kitty/tools/tui/readline/actions.go

// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>

package readline

import (
	"fmt"
	"strings"

	"kitty/tools/utils"
	"kitty/tools/wcswidth"
)

var _ = fmt.Print

func (self *Readline) text_upto_cursor_pos() string {
	buf := strings.Builder{}
	buf.Grow(1024)
	for i, line := range self.lines {
		if i == self.cursor_line {
			buf.WriteString(line[:self.cursor_pos_in_line])
			break
		} else {
			buf.WriteString(line)
			buf.WriteString("\n")
		}
	}
	return buf.String()
}

func (self *Readline) text_after_cursor_pos() string {
	buf := strings.Builder{}
	buf.Grow(1024)
	for i, line := range self.lines {
		if i == self.cursor_line {
			buf.WriteString(line[self.cursor_pos_in_line:])
			buf.WriteString("\n")
		} else if i > self.cursor_line {
			buf.WriteString(line)
			buf.WriteString("\n")
		}
	}
	ans := buf.String()
	ans = ans[:len(ans)-1]
	return ans
}

func (self *Readline) all_text() string {
	return strings.Join(self.lines, "\n")
}

func (self *Readline) add_text(text string) {
	new_lines := make([]string, 0, len(self.lines)+4)
	new_lines = append(new_lines, self.lines[:self.cursor_line]...)
	var lines_after []string
	if len(self.lines) > self.cursor_line+1 {
		lines_after = self.lines[self.cursor_line+1:]
	}
	has_trailing_newline := strings.HasSuffix(text, "\n")

	add_line_break := func(line string) {
		new_lines = append(new_lines, line)
		self.cursor_pos_in_line = len(line)
		self.cursor_line += 1
	}
	cline := self.lines[self.cursor_line]
	before_first_line := cline[:self.cursor_pos_in_line]
	after_first_line := ""
	if self.cursor_pos_in_line < len(cline) {
		after_first_line = cline[self.cursor_pos_in_line:]
	}
	for i, line := range utils.Splitlines(text) {
		if i > 0 {
			add_line_break(line)
		} else {
			line := before_first_line + line
			self.cursor_pos_in_line = len(line)
			new_lines = append(new_lines, line)
		}
	}
	if has_trailing_newline {
		add_line_break("")
	}
	if after_first_line != "" {
		if len(new_lines) == 0 {
			new_lines = append(new_lines, "")
		}
		new_lines[len(new_lines)-1] += after_first_line
	}
	if len(lines_after) > 0 {
		new_lines = append(new_lines, lines_after...)
	}
	self.lines = new_lines
}

func (self *Readline) move_cursor_left(amt uint, traverse_line_breaks bool) uint {
	var amt_moved uint
	for ; amt > 0; amt -= 1 {
		if self.cursor_pos_in_line == 0 {
			if !traverse_line_breaks || self.cursor_line == 0 {
				return amt_moved
			}
			self.cursor_line -= 1
			self.cursor_pos_in_line = len(self.lines[self.cursor_pos_in_line])
			amt_moved += 1
			continue
		}
		// This is an extremely inefficient algorithm but it does not matter since
		// lines are not large.
		line := self.lines[self.cursor_line]
		runes := []rune(line[:self.cursor_pos_in_line])
		orig_width := wcswidth.Stringwidth(line[:self.cursor_pos_in_line])
		current_width := orig_width
		for current_width == orig_width && len(runes) > 0 {
			runes = runes[:len(runes)-1]
			s := string(runes)
			current_width = wcswidth.Stringwidth(s)
		}
		self.cursor_pos_in_line = len(string(runes))
		amt_moved += 1
	}
	return amt_moved
}

func (self *Readline) move_cursor_right(amt uint, traverse_line_breaks bool) uint {
	var amt_moved uint
	for ; amt > 0; amt -= 1 {
		line := self.lines[self.cursor_line]
		if self.cursor_pos_in_line >= len(line) {
			if !traverse_line_breaks || self.cursor_line == len(self.lines)-1 {
				return amt_moved
			}
			self.cursor_line += 1
			self.cursor_pos_in_line = 0
			amt_moved += 1
			continue
		}
		// This is an extremely inefficient algorithm but it does not matter since
		// lines are not large.
		before_runes := []rune(line[:self.cursor_pos_in_line])
		after_runes := []rune(line[self.cursor_pos_in_line:])
		orig_width := wcswidth.Stringwidth(line[:self.cursor_pos_in_line])
		current_width := orig_width
		for current_width == orig_width && len(after_runes) > 0 {
			before_runes = append(before_runes, after_runes[0])
			current_width = wcswidth.Stringwidth(string(before_runes))
			after_runes = after_runes[1:]
		}
		// soak up any more runes that dont affect width
		for len(after_runes) > 0 {
			q := append(before_runes, after_runes[0])
			w := wcswidth.Stringwidth(string(q))
			if w != current_width {
				break
			}
			after_runes = after_runes[1:]
			before_runes = q
		}
		self.cursor_pos_in_line = len(string(before_runes))
		amt_moved += 1
	}
	return amt_moved
}