#!/usr/bin/env bash
# Releases Halkyon Learn. It works out the next version from the commits since the
# last release, writes it into the app's pubspec in a signed commit with a signed tag,
# builds the Android APK (one for every phone, signed with the app's key) and the
# Linux snap, both connecting to learn.halkyon.eu, the project's instance, checks
# them, signs a list of their checksums with GPG, pushes, and publishes on every
# channel: a release on code.halkyon.app (APK, snap, checksums), the APK in the
# F-Droid repository at halkyon.app (tool/fdroid_repo.sh), and, once switched on
# below, the snap in the Snap Store. Run on a developer's laptop, never in CI: the
# app's key never leaves it.
#
#   tool/release.sh          the version the commits call for
#   tool/release.sh minor    or major, or patch: that one instead
#
# Versions follow semantic versioning, <major>.<minor>.<patch>, and a build number
# (+N) that rises by one with every release: Android installs only a higher one over
# an older, and the server tells apps below the build it supports to update. Since
# the last release, a commit typed feat raises the minor number, fix or perf the
# patch number, and a breaking one (feat!: or a BREAKING CHANGE: line) the major
# number from 1.0 on, the minor one before. Other commits (docs, test, chore, ...)
# release nothing by themselves. The first release is the version the pubspec holds.
# Raising minimumAppBuild in the server, for changes older apps can't follow, stays a
# decision of its own.
#
# The script shows the version and its commits and asks before it changes anything.
# It needs main clean and as pushed, CI green on its newest commit, and asks for the
# app key's password, the F-Droid repository key's password and a Forgejo token
# (scope write:repository) first; then it runs on its own until GPG asks for its
# passphrase (and ssh for the upload key's, unless an agent holds them). None of
# them is ever written down. Nothing is pushed or published before both builds have
# passed their checks; a run that stopped after making the release commit and tag
# carries on with them when started again.
#
# The app's key is a PKCS #12 keystore at $HALKYON_ANDROID_KEYSTORE (default below),
# alias $HALKYON_ANDROID_KEY_ALIAS. Its certificate's SHA-256 is committed in
# tool/release/android-certificate.sha256, and nothing signed otherwise is released.
set -euo pipefail
cd "$(git rev-parse --show-toplevel)"

readonly server_url='https://learn.halkyon.eu/'
readonly forgejo='https://code.halkyon.app'
readonly repository='project-halkyon/halkyon_learn'
readonly pubspec='halkyon_learn_flutter/pubspec.yaml'
readonly certificate_file='tool/release/android-certificate.sha256'
readonly fdroid_certificate_file='tool/release/fdroid-index-certificate.sha256'
# The Snap Store channel the snap goes to, e.g. edge; empty: not to the Store yet,
# only attached to the release on code.halkyon.app.
readonly snap_store_channel=''
keystore="${HALKYON_ANDROID_KEYSTORE:-$HOME/.local/share/halkyon-learn/android-release.p12}"
readonly key_alias="${HALKYON_ANDROID_KEY_ALIAS:-halkyon-learn}"

fail() {
  echo "✗ $*" >&2
  exit 1
}
step() { echo "▸ $*"; }

[ $# -le 1 ] || fail 'Usage: tool/release.sh [major | minor | patch]'
chosen="${1:-}"
case "$chosen" in
  '' | major | minor | patch) ;;
  *) fail "$chosen is none of major, minor, patch." ;;
esac

step 'Checking the repository'
[ -z "$(git status --porcelain)" ] || fail 'The working tree has changes.'
[ "$(git symbolic-ref --quiet --short HEAD)" = main ] || fail 'Not on main.'
git fetch --quiet origin main
declared=$(sed -n 's/^version: *//p' "$pubspec")
current="${declared%%+*}"
current_build="${declared#*+}"
[[ "$current" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ && "$current_build" =~ ^[0-9]+$ ]] ||
  fail "$pubspec's version isn't <major>.<minor>.<patch>+<build>: $declared"

# A run that stopped after its release commit and tag: HEAD is that tag, as pushed
# or one commit ahead of origin/main.
resumed=$(git describe --exact-match --tags --match 'v[0-9]*' HEAD 2>/dev/null || true)
if [ -n "$resumed" ]; then
  git merge-base --is-ancestor origin/main HEAD ||
    fail 'main and origin/main have gone apart.'
  [ "$(git rev-list --count origin/main..HEAD)" -le 1 ] ||
    fail "main is more than the release commit ahead of origin/main."
  [ -z "$chosen" ] || fail "HEAD is $resumed already; carrying on with it takes no argument."
  [ "$resumed" = "v$current" ] || fail "HEAD is $resumed, but $pubspec says $current."
  readonly tag="$resumed" version="$current" build="$current_build"
  previous=$(git describe --tags --abbrev=0 --match 'v[0-9]*' "$tag^" 2>/dev/null || true)
  echo "  Carrying on with $tag (build $build)."
else
  [ "$(git rev-parse HEAD)" = "$(git rev-parse origin/main)" ] ||
    fail 'main differs from origin/main: pull or push first.'
  previous=$(git describe --tags --abbrev=0 --match 'v[0-9]*' 2>/dev/null || true)
  if [ -z "$previous" ]; then
    # The first release: the version the pubspec holds.
    [ -z "$chosen" ] || fail 'The first release is the version the pubspec holds.'
    version="$current"
    build="$current_build"
    kind='the first release'
  else
    [ "$previous" = "v$current" ] ||
      fail "$pubspec says $current, but the last release is $previous."
    subjects=$(git log --format='%s' "$previous..HEAD")
    bodies=$(git log --format='%B' "$previous..HEAD")
    typed='^[a-z]+(\([^)]*\))?'
    if [ -n "$chosen" ]; then
      bump="$chosen"
    elif grep -qE "$typed!:" <<<"$subjects" || grep -q '^BREAKING CHANGE:' <<<"$bodies"; then
      bump='breaking'
    elif grep -qE '^feat(\([^)]*\))?:' <<<"$subjects"; then
      bump='minor'
    elif grep -qE '^(fix|perf)(\([^)]*\))?:' <<<"$subjects"; then
      bump='patch'
    else
      echo "Nothing to release: no feat, fix or perf commit since $previous."
      exit 0
    fi
    IFS=. read -r major minor patch <<<"$current"
    if [ "$bump" = breaking ]; then
      # Before 1.0, a breaking change raises the minor number.
      if [ "$major" -ge 1 ]; then bump='major'; else bump='minor'; fi
    fi
    case "$bump" in
      major) version="$((major + 1)).0.0" ;;
      minor) version="$major.$((minor + 1)).0" ;;
      patch) version="$major.$minor.$((patch + 1))" ;;
    esac
    build=$((current_build + 1))
    kind="a $bump release"
  fi
  readonly tag="v$version" version build
  git rev-parse --quiet --verify "refs/tags/$tag" >/dev/null &&
    fail "The tag $tag exists already."

  echo "  Release $tag (build $build), $kind${previous:+, since $previous}."
  if [ -n "$previous" ]; then
    git log --format='    %s' "$previous..HEAD" | grep -E '^    [a-z]+(\([^)]*\))?!?:' |
      grep -vE '^    chore\(release\):' || true
  fi
  read -rp 'Go on? [y/N] ' answer
  [ "$answer" = y ] || [ "$answer" = Y ] || fail 'Stopped; nothing changed.'
fi

pinned=$(sed -n 's/^ *FLUTTER_VERSION: *//p' .forgejo/workflows/ci.yaml)
running=$(flutter --version --machine | sed -n 's/^ *"frameworkVersion": *"\([^"]*\)".*/\1/p')
[ "$running" = "$pinned" ] || fail "Flutter is $running here, CI pins $pinned."

step 'Checking the tools'
for tool in snapcraft unsquashfs gpg curl jq sha256sum unzip; do
  command -v "$tool" >/dev/null || fail "$tool is missing."
done
sdk="${ANDROID_HOME:-${ANDROID_SDK_ROOT:-$HOME/Android/Sdk}}"
build_tools=$(find "$sdk/build-tools" -mindepth 1 -maxdepth 1 -type d 2>/dev/null | sort -V | tail -n 1)
[ -n "$build_tools" ] || fail "No Android build tools in $sdk (ANDROID_HOME)."
readonly apksigner="$build_tools/apksigner" aapt2="$build_tools/aapt2"
# keytool, and the java apksigner runs on, come with a JDK: the one on the PATH, else
# the one Android Studio brings.
jdk_bin=$(dirname "$(command -v java || echo /snap/android-studio/current/jbr/bin/java)")
[ -x "$jdk_bin/java" ] && [ -x "$jdk_bin/keytool" ] || fail 'No JDK found (java, keytool).'
export PATH="$jdk_bin:$PATH"
readonly keytool="$jdk_bin/keytool"
if [ -n "$snap_store_channel" ]; then
  account=$(snapcraft whoami 2>/dev/null | sed -n 's/^username: *//p' || true)
  [ -n "$account" ] || fail 'Not logged in to the Snap Store: snapcraft login'
fi

[ -f "$certificate_file" ] || fail "$certificate_file is missing."
certificate=$(grep -v '^#' "$certificate_file" | tr -d ' :\n' | tr 'A-F' 'a-f' || true)
readonly certificate
[[ "$certificate" =~ ^[0-9a-f]{64}$ ]] || fail "$certificate_file holds no SHA-256."
[ -f "$keystore" ] || fail "No keystore at $keystore (HALKYON_ANDROID_KEYSTORE)."
keystore=$(realpath "$keystore")
readonly keystore

step 'Asking for the secrets'
read -rsp "Password of $keystore: " password
echo
key_certificate=$(HALKYON_ANDROID_KEYSTORE_PASSWORD="$password" "$keytool" -list -v \
  -keystore "$keystore" -alias "$key_alias" \
  -storepass:env HALKYON_ANDROID_KEYSTORE_PASSWORD 2>/dev/null |
  sed -n 's/^.*SHA256: *//p' | head -n 1 | tr -d ':' | tr 'A-F' 'a-f' || true)
[ -n "$key_certificate" ] || fail "Wrong password, or no key $key_alias in $keystore."
[ "$key_certificate" = "$certificate" ] ||
  fail "The key $key_alias in $keystore isn't the one in $certificate_file."

read -rsp "Password of the F-Droid repository's key: " HALKYON_FDROID_KEYSTORE_PASSWORD
echo
export HALKYON_FDROID_KEYSTORE_PASSWORD
tool/fdroid_repo.sh --check
fdroid_fingerprint=$(grep -v '^#' "$fdroid_certificate_file" | tr -d ' :\n' | tr 'a-f' 'A-F')
readonly fdroid_fingerprint

read -rsp "Forgejo token for $forgejo (write:repository): " token
echo
# The token goes to curl in a configuration read from a file descriptor, so it never
# shows in the list of processes as an argument would.
forgejo_api() {
  curl --fail-with-body --silent --show-error \
    --config <(printf 'header = "Authorization: token %s"\n' "$token") "$@"
}
# The token's scope, write:repository, covers the repository, not the account.
forgejo_api --output /dev/null "$forgejo/api/v1/repos/$repository" ||
  fail "$forgejo doesn't take the token for $repository."
[ "$(forgejo_api --output /dev/null --write-out '%{http_code}' \
  "$forgejo/api/v1/repos/$repository/releases/tags/$tag" 2>/dev/null || true)" = 404 ] ||
  fail "A release of $tag exists already on $forgejo. If only publishing it in the" \
    "F-Droid repository failed: tool/fdroid_repo.sh build/release/$tag/halkyon-learn-$version.apk"
# CI checked the newest commit with code in it: release commits change only the
# version.
checked=$(git log -1 --format=%H --invert-grep --grep='^chore(release):' origin/main)
ci=$(forgejo_api "$forgejo/api/v1/repos/$repository/commits/$checked/status" |
  jq -r .state)
[ "$ci" = success ] || fail "CI isn't green on ${checked:0:7} ($ci)."

if [ -z "$resumed" ]; then
  if [ -n "$previous" ]; then
    step "Writing $version+$build into the pubspec"
    sed -i "s/^version: .*/version: $version+$build/" "$pubspec"
    git commit --quiet -S -m "chore(release): $tag" -m "Build $build." -- "$pubspec"
  fi
  git tag -s "$tag" -m "Halkyon Learn $version"
fi
# Signed by a key deploys accept too: the primary key's fingerprint ends GnuPG's
# VALIDSIG line, as %GP gives it for the commits deploy/redeploy.sh checks.
validsig=$(git verify-tag --raw "$tag" 2>&1 | grep '^\[GNUPG:\] VALIDSIG ' || true)
readonly signer="${validsig##* }"
if [ -z "$validsig" ] || ! grep -qx "$signer" deploy/allowed-signers; then
  fail "$tag isn't signed by a key in deploy/allowed-signers."
fi

readonly out="build/release/$tag"
readonly source="$out/source"
readonly apk="halkyon-learn-$version.apk"
readonly snap="halkyon-learn_${version}_amd64.snap"
rm -rf "$out"
git worktree prune
mkdir -p "$out"
cleanup() { git worktree remove --force "$source" 2>/dev/null || true; }
trap cleanup EXIT

# The APK is built from a checkout of the tag, so nothing in the working tree (build
# caches, files git ignores) can get into it.
step "Building the APK from $tag"
git worktree add --quiet --detach "$source" "$tag"
(
  cd "$source/halkyon_learn_flutter"
  flutter pub get --enforce-lockfile
  HALKYON_ANDROID_KEYSTORE="$keystore" \
    HALKYON_ANDROID_KEY_ALIAS="$key_alias" \
    HALKYON_ANDROID_KEYSTORE_PASSWORD="$password" \
    flutter build apk --release --dart-define=SERVER_URL="$server_url"
  # The Gradle daemon would otherwise live on with the password in its environment.
  (cd android && ./gradlew --stop >/dev/null) || true
)
cp "$source/halkyon_learn_flutter/build/app/outputs/flutter-apk/app-release.apk" "$out/$apk"
unset password

step 'Checking the APK'
signers=$("$apksigner" verify --print-certs "$out/$apk" |
  sed -n 's/^Signer #[0-9]* certificate SHA-256 digest: //p' || true)
[ "$signers" = "$certificate" ] ||
  fail "The APK isn't signed by the app's key alone, but by: $signers"
badging=$("$aapt2" dump badging "$out/$apk")
grep -q "^package: name='app.halkyon.learn' versionCode='$build' versionName='$version'" \
  <<<"$badging" || fail "The APK isn't app.halkyon.learn $version, build $build."
! grep -q '^application-debuggable' <<<"$badging" || fail 'The APK is debuggable.'
# grep's count is kept, not sent to /dev/null: there grep stops at the first match, which
# ends unzip with SIGPIPE, and pipefail counts that as a failure.
named=$(unzip -p "$out/$apk" lib/arm64-v8a/libapp.so | grep -caF "$server_url" || true)
[ "${named:-0}" -gt 0 ] || fail "The APK doesn't name $server_url."

# The snap builds the repository's committed HEAD, which is the tag. Its app part is
# cleaned so that it is built anew from this commit; the Flutter part stays.
step "Building the snap from $tag (in LXD)"
snapcraft clean halkyon-learn
snapcraft pack --output "$out"
[ -f "$out/$snap" ] || fail "snapcraft made no $snap."
snap_yaml=$(unsquashfs -cat "$out/$snap" meta/snap.yaml)
grep -qx "version: '\{0,1\}$version'\{0,1\}" <<<"$snap_yaml" ||
  fail "The snap isn't version $version."

step 'Signing the checksums'
(cd "$out" && sha256sum "$apk" "$snap" >SHA256SUMS)
gpg --local-user "$signer" --armor --detach-sign --output "$out/SHA256SUMS.asc" \
  "$out/SHA256SUMS"

step "Pushing $tag"
# The release commit goes through the pre-push check like any other; the tag, on the
# same commit, then needs none.
if ! git merge-base --is-ancestor HEAD origin/main; then
  git push origin main
fi
git push --no-verify origin "$tag"

step "Publishing the release on $forgejo"
# What it brings: the commits since the last release, by their type.
changes() {
  [ -n "$previous" ] || return 0
  git log --reverse --format='%s' "$previous..$tag" |
    sed -nE "s/^($1)(\([^)]*\))?!?: (.*)/- \3/p"
}
features=$(changes feat)
fixes=$(changes 'fix|perf')
if [ -z "$previous" ]; then
  summary='The first release.'
elif [ -z "$features$fixes" ]; then
  summary="No features or fixes since $previous."
else
  summary="${features:+### Features

$features

}${fixes:+### Fixes

$fixes}"
fi
if [ -n "$snap_store_channel" ]; then
  linux="\`$snap\`, also in the Snap Store: \`snap install halkyon-learn --$snap_store_channel\`."
else
  linux="\`$snap\`: \`sudo snap install --dangerous $snap\` (not in the Snap Store yet)."
fi
notes="Halkyon Learn $version for Android and Linux. Both connect to learn.halkyon.eu, \
the project's instance.

$summary

### Installing

- **Android:** \`$apk\`, one APK for every phone, signed with the app's key; the \
SHA-256 of its certificate is \`$certificate\`.
- **F-Droid:** the same APK in the repository \
https://halkyon.app/fdroid/repo?fingerprint=$fdroid_fingerprint
- **Linux:** $linux

\`SHA256SUMS\` lists the files' checksums, signed with the GPG key \`$signer\` \
(\`SHA256SUMS.asc\`)."
release=$(jq -n --arg tag "$tag" --arg name "Halkyon Learn $version" --arg body "$notes" \
  '{tag_name: $tag, name: $name, body: $body}' |
  forgejo_api --header 'Content-Type: application/json' --data @- \
    "$forgejo/api/v1/repos/$repository/releases" | jq -r .id)
for file in "$apk" "$snap" SHA256SUMS SHA256SUMS.asc; do
  forgejo_api --output /dev/null --form "attachment=@$out/$file" \
    "$forgejo/api/v1/repos/$repository/releases/$release/assets?name=$file"
done
echo "  $forgejo/$repository/releases/tag/$tag"

step 'Publishing the APK in the F-Droid repository'
tool/fdroid_repo.sh "$out/$apk"
unset HALKYON_FDROID_KEYSTORE_PASSWORD

# Last, as the Store may hold a revision for review; the releases above stand either way.
if [ -n "$snap_store_channel" ]; then
  step "Uploading the snap to the Snap Store's $snap_store_channel channel (as $account)"
  snapcraft upload --release="$snap_store_channel" "$out/$snap" ||
    fail "The upload failed; once fixed: snapcraft upload --release=$snap_store_channel $out/$snap"
fi

echo "✓ Released $tag."