using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using UnityEngine;

public class SignHelper
{
    /// <summary>
    /// 生成 sign
    /// </summary>
    /// <param name="parameters">请求参数字典（包含所有参数，但要去掉 sign）</param>
    /// <param name="secret">AppSecret</param>
    /// <returns>MD5 sign</returns>
    public static string GetSign(Dictionary<string, object> parameters, string secret)
    {
        // 1. 移除 sign
        if (parameters.ContainsKey("sign"))
        {
            parameters.Remove("sign");
        }

        // 2. 按照 key ASCII 排序
        var sorted = parameters.OrderBy(p => p.Key, StringComparer.Ordinal);

        // 3. 拼接成字符串 key+value
        StringBuilder sb = new StringBuilder();
        foreach (var kv in sorted)
        {
            string valueStr;
            if (kv.Value is Array || kv.Value is List<object>)
            {
                // 数组需要转成 JSON 字符串
                valueStr = JsonUtility.ToJson(kv.Value);
            }
            else
            {
                valueStr = kv.Value.ToString();
            }
            sb.Append(kv.Key).Append(valueStr);
        }

        // 4. 拼接 secret
        sb.Append(secret);

        // 5. 做 MD5 加密
        using (MD5 md5 = MD5.Create())
        {
            byte[] inputBytes = Encoding.UTF8.GetBytes(sb.ToString());
            byte[] hashBytes = md5.ComputeHash(inputBytes);

            // 转换成 32 位小写 hex
            return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();
        }
    }
}