#!/usr/bin/env bash
set -Eeuo pipefail

SCRIPT_NAME="$(basename "${BASH_SOURCE[0]}")"
readonly SCRIPT_NAME

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
readonly SCRIPT_DIR
BACKENDS_DIR="$(cd "${SCRIPT_DIR}/../../backends" && pwd)"
readonly BACKENDS_DIR

readonly ORCHESTRATOR_BLUEPRINT_FILE="/run/tuxflotte/runtime/runtime_blueprint.json"

log() {
    printf '[%s] %s\n' "${SCRIPT_NAME}" "$*" >&2
}

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

require_root() {
    if [[ "${EUID}" -ne 0 ]]; then
        fatal "Das Backend-Modul muss als root ausgeführt werden."
    fi
}

load_backend() {
    local backend_id
    local backend_script

    [[ -r "${ORCHESTRATOR_BLUEPRINT_FILE}" ]] ||
        fatal "Runtime Blueprint nicht gefunden: ${ORCHESTRATOR_BLUEPRINT_FILE}"

    backend_id="$(jq --raw-output '.runtime_blueprint.backend_id // empty' "${ORCHESTRATOR_BLUEPRINT_FILE}")"
    [[ -n "${backend_id}" ]] ||
        fatal "Runtime Blueprint enthält keine gültige Backend-ID."

    backend_script="${BACKENDS_DIR}/${backend_id}/backend.sh"
    [[ -r "${backend_script}" ]] ||
        fatal "Kein Backend für '${backend_id}' gefunden: ${backend_script}"

    log "Lade Backend '${backend_id}' aus ${backend_script}"

    # shellcheck disable=SC1090
    source "${backend_script}"
}

run_lifecycle() {
    local step

    for step in backend_init backend_validate backend_generate_config backend_launch backend_postinstall; do
        declare -f "${step}" >/dev/null ||
            fatal "Backend implementiert erforderliche Funktion nicht: ${step}"

        log "Führe ${step}() aus."

        "${step}" ||
            fatal "${step}() ist fehlgeschlagen."
    done
}

main() {
    require_root
    load_backend
    run_lifecycle
}

main "$@"