//! Map file entry type.

use crate::err::*;
use super::head;
use std::collections::BTreeMap;

/// Read an entry from a Map file.
pub fn read(map: &head::Map, i: usize) -> ResultS<(u16, Entry<'_>)>
{
   let size = map.head().size_entry();

   read_data! {
      endian: BIG, buf: map.dir(), size: size, start: size * i, data {
         let offset   = u32[0] usize;
         let dsize    = u32[4] usize;
         let index    = u16[8];
         let app_data = u8[10; map.head().size_appl()];
      }
   }

   let data  = &map.data()[offset..offset + dsize];
   let index = if map.head().old_wad() {i as u16} else {index};

   Ok((index, Entry{data, app_data}))
}

/// Reads all entries in a Map file.
pub fn read_all(map: &head::Map) -> ResultS<EntryMap<'_>>
{
   let mut entries = EntryMap::new();

   for i in 0..map.num_ent() {
      let (index, entry) = read(map, i)?;

      if entries.contains_key(&index) {
         bail!("entry index already exists");
      }

      entries.insert(index, entry);
   }

   Ok(entries)
}

/// An entry containing chunked data and application-specific data.
#[cfg_attr(feature = "serde_obj", derive(serde::Serialize))]
#[derive(Debug, Eq, PartialEq)]
pub struct Entry<'a>
{
   /// The data in this `Entry`.
   pub data: &'a [u8],

   /// The application specific data for this Entry.
   pub app_data: &'a [u8],
}

/// A map of indexed entries.
pub type EntryMap<'a> = BTreeMap<u16, Entry<'a>>;

// EOF