From ee63abd7addfd112e4b3f053b2649f9e044c940e Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Mon, 19 Aug 2019 16:14:33 -0400
Subject: [PATCH] Add status bar

---
 kilo.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 84 insertions(+), 6 deletions(-)

diff --git a/kilo.c b/kilo.c
index 1772c48..2d45865 100644
--- a/kilo.c
+++ b/kilo.c
@@ -44,12 +44,14 @@ typedef struct erow {
 
 struct editorConfig {
 	int cx, cy;
+	int rx;
 	int rowoff;
 	int coloff;
 	int screenrows;
 	int screencols;
 	int numrows;
 	erow *row;
+	char *filename;
 	struct termios orig_termios;
 };
 
@@ -236,6 +238,23 @@ int getWindowSize(int *rows, int *cols)
 
 /*** row operations ***/
 
+int editorRowCxToRx(erow *row, int cx)
+{
+	int rx = 0;
+	int j;
+
+	for (j = 0; j < cx; j++)
+	{
+		if (row->chars[j] == '\t')
+		{
+			rx += (KILO_TAB_STOP -1) - (rx % KILO_TAB_STOP);
+		}
+		rx++;
+	}
+
+	return rx;
+}
+
 void editorUpdateRow(erow *row)
 {
 	int tabs = 0;
@@ -292,6 +311,9 @@ void editorAppendRow(char *s, size_t len)
 /*** file i/o ***/
 void editorOpen(char *filename)
 {
+	free(E.filename);
+	E.filename = strdup(filename);
+
 	FILE *fp = fopen(filename, "r");
 	if ( ! fp)
 	{
@@ -348,6 +370,12 @@ void abFree(struct abuf *ab)
 
 void editorScroll()
 {
+	E.rx = 0;
+	if (E.cy < E.numrows)
+	{
+		E.rx = editorRowCxToRx(&E.row[E.cy], E.cx);
+	}
+
 	if (E.cy < E.rowoff)
 	{
 		E.rowoff = E.cy;
@@ -360,12 +388,12 @@ void editorScroll()
 
 	if (E.cx < E.coloff)
 	{
-		E.coloff = E.cx;
+		E.coloff = E.rx;
 	}
 
 	if (E.cx >= E.coloff + E.screencols)
 	{
-		E.coloff = E.cx - E.screencols + 1;
+		E.coloff = E.rx - E.screencols + 1;
 	}
 }
 
@@ -424,11 +452,40 @@ void editorDrawRows(struct abuf *ab)
 		}
 
 		abAppend(ab, "\x1b[K", 3);
-		if (y < E.screenrows - 1)
+		abAppend(ab, "\r\n", 2);
+	}
+}
+
+void editorDrawStatusBar(struct abuf *ab)
+{
+	abAppend(ab, "\x1b[7m", 4);
+	char status[80], rstatus[80];
+	int len = snprintf(status, sizeof(status), "%.20s - %d lines",
+			E.filename ? E.filename : "[No Name]", E.numrows);
+	int rlen = snprintf(rstatus, sizeof(rstatus), "%d/%d",
+			E.cy + 1, E.numrows);
+
+	if (len > E.screencols)
+	{
+		len = E.screencols;
+	}
+	abAppend(ab, status, len);
+
+	while (len < E.screencols)
+	{
+		if (E.screencols - len == rlen)
 		{
-			abAppend(ab, "\r\n", 2);
+			abAppend(ab, rstatus, rlen);
+			break;
+		}
+		else
+		{
+			abAppend(ab, " ", 1);
+			len++;
 		}
 	}
+
+	abAppend(ab, "\x1b[m", 3);
 }
 
 void editorRefreshScreen()
@@ -441,10 +498,11 @@ void editorRefreshScreen()
 	abAppend(&ab, "\x1b[H", 3);
 
 	editorDrawRows(&ab);
+	editorDrawStatusBar(&ab);
 
 	char buf[32];
 	snprintf(buf, sizeof(buf), "\x1b[%d;%dH",
-			(E.cy - E.rowoff) + 1, (E.cx - E.coloff) + 1);
+			(E.cy - E.rowoff) + 1, (E.rx - E.coloff) + 1);
 	abAppend(&ab, buf, strlen(buf));
 
 	abAppend(&ab, "\x1b[?25h", 6);
@@ -525,11 +583,27 @@ void editorProcessKeypress()
 		break;
 
 		case END_KEY:
-			E.cx = E.screencols - 1;
+			if (E.cy < E.numrows)
+			{
+				E.cx = E.row[E.cy].size;
+			}
 		break;
 
 		case PAGE_UP:
 		case PAGE_DOWN: {
+			if (c == PAGE_UP)
+			{
+				E.cy = E.rowoff;
+			}
+			else if (c == PAGE_DOWN)
+			{
+				E.cy = E.rowoff + E.screenrows - 1;
+				if (E.cy > E.numrows)
+				{
+					E.cy = E.numrows;
+				}
+			}
+
 			int times = E.screenrows;
 			while (times--)
 			{
@@ -553,15 +627,19 @@ void initEditor()
 {
 	E.cx = 0;
 	E.cy = 0;
+	E.rx = 0;
 	E.rowoff = 0;
 	E.coloff = 0;
 	E.numrows = 0;
 	E.row = NULL;
+	E.filename = NULL;
 
 	if (getWindowSize(&E.screenrows, &E.screencols) == -1)
 	{
 		die("getWindowSize");
 	}
+
+	E.screenrows -= 1;
 }
 
 int main(int argc, char *argv[])