using System;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Text.Encodings.Web;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Text.RegularExpressions;
using System.Text.Unicode;

namespace SimApi.Helpers;

public static class SimApiUtil
{
    /// <summary>
    /// 当前CST时间
    /// </summary>
    public static DateTime CstNow => DateTime.UtcNow.AddHours(8);

    /// <summary>
    /// JSON序列化常规选项
    /// </summary>
    public static JsonSerializerOptions JsonOption => new()
    {
        Encoder = JavaScriptEncoder.Create(UnicodeRanges.All),
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
    };

    /// <summary>
    /// 当前秒级时间戳
    /// </summary>
    public static double TimestampNow => (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0)).TotalSeconds;

    /// <summary>
    /// 检测手机号是否正确
    /// </summary>
    /// <param name="cell">手机号码</param>
    /// <returns></returns>
    public static bool CheckCell(string cell)
    {
        var regex = new Regex("^1[3456789]\\d{9}$");
        return regex.IsMatch(cell);
    }

    /// <summary>
    /// MD5加密字符串
    /// </summary>
    /// <param name="source">源字符串</param>
    /// <param name="mode">加密结果"x2"结果为32位,"x3"结果为48位,"x4"结果为64位</param>
    /// <returns></returns>
    public static string Md5(string source, string mode = "x2")
    {
        var sourceBytes = Encoding.UTF8.GetBytes(source);
        var result = MD5.HashData(sourceBytes);
        var stringBuilder = new StringBuilder(40);
        foreach (var t in result)
        {
            stringBuilder.Append(t.ToString(mode));
        }

        return stringBuilder.ToString();
    }

    /// <summary>
    /// 将对象序列化成JSON （控制台输出中文不会被编码）
    /// </summary>
    /// <param name="obj"></param>
    /// <returns></returns>
    public static string Json(object obj)
    {
        return JsonSerializer.Serialize(obj, JsonOption);
    }

    /// <summary>
    /// 分页
    /// </summary>
    /// <param name="query"></param>
    /// <param name="page">页码</param>
    /// <param name="count">每页数量</param>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    public static IQueryable<T> Paginate<T>(this IQueryable<T> query, int page, int count)
    {
        if (page < 1)
            page = 1;
        if (count <= 0)
            count = 10;
        return query.Skip((page - 1) * count).Take(count);
    }
}