using System;
using System.Collections;
using System.Collections.Generic;
using Newtonsoft.Json;

namespace Aop.Api.Util
{
    /// <summary>
    /// AOP系统工具类。
    /// </summary>
    public abstract class AopUtils
    {
        /// <summary>
        /// AES加密
        /// </summary>
        /// <param name="encryptKey"></param>
        /// <param name="bizContent"></param>
        /// <param name="charset"></param>
        /// <returns></returns>
        public static string AesEncrypt(string encryptKey, string bizContent, string charset)
        {
            return AlipayEncrypt.AesEncrypt(encryptKey, bizContent, charset);

        }

        /// <summary>
        /// 对指定参数进行签名
        /// </summary>
        /// <param name="parameters">参数集合</param>
        /// <param name="privateKey">商户私钥</param>
        /// <param name="charset">字符集编码</param>
        /// <param name="signType">签名算法类型，RSA2或RSA、SM2</param>
        /// <param name="keyFromFile">是否从私钥证书文件中加载私钥
        /// 如果该参数为true，privateKey为私钥证书文件路径；
        /// 如果该参数为false，privateKey为私钥内容字符串
        /// </param>
        /// <returns>签名字符串</returns>
        public static string SignAopRequest(IDictionary<string, string> parameters, string privateKey, string charset, bool keyFromFile, string signType)
        {
            return AlipaySignature.RSASign(parameters, privateKey, charset, signType, keyFromFile);
        }

        /// <summary>
        /// 清除字典中值为空的项。
        /// </summary>
        /// <param name="dict">待清除的字典</param>
        /// <returns>清除后的字典</returns>
        public static IDictionary<string, T> CleanupDictionary<T>(IDictionary<string, T> dict)
        {
            IDictionary<string, T> newDict = new Dictionary<string, T>(dict.Count);
            IEnumerator<KeyValuePair<string, T>> dem = dict.GetEnumerator();

            while (dem.MoveNext())
            {
                string name = dem.Current.Key;
                T value = dem.Current.Value;
                if (value != null)
                {
                    newDict.Add(name, value);
                }
            }

            return newDict;
        }

        /// <summary>
        /// 获取文件的真实后缀名。目前只支持JPG, GIF, PNG, BMP四种图片文件。
        /// </summary>
        /// <param name="fileData">文件字节流</param>
        /// <returns>JPG, GIF, PNG or null</returns>
        public static string GetFileSuffix(byte[] fileData)
        {
            if (fileData == null || fileData.Length < 10)
            {
                return null;
            }

            if (fileData[0] == 'G' && fileData[1] == 'I' && fileData[2] == 'F')
            {
                return "GIF";
            }
            else if (fileData[1] == 'P' && fileData[2] == 'N' && fileData[3] == 'G')
            {
                return "PNG";
            }
            else if (fileData[6] == 'J' && fileData[7] == 'F' && fileData[8] == 'I' && fileData[9] == 'F')
            {
                return "JPG";
            }
            else if (fileData[0] == 'B' && fileData[1] == 'M')
            {
                return "BMP";
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// 获取文件的真实媒体类型。目前只支持JPG, GIF, PNG, BMP四种图片文件。
        /// </summary>
        /// <param name="fileData">文件字节流</param>
        /// <returns>媒体类型</returns>
        public static string GetMimeType(byte[] fileData)
        {
            string suffix = GetFileSuffix(fileData);
            string mimeType;

            switch (suffix)
            {
                case "JPG": mimeType = "image/jpeg"; break;
                case "GIF": mimeType = "image/gif"; break;
                case "PNG": mimeType = "image/png"; break;
                case "BMP": mimeType = "image/bmp"; break;
                default: mimeType = "application/octet-stream"; break;
            }

            return mimeType;
        }

        /// <summary>
        /// 根据文件后缀名获取文件的媒体类型。
        /// </summary>
        /// <param name="fileName">带后缀的文件名或文件全名</param>
        /// <returns>媒体类型</returns>
        public static string GetMimeType(string fileName)
        {
            string mimeType;
            fileName = fileName.ToLower();

            if (fileName.EndsWith(".bmp", StringComparison.CurrentCulture))
            {
                mimeType = "image/bmp";
            }
            else if (fileName.EndsWith(".gif", StringComparison.CurrentCulture))
            {
                mimeType = "image/gif";
            }
            else if (fileName.EndsWith(".jpg", StringComparison.CurrentCulture) || fileName.EndsWith(".jpeg", StringComparison.CurrentCulture))
            {
                mimeType = "image/jpeg";
            }
            else if (fileName.EndsWith(".png", StringComparison.CurrentCulture))
            {
                mimeType = "image/png";
            }
            else
            {
                mimeType = "application/octet-stream";
            }

            return mimeType;
        }

        /// <summary>
        /// 根据API名称获取响应根节点名称。
        /// </summary>
        /// <param name="api">API名称</param>
        /// <returns></returns>
        public static string GetRootElement(string api)
        {
            int pos = api.IndexOf(".", StringComparison.Ordinal);
            if (pos != -1 && api.Length > pos)
            {
                api = api.Substring(pos + 1).Replace('.', '_');
            }
            return api + "_response";
        }

        public static IDictionary ParseJson(string body)
        {
            return JsonConvert.DeserializeObject<IDictionary>(body);
        }

        [Obsolete("请替换为未废弃的有完整参数列表的重载版本，明确指定各参数的值")]
        public static string SignAopRequest(IDictionary<string, string> parameters, string privateKeyPem, string charset, string signType)
        {
            return AlipaySignature.RSASign(parameters, privateKeyPem, charset, signType);
        }
    }
}
