#!/usr/bin/env bash
set -e

if [ "$EUID" -ne 0 ]; then
    echo "Error: This script must be run as root" >&2
    exit 1
fi
set -x

# What user should we use for connecting to the database
POSTGRES_USER="${POSTGRES_USER:-postgres}"

# What database name and username to use when connecting to the database
DATABASE_NAME=$(crudini --get /etc/zulip/zulip.conf postgresql database_name 2>/dev/null || echo zulip)
DATABASE_USER=$(crudini --get /etc/zulip/zulip.conf postgresql database_user 2>/dev/null || echo zulip)

if [ "$(su "$POSTGRES_USER" -c "cd / && psql -v ON_ERROR_STOP=1 -Atc \"SELECT 1 FROM pg_database WHERE datname='$DATABASE_NAME';\"")" = "1" ]; then
    records="$(su "$POSTGRES_USER" -c "cd / && psql -v ON_ERROR_STOP=1 -Atc 'SELECT COUNT(*) FROM $DATABASE_NAME.zerver_message;' $DATABASE_USER" || echo 0)"
    if [ "$records" -gt 200 ]; then
        set +x
        echo "WARNING: This will delete your Zulip database which currently contains $records messages."
        read -p "Do you want to proceed? [y/N] " -r
        echo
        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
            exit 1
        fi
        set -x
    fi
fi

# Shut down all services to ensure a quiescent state.
if [ -e "/home/zulip/deployments" ]; then
    su zulip -c "/home/zulip/deployments/current/scripts/stop-server"
fi

# Drop any open connections to any old database.
# Send the script via stdin in case the postgres user lacks permission to read it.
su -s /usr/bin/env - -- "$POSTGRES_USER" \
    bash -s - zulip zulip_base <"$(dirname "$0")/terminate-psql-sessions"

(
    cd / # Make sure the current working directory is readable by postgres
    su "$POSTGRES_USER" -c "psql -v ON_ERROR_STOP=1 -v dbname=$DATABASE_NAME -v dbuser=$DATABASE_USER -e"
) <"$(dirname "$0")/create-db.sql"

# Set a postgres password if the postgres username is not "zulip".
# When the username is zulip, we rely on running as the zulip system
# user for authentication via postgres' peer authentication.
if [ "$DATABASE_USER" != "zulip" ]; then
    PASSWORD=$(crudini --get /etc/zulip/zulip-secrets.conf secrets postgres_password)
    su "$POSTGRES_USER" -c "psql -v ON_ERROR_STOP=1  -e postgres" <<EOF
ALTER ROLE $DATABASE_USER PASSWORD '$PASSWORD';
EOF
fi

# Clear memcached to avoid contamination from previous database state
if [ -e "/home/zulip/deployments" ]; then
    /home/zulip/deployments/current/scripts/setup/flush-memcached
fi

echo "Database created"