#!/usr/bin/env sh
set -eu

SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
PROJECT_DIR=$(dirname -- "$SCRIPT_DIR")
cd "$PROJECT_DIR"

fatal() {
    printf 'enterdb: %s\n' "$*" >&2
    exit 1
}

command -v docker >/dev/null 2>&1 || fatal "docker is not available in PATH"
docker compose version >/dev/null 2>&1 || fatal "docker compose is not available"

service_running() {
    docker compose ps --status running --services 2>/dev/null | grep -Fxq "$1"
}

# DATABASE_URL from the running application is the source of truth for the selected database engine.
DATABASE_URL_VALUE=""
if service_running app; then
    DATABASE_URL_VALUE=$(docker compose exec -T app sh -c 'printf "%s" "${DATABASE_URL:-}"' 2>/dev/null || true)
fi

case "$DATABASE_URL_VALUE" in
    postgres://*|postgresql://*)
        DATABASE_ENGINE=postgres
        ;;
    mysql://*)
        DATABASE_ENGINE=mysql
        ;;
    sqlite://*)
        fatal "the application uses SQLite; this script supports PostgreSQL and MySQL"
        ;;
    "")
        POSTGRES_RUNNING=false
        MYSQL_RUNNING=false
        service_running postgres && POSTGRES_RUNNING=true
        service_running mysql && MYSQL_RUNNING=true

        if [ "$POSTGRES_RUNNING" = true ] && [ "$MYSQL_RUNNING" = false ]; then
            DATABASE_ENGINE=postgres
        elif [ "$MYSQL_RUNNING" = true ] && [ "$POSTGRES_RUNNING" = false ]; then
            DATABASE_ENGINE=mysql
        elif [ "$POSTGRES_RUNNING" = true ] && [ "$MYSQL_RUNNING" = true ]; then
            fatal "PostgreSQL and MySQL are both running, and DATABASE_URL could not be read from the app service"
        else
            fatal "no running postgres or mysql service was found"
        fi
        ;;
    *)
        fatal "unsupported DATABASE_URL: $DATABASE_URL_VALUE"
        ;;
esac

case "$DATABASE_ENGINE" in
    postgres)
        service_running postgres || fatal "the postgres service is not running"
        printf 'Connecting to PostgreSQL...\n' >&2
        exec docker compose exec postgres sh -lc '
            export PGPASSWORD="${POSTGRES_PASSWORD:-rustpad}"
            exec psql --host=127.0.0.1 --username="${POSTGRES_USER:-rustpad}" --dbname="${POSTGRES_DB:-rustpad}"
        '
        ;;
    mysql)
        service_running mysql || fatal "the mysql service is not running"
        printf 'Connecting to MySQL...\n' >&2
        exec docker compose exec mysql sh -lc '
            if command -v mysql >/dev/null 2>&1; then
                client=mysql
            elif command -v mariadb >/dev/null 2>&1; then
                client=mariadb
            else
                echo "enterdb: no mysql/mariadb client is available in the container" >&2
                exit 1
            fi

            export MYSQL_PWD="${MYSQL_PASSWORD:-rustpad}"
            exec "$client" --user="${MYSQL_USER:-rustpad}" "${MYSQL_DATABASE:-rustpad}"
        '
        ;;
esac