From 271ab508da3565dd3a333f96748518c6cd4c2a29 Mon Sep 17 00:00:00 2001
From: Tyrel Souza <923113+tyrelsouza@users.noreply.github.com>
Date: Wed, 20 Oct 2021 23:37:39 -0400
Subject: [PATCH] inputs

---
 kilo.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 121 insertions(+), 6 deletions(-)

diff --git a/kilo.c b/kilo.c
index 1e7400b..59aa7ad 100644
--- a/kilo.c
+++ b/kilo.c
@@ -9,9 +9,21 @@
 #include <unistd.h>
 
 /** defines ***/
-#define KILO_VERSION "0.0.1"
+#define TYREL_VERSION "0.0.1"
 #define CTRL_KEY(k) ((k) & 0x1f)
 
+enum editorKey {
+    ARROW_LEFT = 1000,
+    ARROW_RIGHT,
+    ARROW_UP,
+    ARROW_DOWN,
+    DEL_KEY,
+    HOME_KEY,
+    END_KEY,
+    PAGE_UP,
+    PAGE_DOWN
+};
+
 
 /*** data ***/
 struct editorConfig {
@@ -52,13 +64,66 @@ void enableRawMode() {
     if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) die("tcsetattr");
 }
 
-char editorReadKey() {
+int editorReadKey() {
     int nread;
     char c;
     while ((nread = read(STDIN_FILENO, &c, 1)) != 1) {
         if (nread == -1 && errno != EAGAIN) die("read");
     }
-    return c;
+
+    if (c == '\x1b') {
+        char seq[3];
+        if (read(STDIN_FILENO, &seq[0], 1) != 1) return '\x1b';
+        if (read(STDIN_FILENO, &seq[1], 1) != 1) return '\x1b';
+        if (seq[0] == '[') {
+            if (seq[1] >= '0' && seq[1] <= '9') {
+                if (read(STDIN_FILENO, &seq[2], 1) != 1) return '\x1b';
+                if (seq[2] == '~') {
+                    switch (seq[1]) {
+                        case '1':
+                            return HOME_KEY;
+                        case '3':
+                            return DEL_KEY;
+                        case '4':
+                            return END_KEY;
+                        case '5':
+                            return PAGE_UP;
+                        case '6':
+                            return PAGE_DOWN;
+                        case '7':
+                            return HOME_KEY;
+                        case '8':
+                            return END_KEY;
+                    }
+                }
+            } else {
+                switch (seq[1]) {
+                    case 'A':
+                        return ARROW_UP;
+                    case 'B':
+                        return ARROW_DOWN;
+                    case 'C':
+                        return ARROW_RIGHT;
+                    case 'D':
+                        return ARROW_LEFT;
+                    case 'H':
+                        return HOME_KEY;
+                    case 'F':
+                        return END_KEY;
+                }
+            }
+        } else if (seq[0] == 'O') {
+            switch (seq[1]) {
+                case 'H':
+                    return HOME_KEY;
+                case 'F':
+                    return END_KEY;
+            }
+        }
+        return '\x1b';
+    } else {
+        return c;
+    }
 }
 
 int getCursorPosition(int *rows, int *cols) {
@@ -116,7 +181,7 @@ void editorDrawRows(struct abuf *ab) {
     for (y = 0; y < E.screenrows; y++) {
         if (y == E.screenrows / 3) {
             char welcome[80];
-            int welcomelen = snprintf(welcome, sizeof welcome, "Kilo Editor -- version %s", KILO_VERSION);
+            int welcomelen = snprintf(welcome, sizeof welcome, "Tyrel Editor -- version %s", TYREL_VERSION);
             int padding = (E.screencols - welcomelen) / 2;
             if (padding) {
                 abAppend(ab, "~", 1);
@@ -140,7 +205,10 @@ void editorRefreshScreen() {
     abAppend(&ab, "\x1b[?25l", 6);
     abAppend(&ab, "\x1b[H", 3); // Cursor Position home
     editorDrawRows(&ab);
-    abAppend(&ab, "\x1b[H", 3); // Cursor Position home
+
+    char buf[32];
+    snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
+    abAppend(&ab, buf, strlen(buf));
     abAppend(&ab, "\x1b[?25h", 6);
 
     write(STDOUT_FILENO, ab.b, ab.len);
@@ -149,14 +217,61 @@ void editorRefreshScreen() {
 
 
 /*** input ***/
+void editorMoveCursor(int key) {
+    switch (key) {
+        case ARROW_LEFT:
+            if (E.cx != 0) {
+                E.cx--;
+            }
+            break;
+        case ARROW_RIGHT:
+            if (E.cx != E.screencols - 1) {
+                E.cx++;
+            }
+            break;
+        case ARROW_UP:
+            if (E.cy != 0) {
+                E.cy--;
+            }
+            break;
+        case ARROW_DOWN:
+            if (E.cy != E.screenrows - 1) {
+                E.cy++;
+            }
+            break;
+    }
+}
+
 void editorProcessKeypress() {
-    char c = editorReadKey();
+    int c = editorReadKey();
     switch (c) {
         case CTRL_KEY('q'):
             write(STDOUT_FILENO, "\x1b[2J", 4);
             write(STDOUT_FILENO, "\x1b[H", 3);
             exit(0);
             break;
+
+        case HOME_KEY:
+            E.cx = 0;
+            break;
+
+        case END_KEY:
+            E.cx = E.screencols - 1;
+            break;
+
+        case PAGE_UP:
+        case PAGE_DOWN: {
+            int times = E.screenrows;
+            while (times--)
+                editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
+        }
+            break;
+        case ARROW_UP:
+        case ARROW_DOWN:
+        case ARROW_LEFT:
+        case ARROW_RIGHT:
+            editorMoveCursor(c);
+            break;
     }
 }