#!/usr/bin/env bash
# 006-install-postgres - Install PostgreSQL (Debian 13 -> PG 17).
# Must run after 005: with /var/lib/postgresql already being the dedicated
# disk, the Debian installer creates the cluster directly on it - no
# data_directory changes needed.
# up:   apt install postgresql + contrib, cluster started/enabled
# down: stop + purge packages and /etc/postgresql; data on disk is kept
set -euo pipefail

export DEBIAN_FRONTEND=noninteractive
PGROOT=/var/lib/postgresql

case "${1:-}" in
  up)
    if command -v pg_lsclusters >/dev/null 2>&1 && pg_lsclusters --no-header | grep -q .; then
      echo "    postgres cluster already present - skipping"
      exit 0
    fi
    apt-get update -qq
    apt-get install -y postgresql postgresql-contrib >/dev/null
    chown postgres:postgres "$PGROOT"
    systemctl enable --now postgresql >/dev/null
    pg_isready -q
    pg_lsclusters --no-header | while read -r _ _ _ _ _ datadir _; do
      if findmnt -rn "$datadir" >/dev/null; then
        echo "    cluster data on dedicated disk: $datadir"
      else
        echo "    WARNING: $datadir is NOT on the dedicated disk" >&2
      fi
    done
    pg_lsclusters --no-header
    ;;
  down)
    { pg_lsclusters --no-header 2>/dev/null || true; } | while read -r ver name _; do
      pg_ctlcluster "$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
    echo "    postgres stopped + packages purged (data kept under $PGROOT)"
    ;;
esac