use std::fmt;

#[derive(Debug)]
pub struct MultiBar<'s, const N: usize>(pub [(&'s str, u64); N]);

impl<const N: usize> MultiBar<'_, N> {
    /// Total length of the bar
    pub(crate) fn length(&self) -> u64 {
        self.0.iter().map(|(_, len)| *len).sum()
    }

    /// Transforms the bar to be of target size
    pub(crate) fn scale(&self, size: u64) -> Self {
        let length = std::cmp::max(self.length(), 1);
        let mut prev_prop = 0;
        let mut curr_prop = 0;

        let inner = self.0.map(|(c, len)| {
            curr_prop += len;
            let nb_chars = size * curr_prop / length - size * prev_prop / length;
            prev_prop = curr_prop;
            (c, nb_chars)
        });

        Self(inner)
    }
}

impl<const N: usize> fmt::Display for MultiBar<'_, N> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for &(c, len) in &self.0 {
            for _ in 0..len {
                f.write_str(c)?;
            }
        }

        Ok(())
    }
}