tracking selection from input

src/main.odin

@@ -1,7 +1,7 @@
 /*
 - DONE implement movement up and down by paragraph
 - DONE implement scrolling/viewport
-- TODO implement deletion by word
+- DONE implement deletion by word
 - TODO implement selection
 - TODO implement duplicate selection/line
 - TODO implement move selection/line up/down
@@ -37,6 +37,14 @@ Cursor :: struct {
 	char: int,
 }
 
+Selection :: struct {
+	active:     bool,
+	start_line: int,
+	end_line:   int,
+	start_char: int,
+	end_char:   int,
+}
+
 window_width := 800
 window_height := 600
 font_size: f32 = 20.0
@@ -48,6 +56,7 @@ viewport := Viewport {
 	start = 0,
 	end   = viewport_size,
 }
+selection := Selection{}
 
 main :: proc() {
 	r.InitWindow(i32(window_width), i32(window_height), "odit")
@@ -76,78 +85,7 @@ main :: proc() {
 			cursor.char += 1
 		}
 
-		if repeatable_key_pressed(r.KeyboardKey.RIGHT) {
-			preferred_position := cursor.char + 1
-			if cursor.char == len(current_line()) && cursor.line != len(lines) - 1 {
-				cursor.char = 0
-				cursor.line += 1
-			}
-			if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && cursor.char + 1 < len(current_line()) {
-				seen_space := false
-				for c, c_index in current_line()[cursor.char + 1:] {
-					if seen_space && !is_whitespace(c) {
-						preferred_position = cursor.char + c_index
-						break
-					}
-					if is_whitespace(c) {
-						seen_space = true
-					}
-				}
-				if !seen_space {
-					preferred_position = len(current_line())
-				}
-			}
-			cursor.char = min(preferred_position, len(current_line()))
-		}
-
-		if repeatable_key_pressed(r.KeyboardKey.LEFT) {
-			preferred_position := cursor.char - 1
-			if cursor.char == 0 && cursor.line != 0 {
-				cursor.line -= 1
-				cursor.char = len(current_line())
-			}
-			if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && 0 < cursor.char {
-				found := false
-				preferred_position, found = find_previous_space(cursor.char, current_line()[:])
-			}
-			cursor.char = max(preferred_position, 0)
-		}
-
-		if repeatable_key_pressed(r.KeyboardKey.UP) {
-			preferred_line := cursor.line - 1
-
-			if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && 0 < cursor.line {
-				#reverse for l, l_index in lines[:cursor.line] {
-					if len(l) == 0 || all_whitespace(l[:]) {
-						preferred_line = l_index
-						break
-					}
-				}
-			}
-
-			cursor.line = max(0, preferred_line)
-			if len(current_line()) < cursor.char {
-				cursor.char = len(current_line())
-			}
-		}
-
-		if repeatable_key_pressed(r.KeyboardKey.DOWN) {
-			preferred_line := cursor.line + 1
-
-			if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && cursor.line + 1 < len(lines) {
-				for l, l_index in lines[cursor.line + 1:] {
-					if len(l) == 0 || all_whitespace(l[:]) {
-						preferred_line = cursor.line + l_index + 1
-						break
-					}
-				}
-			}
-
-			cursor.line = min(preferred_line, len(lines) - 1)
-			if len(current_line()) < cursor.char {
-				cursor.char = len(current_line())
-			}
-		}
+		move_cursor()
 
 		if repeatable_key_pressed(r.KeyboardKey.ENTER) {
 			new_line_cap := len(current_line()) - cursor.char
@@ -288,3 +226,105 @@ find_previous_space :: proc(current_position: int, line: []u8) -> (result: int,
 
 	return result, found
 }
+
+handle_selection_start :: proc() {
+	was_active := selection.active
+	if r.IsKeyDown(r.KeyboardKey.LEFT_SHIFT) {
+		selection.active = true
+	} else {
+		selection = {}
+		return
+	}
+	if selection.active && was_active do return
+	selection.start_line = cursor.line
+	selection.start_char = cursor.char
+}
+
+handle_selection_end :: proc() {
+	if !selection.active do return
+	selection.end_char = cursor.char
+	selection.end_line = cursor.line
+}
+
+move_cursor :: proc() {
+	if repeatable_key_pressed(r.KeyboardKey.RIGHT) {
+		handle_selection_start()
+		defer handle_selection_end()
+		preferred_position := cursor.char + 1
+		if cursor.char == len(current_line()) && cursor.line != len(lines) - 1 {
+			cursor.char = 0
+			cursor.line += 1
+		}
+		if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && cursor.char + 1 < len(current_line()) {
+			seen_space := false
+			for c, c_index in current_line()[cursor.char + 1:] {
+				if seen_space && !is_whitespace(c) {
+					preferred_position = cursor.char + c_index
+					break
+				}
+				if is_whitespace(c) {
+					seen_space = true
+				}
+			}
+			if !seen_space {
+				preferred_position = len(current_line())
+			}
+		}
+		cursor.char = min(preferred_position, len(current_line()))
+	}
+
+	if repeatable_key_pressed(r.KeyboardKey.LEFT) {
+		handle_selection_start()
+		defer handle_selection_end()
+		preferred_position := cursor.char - 1
+		if cursor.char == 0 && cursor.line != 0 {
+			cursor.line -= 1
+			cursor.char = len(current_line())
+		}
+		if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && 0 < cursor.char {
+			found := false
+			preferred_position, found = find_previous_space(cursor.char, current_line()[:])
+		}
+		cursor.char = max(preferred_position, 0)
+	}
+
+	if repeatable_key_pressed(r.KeyboardKey.UP) {
+		handle_selection_start()
+		defer handle_selection_end()
+		preferred_line := cursor.line - 1
+
+		if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && 0 < cursor.line {
+			#reverse for l, l_index in lines[:cursor.line] {
+				if len(l) == 0 || all_whitespace(l[:]) {
+					preferred_line = l_index
+					break
+				}
+			}
+		}
+
+		cursor.line = max(0, preferred_line)
+		if len(current_line()) < cursor.char {
+			cursor.char = len(current_line())
+		}
+	}
+
+	if repeatable_key_pressed(r.KeyboardKey.DOWN) {
+		handle_selection_start()
+		defer handle_selection_end()
+		preferred_line := cursor.line + 1
+
+		if r.IsKeyDown(r.KeyboardKey.LEFT_ALT) && cursor.line + 1 < len(lines) {
+			for l, l_index in lines[cursor.line + 1:] {
+				if len(l) == 0 || all_whitespace(l[:]) {
+					preferred_line = cursor.line + l_index + 1
+					break
+				}
+			}
+		}
+
+		cursor.line = min(preferred_line, len(lines) - 1)
+		if len(current_line()) < cursor.char {
+			cursor.char = len(current_line())
+		}
+	}
+}