use super::model::{Line, Point};
use crate::parsing::{newline, parse_number};
use yap::{IntoTokens, Tokens};

pub fn parse_point(tokens: &mut impl Tokens<Item = char>) -> Option<Point> {
    let numbers: Vec<usize> = tokens
        .sep_by(|t| parse_number(t), |t| t.token(','))
        .collect();
    if numbers.len() == 2 {
        Some(Point {
            x: numbers[0],
            y: numbers[1],
        })
    } else {
        None
    }
}

pub fn parse_line(tokens: &mut impl Tokens<Item = char>) -> Option<Line> {
    let points: Vec<Point> = tokens
        .sep_by(|t| parse_point(t), |t| t.tokens(" -> ".into_tokens()))
        .collect();
    if points.len() == 2 {
        Some(Line {
            start: points[0],
            end: points[1],
        })
    } else {
        None
    }
}

pub fn parse_lines(tokens: &mut impl Tokens<Item = char>) -> Vec<Line> {
    tokens.sep_by(|t| parse_line(t), |t| newline(t)).collect()
}

#[cfg(test)]
mod test {
    use super::super::model::{Line, Point};
    use yap::IntoTokens;

    #[test]
    fn parse_point() {
        assert_eq!(
            Some(Point { x: 1, y: 3 }),
            super::parse_point(&mut "1,3".into_tokens())
        );
    }

    #[test]
    fn parse_line() {
        assert_eq!(
            Some(Line {
                start: Point { x: 1, y: 3 },
                end: Point { x: 5, y: 3 }
            }),
            super::parse_line(&mut "1,3 -> 5,3".into_tokens())
        );
    }
}