use core::fmt;

use crate::color::{Bold, Dim, Fg, Reset};
use crate::domain;
use crate::palette;
use crate::severity::Severity;

const SPACES: &str = "                ";

fn write_padding(w: &mut dyn fmt::Write, n: usize) -> fmt::Result {
    w.write_str(&SPACES[..n.min(SPACES.len())])
}

pub fn write_gutter(
    w: &mut dyn fmt::Write,
    domain: &str,
    severity: Severity,
    message: fmt::Arguments<'_>,
    gutter_width: usize,
) -> fmt::Result {
    let group = domain::classify(domain);
    let label_color = group.label_color();
    let msg_color = severity.message_color();
    let padding = gutter_width.saturating_sub(domain.len() + 1);
    write_padding(w, padding)?;
    write!(
        w,
        "{}{}{}{} {}|{} {}{}{}",
        Bold,
        Fg(label_color),
        domain,
        Reset,
        Fg(palette::BAR_DIM),
        Reset,
        Fg(msg_color),
        message,
        Reset
    )
}

pub fn write_message_only(
    w: &mut dyn fmt::Write,
    severity: Severity,
    message: fmt::Arguments<'_>,
) -> fmt::Result {
    write!(w, "{}{}{}", Fg(severity.message_color()), message, Reset)
}

pub fn write_gutter_label(
    w: &mut dyn fmt::Write,
    domain: &str,
    dim: bool,
    gutter_width: usize,
) -> fmt::Result {
    let group = domain::classify(domain);
    let label_color = group.label_color();
    let padding = gutter_width.saturating_sub(domain.len() + 1);
    write_padding(w, padding)?;
    match dim {
        true => write!(
            w,
            "{}{}{}{} {}|{} ",
            Dim,
            Fg(label_color),
            domain,
            Reset,
            Fg(palette::BAR_DIM),
            Reset
        ),
        false => write!(
            w,
            "{}{}{}{} {}|{} ",
            Bold,
            Fg(label_color),
            domain,
            Reset,
            Fg(palette::BAR_DIM),
            Reset
        ),
    }
}

pub fn write_continuation(w: &mut dyn fmt::Write, gutter_width: usize) -> fmt::Result {
    write_padding(w, gutter_width)?;
    write!(w, "{}|{} ", Fg(palette::BAR_DIM), Reset)
}