use std::collections::HashMap;

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

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

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

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

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

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