use std::collections::HashMap;
use std::fmt;

use crate::ast::ItemId;

pub type LineNumber = usize;

#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Location {
  pub line_num: LineNumber,
  pub char_num: usize,
}

impl fmt::Display for Location {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}:{}", self.line_num, self.char_num)
  }
}

pub struct SourceMap {
  map: HashMap<ItemId, Location>
}

impl SourceMap {
  pub fn new() -> SourceMap {
    SourceMap { map: HashMap::new() }
  }

  pub fn add_location(&mut self, id: &ItemId, loc: Location) {
    self.map.insert(id.clone(), loc);
  }

  pub fn lookup(&self, id: &ItemId) -> Option<Location> {
    match self.map.get(id) {
      Some(loc) => Some(loc.clone()),
      None => None
    }
  }
}