActionResult CreateErrorResponse(HttpStatusCode code, string message) {
            return ResponseMessage(new HttpResponseMessage(code) {
                Headers = { },
                Content = new StringContent(message)
            });
        }

        private CheckHeadersResult CreateCheckHeadersResult(bool isSuccess, HttpStatusCode code = HttpStatusCode.OK, string message = "") {
            return new CheckHeadersResult {
                code = code,
                message = message,
                isSuccess = isSuccess
            };
        }

        // 计算请求验证串
        private string CalculateRequestVerify(string appKey, string appSecret, long reqTime) {
            using (var md5 = MD5.Create()) {
                var input = $"{appKey}{appSecret}{reqTime}";
                var inputBytes = Encoding.UTF8.GetBytes(input);
                var hashBytes = md5.ComputeHash(inputBytes);

                // 将字节数组转换为十六进制字符串
                var sb = new StringBuilder();
                foreach (var b in hashBytes) {
                    sb.Append(b.ToString("x2"));
                }
                return sb.ToString();
            }
        }
    }

    // 请求模型
    public class SecureRequest {
        public string AppKey { get; set; }
        public long ReqTime { get; set; }
        public string ReqVerify { get; set; }
    }

    public class CheckHeadersResult {
        public bool isSuccess { get; set; }
        public HttpStatusCode code { get; set; }
        public string message { get; set; }
    }
}