#!/bin/sh
# Builds one test app's APK. Run from the test project's own directory,
# which is where Dev Updater runs a component's build from.
#
#   ../lib/build-apk.sh --package com.example.dutest.hello --label "Hello" \
#       [--variant debug]
#
# Deliberately not Gradle, which is the obvious way to build an Android app
# and the wrong one here for two reasons. A Gradle daemon is around a
# gigabyte resident, and several test projects each holding one is how this
# machine ran itself out of memory on 2026-08-30 -- the emulators alone are
# already close to the limit. And a Gradle build takes tens of seconds to do
# what this does in about two, which matters because the thing under test is
# Dev Updater, not the app: a fixture you wait for stops getting used.
#
# What it costs is that this is a small build system rather than a
# declaration. It is kept to one file, and the whole of it is: link a
# manifest, compile one class, dex it, add it, align, sign. Nothing here is
# a general Android build and it should not grow into one -- a test project
# needing more than a screen with its own name on it wants a real project.
#
# The signing key lives outside the repository
# ($XDG_DATA_HOME/dev-updater/test-projects/debug.keystore) because the
# repository is a mount shared with the host, and because a stable key is
# what lets a rebuilt APK install *over* the copy already on the emulator
# rather than being refused for a signature mismatch. Deleting it is how you
# produce that refusal on purpose.
set -eu

PACKAGE=
LABEL=
VARIANT=debug
while [ $# -gt 0 ]; do
    case "$1" in
        --package) PACKAGE=$2; shift 2 ;;
        --label) LABEL=$2; shift 2 ;;
        --variant) VARIANT=$2; shift 2 ;;
        *) echo "usage: $0 --package ID --label TEXT [--variant NAME]" >&2; exit 2 ;;
    esac
done
[ -n "$PACKAGE" ] || { echo "$0: --package is required" >&2; exit 2; }
[ -n "$LABEL" ] || { echo "$0: --label is required" >&2; exit 2; }

LIB=$(cd "$(dirname "$0")" && pwd)
PROJECT=$(pwd)
NAME=$(basename "$PROJECT")

# Same cascade as app/build-apk.sh: the host and this VM do not keep the SDK
# in the same place, and the ambient ANDROID_HOME points at one with no
# build-tools under it.
if [ -n "${ANDROID_HOME:-}" ] && [ -d "${ANDROID_HOME}/build-tools" ]; then
    SDK="$ANDROID_HOME"
elif [ -n "${ANDROID_SDK_ROOT:-}" ] && [ -d "${ANDROID_SDK_ROOT}/build-tools" ]; then
    SDK="$ANDROID_SDK_ROOT"
elif [ -d "$HOME/Android/Sdk/build-tools" ]; then
    SDK="$HOME/Android/Sdk"
else
    echo "No Android SDK with build-tools found. Set ANDROID_HOME to one." >&2
    exit 1
fi

# Newest of whatever is installed, rather than a pinned version this script
# would have to be edited to follow.
TOOLS="$SDK/build-tools/$(ls "$SDK/build-tools" | sort -V | tail -n1)"
PLATFORM="$SDK/platforms/$(ls "$SDK/platforms" | sort -V | tail -n1)"
JAR="$PLATFORM/android.jar"
[ -f "$JAR" ] || { echo "No android.jar under $PLATFORM -- install a platform." >&2; exit 1; }

MIN_SDK=24
TARGET_SDK=$(basename "$PLATFORM" | sed 's/^android-//; s/\..*//')

KEYSTORE="${XDG_DATA_HOME:-$HOME/.local/share}/dev-updater/test-projects/debug.keystore"

# Six steps, counted out for the progress bar. Emitted directly rather than
# through $DEV_UPDATER_PROGRESS: that wrapper exists to count Gradle tasks
# for a build that cannot report its own, and this one knows exactly what it
# is doing. The format is the same either way -- see server/src/build_state.rs.
STEPS=6
step() {
    echo "@@progress $1/$STEPS"
    echo "==> $2"
}

BUILD="$PROJECT/app/build"
GEN="$BUILD/gen"
OUT="$BUILD/outputs/apk/$VARIANT"
# `app/` is not decoration. Dev Updater matches APKs at up to two directories
# below a project root, so a test project building straight into
# test-projects/<name>/build/ would also be found from the repository root --
# i.e. offered as a build of Dev Updater itself, and being newest, served as
# the default. One more level puts it out of that reach while keeping it one
# level below the test project, where its own patterns find it.
rm -rf "$GEN"
mkdir -p "$GEN/classes" "$OUT"

step 1 "Writing the manifest for $PACKAGE"
sed -e "s|__PACKAGE__|$PACKAGE|" -e "s|__LABEL__|$LABEL|" \
    "$LIB/AndroidManifest.xml" >"$GEN/AndroidManifest.xml"

step 2 "Linking resources (aapt2)"
"$TOOLS/aapt2" link \
    -I "$JAR" \
    --manifest "$GEN/AndroidManifest.xml" \
    --min-sdk-version "$MIN_SDK" \
    --target-sdk-version "$TARGET_SDK" \
    -o "$GEN/linked.apk"

step 3 "Compiling StubActivity"
javac -nowarn -Xlint:-options --release 17 \
    -classpath "$JAR" -d "$GEN/classes" "$LIB/StubActivity.java"

step 4 "Dexing"
find "$GEN/classes" -name '*.class' -print0 | xargs -0 \
    "$TOOLS/d8" --release --lib "$JAR" --min-api "$MIN_SDK" --output "$GEN"

step 5 "Packaging and aligning"
(cd "$GEN" && jar --update --file linked.apk classes.dex)
"$TOOLS/zipalign" -p -f 4 "$GEN/linked.apk" "$GEN/aligned.apk"

step 6 "Signing"
if [ ! -f "$KEYSTORE" ]; then
    echo "    (generating a signing key at $KEYSTORE)"
    mkdir -p "$(dirname "$KEYSTORE")"
    chmod 700 "$(dirname "$KEYSTORE")"
    keytool -genkeypair -keystore "$KEYSTORE" \
        -storepass android -keypass android -alias test \
        -keyalg RSA -keysize 2048 -validity 10000 \
        -dname "CN=dev-updater test projects" >/dev/null
fi
"$TOOLS/apksigner" sign \
    --ks "$KEYSTORE" --ks-pass pass:android --key-pass pass:android \
    --ks-key-alias test --min-sdk-version "$MIN_SDK" \
    --out "$OUT/$NAME-$VARIANT.apk" "$GEN/aligned.apk"

echo "@@progress $STEPS/$STEPS"
echo "==> Built $OUT/$NAME-$VARIANT.apk"