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

/* Resource Interchange File Format */
/* only the bare minimum needed to read PCM wavs */

VGMSTREAM * init_vgmstream_riff(STREAMFILE *streamFile) {
    VGMSTREAM * vgmstream = NULL;
    char filename[260];

    off_t file_size = -1;
    int channel_count = 0;
    int sample_count = 0;
    int sample_rate = 0;
    int coding_type = -1;
    off_t start_offset = -1;
    int interleave = -1;

    int loop_flag = 0;
    int32_t loop_start = -1;
    int32_t loop_end = -1;
    uint32_t riff_size;
    uint32_t data_size = 0;

    int FormatChunkFound = 0;
    int DataChunkFound = 0;

    /* check extension, case insensitive */
    streamFile->get_name(streamFile,filename,sizeof(filename));
    if (strcasecmp("wav",filename_extension(filename))) goto fail;

    /* check header */
    if ((uint32_t)read_32bitBE(0,streamFile)!=0x52494646) /* "RIFF" */
        goto fail;
    /* check for WAVE form */
    if ((uint32_t)read_32bitBE(8,streamFile)!=0x57415645) /* "WAVE" */
        goto fail;

    riff_size = read_32bitLE(4,streamFile);
    file_size = get_streamfile_size(streamFile);

    /* check for tructated RIFF */
    if (file_size < riff_size+8) goto fail;

    /* read through chunks to verify format and find metadata */
    {
        off_t current_chunk = 0xc; /* start with first chunk */

        while (current_chunk < file_size) {
            uint32_t chunk_type = read_32bitBE(current_chunk,streamFile);
            off_t chunk_size = read_32bitLE(current_chunk+4,streamFile);

            if (current_chunk+8+chunk_size > file_size) goto fail;

            switch(chunk_type) {
                case 0x666d7420:    /* "fmt " */
                    /* only one per file */
                    if (FormatChunkFound) goto fail;
                    FormatChunkFound = 1;

                    sample_rate = read_32bitLE(current_chunk+0x0c,streamFile);
                    channel_count = read_16bitLE(current_chunk+0x0a,streamFile);

                    switch (read_16bitLE(current_chunk+0x8,streamFile)) {
                        case 1: /* PCM */
                            switch (read_16bitLE(current_chunk+0x16,streamFile)) {
                                case 16:
                                    coding_type = coding_PCM16LE;
                                    interleave = 2;
                                    break;
                                case 8:
                                    coding_type = coding_PCM8;
                                    interleave = 1;
                                    break;
                                default:
                                    goto fail;
                            }
                            break;
                        default:
                            goto fail;
                    }
                    break;
                case 0x64617461:    /* data */
                    /* at most one per file */
                    if (DataChunkFound) goto fail;
                    DataChunkFound = 1;

                    start_offset = current_chunk + 8;
                    data_size = chunk_size;
                    break;
                default:
                    /* ignorance is bliss */
                    break;
            }

            current_chunk += 8+chunk_size;
        }
    }

    if (!FormatChunkFound || !DataChunkFound) goto fail;

    switch (coding_type) {
        case coding_PCM16LE:
            sample_count = data_size/2/channel_count;
            break;
        case coding_PCM8:
            sample_count = data_size/channel_count;
            break;
    }

    /* build the VGMSTREAM */

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

    /* fill in the vital statistics */
    vgmstream->num_samples = sample_count;
    vgmstream->sample_rate = sample_rate;

    vgmstream->coding_type = coding_type;
    if (channel_count > 1)
        vgmstream->layout_type = layout_interleave;
    else
        vgmstream->layout_type = layout_none;
    vgmstream->interleave_block_size = interleave;
    vgmstream->loop_start_sample = loop_start;
    vgmstream->loop_end_sample = loop_end;

    vgmstream->meta_type = meta_RIFF_WAVE;

    /* open the file, set up each channel */
    {
        int i;

        vgmstream->ch[0].streamfile = streamFile->open(streamFile,filename,
                STREAMFILE_DEFAULT_BUFFER_SIZE);
        if (!vgmstream->ch[0].streamfile) goto fail;

        for (i=0;i<channel_count;i++) {
            vgmstream->ch[i].streamfile = vgmstream->ch[0].streamfile;
            vgmstream->ch[i].offset = vgmstream->ch[i].channel_start_offset =
                start_offset+i*interleave;
        }
    }

    return vgmstream;

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