grid.rs

struct GridLayout {
    raw: String,
    lines: Vec<String>,
    line_starts: Vec<usize>,
}

impl GridLayout {
    fn new(raw: String, max_width: usize) -> Self {
        let mut lines = Vec::new();
        let mut line_starts = Vec::new();
        let mut current_index = 0;

        for line in raw.split('\n') {
            let mut current_line = String::new();
            let mut words = line.split_whitespace().peekable();

            while let Some(word) = words.next() {
                if current_line.len() + word.len() > max_width && !current_line.is_empty() {
                    lines.push(current_line.trim().to_string());
                    line_starts.push(current_index);
                    current_index += current_line.len();
                    current_line = String::new();
                }
                current_line.push_str(word);
                if words.peek().is_some() {
                    current_line.push(' ');
                }
            }

            if !current_line.is_empty() {
                lines.push(current_line.trim().to_string());
                line_starts.push(current_index);
                current_index += current_line.len();
            }
        }

        GridLayout { raw, lines, line_starts }
    }

    fn find_position(&self, raw_index: usize) -> (usize, usize) {
        for (row, &start) in self.line_starts.iter().enumerate() {
            if row + 1 == self.line_starts.len() || self.line_starts[row + 1] > raw_index {
                return (row, raw_index - start);
            }
        }
        (self.lines.len() - 1, self.lines.last().unwrap().len())
    }

    fn get_line(&self, row: usize) -> &str { &self.lines[row] }

    fn line_count(&self) -> usize { self.lines.len() }
}

fn main() {
    let raw = "I have a lovely lemon sorbet".to_string();
    let grid = GridLayout::new(raw, 12);

    let target_index = 16;
    let (row, column) = grid.find_position(target_index);
    println!("Raw index {} is at row {}, column {}", target_index, row, column);

    for i in 0..grid.line_count() {
        println!("Line {}: '{}'", i, grid.get_line(i));
    }
}