From b95e43a9e16dfd6aa1ecf3d8bad6b507760206ec Mon Sep 17 00:00:00 2001
From: Benjamin Popp <haven1433@gmail.com>
Date: Wed, 17 Oct 2018 22:45:04 -0500
Subject: [PATCH] wrote basics of the edit algorithm. It's long and needs to be
 refactored. It tracks what changes could be undone, but undo isn't
 implemented yet. CanEditData now passes, as does CanEditMultipleBytesInARow.

---
 Gen3Hex/ViewModel/ViewPort.cs | 61 +++++++++++++++++++++++++++++------
 HexTests/ViewPortEditTests.cs |  6 ++--
 2 files changed, 55 insertions(+), 12 deletions(-)

diff --git a/Gen3Hex/ViewModel/ViewPort.cs b/Gen3Hex/ViewModel/ViewPort.cs
index 5426abf9..b52a282d 100644
--- a/Gen3Hex/ViewModel/ViewPort.cs
+++ b/Gen3Hex/ViewModel/ViewPort.cs
@@ -4,6 +4,8 @@ using System;
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.ComponentModel;
+using System.Globalization;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Windows.Input;
 
@@ -155,7 +157,9 @@ namespace HavenSoft.Gen3Hex.ViewModel {
          get => selectionEnd;
          set {
             value = ScrollToPoint(value);
-            TryUpdate(ref selectionEnd, value);
+            if (TryUpdate(ref selectionEnd, value)) {
+               history.ChangeCompleted();
+            }
          }
       }
 
@@ -237,10 +241,9 @@ namespace HavenSoft.Gen3Hex.ViewModel {
       public bool IsSelected(Point point) {
          if (point.X < 0 || point.X >= width) return false;
 
-         int linearize(Point p) => p.Y * width + p.X;
-         var selectionStart = linearize(SelectionStart);
-         var selectionEnd = linearize(SelectionEnd);
-         var middle = linearize(point);
+         var selectionStart = Linearize(SelectionStart);
+         var selectionEnd = Linearize(SelectionEnd);
+         var middle = Linearize(point);
 
          var leftEdge = Math.Min(selectionStart, selectionEnd);
          var rightEdge = Math.Max(selectionStart, selectionEnd);
@@ -249,15 +252,55 @@ namespace HavenSoft.Gen3Hex.ViewModel {
       }
 
       public void Edit(string input) {
-         if (input.Length == 0) return;
-         if (input.Length > 1) {
-            for (int i = 0; i < input.Length; i++) Edit(input.Substring(i, 1));
+         for (int i = 0; i < input.Length; i++) Edit(input[i]);
+      }
+
+      private void Edit(char input) {
+         var selectionStart = Linearize(SelectionStart);
+         var selectionEnd = Linearize(SelectionEnd);
+         var leftEdge = Math.Min(selectionStart, selectionEnd);
+         var point = new Point(leftEdge % width, leftEdge / width);
+         if (leftEdge < 0) point = new Point(width - ((-leftEdge) % width), leftEdge / width - 1);
+         var point2 = ScrollToPoint(point);
+         if (!point2.Equals(point)) {
+            RefreshBackingData();
+            point = point2;
+         }
+         var element = currentView[point.X, point.Y];
+         var underEdit = element.Format as UnderEdit;
+
+         if (!"0123456789ABCDEFabcdef".Contains(input)) {
+            if (underEdit != null) {
+               currentView[point.X, point.Y] = new HexElement(element.Value, underEdit.OriginalFormat);
+            }
             return;
          }
 
-         // TODO working here
+         SelectionStart = point;
+
+         if (underEdit != null) {
+            currentView[point.X, point.Y] = new HexElement(element.Value, new UnderEdit(underEdit.OriginalFormat, underEdit.CurrentText + input));
+         } else {
+            currentView[point.X, point.Y] = new HexElement(element.Value, new UnderEdit(element.Format, input.ToString()));
+         }
+
+         underEdit = (UnderEdit)currentView[point.X, point.Y].Format;
+         if (underEdit.CurrentText.Length == 2) {
+            var byteValue = byte.Parse(underEdit.CurrentText, NumberStyles.HexNumber);
+            var memoryLocation = Linearize(point) + dataIndex;
+            history.CurrentChange[memoryLocation] = currentView[point.X, point.Y];
+            data[memoryLocation] = byteValue;
+            var nextPoint = point + new Point(1, 0);
+            if (nextPoint.X == width) nextPoint += new Point(-width, 1);
+            nextPoint = ScrollToPoint(nextPoint);
+            TryUpdate(ref this.selectionStart, nextPoint, nameof(SelectionStart));
+            TryUpdate(ref this.selectionEnd, nextPoint, nameof(SelectionEnd));
+            RefreshBackingData();
+         }
       }
 
+      private int Linearize(Point p) => p.Y * width + p.X;
+
       private void RefreshBackingData() {
          currentView = new HexElement[Width, Height];
          for (int y = 0; y < Height; y++) {
diff --git a/HexTests/ViewPortEditTests.cs b/HexTests/ViewPortEditTests.cs
index d1959ad7..d6c4a443 100644
--- a/HexTests/ViewPortEditTests.cs
+++ b/HexTests/ViewPortEditTests.cs
@@ -26,9 +26,9 @@ namespace HavenSoft.HexTests {
          viewPort.Edit("DEADBEEF");
 
          Assert.Equal(0xDE, viewPort[2, 2].Value);
-         Assert.Equal(0xAD, viewPort[2, 3].Value);
-         Assert.Equal(0xBE, viewPort[2, 4].Value);
-         Assert.Equal(0xEF, viewPort[3, 0].Value);
+         Assert.Equal(0xAD, viewPort[3, 2].Value);
+         Assert.Equal(0xBE, viewPort[4, 2].Value);
+         Assert.Equal(0xEF, viewPort[0, 3].Value);
       }
 
       [Fact]