Encapsulate calculations and graph logic

13_Bounce/csharp/Graph.cs

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+using System.Text;
+
+namespace Bounce;
+
+/// <summary>
+/// Provides support for plotting a graph of height vs time, and rendering it to a string.
+/// </summary>
+internal class Graph
+{
+    private readonly Dictionary<int, Row> _rows;
+
+    public Graph(float maxHeight, float timeIncrement)
+    {
+        // 1 row == 1/2 foot + 1 row for zero
+        var rowCount = 2 * (int)Math.Round(maxHeight, MidpointRounding.AwayFromZero) + 1;
+        _rows = Enumerable.Range(0, rowCount)
+            .ToDictionary(x => x, x => new Row(x % 2 == 0 ? $" {x / 2} " : ""));
+        TimeIncrement = timeIncrement;
+    }
+
+    public float TimeIncrement { get; }
+    public float MaxTimePlotted { get; private set; }
+
+    public void Plot(float time, float height)
+    {
+        var rowIndex = (int)Math.Round(height * 2, MidpointRounding.AwayFromZero);
+        var colIndex = (int)(time / TimeIncrement) + 1;
+        if (_rows.TryGetValue(rowIndex, out var row))
+        {
+            row[colIndex] = '0';
+        }
+        MaxTimePlotted = Math.Max(time, MaxTimePlotted);
+    }
+
+    public override string ToString()
+    {
+        var sb = new StringBuilder().AppendLine("Feet").AppendLine();
+        foreach (var (_, row) in _rows.OrderByDescending(x => x.Key))
+        {
+            sb.Append(row).AppendLine();
+        }
+        sb.Append(new Axis(MaxTimePlotted, TimeIncrement));
+
+        return sb.ToString();
+    }
+
+    internal class Row
+    {
+        public const int Width = 70;
+
+        private readonly char[] _chars = new char[Width + 2];
+        private int nextColumn = 0;
+
+        public Row(string label)
+        {
+            Array.Fill(_chars, ' ');
+            Array.Copy(label.ToCharArray(), _chars, label.Length);
+            nextColumn = label.Length;
+        }
+
+        public char this[int column]
+        {
+            set
+            {
+                if (column >= _chars.Length) { return; }
+                if (column < nextColumn) { column = nextColumn; }
+                _chars[column] = value;
+                nextColumn = column + 1;
+            }
+        }
+
+        public override string ToString() => new string(_chars);
+    }
+
+    internal class Axis
+    {
+        private readonly int _maxTimeMark;
+        private readonly float _timeIncrement;
+        private readonly Labels _labels;
+
+        internal Axis(float maxTimePlotted, float timeIncrement)
+        {
+            _maxTimeMark = (int)Math.Ceiling(maxTimePlotted);
+            _timeIncrement = timeIncrement;
+
+            _labels = new Labels();
+            for (var i = 1; i <= _maxTimeMark; i++)
+            {
+                _labels.Add((int)(i / _timeIncrement), $" {i} ");
+            }
+        }
+
+        public override string ToString()
+            => new StringBuilder()
+                .Append(' ').Append('.', (int)(_maxTimeMark / _timeIncrement) + 1).AppendLine()
+                .Append(_labels).AppendLine()
+                .Append(' ', (int)(_maxTimeMark / _timeIncrement / 2 - 2)).AppendLine("Seconds")
+                .ToString();
+    }
+
+    internal class Labels : Row
+    {
+        public Labels()
+            : base(" 0")
+        {
+        }
+
+        public void Add(int column, string label)
+        {
+            for (var i = 0; i < label.Length; i++)
+            {
+                this[column + i] = label[i];
+            }
+        }
+    }
+}