/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2009 Mohamed Tarek
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <string.h>

#include "codeclib.h"
#include "inttypes.h"
#include "libatrac/atrac3.h"

CODEC_HEADER

static RMContext rmctx  IBSS_ATTR_LARGE_IRAM;
static RMPacket pkt     IBSS_ATTR_LARGE_IRAM;
static ATRAC3Context q  IBSS_ATTR;

static void init_rm(RMContext *rmctx)
{
    /* initialize the RMContext */
    memcpy(rmctx, (void*)(( (intptr_t)ci->id3->id3v2buf + 3 ) &~ 3), sizeof(RMContext));

    /* and atrac3 expects extradata in id3v2buf, so we shall give it that */
    memcpy(ci->id3->id3v2buf, (char*)rmctx->codec_extradata, rmctx->extradata_size*sizeof(char));
}

static int request_packet(int size)
{
    int consumed = 0;
    while (1)
    {
        uint8_t *buffer = ci->request_buffer((size_t *)(&consumed), size);
        if (!consumed)
            break;
        consumed = rm_get_packet(&buffer, &rmctx, &pkt);
        if (consumed < 0 || consumed == size)
            break;
        ci->advance_buffer(size);
    }
    return consumed;
}

/* this is the codec entry point */
enum codec_status codec_main(enum codec_entry_call_reason reason)
{
    /* Nothing to do */
    return CODEC_OK;
    (void)reason;
}

/* this is called for each file to process */
enum codec_status codec_run(void)
{
    int datasize, res, consumed, i, time_offset;
    uint16_t fs,sps,h;
    uint32_t packet_count;
    int spn, packet_header_size, scrambling_unit_size, num_units, elapsed;
    int playback_on = -1;
    size_t resume_offset;
    intptr_t param;
    long action;

    if (codec_init()) {
        DEBUGF("codec init failed\n");
        return CODEC_ERROR;
    }

    action = CODEC_ACTION_NULL;
    elapsed = ci->id3->elapsed;
    resume_offset = ci->id3->offset;

    codec_set_replaygain(ci->id3);
    ci->memset(&rmctx,0,sizeof(RMContext));
    ci->memset(&pkt,0,sizeof(RMPacket));
    ci->memset(&q,0,sizeof(ATRAC3Context));

    ci->seek_buffer(0);
    init_rm(&rmctx);
 
    ci->configure(DSP_SET_FREQUENCY, ci->id3->frequency);
    ci->configure(DSP_SET_SAMPLE_DEPTH, 17); /* Remark: atrac3 uses s15.0 by default, s15.2 was hacked. */
    ci->configure(DSP_SET_STEREO_MODE, rmctx.nb_channels == 1 ?
        STEREO_MONO : STEREO_NONINTERLEAVED);

    packet_header_size = PACKET_HEADER_SIZE +
      ((rmctx.flags & RM_PKT_V1) ? 1 : 0);
    packet_count = rmctx.nb_packets;
    rmctx.audio_framesize = rmctx.block_align;
    rmctx.block_align = rmctx.sub_packet_size;
    fs = rmctx.audio_framesize;
    sps= rmctx.block_align;
    h = rmctx.sub_packet_h;
    scrambling_unit_size = h * (fs + packet_header_size);
    spn = h * fs / sps;

    res = atrac3_decode_init(&q, ci->id3);
    if(res < 0) {
        DEBUGF("failed to initialize RM atrac decoder\n");
        return CODEC_ERROR;
    }
    
    /* check for a mid-track resume and force a seek time accordingly */
    if(resume_offset) {
        resume_offset -= MIN(resume_offset, rmctx.data_offset + DATA_HEADER_SIZE);
        num_units = (int)resume_offset / scrambling_unit_size;
        /* put number of packets to skip in resume_offset */
        resume_offset = num_units * h;
        elapsed = (int)resume_offset * ((8000LL * fs)/rmctx.bit_rate);
    }

    if (elapsed > 0) {
        param = elapsed;
        action = CODEC_ACTION_SEEK_TIME;
    }
    else {
        elapsed = 0;
        ci->set_elapsed(0);
    }

    ci->advance_buffer(rmctx.data_offset + DATA_HEADER_SIZE);

    /* The main decoder loop */  
seek_start :         
    while((unsigned)elapsed < rmctx.duration)
    {  
        consumed = request_packet(scrambling_unit_size);
        if (!consumed)
            break;
        if(consumed < 0 && playback_on != 0) {
            if(playback_on == -1) {
            /* Error only if packet-parsing failed and playback hadn't started */
                DEBUGF("rm_get_packet failed\n");
                return CODEC_ERROR;
            }
            else
                return CODEC_OK;
        }

        for (i = 0; i < spn; i++)
        { 
            if (action == CODEC_ACTION_NULL)
                action = ci->get_command(&param);

            if (action == CODEC_ACTION_HALT)
                return CODEC_OK;

            if (action == CODEC_ACTION_SEEK_TIME) {
                /* Do not allow seeking beyond the file's length */
                if ((unsigned) param > ci->id3->length) {
                    ci->set_elapsed(ci->id3->length);
                    ci->seek_complete();
                    return CODEC_OK;
                }       

                ci->seek_buffer(rmctx.data_offset + DATA_HEADER_SIZE);
                packet_count = rmctx.nb_packets;
                rmctx.audio_pkt_cnt = 0;
                rmctx.frame_number = 0;

                /* Seek to the start of the track */
                if (param == 0) {
                    elapsed = 0;
                    ci->set_elapsed(0);
                    ci->seek_complete();
                    action = CODEC_ACTION_NULL;
                    goto seek_start;           
                }                                                                
                num_units = (param/(sps*1000*8/rmctx.bit_rate))/spn;
                ci->seek_buffer(rmctx.data_offset + DATA_HEADER_SIZE + scrambling_unit_size * num_units);
                consumed = request_packet(scrambling_unit_size);
                if (!consumed)
                    return CODEC_OK;
                if(consumed < 0 && playback_on != 0) {
                    if(playback_on == -1) {
                    /* Error only if packet-parsing failed and playback hadn't started */
                        DEBUGF("rm_get_packet failed\n");
                        return CODEC_ERROR;
                    }
                    else
                        return CODEC_OK;
                }

                packet_count = rmctx.nb_packets - h * num_units;
                rmctx.frame_number = (param/(sps*1000*8/rmctx.bit_rate)); 
                while (rmctx.audiotimestamp > (unsigned)param && num_units-- > 0) {
                    rmctx.audio_pkt_cnt = 0;
                    ci->seek_buffer(rmctx.data_offset + DATA_HEADER_SIZE + scrambling_unit_size * num_units);
                    consumed = request_packet(scrambling_unit_size);
                    if (!consumed)
                        return CODEC_OK;
                    if(consumed < 0 && playback_on != 0) {
                        if(playback_on == -1) {
                        /* Error only if packet-parsing failed and playback hadn't started */
                            DEBUGF("rm_get_packet failed\n");
                            return CODEC_ERROR;
                        }
                        else
                            return CODEC_OK;
                    }

                    packet_count += h;
                }

                if (num_units < 0)
                    rmctx.audiotimestamp = 0;
                time_offset = param - rmctx.audiotimestamp;
                i = (time_offset/((sps * 8 * 1000)/rmctx.bit_rate));
                elapsed = param;
                ci->set_elapsed(elapsed);
                ci->seek_complete(); 
            }

            action = CODEC_ACTION_NULL;

            if(pkt.length)    
                res = atrac3_decode_frame(sps, &q, &datasize, pkt.frames[i], sps);
            else /* indicates that there are no remaining frames */
                return CODEC_OK;

            if (res != sps) {
                DEBUGF("codec error\n");
                return CODEC_ERROR;
            }

            if(datasize)
                ci->pcmbuf_insert(q.outSamples, q.outSamples + 1024, q.samples_per_frame / rmctx.nb_channels);
            playback_on = 1;
            elapsed = rmctx.audiotimestamp+(1000*8*sps/rmctx.bit_rate)*i;
            ci->set_elapsed(elapsed);
            rmctx.frame_number++;
        }
        packet_count -= h;
        rmctx.audio_pkt_cnt = 0;
        ci->advance_buffer(scrambling_unit_size);
    }

    return CODEC_OK;
}