#include <GL/gl.h>
#include <GL/glu.h>
#include <SDL.h>
#include <SDL_sound.h>
#include <math.h>
#include <limits.h>

#include <iostream>

#include "AV.h"

using namespace std;

#define SOUND_RATE          44100
#define CALLBACK_SAMPLES    4096
#define CHANNELS            2
#define BYTES_PER_SAMPLE    2

void AV_sound_callback(void * userdata, Uint8 * stream, int len)
{
    ((AV *)userdata)->playCallback(stream, len);
}

AV::AV()
{
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
    {
        cerr << "SDL_Init() returned error!" << endl;
        exit(3);
    }

    const SDL_VideoInfo * vidInfo = SDL_GetVideoInfo();
    if (vidInfo != NULL)
    {
        m_defaultWidth = vidInfo->current_w;
        m_defaultHeight = vidInfo->current_h;
    }
    else
    {
        cerr << "Warning: SDL_GetVideoInfo() returned NULL!" << endl;
        m_defaultWidth = 1024;
        m_defaultHeight = 768;
    }

    m_surface = NULL;
    m_width = 0;
    m_height = 0;

    Sound_Init();
    SDL_AudioSpec desired;
    desired.freq = SOUND_RATE;
    desired.format = AUDIO_S16SYS;
    desired.channels = CHANNELS;
    desired.samples = CALLBACK_SAMPLES;
    desired.callback = AV_sound_callback;
    desired.userdata = this;
    if (SDL_OpenAudio(&desired, NULL) < 0)
    {
        cerr << "SDL_OpenAudio() error." << endl;
        exit(3);
    }

    m_active_sounds_mutex = SDL_CreateMutex();
}

AV::~AV()
{
    SDL_PauseAudio(1);
    SDL_DestroyMutex(m_active_sounds_mutex);
    SDL_CloseAudio();
    Sound_Quit();
    SDL_Quit();
}

void AV::start(int width, int height, bool fullscreen, bool grab_input,
        int samples)
{
    if (m_surface == NULL)
    {
        if (width == 0)
            width = m_defaultWidth;
        if (height == 0)
            height = m_defaultHeight;
        int flags = SDL_HWSURFACE | SDL_OPENGL;
        if (fullscreen)
            flags |= SDL_FULLSCREEN;

        SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
        if (samples > 1)
        {
            SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
            SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, samples);
        }
        m_surface = SDL_SetVideoMode(width, height, 32, flags);
        if (grab_input)
        {
            SDL_ShowCursor(SDL_DISABLE);
            SDL_WM_GrabInput(SDL_GRAB_ON);
        }
        SDL_WM_SetCaption("Anaglym", "Anaglym");
        m_fullscreen = fullscreen;
        m_width = width;
        m_height = height;

        glEnable(GL_DEPTH_TEST);
        glEnable(GL_LIGHTING);
        glEnable(GL_LIGHT0);
        glShadeModel(GL_SMOOTH);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(60.0, (double) width / (double) height, 0.01, 10000.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    }
}

void AV::stop()
{
    if (m_surface != NULL)
    {
        SDL_FreeSurface(m_surface);
        m_surface = NULL;
    }
}

refptr<AV::Sound> AV::createSound()
{
    refptr<Sound> s = new Sound(*this);
#if 0
    m_sounds.insert(s);
#endif
    return s;
}

void AV::playSound(AV::Sound * s)
{
    SDL_mutexP(m_active_sounds_mutex);
    m_active_sounds.insert(s);
    SDL_mutexV(m_active_sounds_mutex);
    SDL_PauseAudio(0);
}

void AV::playCallback(Uint8 * stream, int len)
{
    memset(stream, 0, len);
    SDL_mutexP(m_active_sounds_mutex);
    for (std::set<Sound *>::iterator it = m_active_sounds.begin();
         it != m_active_sounds.end();
         it++)
    {
        if ((*it)->decode(stream, len) == 0)
        {
            m_active_sounds.erase(it);
        }
    }
    if (m_active_sounds.size() == 0)
    {
        SDL_PauseAudio(1);
    }
    SDL_mutexV(m_active_sounds_mutex);
}

AV::Sound::Sound(AV & av)
    : m_av(av),
      m_buff(1)
{
    m_rwops = NULL;
    m_ss = NULL;
}

AV::Sound::~Sound()
{
    if (m_ss != NULL)
    {
        Sound_FreeSample(m_ss);
    }
}

bool AV::Sound::load(FileLoader & fileLoader, const FileLoader::Path & path)
{
    m_buff = fileLoader.load(path);
    if (m_buff.size > 0)
    {
        m_rwops = SDL_RWFromMem(m_buff.data, m_buff.size);
        Sound_AudioInfo desired;
        desired.channels = CHANNELS;
        desired.format = AUDIO_S16SYS;
        desired.rate = SOUND_RATE;
        m_ss = Sound_NewSample(m_rwops, NULL, &desired,
                CALLBACK_SAMPLES * BYTES_PER_SAMPLE * CHANNELS);
        if (m_ss != NULL)
        {
            return true;
        }
        else
        {
            SDL_FreeRW(m_rwops);
            m_rwops = NULL;
            cerr << "Error loading sound " << path.toString() << ": "
                << Sound_GetError() << endl;
        }
    }
    return false;
}

void AV::Sound::play()
{
    if (m_ss != NULL)
    {
#if 0
        cerr << "play()" << endl;
        Sound_Rewind(m_ss);
        cerr << "end play()" << endl;
#endif
        m_av.playSound(this);
    }
}

void AV::Sound::stop()
{
}

void AV::Sound::loop(int times)
{
}

int AV::Sound::decode(Uint8 * stream, int len)
{
    int len_decoded = 0, len_decoded_now;
    int samples_decoded_now;
    int spos = 0;
    int16_t * s16stream = (int16_t *) stream;
    int16_t * decoded_stream = (int16_t *) m_ss->buffer;
    do
    {
        len_decoded_now = Sound_Decode(m_ss);
        samples_decoded_now = len_decoded_now / BYTES_PER_SAMPLE;
        len_decoded += len_decoded_now;
        for (int i = 0; i < samples_decoded_now; i++)
        {
            int val = s16stream[spos] + decoded_stream[i];
            s16stream[spos] = (val > SHRT_MAX) ? SHRT_MAX : val;
            spos++;
        }
    } while ( (len_decoded_now == (int) m_ss->buffer_size)
           && (len_decoded < len) );

    return len_decoded;
}