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

public static class SignUtil
{
    public static string LastPlainText { get; private set; } = "";
    public static string GetSign(Dictionary<string, string> parameters, string secret)
    {
        // 排序并拼接
        var sorted = new SortedDictionary<string, string>(parameters, StringComparer.Ordinal);
        sorted.Remove("sign"); // sign 不参与
        StringBuilder sb = new StringBuilder();
        foreach (var kv in sorted)
            sb.Append(kv.Key).Append(kv.Value);
        sb.Append(secret);

        // MD5 小写
        using var md5 = System.Security.Cryptography.MD5.Create();
        byte[] input = Encoding.UTF8.GetBytes(sb.ToString());
        byte[] hash = md5.ComputeHash(input);
        return BitConverter.ToString(hash).Replace("-", "").ToLowerInvariant();
    }
    public static string GetSign(IDictionary<string, object> parameters, string secret)
    {
        // 拷贝并排除 sign
        var dict = parameters
            .Where(kv => !string.Equals(kv.Key, "sign", StringComparison.Ordinal))
            .ToDictionary(kv => kv.Key, kv => kv.Value);

        // 按 key ASCII 排序（等同 PHP 的 ksort）
        var ordered = dict.OrderBy(k => k.Key, StringComparer.Ordinal);

        // 拼接 key + value
        var sb = new StringBuilder();
        foreach (var kv in ordered)
        {
            string v = ToFlatString(kv.Value);
            sb.Append(kv.Key).Append(v);
        }

        // // 追加 AppSecret
        sb.Append(secret);

        // 记录签名原文，便于排错
        LastPlainText = sb.ToString();
        
        
        Debug.Log(LastPlainText);
        
        
        // MD5 小写32位
        using var md5 = MD5.Create();
        var bytes = md5.ComputeHash(Encoding.UTF8.GetBytes(LastPlainText));
        return BitConverter.ToString(bytes).Replace("-", "").ToLowerInvariant();
    }

    // 将值转成“紧凑字符串”，数组按紧凑 JSON（无空格）序列化
    private static string ToFlatString(object val)
    {
        if (val == null) return "";
        switch (val)
        {
            case string s: return s;
            case bool b: return b ? "true" : "false";
            case Array a: return JsonArrayCompact(a);
            case IList<object> l: return JsonArrayCompact(l.ToArray());
            default:
                if (val is IFormattable f)
                    return f.ToString(null, System.Globalization.CultureInfo.InvariantCulture);
                return val.ToString();
        }
    }

    private static string JsonArrayCompact(Array arr)
    {
        var parts = new List<string>(arr.Length);
        foreach (var x in arr)
        {
            if (x == null) { parts.Add("null"); continue; }
            if (x is string s) parts.Add($"\"{Escape(s)}\"");
            else if (x is bool b) parts.Add(b ? "true" : "false");
            else if (x is IFormattable f) parts.Add(f.ToString(null, System.Globalization.CultureInfo.InvariantCulture));
            else parts.Add($"\"{Escape(x.ToString())}\"");
        }
        return "[" + string.Join(",", parts) + "]";
    }

    private static string Escape(string s) => s.Replace("\\", "\\\\").Replace("\"", "\\\"");
}