use std::{collections::HashMap, str::FromStr};

use lazy_static::lazy_static;
use mime::Mime;

lazy_static! {
    static ref ALIASES: HashMap<Mime, Mime> = get_mime_aliases();
    static ref PARENTS: Vec<(Mime, Mime)> = get_mime_parent_relations();
}

fn get_mime_aliases() -> HashMap<Mime, Mime> {
    tree_magic_db::aliases()
        .lines()
        .flat_map(|line| line.split_once(' '))
        .flat_map(|(a, b)| Some((Mime::from_str(a).ok()?, Mime::from_str(b).ok()?)))
        .collect()
}

pub(crate) fn get_alias(mimetype: &Mime) -> &Mime {
    match ALIASES.get(mimetype) {
        Some(x) => x,
        None => mimetype,
    }
}

fn get_mime_parent_relations() -> Vec<(Mime, Mime)> {
    tree_magic_db::subclasses()
        .lines()
        .flat_map(|line| line.split_once(' '))
        .flat_map(|(child, parent)| {
            Some((Mime::from_str(child).ok()?, Mime::from_str(parent).ok()?))
        })
        .collect()
}

fn get_mime_parents(mimetype: &Mime) -> Vec<&Mime> {
    PARENTS
        .iter()
        .filter_map(|(child, parent)| (child == mimetype).then_some(parent))
        .collect()
}

pub(crate) fn matches_text(mime: &Mime) -> bool {
    if mime.type_() == mime::TEXT {
        return true;
    }
    return get_mime_parents(mime).into_iter().any(matches_text);
}