using Apimanager_backend.Dtos;
using Newtonsoft.Json;
using System.Security.Cryptography;
using System.Text;

namespace Apimanager_backend.Tools
{
    public static class EpayHelper
    {
        /// <summary>
        /// 创建签名
        /// </summary>
        public static string CreateSign(Dictionary<string, string> parameters, string key)
        {
            var sorted = parameters
                .Where(kv => !string.IsNullOrEmpty(kv.Value) && kv.Key != "sign" && kv.Key != "sign_type")
                .OrderBy(kv => kv.Key)
                .ToList();

            string query = string.Join("&", sorted.Select(kv => $"{kv.Key}={kv.Value}"));
            string toSign = query + key;

            using (var md5 = MD5.Create())
            {
                byte[] hash = md5.ComputeHash(Encoding.UTF8.GetBytes(toSign));
                return BitConverter.ToString(hash).Replace("-", "").ToLower();
            }
        }
        /// <summary>
        /// 发起API支付（返回 json）
        /// </summary>
        public static async Task<EpayResponse?> ApiPayAsync(Dictionary<string, string> parameters, string key,string baseUrl)
        {
            parameters["sign_type"] = "MD5";
            parameters["sign"] = CreateSign(parameters, key);

            using var client = new HttpClient();
            var content = new FormUrlEncodedContent(parameters);
            var response = await client.PostAsync($"{baseUrl}/mapi.php", content);
            var responseJson = await response.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<EpayResponse>(responseJson);
        }

        /// <summary>
        /// 校验签名（通常用于异步通知/页面跳转）
        /// </summary>
        public static bool VerifySign(Dictionary<string, string> parameters, string key)
        {
            if (!parameters.TryGetValue("sign", out string originalSign)) return false;
            string newSign = CreateSign(parameters, key);
            return originalSign.Equals(newSign, StringComparison.OrdinalIgnoreCase);
        }
    }
}