<?php

class FailSafeManager
{
    public function evaluate(array $state): array
    {
        $now = time();
        $warnings = [];
        $blockingReason = '';
        $safePowerW = null;

        $emsAge = $now - (int)($state['lastEmsUpdate'] ?? 0);
        if (($state['lastEmsUpdate'] ?? 0) > 0 && $emsAge > (int)($state['emsWatchdogSeconds'] ?? 120)) {
            $warnings[] = 'EMS watchdog expired';
            $safePowerW = $this->safePower($state);
        }

        $heartbeatAge = $now - (int)($state['lastOcppHeartbeat'] ?? 0);
        if (($state['ocppOnline'] ?? false) && ($state['lastOcppHeartbeat'] ?? 0) > 0 && $heartbeatAge > (int)($state['ocppHeartbeatTimeoutSeconds'] ?? 90)) {
            $warnings[] = 'OCPP heartbeat timeout';
            $blockingReason = 'OCPP timeout';
        }

        if (($state['criticalFault'] ?? false) === true) {
            $warnings[] = 'Critical fault';
            $blockingReason = 'Critical fault';
            $safePowerW = 0;
        }

        return [
            'warnings' => $warnings,
            'blockingReason' => $blockingReason,
            'safePowerW' => $safePowerW
        ];
    }

    private function safePower(array $state): int
    {
        $strategy = (string)($state['safeOffStrategy'] ?? 'SafeCurrent');
        if ($strategy === '0A' || $strategy === 'Unavailable') {
            return 0;
        }
        $phases = PhaseManager::normalizePhaseCount((int)($state['numberPhases'] ?? 3));
        $safeCurrent = (float)($state['safeCurrentA'] ?? 6.0);
        return PhaseManager::wattsFromCurrent($safeCurrent, $phases);
    }
}

?>