From e0ce095657cc0458fa8a217d27872ec32ed814f1 Mon Sep 17 00:00:00 2001
From: Keith Smiley <keithbsmiley@gmail.com>
Date: Fri, 21 Jul 2017 20:58:04 -0700
Subject: Support arrow key movements

---
 src/tty_interface.c | 50 +++++++++++++++++++++++++++++++++++++++++++++-----
 src/tty_interface.h |  1 +
 2 files changed, 46 insertions(+), 5 deletions(-)

(limited to 'src')

diff --git a/src/tty_interface.c b/src/tty_interface.c
index fc903e6..ab20eec 100644
--- a/src/tty_interface.c
+++ b/src/tty_interface.c
@@ -93,7 +93,9 @@ static void draw(tty_interface_t *state) {
 	if (num_lines > 0) {
 		tty_moveup(tty, num_lines);
 	}
-	tty_setcol(tty, strlen(options->prompt) + strlen(state->search));
+
+	int length = strlen(options->prompt) + strlen(state->search);
+	tty_setcol(tty, length + state->offset);
 	tty_flush(tty);
 }
 
@@ -131,8 +133,15 @@ static void action_emit(tty_interface_t *state) {
 }
 
 static void action_del_char(tty_interface_t *state) {
-	if (*state->search)
-		state->search[strlen(state->search) - 1] = '\0';
+	if (*state->search) {
+		int length = strlen(state->search);
+		int index = length + state->offset - 1;
+		if (index < 0) {
+			return;
+		}
+
+		memmove(&state->search[index], &state->search[index + 1], length - index);
+	}
 }
 
 static void action_del_word(tty_interface_t *state) {
@@ -161,6 +170,24 @@ static void action_next(tty_interface_t *state) {
 	choices_next(state->choices);
 }
 
+static void action_left(tty_interface_t *state) {
+	if ((unsigned long)abs(state->offset) < strlen(state->search))
+		state->offset--;
+}
+
+static void action_right(tty_interface_t *state) {
+	if (state->offset < 0)
+		state->offset++;
+}
+
+static void action_beginning(tty_interface_t *state) {
+	state->offset = -strlen(state->search);
+}
+
+static void action_end(tty_interface_t *state) {
+	state->offset = 0;
+}
+
 static void action_pageup(tty_interface_t *state) {
 	update_state(state);
 	for(size_t i = 0; i < state->options->num_lines && state->choices->selection > 0; i++)
@@ -192,8 +219,14 @@ static void append_search(tty_interface_t *state, char ch) {
 	char *search = state->search;
 	size_t search_size = strlen(search);
 	if (search_size < SEARCH_SIZE_MAX) {
-		search[search_size++] = ch;
-		search[search_size] = '\0';
+		int location = state->offset + search_size;
+		for (int i = search_size; i >= 0; i--) {
+			if (i >= location) {
+				search[i + 1] = search[i];
+			}
+		}
+
+		search[location] = ch;
 	}
 }
 
@@ -201,6 +234,7 @@ void tty_interface_init(tty_interface_t *state, tty_t *tty, choices_t *choices,
 	state->tty = tty;
 	state->choices = choices;
 	state->options = options;
+	state->offset = 0;
 
 	strcpy(state->input, "");
 	strcpy(state->search, "");
@@ -233,7 +267,13 @@ static const keybinding_t keybindings[] = {{"\x7f", action_del_char},	/* DEL */
 					   {KEY_CTRL('N'), action_next},	 /* C-N */
 					   {KEY_CTRL('K'), action_prev},	 /* C-J */
 					   {KEY_CTRL('J'), action_next},	 /* C-K */
+					   {KEY_CTRL('A'), action_beginning},    /* C-A */
+					   {KEY_CTRL('E'), action_end},		 /* C-E */
 
+					   {"\x1bOD", action_left}, /* LEFT */
+					   {"\x1b[D", action_left}, /* LEFT */
+					   {"\x1bOC", action_right}, /* RIGHT */
+					   {"\x1b[C", action_right}, /* RIGHT */
 					   {"\x1b[A", action_prev}, /* UP */
 					   {"\x1bOA", action_prev}, /* UP */
 					   {"\x1b[B", action_next}, /* DOWN */
diff --git a/src/tty_interface.h b/src/tty_interface.h
index 438cc55..34f4e59 100644
--- a/src/tty_interface.h
+++ b/src/tty_interface.h
@@ -14,6 +14,7 @@ typedef struct {
 
 	char search[SEARCH_SIZE_MAX + 1];
 	char last_search[SEARCH_SIZE_MAX + 1];
+	int offset;
 
 	char input[32]; /* Pending input buffer */
 
-- 
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