use std::collections::HashMap;

use resources::Resource;
use symbols::Symbol;

pub trait SymbolRepository<'a> {
  fn get_symbol(&'a self, resource: &Resource) -> Option<Box<dyn Symbol + 'a>>;
}

impl<'a, C> SymbolRepository<'a> for C
where
  C: Fn(&Resource) -> Option<Box<dyn Symbol + 'a>>,
{
  fn get_symbol(&'a self, resource: &Resource) -> Option<Box<dyn Symbol + 'a>> {
    self(resource)
  }
}

pub struct DispatchingSymbolRepository<'a> {
  repositories: HashMap<&'a str, Box<dyn SymbolRepository<'a> + 'a>>,
}

impl<'a> DispatchingSymbolRepository<'a> {
  pub fn new(repositories: HashMap<&'a str, Box<dyn SymbolRepository<'a> + 'a>>) -> Self {
    DispatchingSymbolRepository { repositories }
  }
}

impl<'a> SymbolRepository<'a> for DispatchingSymbolRepository<'a> {
  fn get_symbol(&'a self, resource: &Resource) -> Option<Box<dyn Symbol + 'a>> {
    self
      .repositories
      .get(resource.get_type())
      .and_then(|repo| repo.get_symbol(resource))
  }
}