scripts: Add queue functionality to vidl

When adding new links to vidl, it will now put them in a queue (file)
from which it then begins downloading links one after the other. Only
one downloading instance of vidl will ever be running, but you can still
add more links by invoking it again while it is.

Added one new command line option `-c` to quickly empty the queue and
start over.

Fixes #8.

scripts/.local/bin/vidl

@@ -2,13 +2,6 @@
 # download a file if it does not exist in the archive alread
 # otherwise just re-link it from the archive
 
-DL_FOLDER="${DL_FOLDER:-${XDG_VIDEOS_DIR:-$HOME/videos}}/inbox"
-ARCHIVE_FOLDER="${ARCHIVE_FOLDER:-${XDG_VIDEOS_DIR:-$HOME/videos}}/archive"
-YT_DL_CMD="${YT_DL_CMD:-yt-dlp}"
-yt_default_opts=(-f "best[height\<=1080]" --retries 15 --embed-subs --sub-lang "en,de,es,fr")
-declare -a YT_DL_OPTS=${YT_DL_OPTS:-( "${yt_default_opts[@]}" )}
-YT_DL_TITLE="""${YT_DL_TITLE:-%(channel)s_%(title)s_%(id)s}"""
-
 show_help() {
     printf """
 archive.sh: Hard linking your stuff.
@@ -22,19 +15,24 @@ Point it to a link you want downloaded.
 
 Options:
 
-	-h		Display this help.
+    -h      Display this help.
 
-	-d		Directory to check for existence of file and archive to if needed.
+    -d      Directory to check for existence of file and archive to if needed.
+            If this is passed will not download existing archived files again.
 
-	-f		Directory to download to.
+    -f      Directory to download to.
+
+    -c      Clear existing download queue.
 
     -t      Point to youtube-dl command to use. Can be command or absolute link.
             By default will use \`yt-dlp\` which is a more up to date fork of the 
-            program.
+            youtube-dl program.
 """
 }
 
-while getopts "t:f:d:h" opt; do
+urls=("$@")
+
+while getopts "t:f:d:hc" opt; do
     case "$opt" in
     # v)  verbose=1
     # ;;
@@ -47,6 +45,9 @@ while getopts "t:f:d:h" opt; do
     d)
         ARCHIVE_FOLDER="$OPTARG"
         ;;
+    c)
+        ONLY_DO=clear
+        ;;
     h | \? | *)
         show_help
         exit 0
@@ -55,7 +56,15 @@ while getopts "t:f:d:h" opt; do
 done
 shift $((OPTIND - 1))
 
-_call_archive() {
+get_ytdl_fname() {
+    yt_dl_fname=$("$YT_DL_CMD" --get-filename -o "$YT_DL_TITLE" "$*")
+    if [ -z "$yt_dl_fname" ]; then
+        echo Could not get video filename, error with youtube-dl.
+        exit 1
+    fi
+}
+
+_call_archive() { # 1=new_file, 2=archive_location
     command -v archive >/dev/null 2>&1 || {
         echo "archive command not found."
         exit 1
@@ -64,43 +73,119 @@ _call_archive() {
 }
 
 vid_ext="\(mp4\|avi\|webm\|mkv\|mpe?g\|3gp\|m4a\)"
-_findfile() {
+_findfile() { # 1=directory, 2=file
-    dir="$1"
+    find "$1" -type f -name "$2.*" | sed -ne "/$2\.$vid_ext$/Ip"
-    fname="$2"
-    find "$dir" -type f -name "$fname.*" | sed -ne "/$fname\.$vid_ext$/Ip"
 }
 
-YT_DL_TITLE="%(channel)s_%(title)s_%(id)s"
+_alreadyexists() { # 1=video_regex
-_download() {
+    if [ ! -d "$ARCHIVE_FOLDER" ]; then return 0; fi
+    local found
+    found=$(_findfile "$ARCHIVE_FOLDER" "$1")
+    if [ -n "$found" ]; then
+        return 0
+    else
+        return 1
+    fi
+}
+
+_download_cmd() {
     "$YT_DL_CMD" \
         -o "$DL_FOLDER/$YT_DL_TITLE.%(ext)s" \
         "${YT_DL_OPTS[@]}" \
-        "$url"
+        "$*"
 }
 
-url="$*"
+download() { # 1=url
-dl_fn=$("$YT_DL_CMD" --get-filename -o "$YT_DL_TITLE" "$url")
+    # # download the video to download folder
-video_file_regex="${dl_fn}"
+    if ! _alreadyexists "$yt_dl_fname"; then
+        _download_cmd "$*"
 
-if [ -z "$dl_fn" ]; then
+        # yt-dl never knows the exact filename in advance
-    echo Could not get video filename, error with youtube-dl.
+        file=$(_findfile "$DL_FOLDER" "$yt_dl_fname")
-    exit 1
+        if [ -z "$file" ]; then exit 1; fi
-fi
+        _call_archive "$file" "$ARCHIVE_FOLDER"
+    # only link old file if one exists
+    else
+        archive_file=$(_findfile "$ARCHIVE_FOLDER" "$yt_dl_fname")
+        echo "$archive_file" | while read -r file; do
+            echo "file $file exists, not downloading duplicate"
+            _call_archive "$file" "$DL_FOLDER"
+        done
+    fi
+}
 
-alreadyexists=$(_findfile "$ARCHIVE_FOLDER" "$video_file_regex")
+setup() {
+    DL_FOLDER="${DL_FOLDER:-${XDG_VIDEOS_DIR:-$HOME/videos}}/inbox"
+    ARCHIVE_FOLDER="${ARCHIVE_FOLDER:-${XDG_VIDEOS_DIR:-$HOME/videos}}/archive"
+    YT_DL_CMD="${YT_DL_CMD:-yt-dlp}"
+    yt_default_opts=(-f "best[height\<=1080]" --retries 15 --embed-subs --sub-lang "en,de,es,fr")
+    declare -a YT_DL_OPTS=${YT_DL_OPTS:-( "${yt_default_opts[@]}" )}
+    YT_DL_TITLE="${YT_DL_TITLE:-%(channel)s_%(title)s_%(id)s}" # this title needs to be without extension
 
-# # download the video to download folder
+    queue_file="${XDG_CACHE_HOME:-$HOME/.cache}/vidl_queue"
-if [ "$alreadyexists" = "" ] || [ -z "$alreadyexists" ]; then
+    if [ ! -f "$queue_file" ]; then
-    _download
+        mkdir -p $(dirname "$queue_file")
+        touch "$queue_file"
+    fi
+    lock_dir="${XDG_CACHE_HOME:-$HOME/.cache}/vidl_lock"
+}
 
-    # yt-dl never knows the exact filename in advance
+is_in_queue() { # 1=url
-    file=$(_findfile "$DL_FOLDER" "$video_file_regex")
+    [ -f "$queue_file" ] || return 1
-    if [ -z "$file" ]; then exit 1; fi
+    grep -q "$1" "$queue_file"
-    _call_archive "$file" "$ARCHIVE_FOLDER"
+}
-# only link old file if one exists
+
-else
+add_to_queue() { # 1=url
-    echo "$alreadyexists" | while read -r file; do
+    if is_in_queue "$1"; then return; fi
-        echo "file $file exists, not downloading duplicate"
+    echo "$1" >>"$queue_file"
-        _call_archive "$file" "$DL_FOLDER"
+    echo "added $url to queue."
+}
+
+remove_from_queue() { # 1=url
+    sed -i.bak -e "\|$1|d" "$queue_file"
+}
+
+clear_queue() {
+    rm "$queue_file"
+}
+
+remove_lock() {
+    if ! rmdir $lock_dir; then
+        echo "Failed to remove lock '$lock_dir'. Please remove manually before next run."
+        exit 1
+    fi
+}
+
+is_only_instance() {
+    if mkdir $lock_dir 2>/dev/null; then
+        trap "remove_lock" EXIT
+        return 0
+    else
+        return 1
+    fi
+}
+
+main() {
+    setup
+    if [ "$ONLY_DO" = "clear" ]; then
+        clear_queue
+        exit
+    fi
+
+    for url in $*; do
+        add_to_queue "$url"
     done
-fi
+    if is_only_instance; then
+        echo "Download starting..."
+        while read -r line; do
+            get_ytdl_fname "$line"
+            download "$line"
+            remove_from_queue "$line"
+        done <"$queue_file"
+    else
+        echo "Download already running, only adding to queue."
+    fi
+    echo "Download done..."
+}
+
+main "${urls[@]}"