using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;

namespace TemuKJD.UserComponent
{
    [DefaultEvent(nameof(ValueChanged))]
    public class UcNumericRange : UserControl
    {
        private const decimal DefaultMaximum = 1000000m;
        private const int NormalWidth = 220;
        private const int CompactWidth = 112;
        private readonly Label separator = new Label { Text = "至", AutoSize = true, Anchor = AnchorStyles.None };
        private readonly NumericUpDown lower = CreateEditor("起始值");
        private readonly NumericUpDown upper = CreateEditor("结束值");
        private bool updating;

        public UcNumericRange()
        {
            upper.Value = DefaultMaximum;
            var layout = new TableLayoutPanel { Dock = DockStyle.Fill, ColumnCount = 3, RowCount = 1 };
            layout.RowStyles.Add(new RowStyle(SizeType.Percent, 100));
            layout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50));
            layout.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            layout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50));
            layout.Controls.Add(CreateCell(lower), 0, 0);
            layout.Controls.Add(separator, 1, 0);
            layout.Controls.Add(CreateCell(upper), 2, 0);
            Controls.Add(layout);
            Size = new Size(NormalWidth, lower.PreferredHeight + 2);
            lower.ValueChanged += (s, e) => UpdateRange(lower, upper);
            upper.ValueChanged += (s, e) => UpdateRange(upper, lower);
        }

        [Description("两个数值之间显示的文字。"), DefaultValue("至")]
        public string SeparatorText
        {
            get => separator.Text;
            set => separator.Text = value;
        }

        [Description("使用窄布局并隐藏微调按钮，仍可用方向键调整数值。"), DefaultValue(false)]
        public bool Compact
        {
            get => separator.Margin == Padding.Empty;
            set
            {
                if (value == Compact) return;
                separator.Margin = value ? Padding.Empty : new Padding(3, 0, 3, 0);
                SetCompactBorder(lower, value);
                SetCompactBorder(upper, value);
                if (Dock == DockStyle.None && Width == (value ? NormalWidth : CompactWidth))
                    Width = value ? CompactWidth : NormalWidth;
            }
        }

        private static void SetCompactBorder(NumericUpDown editor, bool compact)
        {
            var cell = (Panel)editor.Parent;
            editor.BorderStyle = compact ? BorderStyle.None : BorderStyle.Fixed3D;
            cell.BorderStyle = compact ? BorderStyle.FixedSingle : BorderStyle.None;
            cell.BackColor = compact ? editor.BackColor : Color.Empty;
            cell.PerformLayout();
        }

        private Panel CreateCell(NumericUpDown editor)
        {
            var cell = new Panel { Dock = DockStyle.Fill, Margin = Padding.Empty };
            cell.Controls.Add(editor);
            var buttons = editor.Controls[0] is TextBox ? editor.Controls[1] : editor.Controls[0];
            // 紧凑模式将右侧按钮移出可见区域，保留原生数字输入和键盘操作。
            cell.Layout += (s, e) =>
            {
                int clippedWidth = Compact ? editor.Width - buttons.Left : 0;
                editor.Width = cell.ClientSize.Width + clippedWidth;
                editor.Top = Compact ? Math.Max(0, (cell.ClientSize.Height - editor.Height) / 2) : 0;
            };
            return cell;
        }

        private static NumericUpDown CreateEditor(string name)
        {
            return new NumericUpDown { AccessibleName = name, Margin = Padding.Empty, Maximum = DefaultMaximum };
        }

        [Description("允许输入的最小值。"), DefaultValue(typeof(decimal), "0")]
        public decimal Minimum
        {
            get => lower.Minimum;
            set => SetLimits(value, Math.Max(value, Maximum));
        }

        [Description("允许输入的最大值。"), DefaultValue(typeof(decimal), "1000000")]
        public decimal Maximum
        {
            get => lower.Maximum;
            set => SetLimits(Math.Min(value, Minimum), value);
        }

        [Description("选中范围的起始值。"), DefaultValue(typeof(decimal), "0")]
        public decimal LowerValue
        {
            get => lower.Value;
            set => lower.Value = value;
        }

        [Description("选中范围的结束值。"), DefaultValue(typeof(decimal), "1000000")]
        public decimal UpperValue
        {
            get => upper.Value;
            set => upper.Value = value;
        }

        [Description("数字输入框显示的小数位数。"), DefaultValue(0)]
        public int DecimalPlaces
        {
            get => lower.DecimalPlaces;
            set
            {
                if (value < 0 || value > 28) throw new ArgumentOutOfRangeException(nameof(value));
                lower.DecimalPlaces = upper.DecimalPlaces = value;
                decimal increment = 1m;
                for (int i = 0; i < value; i++)
                    increment /= 10m;
                lower.Increment = upper.Increment = increment;
            }
        }

        public event EventHandler ValueChanged;

        private void SetLimits(decimal minimum, decimal maximum)
        {
            decimal oldLower = LowerValue, oldUpper = UpperValue;
            updating = true;
            try
            {
                lower.Minimum = upper.Minimum = minimum;
                lower.Maximum = upper.Maximum = maximum;
            }
            finally { updating = false; }
            if (LowerValue != oldLower || UpperValue != oldUpper)
                ValueChanged?.Invoke(this, EventArgs.Empty);
        }

        private void UpdateRange(NumericUpDown edited, NumericUpDown other)
        {
            if (updating) return;
            updating = true;
            try
            {
                if (LowerValue > UpperValue)
                    other.Value = edited.Value;
            }
            finally { updating = false; }
            ValueChanged?.Invoke(this, EventArgs.Empty);
        }
    }
}