use super::{Add, AddGeneric, AddResult, AddableResource, Runnable, SymbolRunner};
use crate::{ImplementationBuilder, ResourceLocator};
use async_trait::async_trait;
use slog::{debug, o, trace, Logger};
use std::fmt::Debug;
use std::marker::PhantomData;
use std::rc::{Rc, Weak};

#[derive(Debug)]
pub struct Realizer<SR, L, B, S> {
  symbol_runner: Rc<SR>,
  outer: Weak<S>,
  phantom: PhantomData<(L, B)>,
}

impl<SR, L, B, S> Realizer<SR, L, B, S> {
  pub fn new(symbol_runner: Rc<SR>, outer: Weak<S>) -> Self {
    Self {
      symbol_runner,
      outer,
      phantom: PhantomData::default(),
    }
  }
}

#[async_trait(?Send)]
impl<R, SR, L, B, S> Add<R> for Realizer<SR, L, B, S>
where
  R: AddableResource,
  SR: SymbolRunner,
  L: ResourceLocator<R>,
  B: ImplementationBuilder<R>,
  <B as ImplementationBuilder<R>>::Implementation: Runnable + Debug,
  S: AddGeneric<B::Prerequisites> + AddGeneric<<L as ResourceLocator<R>>::Prerequisites>,
{
  async fn add(&self, logger: &Rc<Logger>, resource: Rc<R>, force_run: bool) -> AddResult<R> {
    let setup = self.outer.upgrade().unwrap();
    let logger = Rc::new(logger.new(o!("resource" => format!("{resource:?}"))));
    trace!(logger, "(force_run is {})", force_run);
    let (location, location_prereqs) = L::locate(&resource);
    trace!(logger, "Adding location prereqs ...");
    let (_, location_prereqs_did_run) = (*setup)
      .add_generic(&logger, location_prereqs, false)
      .await?;
    trace!(
      logger,
      "Location prereqs did_run: {}",
      location_prereqs_did_run
    );

    trace!(logger, "Adding implementation prereqs ...");
    let (prereqs, prereqs_did_run) = (*setup)
      .add_generic(&logger, B::prerequisites(&resource), false)
      .await?;
    trace!(
      logger,
      "Implementation prereqs did_run: {}",
      prereqs_did_run
    );

    trace!(logger, "Running implementation ...");
    let implementation = B::create(&resource, &location, prereqs);
    let did_run = implementation
      .run(
        &*self.symbol_runner,
        &logger,
        force_run || location_prereqs_did_run || prereqs_did_run,
      )
      .await?;
    debug!(logger, "done.");

    Ok((location, did_run))
  }
}