From d5618831447f0af99834c1126c38e06e4212b4a2 Mon Sep 17 00:00:00 2001
From: Krzosa Karol <krzosa.karol@gmail.com>
Date: Fri, 28 Jun 2024 17:24:58 +0200
Subject: [PATCH] Work on end of buffer

---
 src/text_editor/buffer.cpp | 20 ++++++++++++++------
 src/text_editor/layout.cpp |  8 +++++---
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/text_editor/buffer.cpp b/src/text_editor/buffer.cpp
index 2e42def..c626317 100644
--- a/src/text_editor/buffer.cpp
+++ b/src/text_editor/buffer.cpp
@@ -24,6 +24,8 @@ struct Range {
     // <0,4> = 0,1,2,3
 };
 
+// @end_of_buffer - need to make sure that we can actually lookup the end of buffer line.
+// This end of buffer is also incorporated into the layout.
 struct Line {
     int64_t number;
     Range   range;
@@ -453,7 +455,8 @@ BufferIter Iterate(Buffer &buffer, Range range, int64_t direction = ITERATE_FORW
     range.min = Clamp(buffer, range.min);
     range.max = Clamp(buffer, range.max);
 
-    BufferIter result = {&buffer, range.min, range.max, direction};
+    BufferIter result      = {&buffer, range.min, range.max, direction};
+    result.codepoint_index = -1;
     if (direction == ITERATE_BACKWARD) {
         result.end = range.min;
         result.pos = range.max;
@@ -465,22 +468,21 @@ BufferIter Iterate(Buffer &buffer, Range range, int64_t direction = ITERATE_FORW
 
 Line GetLineByIndex(Buffer &buffer, int64_t line) {
     Assert(buffer.lines.len);
-
     line         = Clamp(line, (int64_t)0, buffer.lines.len - 1);
     Range range  = buffer.lines[line];
     Line  result = {line, range, range.max};
-    if (GetChar(buffer, range.max - 1) == '\n') result.max_without_new_line -= 1;
+    if (range.max > range.min && GetChar(buffer, range.max - 1) == '\n') result.max_without_new_line -= 1;
     return result;
 }
 
 Line FindLine(Buffer &buffer, int64_t pos) {
     Line result = {};
     For(buffer.lines) {
-        bool found_last = (pos == it.min && pos == it.max);
+        bool found_last = (pos == it.min && pos == it.max); // @end_of_buffer
         bool found      = pos >= it.min && pos < it.max;
         if (found || found_last) {
             result = {buffer.lines.get_index(it), it, it.max};
-            if (GetChar(buffer, it.max - 1) == '\n') result.max_without_new_line -= 1;
+            if (it.max > it.min && GetChar(buffer, it.max - 1) == '\n') result.max_without_new_line -= 1;
             break;
         }
     }
@@ -489,8 +491,14 @@ Line FindLine(Buffer &buffer, int64_t pos) {
 
 LineAndColumn FindLineAndColumn(Buffer &buffer, int64_t pos) {
     LineAndColumn result = {};
-    result.column        = 1;
+    result.column        = 0;
     result.line          = FindLine(buffer, pos);
+
+    // @end_of_buffer
+    if (pos == result.line.range.min && pos == result.line.range.max) {
+        return result;
+    }
+
     for (BufferIter iter = Iterate(buffer, result.line.range); IsValid(iter); Advance(&iter)) {
         // @todo: make sure we handle when there is invalid unicode in the stream
         if (iter.pos == pos) {
diff --git a/src/text_editor/layout.cpp b/src/text_editor/layout.cpp
index 4e8d320..a055496 100644
--- a/src/text_editor/layout.cpp
+++ b/src/text_editor/layout.cpp
@@ -75,12 +75,14 @@ Layout CalculateLayout(Arena *arena, Buffer &buffer, Font font, float font_size,
 
     // Add end of buffer as layout cell at the end
     {
-        LayoutRow *row         = layout.rows.alloc();
-        row->columns.allocator = *arena;
+        LayoutRow *row = NULL;
         if (last_range->min == last_range->max) {
-            text_offset_x = 0;
+            LayoutRow *row         = layout.rows.alloc();
+            row->columns.allocator = *arena;
+            text_offset_x          = 0;
         } else {
             text_offset_y -= line_spacing;
+            row = layout.rows.last();
         }
         int        index          = GetGlyphIndex(font, ' ');
         GlyphInfo *glyph          = font.glyphs + index;