#include "meta.h"
#include "../util.h"

VGMSTREAM * init_vgmstream_brstm(STREAMFILE *streamFile) {
    VGMSTREAM * vgmstream = NULL;
    char filename[PATH_LIMIT];

    coding_t coding_type;

    off_t head_offset;
    int codec_number;
    int channel_count;
    int loop_flag;
    /* Certain Super Paper Mario tracks have a 44.1KHz sample rate in the
     * header, but they should be played at 22.05KHz. We will make this
     * correction if we see a file with a .brstmspm extension. */
    int spm_flag = 0;
    /* Trauma Center Second Opinion has an odd, semi-corrupt header */
    int atlus_shrunken_head = 0;

    off_t start_offset;

    /* check extension, case insensitive */
    streamFile->get_name(streamFile,filename,sizeof(filename));
    if (strcasecmp("brstm",filename_extension(filename))) {
        if (strcasecmp("brstmspm",filename_extension(filename))) goto fail;
        else spm_flag = 1;
    }

    /* check header */
    if ((uint32_t)read_32bitBE(0,streamFile)!=0x5253544D) /* "RSTM" */
        goto fail;
    if ((uint32_t)read_32bitBE(4,streamFile)!=0xFEFF0100)
    {
        if ((uint32_t)read_32bitBE(4,streamFile)!=0xFEFF0001)
            goto fail;
        else
            atlus_shrunken_head = 1;
    }

    /* get head offset, check */
    head_offset = read_32bitBE(0x10,streamFile);
    if (atlus_shrunken_head)
    {
        /* the HEAD chunk is where we would expect to find the offset of that
         * chunk... */

        if ((uint32_t)head_offset!=0x48454144 || read_32bitBE(0x14,streamFile) != 8)
            goto fail;

        head_offset = -8;   /* most of the normal Nintendo RSTM offsets work
                               with this assumption */
    }
    else
    {
        if ((uint32_t)read_32bitBE(head_offset,streamFile)!=0x48454144) /* "HEAD" */
            goto fail;
    }

    /* check type details */
    codec_number = read_8bit(head_offset+0x20,streamFile);
    loop_flag = read_8bit(head_offset+0x21,streamFile);
    channel_count = read_8bit(head_offset+0x22,streamFile);

    switch (codec_number) {
        case 0:
            coding_type = coding_PCM8;
            break;
        case 1:
            coding_type = coding_PCM16BE;
            break;
        case 2:
            coding_type = coding_NGC_DSP;
            break;
        default:
            goto fail;
    }

    if (channel_count < 1) goto fail;

    /* build the VGMSTREAM */

    vgmstream = allocate_vgmstream(channel_count,loop_flag);
    if (!vgmstream) goto fail;

    /* fill in the vital statistics */
    vgmstream->num_samples = read_32bitBE(head_offset+0x2c,streamFile);
    vgmstream->sample_rate = (uint16_t)read_16bitBE(head_offset+0x24,streamFile);
    /* channels and loop flag are set by allocate_vgmstream */
    vgmstream->loop_start_sample = read_32bitBE(head_offset+0x28,streamFile);
    vgmstream->loop_end_sample = vgmstream->num_samples;

    vgmstream->coding_type = coding_type;
    vgmstream->layout_type = (channel_count == 1) ? layout_none : layout_interleave;
    vgmstream->meta_type = meta_RSTM;
    if (atlus_shrunken_head)
        vgmstream->meta_type = meta_RSTM_shrunken;

    if (spm_flag&& vgmstream->sample_rate == 44100) {
        vgmstream->meta_type = meta_RSTM_SPM;
        vgmstream->sample_rate = 22050;
    }

    vgmstream->interleave_block_size = read_32bitBE(head_offset+0x38,streamFile);
    vgmstream->interleave_last_block_size = read_32bitBE(head_offset+0x48,streamFile);

    if (vgmstream->coding_type == coding_NGC_DSP) {
        off_t coef_offset;
        off_t head_part3_offset;
        off_t adpcm_header_offset;
        int i,j;
        int coef_spacing;

        if (atlus_shrunken_head)
        {
            coef_offset = 0x50;
            coef_spacing = 0x30;

            for (j = 0; j < vgmstream->channels; j++) {
                for (i = 0; i < 16; i++) {
                    vgmstream->ch[j].adpcm_coef[i] = read_16bitBE(head_offset + coef_offset + j * coef_spacing + i * 2,streamFile);
                }
            }
        }
        else
        {
            head_part3_offset = read_32bitBE(head_offset + 0x1c, streamFile);

            for (j = 0; j < vgmstream->channels; j++) {
                adpcm_header_offset = head_offset + 0x08
                    + head_part3_offset + 0x04 /* skip over HEAD part 3 */
                    + j * 0x08 /* skip to channel's ADPCM offset table */
                    + 0x04; /* ADPCM header offset field */

                coef_offset = head_offset + 0x08
                    + read_32bitBE(adpcm_header_offset, streamFile)
                    + 0x08; /* coeffs field */

                for (i = 0; i < 16; i++) {
                    vgmstream->ch[j].adpcm_coef[i] = read_16bitBE(coef_offset + i * 2, streamFile);
                }
            }
        }
    }

    start_offset = read_32bitBE(head_offset+0x30,streamFile);

    /* open the file for reading by each channel */
    {
        int i;
        for (i=0;i<channel_count;i++) {
            vgmstream->ch[i].streamfile = streamFile->open(streamFile,filename,STREAMFILE_DEFAULT_BUFFER_SIZE);

            if (!vgmstream->ch[i].streamfile) goto fail;

            vgmstream->ch[i].channel_start_offset=
                vgmstream->ch[i].offset=
                start_offset + i*vgmstream->interleave_block_size;
        }
    }

    return vgmstream;

    /* clean up anything we may have opened */
fail:
    if (vgmstream) close_vgmstream(vgmstream);
    return NULL;
}