namespace SinMaiLauncher.CustomControls
{
    public class AimeComboBox : ComboBox
    {
        private const int MaxDigits = 20; // 最大数字个数
        private const int SegmentLen = 4; // 每段长度
        private const int MaxLengthWithMask = 24; // 总长度（20数字 + 4连字符）

        public AimeComboBox()
        {
            InitializeControl();
        }

        private void InitializeControl()
        {
            DropDownStyle = ComboBoxStyle.DropDown; // 允许手动输入
            MaxLength = MaxLengthWithMask; // 设置最大长度
            KeyPress += MaskedComboBox_KeyPress;
            TextChanged += MaskedComboBox_TextChanged;
            Leave += MaskedComboBox_Leave;
        }

        private void MaskedComboBox_KeyPress(object sender, KeyPressEventArgs e)
        {
            // 只允许输入数字和控制字符
            if (!char.IsDigit(e.KeyChar) && !char.IsControl(e.KeyChar))
            {
                e.Handled = true;
            }
        }

        private void MaskedComboBox_TextChanged(object sender, EventArgs e)
        {
            var text = Text.Replace("-", ""); // 移除现有连字符
            var maskedText = ApplyMask(text); // 应用掩码
            var cursorPosition = SelectionStart; // 保存光标位置

            // 更新文本
            Text = maskedText;

            // 调整光标位置
            if (cursorPosition > 0 && cursorPosition < maskedText.Length)
            {
                if (maskedText[cursorPosition - 1] == '-')
                    cursorPosition++; // 跳过连字符
                SelectionStart = cursorPosition;
            }
            else
            {
                SelectionStart = maskedText.Length;
            }
        }

        private void MaskedComboBox_Leave(object sender, EventArgs e)
        {
            // 当离开控件时，确保输入完整
            var text = Text.Replace("-", "");
            if (text.Length > 0 && text.Length < MaxDigits)
            {
                text = text.PadRight(MaxDigits, '0'); // 不足20位补0
                Text = ApplyMask(text);
            }
        }

        private string ApplyMask(string input)
        {
            // 提取数字并限制长度
            var digits = new string(input.Where(char.IsDigit).Take(MaxDigits).ToArray());
            var result = "";

            // 应用掩码：0000-0000-0000-0000-0000
            for (var i = 0; i < digits.Length; i++)
            {
                result += digits[i];
                if ((i + 1) % SegmentLen == 0 && i < MaxDigits - 1)
                    result += "-";
            }

            return result;
        }

        // 可选：添加一个方法来设置预设选项
        public void AddPresetOptions(string[] options)
        {
            foreach (var option in options)
            {
                if (IsValidMaskedFormat(option))
                {
                    Items.Add(option);
                }
            }
        }

        // 验证输入是否符合掩码格式
        private bool IsValidMaskedFormat(string input)
        {
            return input.Length == MaxLengthWithMask && input.Split('-').Length == 5 &&
                   input.Replace("-", "").All(char.IsDigit);
        }
    }
}