use std::fmt;

use yansi::Color::Blue;

use crate::format::HorizontalScale;

#[derive(Debug)]
/// A struct that represents a single match bar of a match bar histogram (a
/// bucket for a term/label).
pub struct MatchBarRow {
    pub label: String,
    pub count: usize,
}

impl MatchBarRow {
    pub fn new(string: &str) -> Self {
        Self {
            label: string.to_string(),
            count: 0,
        }
    }

    pub fn inc_if_matches(&mut self, line: &str) {
        if line.contains(&self.label) {
            self.count += 1;
        }
    }
}

#[derive(Debug)]
/// A struct holding data to plot a `MatchBar`: a histogram of the number of
/// occurrences of a set of strings in some input dara.
pub struct MatchBar {
    pub vec: Vec<MatchBarRow>,
    top_values: usize,
    top_length: usize,
}

impl MatchBar {
    /// Creates a Histogram from a vector of `MatchBarRow` elements.
    pub fn new(vec: Vec<MatchBarRow>) -> Self {
        let mut top_length: usize = 0;
        let mut top_values: usize = 0;
        for row in &vec {
            top_length = top_length.max(row.label.len());
            top_values = top_values.max(row.count);
        }
        Self {
            vec,
            top_values,
            top_length,
        }
    }
}

impl fmt::Display for MatchBar {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let width = f.width().unwrap_or(100);
        let horizontal_scale = HorizontalScale::new(self.top_values / width);
        let width_count = format!("{}", self.top_values).len();
        writeln!(
            f,
            "Matches: {}.",
            Blue.paint(format!(
                "{}",
                self.vec.iter().map(|r| r.count).sum::<usize>()
            )),
        )?;
        writeln!(f, "{horizontal_scale}")?;
        for row in &self.vec {
            writeln!(
                f,
                "[{label}] [{count}] {bar}",
                label = Blue.paint(format!("{:width$}", row.label, width = self.top_length)),
                count = horizontal_scale.get_count(row.count, width_count),
                bar = horizontal_scale.get_bar(row.count)
            )?;
        }
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use yansi::Paint;

    #[test]
    fn test_matchbar() {
        let mut row0 = MatchBarRow::new("label1");
        row0.inc_if_matches("labelN");
        row0.inc_if_matches("label1");
        row0.inc_if_matches("label1");
        row0.inc_if_matches("label11");
        let mut row1 = MatchBarRow::new("label2");
        row1.inc_if_matches("label2");
        let mb = MatchBar::new(vec![row0, row1, MatchBarRow::new("label333")]);
        assert_eq!(mb.top_length, 8);
        assert_eq!(mb.top_values, 3);
        Paint::disable();
        let display = format!("{mb}");

        assert!(display.contains("[label1  ] [3] ∎∎∎\n"));
        assert!(display.contains("[label2  ] [1] ∎\n"));
        assert!(display.contains("[label333] [0] \n"));
        assert!(display.contains("represents a count of 1"));
        assert!(display.contains("Matches: 4"));
    }
}