#!/bin/bash

: <<=cut
=pod

=head1 NAME

vid - Play videos matching strings in descending order of size


=head1 SYNOPSIS

B<vid> [[grep options][string]]...


=head1 DESCRIPTION

B<vid> recursively searches for videos and sort them by size. It then
filters out the names matching all the B<grep> expressions.

There can be multiple B<grep> expressions.

The searching is cached in B<.vidlist> in a parent dir or in the
current dir if no parents contain B<.vidlist>.


=head1 EXAMPLE

Play videos matching B<Documentary> but not B<BBC>:

  vid Documentary -v BBC


=head1 AUTHOR

Copyright (C) 2018-2019 Ole Tange,
http://ole.tange.dk and Free Software Foundation, Inc.


=head1 LICENSE

Copyright (C) 2012 Free Software Foundation, Inc.

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 3 of the License, or
at your option any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.


=head1 DEPENDENCIES

B<vid> uses B<G>, and B<vlc>.


=head1 SEE ALSO

B<G>


=cut

find_find_vidlist() {
    # find_find_vidlist(start_dir)
    # Find the file .vidlist in . .. ../.. ../../.. etc
    # If not found: ./.vidlist
    dir="$1"
    if [ -f "$1"/.vidlist ] ; then
	echo "$1"/.vidlist
	return 0
    else
	if [ "/" == $(readlink -f "$dir") ] ; then
	    echo ./.vidlist
	    return 0
	fi
	find_find_vidlist "../$dir"
	return $?
    fi
}

update_list() {
    # update_list(vidlist_file, full_path_vidlist_dir)
    # Update vidlist
    # Update .vidlist with content from full_path_vidlist_dir
    vidlist="$1"
    full_path_vidlist_dir="$2"
    # Subshell to ignore 'cd'
    (cd "$full_path_vidlist_dir" &&
	 # Find video files, print them with size prepended
	 ionice -c 3 find . -iregex \
		'.*\(webm\|rm\|mkv\|mov\|mpg\|mpeg\|asf\|avi\|wmv\|flv\|mp4\|3gp\)$' \
		-type f -printf '%s\t%p\n' ||
	     # If ionice -c 3 fails, try without
	     find . -iregex \
		  '.*\(webm\|rm\|mkv\|mov\|mpg\|mpeg\|asf\|avi\|wmv\|flv\|mp4\|3gp\)$' \
	      -type f -printf '%s\t%p\n') |
	# Sort by size
	sort -rn |
	# Remove size column
	perl -pe 's/^\S+\t//' > "$vidlist".$$
    # Replace old vidlist with new
    mv "$vidlist".$$ "$vidlist"
}

cat_list() {
    # cat the vidlist for file names in current dir
    vidlist="$(find_find_vidlist .)"
    full_path_vidlist_dir="$(dirname $(readlink -f "$vidlist") )"
    full_path_thisdir="$(readlink -f .)"
    if [ -f "$vidlist" ] ; then
	# find background (>/dev/null to detach from tty)
	update_list "$vidlist" "$full_path_vidlist_dir" >/dev/null &
    else
	# find foreground
	update_list "$vidlist" "$full_path_vidlist_dir"
    fi
    subdir="$(echo "$full_path_thisdir" |
	perl -pe 's|\Q'"$full_path_vidlist_dir"'\E|.|')/"
    # cat "$vidlist" | grep matching this dir + remove dirs
    # echo "$vidlist" "$full_path_thisdir" "$full_path_vidlist_dir" = "$subdir" >&2
    cat "$vidlist" |
	perl -ne 's|^(\./)?\Q'"$subdir"'\E|| and print'
}

stdin() {
    if tty -s ; then
	# STDIN is terminal
	cat_list
    else
	# STDIN redir'ed - read it
	cat
    fi
}

stdout() {
    if [ -t 1 ] ; then
	# STDOUT = terminal
	# start VLC
	parallel --lb -Xj1 vlc
    else
	cat
    fi
}

stdin | G "$@" | stdout

exit $?