package parsekit

import "fmt"

// Cursor represents the position of the input cursor in various ways.
type Cursor struct {
	Byte   int // The cursor offset in bytes
	Rune   int // The cursor offset in UTF8 runes
	Column int // The column at which the cursor is (0-indexed)
	Line   int // The line at which the cursor is (0-indexed)
}

func (c *Cursor) String() string {
	return fmt.Sprintf("line %d, column %d", c.Line+1, c.Column+1)
}

// move updates the position of the cursor, based on the provided input string.
func (c *Cursor) move(input string) {
	c.Byte += len(input)
	for _, r := range input {
		c.Rune++
		if r == '\n' {
			c.Column = 0
			c.Line++
		} else {
			c.Column++
		}
	}
}