<?php

class MeterValueNormalizer
{
    public function normalize(array $payload): array
    {
        $result = [
            'powerImportW' => null,
            'powerExportW' => null,
            'energyImportWh' => null,
            'energyExportWh' => null,
            'currentA' => [1 => null, 2 => null, 3 => null],
            'voltageV' => [1 => null, 2 => null, 3 => null],
            'powerPhaseW' => [1 => null, 2 => null, 3 => null],
            'soc' => null,
            'temperature' => null,
            'quality' => 'OCPP-MeterValue',
            'timestamp' => time()
        ];

        foreach ($this->extractSamples($payload) as $sample) {
            $measurand = (string)($sample['measurand'] ?? 'Energy.Active.Import.Register');
            $value = $this->normalizeValue($sample);
            $phase = $this->phaseIndex((string)($sample['phase'] ?? ''));

            switch ($measurand) {
                case 'Power.Active.Import':
                    $this->writePower($result, 'powerImportW', $value, $phase);
                    break;
                case 'Power.Active.Export':
                    $this->writePower($result, 'powerExportW', $value, $phase);
                    break;
                case 'Energy.Active.Import.Register':
                case 'Energy.Active.Import.Interval':
                    $result['energyImportWh'] = $value;
                    break;
                case 'Energy.Active.Export.Register':
                case 'Energy.Active.Export.Interval':
                    $result['energyExportWh'] = $value;
                    break;
                case 'Current.Import':
                    if ($phase > 0) {
                        $result['currentA'][$phase] = $value;
                    }
                    break;
                case 'Voltage':
                    if ($phase > 0) {
                        $result['voltageV'][$phase] = $value;
                    }
                    break;
                case 'SoC':
                    $result['soc'] = $value;
                    break;
                case 'Temperature':
                    $result['temperature'] = $value;
                    break;
            }

            if (isset($sample['timestamp'])) {
                $ts = strtotime((string)$sample['timestamp']);
                if ($ts !== false) {
                    $result['timestamp'] = $ts;
                }
            }
        }

        if ($result['powerImportW'] === null) {
            $result['powerImportW'] = $this->sumPhases($result['powerPhaseW']);
        }

        return $result;
    }

    private function extractSamples(array $payload): array
    {
        $samples = [];
        $containers = $payload['meterValue'] ?? $payload['meterValues'] ?? [$payload];
        if (!is_array($containers)) {
            return [];
        }

        foreach ($containers as $container) {
            if (!is_array($container)) {
                continue;
            }
            $timestamp = $container['timestamp'] ?? null;
            $sampled = $container['sampledValue'] ?? $container['sampledValues'] ?? [];
            if (!is_array($sampled)) {
                continue;
            }
            foreach ($sampled as $sample) {
                if (!is_array($sample)) {
                    continue;
                }
                if ($timestamp !== null && !isset($sample['timestamp'])) {
                    $sample['timestamp'] = $timestamp;
                }
                $samples[] = $sample;
            }
        }

        return $samples;
    }

    private function normalizeValue(array $sample): float
    {
        $rawValue = $sample['value'] ?? 0;
        if (is_array($rawValue)) {
            $rawValue = $rawValue['value'] ?? 0;
        }
        $value = (float)$rawValue;
        $unit = $sample['unit'] ?? ($sample['unitOfMeasure']['unit'] ?? '');
        $unit = strtolower((string)$unit);

        if ($unit === 'kwh') {
            return $value * 1000.0;
        }
        if ($unit === 'kw') {
            return $value * 1000.0;
        }
        return $value;
    }

    private function phaseIndex(string $phase): int
    {
        if (stripos($phase, 'L1') !== false) {
            return 1;
        }
        if (stripos($phase, 'L2') !== false) {
            return 2;
        }
        if (stripos($phase, 'L3') !== false) {
            return 3;
        }
        return 0;
    }

    private function writePower(array &$result, string $key, float $value, int $phase): void
    {
        if ($phase > 0) {
            $result['powerPhaseW'][$phase] = $value;
            return;
        }
        $result[$key] = $value;
    }

    private function sumPhases(array $values): ?float
    {
        $sum = 0.0;
        $found = false;
        foreach ($values as $value) {
            if ($value !== null) {
                $sum += (float)$value;
                $found = true;
            }
        }
        return $found ? $sum : null;
    }
}

?>