#include "meta.h"
#include "../coding/coding.h"
#include "ppst_streamfile.h"


/* PPST - ParaPpa STream (maybe), extracted from .img bigfile [Parappa the Rapper (PSP)] */
VGMSTREAM * init_vgmstream_ppst(STREAMFILE *streamFile) {
    VGMSTREAM * vgmstream = NULL;
    int total_subsongs, target_subsong = streamFile->stream_index;


    /* checks */
    if (!check_extensions(streamFile, "sng"))
        goto fail;
    if (read_32bitBE(0x00,streamFile) != 0x50505354) /* "PPST" */
        goto fail;

    /* header has some control and comment fields then interleaved RIFF .at3 */

    /* count subsongs (mainly 4, rarely 1) */
    {
        off_t offset = 0xa0;

        total_subsongs = 0;
        while (offset < 0x800) {
            if (read_32bitLE(offset + 0x04, streamFile) == 0) /* subsong size */
                break;
            total_subsongs++;
            offset += 0x08;
        }

        if (target_subsong == 0) target_subsong = 1;
        if (target_subsong < 0 || target_subsong > total_subsongs || total_subsongs < 1) goto fail;
    }

    {
        off_t start_offset = 0x800;
        size_t interleave_size = 0x4000;
        size_t stride_size = 0x4000*total_subsongs;
        /* subsong header at 0xa0, 0x00(1): id, 0x01(3): blocks of interleave */
        size_t stream_size = read_32bitLE(0xA0+0x08*(target_subsong-1)+0x04, streamFile);

        STREAMFILE* temp_streamFile = setup_ppst_streamfile(streamFile, start_offset+interleave_size*(target_subsong-1), interleave_size, stride_size, stream_size);
        if (!temp_streamFile) goto fail;

        vgmstream = init_vgmstream_riff(temp_streamFile);
        close_streamfile(temp_streamFile);
        if (!vgmstream) goto fail;

        vgmstream->num_streams = total_subsongs;
        vgmstream->stream_size = stream_size;
        vgmstream->meta_type = meta_PPST;
    }

    return vgmstream;

fail:
    close_vgmstream(vgmstream);
    return NULL;
}