//! Sounds format definition type.

use crate::{bin::{u32b, usize_from_u32}, err::*, fixed::*, sound::Sound16};
use bitflags::bitflags;

/// Reads a sound definition.
pub fn read(b: &[u8]) -> ResultS<Option<(Vec<usize>, u16, SoundDef)>>
{
   read_data! {
      endian: BIG, buf: b, size: 64, start: 0, data {
         let index    = u16[0];
         let volume   = u16[2] enum Volume;
         let flags    = u16[4] flag SoundFlags;
         let chance   = u16[6];
         let pitch_lo = Fixed[8];
         let pitch_hi = Fixed[12];
         let n_sounds = u16[16] usize;
         let grp_ofs  = u32[20] usize;
      }
   }

   if index == u16::max_value() {
      return Ok(None);
   }

   if n_sounds > 5 {
      bail!("too many sounds");
   }

   let mut ofs = Vec::with_capacity(n_sounds);
   let mut p   = 36;

   for _ in 0..n_sounds {
      ofs.push(grp_ofs + usize_from_u32(u32b(&b[p..])));
      p += 4;
   }

   let sounds = Vec::with_capacity(n_sounds);

   Ok(Some((ofs, index,
            SoundDef{volume, flags, chance, pitch_lo, pitch_hi, sounds})))
}

/// A sound definition containing one, many or no sounds.
#[derive(Debug, Eq, PartialEq)]
pub struct SoundDef
{
   /// The volume type for this sound.
   pub volume: Volume,

   /// The flags for this sound.
   pub flags: SoundFlags,

   /// The chance out of `u16::max_value()` that this sound will not play.
   pub chance: u16,

   /// The low random pitch bound.
   pub pitch_lo: Fixed,

   /// The high random pitch bound.
   pub pitch_hi: Fixed,

   /// All of the sounds in this collection.
   pub sounds: Vec<Sound16>,
}

bitflags! {
   /// Flags for `SoundDef`.
   #[cfg_attr(feature = "serde_obj", derive(serde::Serialize))]
   pub struct SoundFlags: u16
   {
      /// The sound will not restart when trying to play over itself.
      const NO_RESTART        = 1;
      /// The sound will not switch channels when trying to play over itself.
      const NO_CHANNEL_SWITCH = 1 << 1;
      /// The pitch variance will be halved.
      const LESS_PITCH_CHANGE = 1 << 2;
      /// The pitch variance will be nullified.
      const NO_PITCH_CHANGE   = 1 << 3;
      /// The sound will play even when completely obstructed by walls.
      const NO_OBSTRUCTION    = 1 << 4;
      /// The sound will play even when completely obstructed by media.
      const NO_MEDIA_OBSTRUCT = 1 << 5;
      /// The sound will have special stereo effects.
      const AMBIENT           = 1 << 6;
   }
}

c_enum! {
   /// The type of volume this sound has.
   #[cfg_attr(feature = "serde_obj", derive(serde::Serialize))]
   pub enum Volume: u16
   {
      Quiet  = 0,
      Normal = 1,
      Loud   = 2,
   }
}

// EOF