#!/usr/bin/env bash
# ---------------------------------------------------
# Thumbnailer for APK archives files
# Display embedded icon and version number (option)
#
# Procedure :
#   http://bernaerts.dyndns.org/linux/76-gnome/284-gnome-shell-generate-apk-thumbnail-nautilus
# Depends on :
#   * unzip
#   * aapt
#   * pngtopnm, pnmtopng, pnmcrop, pnmpad, pnmscalefixed and pnmcomp (netpbm package)
# Parameters :
#   $1 - path of APK archive
#   $2 - path of generated thumbnail
#   $3 - height of thumbnail in pixels
# Revision history :
#   04/08/2013, V1.0 - Creation by N. Bernaerts
#   11/08/2013, V1.1 - Use aapt to get icon file
#   05/11/2014, V2.0 - Add version display
#   06/11/2014, V2.1 - Don't use renamed aapt anymore
#   15/11/2014, V3.0 - Use URI to handle network shares
#   07/10/2017, V3.1 - Speedup with netpbm tools
#   15/12/2018, V3.2 - Rework for bubblewrap compatibility
# ---------------------------------------------------

# check tools availability
command -v aapt >/dev/null 2>&1 || { echo "[error] aapt missing"; exit 1; }
command -v unzip >/dev/null 2>&1 || { echo "[error] unzip missing"; exit 1; }
command -v pbmtextps >/dev/null 2>&1 || { echo "[error] pbmtextps missing"; exit 1; }
command -v pnmcrop >/dev/null 2>&1 || { echo "[error] pnmcrop missing"; exit 1; }
command -v pnmpad >/dev/null 2>&1 || { echo "[error] pnmpad missing"; exit 1; }
command -v pngtopnm >/dev/null 2>&1 || { echo "[error] pngtopnm missing"; exit 1; }
command -v pnmscalefixed >/dev/null 2>&1 || { echo "[error] pnmscalefixed missing"; exit 1; }
command -v pnmcomp >/dev/null 2>&1 || { echo "[error] pnmcomp missing"; exit 1; }
command -v pnmtopng >/dev/null 2>&1 || { echo "[error] pnmtopng missing"; exit 1; }

# check params
[ "$3" = "" ] && { echo "[error] 3 params are needed : file file-thumb thumb-size"; exit 1; }

# set to no to remove version number on the icon
DISPLAY_VERSION="yes"

# get parameters
FILE_LOCAL="$1"
FILE_THUMB="$2"
SIZE="$3"

# generate temporary local filename
TMP_PNM=$(mktemp -t "thumb-apk-XXXXXXXX.pnm")

# get application icon
ICON=$(aapt d badging "${FILE_LOCAL}" | grep "application-icon" | sed 's/^.*icon-\(.*\):.\(.*\).$/\2/' | tail -1)

# if icon exists, extract icon & generate thumbnail 
if [ "$ICON" != "" ]
then 
	# if needed, add version display options
	if [ "$DISPLAY_VERSION" = "yes" ]
	then
		# get version
		VERSION=$(aapt d badging "${FILE_LOCAL}" | grep "versionName=" | sed 's/^.*versionName=.\([0-9.]*\).*$/\1/')

		# calculate optimum font size
		FONT_SIZE=$((${SIZE} / 10 + 1))

		# generate version image
		pbmtextps -fontsize ${FONT_SIZE} "${VERSION}" | pnmcrop - | pnmpad -white -left 4 -right 4 -top 4 -bottom 4 - | pnmpad -black -left 2 -right 2 -top 2 -bottom 2 - > "${TMP_PNM}"

		# generate icon including version number
		unzip -p "${FILE_LOCAL}" "${ICON}" | pngtopnm - | pnmscalefixed -xysize ${SIZE} ${SIZE} - | pnmcomp -align center -valign bottom "${TMP_PNM}" - | pnmtopng > "${FILE_THUMB}"

	# else, no version needed
	else
		# generate plain icon without version number
		unzip -p "${FILE_LOCAL}" "${ICON}" | pngtopnm - | pnmscalefixed -xysize ${SIZE} ${SIZE} - | pnmtopng -downscale -compression 0 - > "${FILE_THUMB}"
	fi
fi

# remove temporary local file
rm -f "${TMP_PNM}"