#!/bin/sh
# Package an ltk app built as a cdylib into an APK, with Debian's own tools:
# aapt, zipalign, apksigner and android-framework-res. The app is a
# NativeActivity with no Java code, whose library android-activity loads as
# `libmain.so`. ASSETS_DIR, when given, becomes the APK's `assets/`; the
# `ltk/` tree from android-assets.sh goes there.
#
# Usage: scripts/android-apk.sh OUT.apk LIB.so PACKAGE LABEL [ASSETS_DIR]
#
# Environment, with its defaults:
#   ANDROID_ABI    arm64-v8a
#   MIN_SDK        26
#   TARGET_SDK     34
#   VERSION_CODE   1
#   VERSION_NAME   0.1
#   PERMISSIONS    (none) space-separated, e.g. "android.permission.INTERNET"
#   ICON           (none) the launcher icon, SVG (through rsvg-convert) or PNG
#   KEEP_ALIVE     (none) 1 adds java/'s KeepAlive service, which ltk::keep_running starts
#   KEEP_ALIVE_USE what keeps the app running, which Android asks of the service
#   ANDROID_JAR    /usr/lib/android-sdk/platforms/android-34/android.jar, to compile it against,
#                  and, unless FRAMEWORK_RES is set, the resources aapt links against
#   KEYSTORE       ~/.android/debug.keystore, created when missing
#   KS_PASS        android
#   BUILD_TOOLS    /usr/lib/android-sdk/build-tools/debian
#   FRAMEWORK_RES  /usr/share/android-framework-res/framework-res.apk
set -eu

if [ $# -lt 4 ]
then
	echo "usage: $0 OUT.apk LIB.so PACKAGE LABEL [ASSETS_DIR]" >&2
	exit 2
fi
out=$1
lib=$2
package=$3
label=$( printf '%s' "$4" | sed 's/&/\&amp;/g; s/</\&lt;/g; s/"/\&quot;/g' )
assets=${5:-}

abi=${ANDROID_ABI:-arm64-v8a}
tools=${BUILD_TOOLS:-/usr/lib/android-sdk/build-tools/debian}
framework=${FRAMEWORK_RES:-/usr/share/android-framework-res/framework-res.apk}
keystore=${KEYSTORE:-$HOME/.android/debug.keystore}
pass=${KS_PASS:-android}

for tool in "$tools/aapt" "$tools/apksigner" "$framework"
do
	if [ ! -e "$tool" ]
	then
		echo "android-apk: $tool missing; install aapt, apksigner, zipalign and android-framework-res" >&2
		exit 1
	fi
done

work=$( mktemp -d )
trap 'rm -rf "$work"' EXIT

icon_attr=
res_args=
if [ -n "${ICON:-}" ]
then
	for density in mdpi:48 hdpi:72 xhdpi:96 xxhdpi:144 xxxhdpi:192
	do
		dir=$work/res/mipmap-${density%%:*}
		mkdir -p "$dir"
		case $ICON in
			*.svg)
				command -v rsvg-convert > /dev/null || { echo "android-apk: rsvg-convert missing; install librsvg2-bin" >&2; exit 1; }
				rsvg-convert -w "${density##*:}" -h "${density##*:}" -o "$dir/ic_launcher.png" "$ICON" ;;
			*)
				cp "$ICON" "$dir/ic_launcher.png" ;;
		esac
	done
	icon_attr=' android:icon="@mipmap/ic_launcher"'
	res_args="-S $work/res"
fi

has_code=false
if [ "${KEEP_ALIVE:-}" = 1 ]
then
	android_jar=${ANDROID_JAR:-/usr/lib/android-sdk/platforms/android-34/android.jar}
	java_dir=$( cd "$( dirname "$0" )/.." && pwd )/java
	for tool in javac dx "$android_jar"
	do
		if ! command -v "$tool" > /dev/null && [ ! -e "$tool" ]
		then
			echo "android-apk: $tool missing; install default-jdk-headless, art-standalone and google-android-platform-34-installer" >&2
			exit 1
		fi
	done
	mkdir -p "$work/classes"
	javac -nowarn -source 8 -target 8 -bootclasspath "$android_jar" -d "$work/classes" $( find "$java_dir" -name '*.java' )
	dx --dex --min-sdk-version=26 --output="$work/classes.dex" "$work/classes"
	has_code=true
	# Debian's framework-res lacks the service type `specialUse`, which Android 14 added.
	framework=${FRAMEWORK_RES:-$android_jar}
	PERMISSIONS="${PERMISSIONS:-} android.permission.FOREGROUND_SERVICE android.permission.FOREGROUND_SERVICE_SPECIAL_USE android.permission.POST_NOTIFICATIONS"
fi

{
	echo '<?xml version="1.0" encoding="utf-8"?>'
	echo '<manifest xmlns:android="http://schemas.android.com/apk/res/android"'
	echo "	package=\"$package\""
	echo "	android:versionCode=\"${VERSION_CODE:-1}\""
	echo "	android:versionName=\"${VERSION_NAME:-0.1}\">"
	echo "	<uses-sdk android:minSdkVersion=\"${MIN_SDK:-26}\" android:targetSdkVersion=\"${TARGET_SDK:-34}\"/>"
	echo '	<uses-feature android:glEsVersion="0x00020000" android:required="true"/>'
	for permission in ${PERMISSIONS:-}
	do
		echo "	<uses-permission android:name=\"$permission\"/>"
	done
	echo "	<application android:label=\"$label\"$icon_attr android:hasCode=\"$has_code\""
	# No action bar: hidden under the native window, it would still be taken from the content rect.
	echo '		android:theme="@android:style/Theme.DeviceDefault.NoActionBar">'
	echo '		<activity android:name="android.app.NativeActivity"'
	echo '			android:exported="true"'
	echo '			android:configChanges="orientation|screenSize|screenLayout|smallestScreenSize|keyboard|keyboardHidden|navigation|density|uiMode"'
	echo '			android:windowSoftInputMode="adjustResize">'
	echo '			<meta-data android:name="android.app.lib_name" android:value="main"/>'
	echo '			<intent-filter>'
	echo '				<action android:name="android.intent.action.MAIN"/>'
	echo '				<category android:name="android.intent.category.LAUNCHER"/>'
	echo '			</intent-filter>'
	echo '		</activity>'
	if [ "$has_code" = true ]
	then
		use=$( printf '%s' "${KEEP_ALIVE_USE:-Keeps the app running in the background}" | sed 's/&/\&amp;/g; s/</\&lt;/g; s/"/\&quot;/g' )
		echo '		<service android:name="net.liberux.ltk.KeepAlive" android:exported="false" android:foregroundServiceType="specialUse">'
		echo "			<property android:name=\"android.app.PROPERTY_SPECIAL_USE_FGS_SUBTYPE\" android:value=\"$use\"/>"
		echo '		</service>'
	fi
	echo '	</application>'
	echo '</manifest>'
} > "$work/AndroidManifest.xml"

mkdir -p "$work/lib/$abi"
cp "$lib" "$work/lib/$abi/libmain.so"

if [ -n "$assets" ]
then
	"$tools/aapt" package -f -M "$work/AndroidManifest.xml" -I "$framework" $res_args -A "$assets" -F "$work/unaligned.apk"
else
	"$tools/aapt" package -f -M "$work/AndroidManifest.xml" -I "$framework" $res_args -F "$work/unaligned.apk"
fi
( cd "$work" && "$tools/aapt" add unaligned.apk "lib/$abi/libmain.so" > /dev/null )
if [ "$has_code" = true ]
then
	( cd "$work" && "$tools/aapt" add unaligned.apk classes.dex > /dev/null )
fi
zipalign -f -p 4 "$work/unaligned.apk" "$work/aligned.apk"

if [ ! -f "$keystore" ]
then
	mkdir -p "$( dirname "$keystore" )"
	keytool -genkeypair -keystore "$keystore" -storepass "$pass" -keypass "$pass" \
		-alias androiddebugkey -keyalg RSA -keysize 2048 -validity 10000 \
		-dname "CN=Android Debug,O=Android,C=US"
fi
mkdir -p "$( dirname "$out" )"
"$tools/apksigner" sign --ks "$keystore" --ks-pass "pass:$pass" --out "$out" "$work/aligned.apk"
echo "android-apk: $out"