/*
  * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
  * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch <clement.boesch@smartjog.com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * Timecode helpers

  * @see https://en.wikipedia.org/wiki/SMPTE_time_code
  * @see http://www.dropframetimecode.org

  */
 
 #include <stdio.h>
 #include "timecode.h"
 #include "log.h"
 #include "error.h"
 

 int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
 {
     /* only works for NTSC 29.97 and 59.94 */
     int drop_frames = 0;

     int d, m, frames_per_10mins;

     if (fps == 30) {

         drop_frames = 2;

         frames_per_10mins = 17982;
     } else if (fps == 60) {

         drop_frames = 4;

         frames_per_10mins = 35964;
     } else

         return framenum;
 

     d = framenum / frames_per_10mins;
     m = framenum % frames_per_10mins;
 
     return framenum + 9 * drop_frames * d + drop_frames * ((m - drop_frames) / (frames_per_10mins / 10));

 }

 
 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
 {
     unsigned fps = tc->fps;
     int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
     int hh, mm, ss, ff;
 
     framenum += tc->start;
     if (drop)

         framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);

     ff = framenum % fps;
     ss = framenum / fps      % 60;
     mm = framenum / (fps*60) % 60;
     hh = framenum / (fps*3600) % 24;
     return 0         << 31 | // color frame flag (0: unsync mode, 1: sync mode)
            drop      << 30 | // drop  frame flag (0: non drop,    1: drop)
            (ff / 10) << 28 | // tens  of frames
            (ff % 10) << 24 | // units of frames
            0         << 23 | // PC (NTSC) or BGF0 (PAL)
            (ss / 10) << 20 | // tens  of seconds
            (ss % 10) << 16 | // units of seconds
            0         << 15 | // BGF0 (NTSC) or BGF2 (PAL)
            (mm / 10) << 12 | // tens  of minutes
            (mm % 10) <<  8 | // units of minutes
            0         <<  7 | // BGF2 (NTSC) or PC (PAL)
            0         <<  6 | // BGF1
            (hh / 10) <<  4 | // tens  of hours
            (hh % 10);        // units of hours
 }
 
 char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
 {
     int fps = tc->fps;
     int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
     int hh, mm, ss, ff, neg = 0;
 
     framenum += tc->start;
     if (drop)

         framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);

     if (framenum < 0) {
         framenum = -framenum;
         neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
     }
     ff = framenum % fps;
     ss = framenum / fps        % 60;
     mm = framenum / (fps*60)   % 60;
     hh = framenum / (fps*3600);
     if (tc->flags & AV_TIMECODE_FLAG_24HOURSMAX)
         hh = hh % 24;
     snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d",
              neg ? "-" : "",
              hh, mm, ss, drop ? ';' : ':', ff);
     return buf;
 }
 
 static unsigned bcd2uint(uint8_t bcd)
 {
    unsigned low  = bcd & 0xf;
    unsigned high = bcd >> 4;
    if (low > 9 || high > 9)
        return 0;
    return low + 10*high;
 }
 
 char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
 {
     unsigned hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
     unsigned mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
     unsigned ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
     unsigned ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
     unsigned drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if not arbitrary bit
     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
              hh, mm, ss, drop ? ';' : ':', ff);
     return buf;
 }
 
 char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
 {
     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
              tc25bit>>19 & 0x1f,              // 5-bit hours
              tc25bit>>13 & 0x3f,              // 6-bit minutes
              tc25bit>>6  & 0x3f,              // 6-bit seconds
              tc25bit     & 1<<24 ? ';' : ':', // 1-bit drop flag
              tc25bit     & 0x3f);             // 6-bit frames
     return buf;
 }
 

 static int check_fps(int fps)
 {
     int i;
     static const int supported_fps[] = {24, 25, 30, 50, 60};
 
     for (i = 0; i < FF_ARRAY_ELEMS(supported_fps); i++)
         if (fps == supported_fps[i])
             return 0;
     return -1;
 }
 

 static int check_timecode(void *log_ctx, AVTimecode *tc)
 {
     if (tc->fps <= 0) {
         av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate must be specified\n");
         return AVERROR(EINVAL);
     }

     if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps != 30 && tc->fps != 60) {
         av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with 30000/1001 or 60000/1001 FPS\n");

         return AVERROR(EINVAL);
     }

     if (check_fps(tc->fps) < 0) {

         av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate %d/%d not supported\n",
                tc->rate.num, tc->rate.den);

         return AVERROR_PATCHWELCOME;
     }

     return 0;

 }
 
 static int fps_from_frame_rate(AVRational rate)
 {
     if (!rate.den || !rate.num)
         return -1;
     return (rate.num + rate.den/2) / rate.den;
 }
 

 int av_timecode_check_frame_rate(AVRational rate)
 {
     return check_fps(fps_from_frame_rate(rate));
 }
 

 int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
 {
     memset(tc, 0, sizeof(*tc));
     tc->start = frame_start;
     tc->flags = flags;
     tc->rate  = rate;
     tc->fps   = fps_from_frame_rate(rate);
     return check_timecode(log_ctx, tc);
 }
 
 int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
 {
     char c;
     int hh, mm, ss, ff, ret;
 
     if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
         av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
                                       "syntax: hh:mm:ss[:;.]ff\n");
         return AVERROR_INVALIDDATA;
     }
 
     memset(tc, 0, sizeof(*tc));
     tc->flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
     tc->rate  = rate;
     tc->fps   = fps_from_frame_rate(rate);
 
     ret = check_timecode(log_ctx, tc);
     if (ret < 0)
         return ret;
 
     tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
     if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
         int tmins = 60*hh + mm;
         tc->start -= 2 * (tmins - tmins/10);
     }
     return 0;
 }