(system-include "SDL2/SDL_mixer.h")
(add-pkg "SDL2_mixer")
(Project.config "cflag" "-Wno-incompatible-pointer-types-discards-qualifiers")

(register-type Mix_Chunk)
(register-type Mix_Music)

(defmodule Mixer

  ;; Setup
  (register open-audio
            ;; freq format channels chunksize
            (Fn [Int Int Int Int] Int)
            "Mix_OpenAudio")

  ;; Argument to open-audio:s "format"
  (register default-format Int "MIX_DEFAULT_FORMAT")

  (register init (Fn [Int] Int) "Mix_Init")

  ;; Argument to "init" function, can be xor:ed
  (register ogg-support Int "MIX_INIT_OGG")
  (register mp3-support Int "MIX_INIT_MP3")
  (register mod-support Int "MIX_INIT_MOD")
  (register flac-support Int "MIX_INIT_FLAC")

  (register quit (Fn [] ()) "Mix_Quit")

  ;; Loading
  (register load-wav
            (Fn [(Ptr CChar)] (Ptr Mix_Chunk))
            "Mix_LoadWAV")

  (register load-music
            (Fn [(Ptr CChar)] (Ptr Mix_Music))
            "Mix_LoadMUS")

  ;; Playing samples (Mix_Chunk:s)
  (register play-channel
            ;; args: channel chunk loops
            ;; ret: channel
            (Fn [Int (Ptr Mix_Chunk) Int] Int)
            "Mix_PlayChannel")

  (register channel-playing?
            (Fn [Int] Bool)
            "Mix_Playing")

  ;; Music
  (register nr-of-music-decoders
            (Fn [] Int)
            "Mix_GetNumMusicDecoders")

  ;; This function seems flakey, returns NULL?
  (register get-music-decoder
            (Fn [Int] (Ptr CChar))
            "Mix_GetMusicDecoder")

  (register play-music
            ;; args: music loops
            ;; ret: ok-code
            (Fn [(Ptr Mix_Music) Int] Int)
            "Mix_PlayMusic")

  ;; Error handling
  (register get-error
            (Fn [] (Ptr CChar))
            "Mix_GetError")

  ;; Helpers
  (defn ok? [error-code]
    (= 0 error-code))

  (def any-free-channel -1)

  (defn valid-channel? [ch]
    (not (= ch -1)))

  )