#!/bin/bash
# get-photos.sh for Mk2 PhotoFrame, last updated 28 Sept. 2016
# GPIO setup (GPIO27 (hdr. pin 13) is used to pull LED lo when loading)
# Start by clearing any current setting (gpio remains set after the script crashes)
sudo sh -c 'echo "27" > /sys/class/gpio/unexport'
sudo sh -c 'echo "27" > /sys/class/gpio/export'
# Tri-state the pin (set it's direction to 'in') - to pull the pin low, we set it's direction 'low'
sudo sh -c 'echo "in" > /sys/class/gpio/gpio27/direction'
#
# source photos are in root of USB stick, set mount point (only done on launch, so doesn't matter if we get an 'already exists' error)
mkdir -p /usbroot
# copy resize is to /photos/ folder (existing files of same name are overwritten)
# loop forever checking for USB stick insert
while [ true ]; do
	# 1) Wait for a USB stick to be inserted (fdisk lists devices, grep looks for sda1 found = true, so need ! (for not found)
	while ! fdisk -l | grep -q "sda1"; do
	sleep 1
	done
	# OK, usb stick found, lets mount it (read only)
	mount /dev/sda1 /usbroot -o noatime
	# 2) Turn on the Loading LED (pull GPIO 27, pin13 Low
	sudo sh -c 'echo "low" > /sys/class/gpio/gpio27/direction'
	# 3) Make/save thumbnials of all .jpg / .JPG in the /usbroot/ to /photos/?.jpg
	for filename in $(ls -A1 /usbroot/*.jpg); do
	convert $filename -resize '1600x1200' /photos$filename
	done
	# some camera jpg's use upper case (.JPG) file extension
	for filename in $(ls -A1 /usbroot/*.JPG); do
	# use SED to substitute (s) JPG with jpg (/g means 'replace all occurances')
	outname="$(echo $filename | sed 's/JPG/jpg/g')"
	convert $filename -resize '1600x1200' /photos$outname
	done
	# all files copied, unmount the usb drive
	umount /dev/sda1
	# 4) Turn off the Loading LED (set GPIO27, pin13 as input)
	sudo sh -c 'echo "in" > /sys/class/gpio/gpio27/direction'
	# 5) Wait until the USB stick is removed
	while fdisk -l | grep -q "sda1"; do
	sleep 1
	done
	# 6) Loop back
done