/*
  * Apple HTTP Live Streaming Protocol Handler
  * Copyright (c) 2010 Martin Storsjo
  *
  * 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
  * Apple HTTP Live Streaming Protocol Handler
  * http://tools.ietf.org/html/draft-pantos-http-live-streaming
  */
 
 #include "libavutil/avstring.h"
 #include "avformat.h"
 #include "internal.h"

 #include "url.h"

 #include <unistd.h>
 
 /*
  * An apple http stream consists of a playlist with media segment files,
  * played sequentially. There may be several playlists with the same
  * video content, in different bandwidth variants, that are played in
  * parallel (preferrably only one bandwidth variant at a time). In this case,
  * the user supplied the url to a main playlist that only lists the variant
  * playlists.
  *
  * If the main playlist doesn't point at any variants, we still create
  * one anonymous toplevel variant for this, to maintain the structure.
  */
 
 struct segment {
     int duration;
     char url[MAX_URL_SIZE];
 };
 
 struct variant {
     int bandwidth;
     char url[MAX_URL_SIZE];
 };
 
 typedef struct AppleHTTPContext {
     char playlisturl[MAX_URL_SIZE];
     int target_duration;
     int start_seq_no;
     int finished;
     int n_segments;
     struct segment **segments;
     int n_variants;
     struct variant **variants;
     int cur_seq_no;
     URLContext *seg_hd;
     int64_t last_load_time;
 } AppleHTTPContext;
 
 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
 {
     int len = ff_get_line(s, buf, maxlen);
     while (len > 0 && isspace(buf[len - 1]))
         buf[--len] = '\0';
     return len;
 }
 
 static void free_segment_list(AppleHTTPContext *s)
 {
     int i;
     for (i = 0; i < s->n_segments; i++)
         av_free(s->segments[i]);
     av_freep(&s->segments);
     s->n_segments = 0;
 }
 
 static void free_variant_list(AppleHTTPContext *s)
 {
     int i;
     for (i = 0; i < s->n_variants; i++)
         av_free(s->variants[i]);
     av_freep(&s->variants);
     s->n_variants = 0;
 }
 
 struct variant_info {
     char bandwidth[20];
 };
 
 static void handle_variant_args(struct variant_info *info, const char *key,
                                 int key_len, char **dest, int *dest_len)
 {
     if (!strncmp(key, "BANDWIDTH=", key_len)) {
         *dest     =        info->bandwidth;
         *dest_len = sizeof(info->bandwidth);
     }
 }
 
 static int parse_playlist(URLContext *h, const char *url)
 {
     AppleHTTPContext *s = h->priv_data;
     AVIOContext *in;
     int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
     char line[1024];
     const char *ptr;
 

     if ((ret = avio_open(&in, url, AVIO_RDONLY)) < 0)

         return ret;
 
     read_chomp_line(in, line, sizeof(line));
     if (strcmp(line, "#EXTM3U"))
         return AVERROR_INVALIDDATA;
 
     free_segment_list(s);
     s->finished = 0;
     while (!url_feof(in)) {
         read_chomp_line(in, line, sizeof(line));
         if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
             struct variant_info info = {{0}};
             is_variant = 1;
             ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
                                &info);
             bandwidth = atoi(info.bandwidth);
         } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
             s->target_duration = atoi(ptr);
         } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
             s->start_seq_no = atoi(ptr);
         } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
             s->finished = 1;
         } else if (av_strstart(line, "#EXTINF:", &ptr)) {
             is_segment = 1;
             duration = atoi(ptr);
         } else if (av_strstart(line, "#", NULL)) {
             continue;
         } else if (line[0]) {
             if (is_segment) {
                 struct segment *seg = av_malloc(sizeof(struct segment));
                 if (!seg) {
                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
                 seg->duration = duration;

                 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);

                 dynarray_add(&s->segments, &s->n_segments, seg);
                 is_segment = 0;
             } else if (is_variant) {
                 struct variant *var = av_malloc(sizeof(struct variant));
                 if (!var) {
                     ret = AVERROR(ENOMEM);
                     goto fail;
                 }
                 var->bandwidth = bandwidth;

                 ff_make_absolute_url(var->url, sizeof(var->url), url, line);

                 dynarray_add(&s->variants, &s->n_variants, var);
                 is_variant = 0;
             }
         }
     }
     s->last_load_time = av_gettime();
 
 fail:
     avio_close(in);
     return ret;
 }
 
 static int applehttp_open(URLContext *h, const char *uri, int flags)
 {
     AppleHTTPContext *s;
     int ret, i;
     const char *nested_url;
 

     if (flags & (AVIO_WRONLY | AVIO_RDWR))

         return AVERROR(ENOSYS);

 
     s = av_mallocz(sizeof(AppleHTTPContext));
     if (!s)
         return AVERROR(ENOMEM);
     h->priv_data = s;
     h->is_streamed = 1;
 
     if (av_strstart(uri, "applehttp+", &nested_url)) {
         av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
     } else if (av_strstart(uri, "applehttp://", &nested_url)) {
         av_strlcpy(s->playlisturl, "http://", sizeof(s->playlisturl));
         av_strlcat(s->playlisturl, nested_url, sizeof(s->playlisturl));
     } else {
         av_log(NULL, AV_LOG_ERROR, "Unsupported url %s\n", uri);
         ret = AVERROR(EINVAL);
         goto fail;
     }
 
     if ((ret = parse_playlist(h, s->playlisturl)) < 0)
         goto fail;
 
     if (s->n_segments == 0 && s->n_variants > 0) {
         int max_bandwidth = 0, maxvar = -1;
         for (i = 0; i < s->n_variants; i++) {
             if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
                 max_bandwidth = s->variants[i]->bandwidth;
                 maxvar = i;
             }
         }
         av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
                    sizeof(s->playlisturl));
         if ((ret = parse_playlist(h, s->playlisturl)) < 0)
             goto fail;
     }
 
     if (s->n_segments == 0) {
         av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
         ret = AVERROR(EIO);
         goto fail;
     }
     s->cur_seq_no = s->start_seq_no;
     if (!s->finished && s->n_segments >= 3)
         s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
 
     return 0;
 
 fail:
     av_free(s);
     return ret;
 }
 
 static int applehttp_read(URLContext *h, uint8_t *buf, int size)
 {
     AppleHTTPContext *s = h->priv_data;
     const char *url;
     int ret;
 
 start:
     if (s->seg_hd) {

         ret = ffurl_read(s->seg_hd, buf, size);

         if (ret > 0)
             return ret;
     }
     if (s->seg_hd) {

         ffurl_close(s->seg_hd);

         s->seg_hd = NULL;
         s->cur_seq_no++;
     }
 retry:
     if (!s->finished) {
         int64_t now = av_gettime();
         if (now - s->last_load_time >= s->target_duration*1000000)
             if ((ret = parse_playlist(h, s->playlisturl)) < 0)
                 return ret;
     }
     if (s->cur_seq_no < s->start_seq_no) {
         av_log(NULL, AV_LOG_WARNING,
                "skipping %d segments ahead, expired from playlist\n",
                s->start_seq_no - s->cur_seq_no);
         s->cur_seq_no = s->start_seq_no;
     }
     if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
         if (s->finished)
             return AVERROR_EOF;
         while (av_gettime() - s->last_load_time < s->target_duration*1000000) {
             if (url_interrupt_cb())

                 return AVERROR_EXIT;

             usleep(100*1000);
         }
         goto retry;
     }
     url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
     av_log(NULL, AV_LOG_DEBUG, "opening %s\n", url);

     ret = ffurl_open(&s->seg_hd, url, AVIO_RDONLY);

     if (ret < 0) {
         if (url_interrupt_cb())

             return AVERROR_EXIT;

         av_log(NULL, AV_LOG_WARNING, "Unable to open %s\n", url);
         s->cur_seq_no++;
         goto retry;
     }
     goto start;
 }
 
 static int applehttp_close(URLContext *h)
 {
     AppleHTTPContext *s = h->priv_data;
 
     free_segment_list(s);
     free_variant_list(s);

     ffurl_close(s->seg_hd);

     av_free(s);
     return 0;
 }
 
 URLProtocol ff_applehttp_protocol = {

     .name      = "applehttp",
     .url_open  = applehttp_open,
     .url_read  = applehttp_read,
     .url_close = applehttp_close,
     .flags     = URL_PROTOCOL_FLAG_NESTED_SCHEME,

 };