extern crate shelf;

use std::collections::HashMap;
use shelf::Shelf;

pub struct Desk {
  desk: HashMap<String, String>,
  shelf: Shelf
}

impl Desk {
  pub fn new(path: Option<&str>) -> Desk {
    let desk = HashMap::new();
    let shelf = match path {
      Some(path) => Shelf::new(path),
      None => Shelf::new("/tmp/shelf")
    };

    Desk {
      desk: desk,
      shelf: shelf
    }
  }

  pub fn set(&mut self, key: &str, value: &str) -> () {
    let prev = self.desk.insert(key.to_string(), value.to_string());

    if self.shelf.get(key) != prev {
      self.shelf.set(key, value);
    }
  }

  pub fn get(&self, key: &str) -> Option<String> {
    match self.desk.get(key) {
      Some(value) => Some(value.to_string()),
      None => match self.shelf.get(key) {
        None => None,
        Some(value) => {
          &self.shelf.set(key, &value);
          Some(value)
        }
      }
    }
  }

  //pub fn delete(&self, key: &str) -> () { }

  //pub fn keys(&self) -> Vec<String> { }

  //pub fn values(&self) -> Vec<String> { }
}

#[cfg(test)]
mod test {
  use super::*;

  #[test]
  fn basic() { }
}