#!/usr/bin/env bash

# encode - Encode for streaming and schedule cron job
# Usage:  encode
#   Called by cron every minute; process oldest .upload file in ./uploadpage/streams)
# Required: file coreutils(readlink ls head mv tail rm) cron(crontab) date ffmpeg
#   mailer[gitlab.com/pepa65/mailer]

# Check for oldest uploaded file
_=$(readlink -f -- "${BASH_SOURCE:-$0}") repopath=${_%/*}
log=$repopath/process.log dir=$repopath/uploadpage/streams
upload=$(ls -tr "$dir"/*.upload 2>/dev/null |head -1)

# Finished if no uploadpage/streams/*.upload files found
[[ $upload ]] || exit 0

Log(){ # 1:message 2:returncode(empty: no exit) I:file
	echo "$1">>"$log"
	[[ $2 ]] && exit $2 || return 0
}

Mail(){ # 1:kind(0:done, 1:wrong type, 2:encoding error) 2:logline I:repopath,email,name,type,start,finish
	source "$repopath/vars"  # I:umail,user,password,smtp,port
	local sbj msg from="Stream Upload server"
	# If proper email set, use it, otherwise it's the authusername: look up email
	[[ $email = *@* ]] && to=$email || to=${umail[$email]}
	[[ $port ]] || port=587
	sbj[0]="Stream Upload encoding done for ${name##*@}"
	sbj[1]="Stream Upload file wrong type: $type"
	sbj[2]="Stream Upload error encoding"
	msg[0]="Heya,\n\nEncoded video with tag '$name'.\nEncoding started on $start and finished on $finish.\n\nStream Upload server"
	msg[1]="Heya,\n\nThe file '$name' from $start is of type '$type' and could not be used.\n\nStream Upload server\n"
	msg[2]="Heya,\n\nThe file '$name' started encoding on $start but ran into an error on $finish.\n\nStream Upload server\n"
	if [[ $to && $user && $password && $smtp && $port ]]
	then
		mailer -m "$(echo -e "${msg[$1]}")" -t "$to" -s "${sbj[$1]}" -u "$user" -p "$password" -S "$smtp" -P "$port" -f "$from" &&
			Log "== Mail with subject '${sbj[$1]}' sent to $to" ||
			Log "== Mail with subject '${sbj[$1]}' failed to send"
		Log "Start encoding on $start, finished on $finish"
	else
		Log "== Mail with subject '${sbj[$1]}' could not be sent"
		(($1==2)) && Log "Start encoding on $start, error on $finish"
	fi
	Log "$2" $1
}

# Rename upload and check type
file=${upload%.upload} video=$file.mp4 name=${file##*/} key=${name%%.*}
rest=${name#*.} date=${rest:0:15} _=${rest:15} email=${_%@*}
mv "$upload" "$file"

# Strip the '_' if email set
[[ $email ]] && email=${email:1}

type=$(file -bL --mime-type "$file")
[[ ! ${type:0:5} = video ]] && Mail 1 "File $name is of type $type"

# Encode video
start=$(date +'%Y-%m-%d at %H:%M:%S') error=0
## Single pass
#ffmpeg -y -i "$file" -c:v libx264 -x264opts no-scenecut -b:v 6M -force_key_frames 'expr:gte(t,n_forced*2)' -c:a copy -tune zerolatency -f mp4 "$video" ||
# Double pass
set -o pipefail  # to get ffmpeg's returncode
ffmpeg -y -i "$file" -c:v libx264 -x264opts no-scenecut -b:v 6M -maxrate 6M -bufsize 12M -force_key_frames 'expr:gte(t,n_forced*2)' -movflags faststart -c:a copy -tune zerolatency -pass 1 -passlogfile "$file" -f mp4 "$video" 2>&1 |tail -n 20 >"$file.1log" &&
	ffmpeg -y -i "$file" -c:v libx264 -x264opts no-scenecut -b:v 6M -maxrate 6M -bufsize 12M -force_key_frames 'expr:gte(t,n_forced*2)' -movflags faststart -c:a copy -tune zerolatency -pass 2 -passlogfile "$file" -f mp4 "$video" 2>&1 |tail -n 20 >"$file.2log" ||
	error=1

# Remove logfiles
rm "$file"-*
finish=$(date +'%Y-%m-%d at %H:%M:%S')
((error)) && Mail 2 "Error encoding $name"

# Remove tailfiles if no errors
rm -- "$file".?log

# Schedule cron job
m=${date:13:2} m=${m#0} h=${date:11:2} h=${h#0}
D=${date:8:2} D=${D#0} M=${date:5:2} M=${M#0}
crontab -l >/dev/null || echo -e "# m h dom mon dow  command\n" |crontab -
line="$m $h $D $M "'*'"  $repopath/stream '$name'"
echo -e "$(crontab -l)\n$line" |crontab -

Mail 0 "crontab: '$line'"