using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace DrillTools
{
    /// <summary>
    /// 涨缩参数输入模式
    /// </summary>
    public enum ScalingMode
    {
        /// <summary>倍率模式</summary>
        Ratio,
        /// <summary>PPM 模式</summary>
        Ppm
    }

    /// <summary>
    /// 钻带涨缩窗口视图模型
    /// </summary>
    public class DrillScalingViewModel : INotifyPropertyChanged
    {
        private ScalingMode _mode = ScalingMode.Ratio;
        private string _inputX = "1.0";
        private string _inputY = "1.0";

        /// <summary>
        /// 缩放模式（倍率 / PPM）
        /// </summary>
        public ScalingMode Mode
        {
            get => _mode;
            set
            {
                if (SetProperty(ref _mode, value))
                {
                    OnPropertyChanged(nameof(ModeLabelX));
                    OnPropertyChanged(nameof(ModeLabelY));
                    OnPropertyChanged(nameof(ModeDescription));
                }
            }
        }

        /// <summary>
        /// X 方向输入值（原始字符串）
        /// </summary>
        public string InputX
        {
            get => _inputX;
            set => SetProperty(ref _inputX, value);
        }

        /// <summary>
        /// Y 方向输入值（原始字符串）
        /// </summary>
        public string InputY
        {
            get => _inputY;
            set => SetProperty(ref _inputY, value);
        }

        /// <summary>
        /// X 方向标签文本（根据模式变化）
        /// </summary>
        public string ModeLabelX => Mode == ScalingMode.Ratio ? "倍率 X" : "PPM X";

        /// <summary>
        /// Y 方向标签文本（根据模式变化）
        /// </summary>
        public string ModeLabelY => Mode == ScalingMode.Ratio ? "倍率 Y" : "PPM Y";

        /// <summary>
        /// 模式说明文本
        /// </summary>
        public string ModeDescription => Mode == ScalingMode.Ratio
            ? "倍率模式：直接输入缩放倍率（如 1.0005）"
            : "PPM 模式：输入百万分率（如 500 表示 +500ppm）";

        /// <summary>
        /// 计算后的 X 方向实际缩放倍率
        /// </summary>
        public double Kx
        {
            get
            {
                if (!double.TryParse(_inputX, out double value))
                    return 1.0;
                return Mode == ScalingMode.Ratio ? value : 1.0 + value / 1e6;
            }
        }

        /// <summary>
        /// 计算后的 Y 方向实际缩放倍率
        /// </summary>
        public double Ky
        {
            get
            {
                if (!double.TryParse(_inputY, out double value))
                    return 1.0;
                return Mode == ScalingMode.Ratio ? value : 1.0 + value / 1e6;
            }
        }

        /// <summary>
        /// 验证输入是否有效
        /// </summary>
        /// <returns>验证结果，null 表示有效，非 null 为错误消息</returns>
        public string? Validate()
        {
            if (!double.TryParse(_inputX, out double xVal))
                return "X 值不是有效的数字";
            if (!double.TryParse(_inputY, out double yVal))
                return "Y 值不是有效的数字";

            if (Mode == ScalingMode.Ratio)
            {
                if (xVal <= 0)
                    return "倍率 X 必须大于 0";
                if (yVal <= 0)
                    return "倍率 Y 必须大于 0";
            }

            return null;
        }

        public event PropertyChangedEventHandler? PropertyChanged;

        protected bool SetProperty<T>(ref T field, T value, [CallerMemberName] string? propertyName = null)
        {
            if (EqualityComparer<T>.Default.Equals(field, value))
                return false;

            field = value;
            OnPropertyChanged(propertyName);
            return true;
        }

        protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}