#!/usr/bin/env bash
# install.sh [--dry-run]
#
# Installs the deploy pipeline from this checkout: steps 1-3 of "Install
# (once, as the admin)" in README.md. Run it as the admin (a user with
# sudo), from anywhere; it finds the repo from its own path.
#
# Safe to re-run, e.g. to upgrade after merging changes here: it never
# replaces the deploy user's SSH key, the webhook secret or the deploy log,
# and restarts deployd so a new binary takes effect.
#
# --dry-run prints every command instead of running it.
set -euo pipefail

dry=false
case ${1:-} in
  --dry-run) dry=true ;;
  "") ;;
  *) echo "usage: install.sh [--dry-run]" >&2; exit 2 ;;
esac

repo=$(cd "$(dirname "$0")" && pwd)
home=/var/lib/deploy
cd "$repo"

say() { printf '\n== %s\n' "$*"; }
run() { # print and run a command (only print with --dry-run)
  printf '+ %s\n' "$*"
  $dry || "$@"
}
as_deploy() { # run a shell snippet as the deploy user
  printf "+ sudo -iu deploy sh -c '%s'\n" "$1"
  $dry || sudo -iu deploy sh -c "$1"
}
exists() { # does a root-only path exist? In a dry run, never prompt: assume not.
  if $dry; then sudo -n test -e "$1" 2>/dev/null; else sudo test -e "$1"; fi
}

for f in deployd/main.go release/release sites.json systemd/deployd.service sudoers/60-deploy; do
  [[ -f $f ]] || { echo "missing $f: run this from a checkout of bajdev/devops" >&2; exit 1; }
done
command -v go >/dev/null || { echo "go is not installed" >&2; exit 1; }
$dry || sudo -v

say "1. deploy user, log and SSH key"
if getent passwd deploy >/dev/null; then
  echo "user deploy exists"
  run sudo usermod -aG webops deploy
else
  run sudo useradd -r -m -d "$home" -s /bin/bash -G webops deploy
fi
if exists /var/log/deploys.log; then
  echo "/var/log/deploys.log exists, kept"
else
  run sudo install -m 664 -o deploy -g webops /dev/null /var/log/deploys.log
fi
if exists "$home/.ssh/id_ed25519"; then
  echo "deploy SSH key exists, kept"
else
  as_deploy 'mkdir -p -m 700 ~/.ssh && ssh-keygen -q -t ed25519 -N "" -f ~/.ssh/id_ed25519 -C deploy@vps'
fi
as_deploy 'git config --global user.name Deploy && git config --global user.email deploy@monoexp.com'
# Record Gogs' host key now. Logging in only works once the Gogs deploy
# account has the key, so a refusal here is expected on a first install.
as_deploy 'ssh -o StrictHostKeyChecking=accept-new -o BatchMode=yes git@git.monoexp.com true 2>/dev/null || true'

say "2. build, test and install"
build=$(mktemp -d); trap 'rm -rf "$build"' EXIT
(cd deployd && run go test ./... && run env CGO_ENABLED=0 go build -trimpath -o "$build/deployd" .)
run sudo install -o root -g root -m 755 "$build/deployd" /usr/local/bin/deployd
run sudo install -o root -g root -m 755 release/release /usr/local/bin/release
run sudo install -d -o root -g root -m 755 /etc/deployd
run sudo install -o root -g root -m 644 sites.json /etc/deployd/sites.json
run sudo install -o root -g root -m 644 systemd/deployd.service /etc/systemd/system/deployd.service
# sudoers: install under a name sudo ignores (it contains a dot), check it,
# then move it into place, so a bad file can never break sudo.
run sudo install -o root -g root -m 440 sudoers/60-deploy /etc/sudoers.d/60-deploy.new
if $dry; then
  echo "+ sudo visudo -cf /etc/sudoers.d/60-deploy.new && sudo mv /etc/sudoers.d/60-deploy.new /etc/sudoers.d/60-deploy"
elif sudo visudo -cf /etc/sudoers.d/60-deploy.new; then
  sudo mv /etc/sudoers.d/60-deploy.new /etc/sudoers.d/60-deploy
else
  sudo rm -f /etc/sudoers.d/60-deploy.new
  echo "sudoers/60-deploy failed visudo; nothing changed" >&2
  exit 1
fi

say "3. webhook secret and service"
if exists /etc/deployd/secret.env; then
  echo "/etc/deployd/secret.env exists, kept"
else
  # umask 077: the file is created readable by root only, never briefly wider.
  echo "+ openssl rand -hex 32 | sed 's/^/WEBHOOK_SECRET=/' | sudo sh -c 'umask 077 && cat > /etc/deployd/secret.env'"
  $dry || openssl rand -hex 32 | sed 's/^/WEBHOOK_SECRET=/' | sudo sh -c 'umask 077 && cat > /etc/deployd/secret.env'
fi
run sudo systemctl daemon-reload
run sudo systemctl enable deployd
run sudo systemctl restart deployd
if ! $dry; then
  sleep 1
  systemctl is-active --quiet deployd || { echo "deployd is not running; see: journalctl -u deployd" >&2; exit 1; }
  echo "deployd is active"
fi

say "Done. Next, by hand"
cat <<EOF
1. Gogs: create a 'deploy' user, add this key to it, and make it a Write
   collaborator on each repo the pipeline releases:
EOF
if $dry; then echo "   (deploy's public key: $home/.ssh/id_ed25519.pub)"; else sudo cat "$home/.ssh/id_ed25519.pub" | sed 's/^/   /'; fi
cat <<EOF
2. Step 4 of README.md: allow Gogs to call 127.0.0.1 (app.ini), restart gogs.
3. For each site, follow "Moving a site onto the pipeline" in README.md.
   The webhook secret is in /etc/deployd/secret.env:
     sudo cat /etc/deployd/secret.env
EOF