#!/bin/bash
# Ensures a local PostgreSQL server is available for the live integration
# tests. Idempotent and safe to re-run.
#
# Layout (matches the goal plan):
#   data dir:   /tmp/pgdata
#   socket dir: /tmp/pgrun
#   port:       5433
#   test role:  postgres (the initdb superuser)
#   test db:    sqltest  (created if missing)
#
# Must run as root (uses `su postgres`); if not root we try without su
# so the script still works in environments where we already are the
# postgres user or own the server.

set -u

PGBIN="${PGBIN:-/usr/bin}"
PGDATA="${PGDATA:-/tmp/pgdata}"
PGSOCK="${PGSOCK:-/tmp/pgrun}"
PGPORT="${PGPORT:-5433}"
PGUSER_NAME="${PGUSER_NAME:-postgres}"
PGDATABASE="${PGDATABASE:-sqltest}"

PSQL="$PGBIN/psql"
INITDB="$PGBIN/initdb"
PG_CTL="$PGBIN/pg_ctl"
PG_ISREADY="$PGBIN/pg_isready"

run_as_pg() {
    # Run a command as the postgres user when we are root; otherwise
    # run it directly.
    if [ "$(id -u)" = "0" ]; then
        su "$PGUSER_NAME" -s /bin/bash -c "$*"
    else
        bash -c "$*"
    fi
}

# --- 1. Server binaries present? -----------------------------------------
for bin in psql initdb pg_ctl; do
    if [ ! -x "$PGBIN/$bin" ]; then
        echo "ensure-postgres: $PGBIN/$bin not found — PostgreSQL server not installed" >&2
        exit 2
    fi
done

# --- 2. Data directory ----------------------------------------------------
if [ ! -f "$PGDATA/PG_VERSION" ]; then
    echo "ensure-postgres: initialising data directory at $PGDATA"
    mkdir -p "$(dirname "$PGDATA")"
    mkdir -p "$PGDATA"
    chown "$PGUSER_NAME":"$PGUSER_NAME" "$PGDATA" 2>/dev/null || true
    chmod 700 "$PGDATA"
    if ! run_as_pg "$INITDB -D $PGDATA --auth=trust -E SQL_ASCII --locale=C" \
         > /tmp/ensure-postgres-initdb.log 2>&1; then
        echo "ensure-postgres: initdb failed:" >&2
        tail -20 /tmp/ensure-postgres-initdb.log >&2
        exit 3
    fi
    # trust auth for local + loopback so the test binary can connect as
    # the postgres role without a password from any local user.
    cat > "$PGDATA/pg_hba.conf" << 'HBA'
local   all             all                                     trust
host    all             all             127.0.0.1/32            trust
host    all             all             ::1/128                 trust
local   replication     all                             trust
host    replication     all             127.0.0.1/32            trust
host    replication     all             ::1/128                 trust
HBA
    chown "$PGUSER_NAME":"$PGUSER_NAME" "$PGDATA/pg_hba.conf" 2>/dev/null || true
fi

# --- 3. Server running? ----------------------------------------------------
mkdir -p "$PGSOCK"
chown "$PGUSER_NAME":"$PGUSER_NAME" "$PGSOCK" 2>/dev/null || true
chmod 775 "$PGSOCK"

if ! run_as_pg "$PG_ISREADY -h $PGSOCK -p $PGPORT -q"; then
    echo "ensure-postgres: starting server on socket $PGSOCK port $PGPORT"
    if ! run_as_pg "$PG_CTL -D $PGDATA -l /tmp/ensure-postgres.log -w -t 30 start -o '-k $PGSOCK -p $PGPORT'" \
         >> /tmp/ensure-postgres.log 2>&1; then
        echo "ensure-postgres: server failed to start:" >&2
        tail -20 /tmp/ensure-postgres.log >&2
        exit 4
    fi
fi

# --- 4. Test database ------------------------------------------------------
# SQL is piped over stdin so no nested shell quoting (and no shared
# temp files with permission races) are needed.
CHECK_SQL="SELECT 1 FROM pg_database WHERE datname = '$PGDATABASE'"
CREATE_SQL="CREATE DATABASE \"$PGDATABASE\""

if ! printf '%s\n' "$CHECK_SQL" | run_as_pg "$PSQL -h $PGSOCK -p $PGPORT -U $PGUSER_NAME -d postgres -tA" | grep -q 1; then
    echo "ensure-postgres: creating database $PGDATABASE"
    printf '%s\n' "$CREATE_SQL" | run_as_pg "$PSQL -h $PGSOCK -p $PGPORT -U $PGUSER_NAME -d postgres" >/dev/null
fi

echo "ensure-postgres: server ready (socket $PGSOCK, port $PGPORT, db $PGDATABASE)"
exit 0