/*
 * CallWeaver -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.callweaver.org for more information about
 * the CallWeaver project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Flat, binary, alaw PCM file format.
 * 
 */
#ifdef HAVE_CONFIG_H
#include "confdefs.h"
#endif
 
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

#include "callweaver.h"

CALLWEAVER_FILE_VERSION("$HeadURL$", "$Revision$")

#include "callweaver/channel.h"
#include "callweaver/file.h"
#include "callweaver/logger.h"
#include "callweaver/sched.h"
#include "callweaver/module.h"

#define BUF_SIZE 160        /* 160 samples */

/* #define REALTIME_WRITE */

struct pvt
{
    FILE *f;                                    /* Descriptor */
#ifdef REALTIME_WRITE
    unsigned long start_time;
#endif
    struct cw_frame fr;                       /* Frame information */
    uint8_t buf[CW_FRIENDLY_OFFSET + BUF_SIZE];                      /* Output Buffer */
};

static struct cw_format format;

static const char desc[] = "Raw aLaw 8kHz PCM audio support";

#if 0
/* Returns time in msec since system boot. */
static unsigned long get_time(void)
{
    struct tms buf;
    clock_t cur;

    cur = times(&buf);
    if (cur < 0)
    {
        cw_log(CW_LOG_WARNING, "Cannot get current time\n");
        return 0;
    }
    return cur * 1000 / sysconf(_SC_CLK_TCK);
}
#endif

static void *pcm_open(FILE *f)
{
    struct pvt *tmp;

    if ((tmp = calloc(1, sizeof(*tmp))))
    {
        tmp->f = f;
        cw_fr_init_ex(&tmp->fr, CW_FRAME_VOICE, CW_FORMAT_ALAW);
        tmp->fr.offset = CW_FRIENDLY_OFFSET;
        tmp->fr.data = &tmp->buf[CW_FRIENDLY_OFFSET];
#ifdef REALTIME_WRITE
        tmp->start_time = get_time();
#endif
        return tmp;
    }

    cw_log(CW_LOG_ERROR, "Out of memory\n");
    return NULL;
}

static void *pcm_rewrite(FILE *f, const char *comment)
{
    struct pvt *tmp;

    if ((tmp = calloc(1, sizeof(*tmp))))
    {
        tmp->f = f;
#ifdef REALTIME_WRITE
        tmp->start_time = get_time();
#endif
        return tmp;
    }

    cw_log(CW_LOG_ERROR, "Out of memory\n");
    return NULL;
}

static void pcm_close(void *data)
{
    struct pvt *pvt = data;

    fclose(pvt->f);
    free(pvt);
}

static struct cw_frame *pcm_read(void *data, int *whennext)
{
    struct pvt *pvt = data;
    int res;

    if ((res = fread(pvt->fr.data, 1, BUF_SIZE, pvt->f)) < 1)
    {
        if (res)
            cw_log(CW_LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
        return NULL;
    }
    pvt->fr.samples = res;
    pvt->fr.datalen = res;
    *whennext = pvt->fr.samples;
    return &pvt->fr;
}

static int pcm_write(void *data, struct cw_frame *f)
{
    struct pvt *pvt = data;
    int res;
#ifdef REALTIME_WRITE
    unsigned long cur_time;
    unsigned long fpos;
    struct stat stat_buf;
#endif

    if (f->frametype != CW_FRAME_VOICE)
    {
        cw_log(CW_LOG_WARNING, "Asked to write non-voice frame!\n");
        return -1;
    }
    if (f->subclass != CW_FORMAT_ALAW)
    {
        cw_log(CW_LOG_WARNING, "Asked to write non-alaw frame (%d)!\n", f->subclass);
        return -1;
    }

#ifdef REALTIME_WRITE
    cur_time = get_time();
    fpos = ( cur_time - pvt->start_time ) * 8;    /* 8 bytes per msec */
    /* Check if we have written to this position yet. If we have, then increment pos by one frame
    *  for some degree of protection against receiving packets in the same clock tick.
    */
    
    fstat(fileno(pvt->f), &stat_buf );
    if (stat_buf.st_size > fpos )
    {
        fpos += f->datalen;    /* Incrementing with the size of this current frame */
    }

    if (stat_buf.st_size < fpos)
    {
        /* fill the gap with 0x55 rather than 0. */
        char buf[512];
        unsigned long cur;
        unsigned long to_write;

        cur = stat_buf.st_size;
        if (fseek(pvt->f, cur, SEEK_SET) < 0)
        {
            cw_log(CW_LOG_WARNING, "Cannot seek in file: %s\n", strerror(errno));
            return -1;
        }
        memset(buf, 0x55, 512);
        while (cur < fpos)
        {
            to_write = fpos - cur;
            if (to_write > 512)
                to_write = 512;
            fwrite(buf, 1, to_write, pvt->f);
            cur += to_write;
        }
    }


    if (fseek(pvt->f, fpos, SEEK_SET) < 0)
    {
        cw_log(CW_LOG_WARNING, "Cannot seek in file: %s\n", strerror(errno));
        return -1;
    }
#endif    /* REALTIME_WRITE */
    
    if ((res = fwrite(f->data, 1, f->datalen, pvt->f)) != f->datalen)
    {
        cw_log(CW_LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
        return -1;
    }
    return 0;
}

static int pcm_seek(void *data, long sample_offset, int whence)
{
    struct pvt *pvt = data;
    off_t offset=0,min,cur,max;

    min = 0;
    cur = ftell(pvt->f);
    fseek(pvt->f, 0, SEEK_END);
    max = ftell(pvt->f);
    if (whence == SEEK_SET)
        offset = sample_offset;
    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
        offset = sample_offset + cur;
    else if (whence == SEEK_END)
        offset = max - sample_offset;
    if (whence != SEEK_FORCECUR)
    {
        offset = (offset > max)  ?  max  :  offset;
    }
    /* Always protect against seeking past begining */
    offset = (offset < min)  ?  min  :  offset;
    return fseek(pvt->f, offset, SEEK_SET);
}

static int pcm_trunc(void *data)
{
    struct pvt *pvt = data;

    return ftruncate(fileno(pvt->f), ftell(pvt->f));
}

static long pcm_tell(void *data)
{
    struct pvt *pvt = data;

    return ftell(pvt->f);
}

static char *pcm_getcomment(void *data)
{
    return NULL;
}

static struct cw_format format =
{
    .name = "alaw",
    .exts = "alaw|al",
    .format = CW_FORMAT_ALAW,
    .open = pcm_open,
    .rewrite = pcm_rewrite,
    .write = pcm_write,
    .seek = pcm_seek,
    .trunc = pcm_trunc,
    .tell = pcm_tell,
    .read = pcm_read,
    .close = pcm_close,
    .getcomment = pcm_getcomment,
};

static int load_module(void)
{
    cw_format_register(&format);
    return 0;
}

static int unload_module(void)
{
    cw_format_unregister(&format);
    return 0;
}

MODULE_INFO(load_module, NULL, unload_module, NULL, desc)