use core::ops;
use std::collections::{BTreeMap, BTreeSet};

use rtic_syntax::{
    analyze::{self, Priority},
    ast::App,
    P,
};
use syn::Ident;

/// Extend the upstream `Analysis` struct with our field
pub struct Analysis {
    parent: P<analyze::Analysis>,
    pub interrupts: BTreeMap<Priority, Ident>,
}

impl ops::Deref for Analysis {
    type Target = analyze::Analysis;

    fn deref(&self) -> &Self::Target {
        &self.parent
    }
}

// Assign an `extern` interrupt to each priority level
pub fn app(analysis: P<analyze::Analysis>, app: &App) -> P<Analysis> {
    let mut interrupts = BTreeMap::new();
    let priorities = app
        .software_tasks
        .values()
        .filter_map(|task| Some(task.args.priority))
        .collect::<BTreeSet<_>>();

    if !priorities.is_empty() {
        interrupts = priorities
            .iter()
            .cloned()
            .rev()
            .zip(app.extern_interrupts.keys().cloned())
            .collect();
    }

    P::new(Analysis {
        parent: analysis,
        interrupts,
    })
}