/*
  SDL_mixer:  An audio mixer library based on the SDL library
  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#if defined(MUSIC_OGG) && defined(OGG_USE_STB)

/* This file supports Ogg Vorbis music streams using a modified stb_vorbis module */

#include "music_ogg.h"
#include "utils.h"
#include <SDL3/SDL_assert.h>

#define STB_VORBIS_SDL 1 /* for SDL_mixer-specific stuff. */
#define STB_VORBIS_NO_STDIO 1
#define STB_VORBIS_NO_CRT 1
#define STB_VORBIS_NO_PUSHDATA_API 1
#define STB_VORBIS_MAX_CHANNELS 8   /* For 7.1 surround sound */
#define STB_FORCEINLINE SDL_FORCE_INLINE
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
#define STB_VORBIS_BIG_ENDIAN 1
#endif
#define STBV_CDECL SDLCALL /* for SDL_qsort() */

#ifdef assert
#undef assert
#endif
#ifdef memset
#undef memset
#endif
#ifdef memcpy
#undef memcpy
#endif
#define assert SDL_assert
#define memset SDL_memset
#define memcmp SDL_memcmp
#define memcpy SDL_memcpy
#define qsort SDL_qsort
#define malloc SDL_malloc
#define realloc SDL_realloc
#define free SDL_free

#define pow SDL_pow
#define floor SDL_floor
#define ldexp(v, e) SDL_scalbn((v), (e))
#define abs(x) SDL_abs(x)
#define cos(x) SDL_cos(x)
#define sin(x) SDL_sin(x)
#define log(x) SDL_log(x)
#define exp(x) SDL_exp(x)

#include "stb_vorbis/stb_vorbis.h"

typedef struct {
    SDL_IOStream *src;
    bool closeio;
    int play_count;
    int volume;
    stb_vorbis *vf;
    stb_vorbis_info vi;
    int section;
    SDL_AudioStream *stream;
    char *buffer;
    int buffer_size;
    int loop;
    Sint64 loop_start;
    Sint64 loop_end;
    Sint64 loop_len;
    Sint64 full_length;
    Mix_MusicMetaTags tags;
} OGG_music;

static int set_ov_error(const char *function, int error)
{
#define HANDLE_ERROR_CASE(X) case X: SDL_SetError("%s: %s", function, #X); break;
    switch (error) {
    HANDLE_ERROR_CASE(VORBIS_need_more_data)
    HANDLE_ERROR_CASE(VORBIS_invalid_api_mixing)
    HANDLE_ERROR_CASE(VORBIS_outofmem)
    HANDLE_ERROR_CASE(VORBIS_feature_not_supported)
    HANDLE_ERROR_CASE(VORBIS_too_many_channels)
    HANDLE_ERROR_CASE(VORBIS_file_open_failure)
    HANDLE_ERROR_CASE(VORBIS_seek_without_length)
    HANDLE_ERROR_CASE(VORBIS_unexpected_eof)
    HANDLE_ERROR_CASE(VORBIS_seek_invalid)
    HANDLE_ERROR_CASE(VORBIS_invalid_setup)
    HANDLE_ERROR_CASE(VORBIS_invalid_stream)
    HANDLE_ERROR_CASE(VORBIS_missing_capture_pattern)
    HANDLE_ERROR_CASE(VORBIS_invalid_stream_structure_version)
    HANDLE_ERROR_CASE(VORBIS_continued_packet_flag_invalid)
    HANDLE_ERROR_CASE(VORBIS_incorrect_stream_serial_number)
    HANDLE_ERROR_CASE(VORBIS_invalid_first_page)
    HANDLE_ERROR_CASE(VORBIS_bad_packet_type)
    HANDLE_ERROR_CASE(VORBIS_cant_find_last_page)
    HANDLE_ERROR_CASE(VORBIS_seek_failed)
    HANDLE_ERROR_CASE(VORBIS_ogg_skeleton_not_supported)
    default:
        SDL_SetError("%s: unknown error %d\n", function, error);
        break;
    }
    return -1;
}

static int OGG_Seek(void *context, double time);
static void OGG_Delete(void *context);

static int OGG_UpdateSection(OGG_music *music)
{
    stb_vorbis_info vi;
    SDL_AudioSpec srcspec;

    vi = stb_vorbis_get_info(music->vf);

    if (vi.channels == music->vi.channels && vi.sample_rate == music->vi.sample_rate) {
        return 0;
    }
    SDL_memcpy(&music->vi, &vi, sizeof(vi));

    if (music->buffer) {
        SDL_free(music->buffer);
        music->buffer = NULL;
    }

    if (music->stream) {
        SDL_DestroyAudioStream(music->stream);
        music->stream = NULL;
    }

    SDL_zero(srcspec);
    srcspec.format = SDL_AUDIO_F32;
    srcspec.channels = vi.channels;
    srcspec.freq = (int)vi.sample_rate;
    music->stream = SDL_CreateAudioStream(&srcspec, &music_spec);
    if (!music->stream) {
        return -1;
    }

    music->buffer_size = 4096/*music_spec.samples*/ * (int)sizeof(float) * vi.channels;
    if (music->buffer_size <= 0) {
        return -1;
    }

    music->buffer = (char *)SDL_malloc((size_t)music->buffer_size);
    if (!music->buffer) {
        return -1;
    }
    return 0;
}

/* Load an OGG stream from an SDL_IOStream object */
static void *OGG_CreateFromIO(SDL_IOStream *src, bool closeio)
{
    OGG_music *music;
    stb_vorbis_comment vc;
    long rate;
    bool is_loop_length = false;
    int i, error;

    music = (OGG_music *)SDL_calloc(1, sizeof *music);
    if (!music) {
        return NULL;
    }
    music->src = src;
    music->volume = MIX_MAX_VOLUME;
    music->section = -1;

    music->vf = stb_vorbis_open_io(src, 0, &error, NULL);

    if (music->vf == NULL) {
        set_ov_error("stb_vorbis_open_io", error);
        SDL_free(music);
        return NULL;
    }

    if (OGG_UpdateSection(music) < 0) {
        OGG_Delete(music);
        return NULL;
    }

    music->vi = stb_vorbis_get_info(music->vf);
    if ((int)music->vi.sample_rate <= 0) {
        SDL_SetError("Invalid sample rate value");
        OGG_Delete(music);
        return NULL;
    }

    rate = music->vi.sample_rate;

    music->full_length = stb_vorbis_stream_length_in_samples(music->vf);
    if (music->full_length <= 0) {
        SDL_SetError("No samples in ogg/vorbis stream.");
        OGG_Delete(music);
        return NULL;
    }

    vc = stb_vorbis_get_comment(music->vf);
    if (vc.comment_list != NULL) {
        for (i = 0; i < vc.comment_list_length; i++) {
            char *param = SDL_strdup(vc.comment_list[i]);
            char *argument = param;
            char *value = SDL_strchr(param, '=');
            if (value == NULL) {
                value = param + SDL_strlen(param);
            } else {
                *(value++) = '\0';
            }

            /* Want to match LOOP-START, LOOP_START, etc. Remove - or _ from
             * string if it is present at position 4. */
            if (_Mix_IsLoopTag(argument) && ((argument[4] == '_') || (argument[4] == '-'))) {
                SDL_memmove(argument + 4, argument + 5, SDL_strlen(argument) - 4);
            }

            if (SDL_strcasecmp(argument, "LOOPSTART") == 0)
                music->loop_start = _Mix_ParseTime(value, rate);
            else if (SDL_strcasecmp(argument, "LOOPLENGTH") == 0) {
                music->loop_len = SDL_strtoll(value, NULL, 10);
                is_loop_length = true;
            } else if (SDL_strcasecmp(argument, "LOOPEND") == 0) {
                music->loop_end = _Mix_ParseTime(value, rate);
                is_loop_length = false;
            } else if (SDL_strcasecmp(argument, "TITLE") == 0) {
                meta_tags_set(&music->tags, MIX_META_TITLE, value);
            } else if (SDL_strcasecmp(argument, "ARTIST") == 0) {
                meta_tags_set(&music->tags, MIX_META_ARTIST, value);
            } else if (SDL_strcasecmp(argument, "ALBUM") == 0) {
                meta_tags_set(&music->tags, MIX_META_ALBUM, value);
            } else if (SDL_strcasecmp(argument, "COPYRIGHT") == 0) {
                meta_tags_set(&music->tags, MIX_META_COPYRIGHT, value);
            }
            SDL_free(param);
        }

        if (is_loop_length) {
            music->loop_end = music->loop_start + music->loop_len;
        } else {
            music->loop_len = music->loop_end - music->loop_start;
        }

        /* Ignore invalid loop tag */
        if (music->loop_start < 0 || music->loop_len < 0 || music->loop_end < 0) {
            music->loop_start = 0;
            music->loop_len = 0;
            music->loop_end = 0;
        }
    }

    if ((music->loop_end > 0) && (music->loop_end <= music->full_length) &&
        (music->loop_start < music->loop_end)) {
        music->loop = 1;
    }

    OGG_Seek(music, 0.0);

    music->closeio = closeio;
    return music;
}

static const char* OGG_GetMetaTag(void *context, Mix_MusicMetaTag tag_type)
{
    OGG_music *music = (OGG_music *)context;
    return meta_tags_get(&music->tags, tag_type);
}

/* Set the volume for an OGG stream */
static void OGG_SetVolume(void *context, int volume)
{
    OGG_music *music = (OGG_music *)context;
    music->volume = volume;
}

/* Get the volume for an OGG stream */
static int OGG_GetVolume(void *context)
{
    OGG_music *music = (OGG_music *)context;
    return music->volume;
}

/* Start playback of a given OGG stream */
static int OGG_Play(void *context, int play_count)
{
    OGG_music *music = (OGG_music *)context;
    music->play_count = play_count;
    return OGG_Seek(music, 0.0);
}

static void OGG_Stop(void *context)
{
    OGG_music *music = (OGG_music *)context;
    SDL_ClearAudioStream(music->stream);
}

/* Play some of a stream previously started with OGG_play() */
static int OGG_GetSome(void *context, void *data, int bytes, bool *done)
{
    OGG_music *music = (OGG_music *)context;
    bool looped = false;
    int filled, amount, result;
    int section;
    Sint64 pcmPos;

    filled = SDL_GetAudioStreamData(music->stream, data, bytes);
    if (filled != 0) {
        return filled;
    }

    if (!music->play_count) {
        /* All done */
        *done = true;
        return 0;
    }

    section = music->section;
    amount = stb_vorbis_get_samples_float_interleaved(music->vf,
                                                music->vi.channels,
                                                (float *)music->buffer,
                                                4096/*music_spec.samples*/ * music->vi.channels);

    amount *= music->vi.channels * sizeof(float);

    if (section != music->section) {
        music->section = section;
        if (OGG_UpdateSection(music) < 0) {
            return -1;
        }
    }

    pcmPos = stb_vorbis_get_playback_sample_offset(music->vf);
    if (music->loop && (music->play_count != 1) && (pcmPos >= music->loop_end)) {
        amount -= (int)((pcmPos - music->loop_end) * music->vi.channels) * (int)sizeof(float);
        result = stb_vorbis_seek(music->vf, (Uint32)music->loop_start);
        if (!result) {
            return set_ov_error("stb_vorbis_seek", stb_vorbis_get_error(music->vf));
        } else {
            int play_count = -1;
            if (music->play_count > 0) {
                play_count = (music->play_count - 1);
            }
            music->play_count = play_count;
        }
        looped = true;
    }

    if (amount > 0) {
        if (!SDL_PutAudioStreamData(music->stream, music->buffer, amount)) {
            return -1;
        }
    } else if (!looped) {
        if (music->play_count == 1) {
            music->play_count = 0;
            SDL_FlushAudioStream(music->stream);
        } else {
            int play_count = -1;
            if (music->play_count > 0) {
                play_count = (music->play_count - 1);
            }
            if (OGG_Play(music, play_count) < 0) {
                return -1;
            }
        }
    }
    return 0;
}
static int OGG_GetAudio(void *context, void *data, int bytes)
{
    OGG_music *music = (OGG_music *)context;
    return music_pcm_getaudio(context, data, bytes, music->volume, OGG_GetSome);
}

/* Jump (seek) to a given position (time is in seconds) */
static int OGG_Seek(void *context, double time)
{
    OGG_music *music = (OGG_music *)context;
    int result;

    result = stb_vorbis_seek(music->vf, (unsigned int)(time * music->vi.sample_rate));
    if (!result) {
        return set_ov_error("stb_vorbis_seek", stb_vorbis_get_error(music->vf));
    }
    return 0;
}

static double OGG_Tell(void *context)
{
    OGG_music *music = (OGG_music *)context;
    return (double)stb_vorbis_get_playback_sample_offset(music->vf) / music->vi.sample_rate;
}

/* Return music duration in seconds */
static double OGG_Duration(void *context)
{
    OGG_music *music = (OGG_music *)context;
    return (double)music->full_length / music->vi.sample_rate;
}

static double OGG_LoopStart(void *music_p)
{
    OGG_music *music = (OGG_music *)music_p;
    if (music->loop > 0) {
        return (double)music->loop_start / music->vi.sample_rate;
    }
    return -1.0;
}

static double OGG_LoopEnd(void *music_p)
{
    OGG_music *music = (OGG_music *)music_p;
    if (music->loop > 0) {
        return (double)music->loop_end / music->vi.sample_rate;
    }
    return -1.0;
}

static double OGG_LoopLength(void *music_p)
{
    OGG_music *music = (OGG_music *)music_p;
    if (music->loop > 0) {
        return (double)music->loop_len / music->vi.sample_rate;
    }
    return -1.0;
}


/* Close the given OGG stream */
static void OGG_Delete(void *context)
{
    OGG_music *music = (OGG_music *)context;
    meta_tags_clear(&music->tags);
    stb_vorbis_close(music->vf);
    if (music->stream) {
        SDL_DestroyAudioStream(music->stream);
    }
    if (music->buffer) {
        SDL_free(music->buffer);
    }
    if (music->closeio) {
        SDL_CloseIO(music->src);
    }
    SDL_free(music);
}

Mix_MusicInterface Mix_MusicInterface_OGG =
{
    "OGG",
    MIX_MUSIC_OGG,
    MUS_OGG,
    false,
    false,

    NULL,   /* Load */
    NULL,   /* Open */
    OGG_CreateFromIO,
    NULL,   /* CreateFromFile */
    OGG_SetVolume,
    OGG_GetVolume,
    OGG_Play,
    NULL,   /* IsPlaying */
    OGG_GetAudio,
    NULL,   /* Jump */
    OGG_Seek,
    OGG_Tell,
    OGG_Duration,
    OGG_LoopStart,
    OGG_LoopEnd,
    OGG_LoopLength,
    OGG_GetMetaTag,   /* GetMetaTag */
    NULL,   /* GetNumTracks */
    NULL,   /* StartTrack */
    NULL,   /* Pause */
    NULL,   /* Resume */
    OGG_Stop,
    OGG_Delete,
    NULL,   /* Close */
    NULL    /* Unload */
};

#endif /* MUSIC_OGG */

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