#!/usr/bin/env bash
# 006-install-postgres - PostgreSQL 18 from the official PGDG apt repository
# (https://www.postgresql.org/download/linux/debian/ - "Manual configuration").
# Debian 13's own repo only ships PG 17, hence the PGDG repo.
# Must run after 005: with /var/lib/postgresql already being the dedicated
# disk, the 18/main cluster is created directly on it - no data_directory
# changes needed. (Contrib modules ship in the server package since PG 10.)
# up:   add PGDG repo (GPG key + deb822 sources) + install postgresql-18
# down: stop + purge packages/config + remove PGDG repo; disk data is kept
set -euo pipefail

export DEBIAN_FRONTEND=noninteractive
PGROOT=/var/lib/postgresql
PGVER=18
KEY=/usr/share/postgresql-common/pgdg/apt.postgresql.org.asc
SRC=/etc/apt/sources.list.d/pgdg.sources

case "${1:-}" in
  up)
    if command -v pg_lsclusters >/dev/null 2>&1 \
       && pg_lsclusters --no-header | awk -v v="$PGVER" '$1==v' | grep -q .; then
      echo "    postgres $PGVER cluster already present - skipping"
      exit 0
    fi
    # --- PGDG repository: official "Manual configuration" steps ---
    apt-get update -qq
    apt-get install -y curl ca-certificates postgresql-common >/dev/null
    install -d "$(dirname "$KEY")"
    curl --fail -o "$KEY" https://www.postgresql.org/media/keys/ACCC4CF8.asc
    . /etc/os-release
    cat > "$SRC" <<EOF
Types: deb
URIs: https://apt.postgresql.org/pub/repos/apt
Suites: ${VERSION_CODENAME}-pgdg
Components: main
Signed-By: $KEY
EOF
    apt-get update -qq
    # --- install: package creates 18/main directly on the dedicated disk ---
    apt-get install -y "postgresql-$PGVER" >/dev/null
    chown postgres:postgres "$PGROOT"
    systemctl enable --now postgresql >/dev/null
    pg_isready -q
    datadir=$(pg_lsclusters --no-header | awk -v v="$PGVER" '$1==v {print $6; exit}')
    if [[ $(findmnt -rn -o TARGET -T "$datadir") == "$PGROOT" ]]; then
      echo "    cluster data on dedicated disk: $datadir"
    else
      echo "FATAL: $datadir is NOT on the dedicated disk - aborting" >&2
      exit 1
    fi
    pg_lsclusters --no-header
    ;;
  status)
    command -v pg_lsclusters >/dev/null 2>&1 \
      || { echo "DRIFT postgresql-common not installed"; exit 1; }
    line=$(pg_lsclusters --no-header | awk -v v="$PGVER" '$1==v' | head -1)
    [[ -n $line ]] || { echo "DRIFT no PG $PGVER cluster"; exit 1; }
    read -r _ name _ st _ datadir _ <<<"$line"
    [[ $st == online ]] || { echo "DRIFT cluster $PGVER/$name is '$st'"; exit 1; }
    [[ $(findmnt -rn -o TARGET -T "$datadir") == "$PGROOT" ]] \
      || { echo "DRIFT $datadir not on $PGROOT"; exit 1; }
    [[ -f $SRC ]] || { echo "DRIFT PGDG repo file $SRC missing"; exit 1; }
    echo "OK PG $PGVER/$name online, data on $PGROOT, PGDG repo present"
    ;;
  down)
    { pg_lsclusters --no-header 2>/dev/null || true; } | while read -r ver name _; do
      pg_ctlcluster "$ver" "$name" stop 2>/dev/null || true
    done
    apt-get purge -y 'postgresql*' >/dev/null
    apt-get autoremove --purge -y >/dev/null
    rm -rf /etc/postgresql
    rm -f "$SRC" "$KEY"
    echo "    postgres stopped + packages purged + PGDG repo removed (data kept under $PGROOT)"
    ;;
esac