#!/usr/bin/env bash
###########################################################################
# Made by    : Ewoud Dronkert
# Licence    : GNU GPL v3
# Platform   : Raspberry Pi, Raspbian
# Requires   : bash, curl, convert, avconv
#              for uploading: rsync, remote server with ssh key access
#              for notification: mail, locally configured mail system
# Location   : /usr/local/bin
# Name       : knmi
# Version    : 2.0.0
# Date       : 2017-06-07
# Purpose    : Download new KNMI temperature & wind charts every 10
#              minutes, make daily video of collected images, upload
#              to web server, send notification mail.
# How to use : Start as a system service
#              or from /etc/rc.local as "knmi &"
#              or from the command line as "sudo nohup knmi &"
# Settings   : SRC1 = web location of fresh image file (temperature)
#              SRC2 = web location of fresh image file (wind)
#              SAVE = local directory for saving images and videos
#              SRV = remote server (plus user and directory)
#              ID = SSH key with access to remote server
###########################################################################

SRC1='http://cdn.knmi.nl/knmi/map/page/weer/actueel-weer/temperatuur.png'
SRC2='http://cdn.knmi.nl/knmi/map/page/weer/actueel-weer/windkracht.png'
SAVE='/home/pi/knmi/'                  # Local working directory

SRV='xxxxx@xxxxx.xxxxxx.xx:xxx/xxxx/'  # Where to upload the video
ID='/home/pi/.ssh/id_rsa'              # SSH key

IMG='img-'     # File name prefix for sequentially numbered images
FMT='%03d'     # Three digits 000-999 is enough for 6*24=144 images per day
EXT='.png'     # File name extension of all images
DIM='640x640'  # Convert downloaded images to these dimensions, mp4 compatible

VID1=video-$(basename "$SRC1" "$EXT")-  # File name prefix "video-temperatuur-" for video
VID2=video-$(basename "$SRC2" "$EXT")-  # File name prefix "video-windkracht-" for video

DL1=dl-${NAME1:0:4}-  # File name prefix "dl-temp-" for downloaded images
DL2=dl-${NAME2:0:4}-  # File name prefix "dl-wind-" for downloaded images

PREV=25  # Hour of the day on the previous loop
while true; do

	H=$(date +%-H)  # Hour of the day
	if (( H < PREV )); then

		# It's a new day (or a fresh start of the script)
		YDAY=$(date -dyesterday +%Y%m%d)

		# Delete all image (but not video) files older than yesterday
		#FIRST=$(ls "$SAVE"dl-*"$YDAY"*"$SUF" | head -n1)
		#KEEP=$(basename "$FIRST")
		#find "$SAVE" -maxdepth 1 -type f -name "*$SUF" ! -newer "$FIRST" ! -name "$KEEP" -delete

		# Count number of saved image files from yesterday
		N=$(ls "$SAVE$YDAY"*"$SUF" 2>/dev/null | wc -l)  # Ignore error if none found
		if (( n == 1 )); then

			# Just one image from yesterday, might as well upload it I guess
			SRC=$(ls "$SAVE$YDAY"*"$SUF")
			DST="temperatuur-$YDAY$SUF"
			rsync -qau -e "ssh -i '$ID'" "$SRC" "$SRV$DST"
			mv -f "$SRC" "$SAVE$DST"

		elif (( n > 1 )); then

			# Delete old sequential files
			rm -f "$SAVE$PRE"*"$SUF"

			# Rename yesterday's files sequentially
			i=0
			for f in "$SAVE$YDAY"*"$SUF"; do
				mv -f "$f" "$SAVE$PRE$(printf $FMT $i)$SUF"
				(( ++i ))
			done

			# Make video from sequential files
			VIDNAME="temperatuur-$YDAY.mp4"
			VID="$SAVE$VIDNAME"
			avconv -y -r 4 -i "$SAVE$PRE$FMT$SUF" -an -r 4 -s $DIM -c:v libx264 "$VID" &>/dev/null

			# Process video if it exists
			if [[ -e "$VID" && -f "$VID" && -r "$VID" && -s "$VID" ]]; then

				chmod 644 "$VID"
				chown pi:pi "$VID"

				# Delete just processed files
				rm -f "$SAVE$PRE"*"$SUF"

				# Upload, 3 tries
				for i in {1..3}; do
					rsync -qau -e "ssh -i '$ID'" "$VID" "$SRV$VIDNAME"
				done

				# Send mail notification of new video
				ADMIN="xxxxx@xxxxxxxx.xxx"
				TO="$ADMIN"
				URL="https://xxxxx.xxxx.xxxxxx.xx/xxxx/"
				BODY="Nieuwe temperatuurvideo:
$URL$VIDNAME

Oudere video's staan op $URL

-- 
Dit is een automatisch verstuurde e-mail."
				echo "$BODY" | mail -s "Nieuwe temperatuurvideo" -r "$ADMIN" "$TO"

			fi
		fi
	fi
	PREV=$H

	# New temperature and wind data gets recorded every 10 minutes at :00, :10,
	# etc. The chart usually gets timestamped 8 minutes later at :08, :18, etc.
	# It may take a few minutes for the new chart to get uploaded to the web
	# server, say a couple of minutes. With safety margin (not too soon or it
	# might not be there yet, not too late or creating the video might make us
	# miss it), check for new charts at :13, :23, etc. where :03 takes care of
	# the charts from :50 in the previous hour.

	M=$(date +%-M)                          # Minutes of the hour
	(( M1 = M % 10 ))                       # Minutes modulo 10 for wind
	(( M2 = M % 20 ))                       # Minutes modulo 20 for temperature
	(( S = 5 - M1 ))                        # Time diff to minute :05
	if (( S < 0 )); then (( S += 10 )); fi  # No negative sleep
	sleep ${S}m                             # Sleep S minutes

	# Get KNMI temperature chart
	FILE="$SAVE$(date +%Y%m%d%H%M)$SUF"
	if curl -s "$DATA" > "$FILE"; then
		convert "$FILE" -define png:color-type=2 -gravity center -extent $DIM "$FILE"
		chmod 644 "$FILE"
		chown pi:pi "$FILE"
	fi

done