namespace Easy.Core;

/// <summary>
/// 金额处理工具类
/// 统一处理货币单位转换、精度控制和四舍五入规则
/// </summary>
public static class AmountHelper
{
    /// <summary>
    /// 金额精度小数位数
    /// </summary>
    private const int DecimalPlaces = 2;

    /// <summary>
    /// 将元转换为分
    /// </summary>
    /// <param name="amount">金额（元）</param>
    /// <returns>金额（分）</returns>
    public static int YuanToFen(decimal amount)
    {
        var roundedAmount = Math.Round(amount, DecimalPlaces, MidpointRounding.AwayFromZero);
        return (int)Math.Round(roundedAmount * 100, MidpointRounding.AwayFromZero);
    }

    /// <summary>
    /// 将分转换为元
    /// </summary>
    /// <param name="amount">金额（分）</param>
    /// <returns>金额（元）</returns>
    public static decimal FenToYuan(int amount)
    {
        return amount / 100m;
    }

    /// <summary>
    /// 将分转换为元（可为空）
    /// </summary>
    /// <param name="amount">金额（分）</param>
    /// <returns>金额（元）</returns>
    public static decimal? FenToYuan(int? amount)
    {
        if (!amount.HasValue) return null;
        return amount.Value / 100m;
    }

    /// <summary>
    /// 四舍五入金额到指定小数位
    /// </summary>
    /// <param name="amount">金额</param>
    /// <param name="decimalPlaces">小数位数，默认2位</param>
    /// <returns>四舍五入后的金额</returns>
    public static decimal Round(decimal amount, int decimalPlaces = DecimalPlaces)
    {
        return Math.Round(amount, decimalPlaces, MidpointRounding.AwayFromZero);
    }

    /// <summary>
    /// 验证金额格式是否正确（最多保留2位小数）
    /// </summary>
    /// <param name="amount">金额</param>
    /// <returns>是否有效</returns>
    public static bool IsValidAmount(decimal amount)
    {
        var rounded = Math.Round(amount, DecimalPlaces, MidpointRounding.AwayFromZero);
        return rounded == amount;
    }

    /// <summary>
    /// 验证金额是否大于0且格式正确
    /// </summary>
    /// <param name="amount">金额</param>
    /// <returns>是否有效</returns>
    public static bool IsValidPositiveAmount(decimal amount)
    {
        return amount > 0 && IsValidAmount(amount);
    }
}