<?php

declare(strict_types=1);

namespace Belevo\EnelixEMS;

use InvalidArgumentException;
use RuntimeException;
use Throwable;

require_once __DIR__ . '/NetzfahrplanV4Bilanzierung.php';

/** Passive, versioned RAW capture. Never grants training/control eligibility.
 * Reader supplies numeric values only; no configuration, credentials or network.
 */
final class NetzfahrplanV4Messaufnahme
{
    public static function configuration(array $c): array
    {
        if (($c['version'] ?? null) !== 1 || !is_string($c['installationId'] ?? null)
            || !preg_match('/^[0-9a-f-]{36}$/D', $c['installationId'])
            || !is_array($c['extraSources'] ?? null) || count($c['extraSources']) > 60
            || !is_string($c['reportedInventorySha256'] ?? null)
            || !preg_match('/^[0-9a-f]{64}$/D', $c['reportedInventorySha256'])) {
            throw new InvalidArgumentException('Invalid capture configuration');
        }
        $c['accounting'] = NetzfahrplanV4Bilanzierung::konfigurieren($c['accounting'] ?? []);
        $keys = []; $ids = [];
        foreach ($c['accounting']['sources'] as $s) { $keys[$s['key']] = true; $ids[$s['variableId']] = true; }
        foreach ($c['extraSources'] as $s) {
            if (count($s) !== 5 || !is_string($s['key'] ?? null)
                || !preg_match('/^[A-Za-z][A-Za-z0-9_-]{0,63}$/D', $s['key']) || isset($keys[$s['key']])
                || !is_int($s['variableId'] ?? null) || $s['variableId'] < 1 || isset($ids[$s['variableId']])
                || !is_int($s['parentId'] ?? null) || $s['parentId'] < 1
                || !is_string($s['ident'] ?? null) || strlen($s['ident']) > 100
                || !in_array($s['unit'] ?? null, ['W','kWh','percent','raw_power','scale'], true)) {
                throw new InvalidArgumentException('Invalid or duplicate raw source');
            }
            $keys[$s['key']] = true; $ids[$s['variableId']] = true;
        }
        usort($c['extraSources'], static fn(array $a, array $b): int => strcmp($a['key'], $b['key']));
        return $c;
    }

    private static function readSource(array $s, callable $read): array
    {
        try {
            $r = $read($s['variableId']);
            if (!is_array($r)) throw new RuntimeException('Missing reading');
        } catch (Throwable $e) {
            return ['value' => null, 'sourceUpdatedAt' => null, 'sourceChangedAt' => null, 'issues' => ['read_failed']];
        }
        $issues = [];
        $v = $r['value'] ?? null;
        if ((!is_int($v) && !is_float($v)) || !is_finite((float) $v) || abs((float)$v) > 1.0e12) {
            $v = null; $issues[] = 'invalid_numeric_value';
        }
        $at = $r['updated'] ?? null;
        if (!is_int($at) || $at < 1) { $at = null; $issues[] = 'missing_original_timestamp'; }
        $changed = $r['changed'] ?? null;
        if (!is_int($changed) || $changed < 0) $changed = null;
        if (($r['parentID'] ?? null) !== $s['parentId'] || ($r['ident'] ?? null) !== $s['ident']) {
            // Do not record a numeric value from an object re-used for a different purpose.
            $v = null; $issues[] = 'source_identity_mismatch';
        }
        return ['value' => $v, 'sourceUpdatedAt' => $at, 'sourceChangedAt' => $changed, 'issues' => $issues];
    }

    public static function capture(array $config, callable $read, callable $clock): array
    {
        $c = self::configuration($config);
        $start = $clock();
        if (!is_int($start) || $start <= 0) throw new InvalidArgumentException('Integer UTC epoch required');
        $sources = array_merge($c['accounting']['sources'], $c['extraSources']);
        $first = []; $second = []; $raw = []; $issues = [];
        foreach ($sources as $s) $first[$s['key']] = self::readSource($s, $read);
        foreach ($sources as $s) $second[$s['key']] = self::readSource($s, $read);
        $end = $clock();
        if (!is_int($end) || $end < $start) throw new RuntimeException('Acquisition clock moved backwards');
        foreach ($sources as $s) {
            $key = $s['key']; $r = $first[$key];
            if ($r !== $second[$key]) {
                $r['issues'][] = 'changed_during_capture';
                $r['secondValue'] = $second[$key]['value'];
                $r['secondUpdatedAt'] = $second[$key]['sourceUpdatedAt'];
            }
            if ($r['sourceUpdatedAt'] !== null && $r['sourceUpdatedAt'] > $end) $r['issues'][] = 'future_source';
            $r['sourceAgeSeconds'] = $r['sourceUpdatedAt'] === null ? null : $end - $r['sourceUpdatedAt'];
            $raw[$key] = ['variableId' => $s['variableId']] + $r;
            foreach ($r['issues'] as $issue) $issues[] = $key . ':' . $issue;
        }
        $assessment = null; $accountingUsable = true; $samples = [];
        foreach ($c['accounting']['sources'] as $s) {
            $r = $raw[$s['key']];
            if ($r['issues'] !== []) $accountingUsable = false;
            $samples[$s['variableId']] = ['value' => $r['value'], 'updated' => $r['sourceUpdatedAt'], 'parentID' => $s['parentId'], 'ident' => $s['ident']];
        }
        if ($accountingUsable) {
            try { $assessment = NetzfahrplanV4Bilanzierung::aufnehmen($c['accounting'], static fn(int $id): array => $samples[$id], $end); }
            catch (Throwable $e) { $issues[] = 'accounting_input_invalid'; }
        } else { $issues[] = 'accounting_snapshot_unusable'; }
        if ($end - $start > 5) $issues[] = 'long_acquisition';
        return ['schemaVersion' => 1, 'kind' => 'raw_accounting_capture', 'installationId' => $c['installationId'],
            'captureStartedAt' => gmdate('c', $start), 'capturedAt' => gmdate('c', $end),
            'mappingSha256' => hash('sha256', json_encode($c, JSON_THROW_ON_ERROR | JSON_PRESERVE_ZERO_FRACTION)),
            'reportedInventorySha256' => $c['reportedInventorySha256'],
            'timestampMeaning' => 'Symcon VariableUpdated; not proof of an independent device timestamp',
            'raw' => $raw, 'issues' => $issues, 'assessment' => $assessment,
            'trainingEligible' => false, 'controlEligible' => false, 'measurementBoundaryVerified' => false,
            'futureSdl' => 'unknown_no_assumption', 'historicalDataRewritten' => false];
    }

    /** Append-only daily JSONL with exclusive lock, bounds and crash-tail detection.
     * No retention deletion; quota stops capture visibly, never deletes old histories.
     */
    public static function append(string $directory, array $record, int $quota = 536870912): string
    {
        if (!is_dir($directory) || is_link($directory) || realpath($directory) !== $directory || $quota < 1) {
            throw new RuntimeException('Invalid dedicated data directory');
        }
        $json = json_encode($record, JSON_THROW_ON_ERROR | JSON_PRESERVE_ZERO_FRACTION) . "\n";
        if (strlen($json) > 262144) throw new RuntimeException('Capture exceeds record limit');
        $epoch = strtotime($record['capturedAt'] ?? '');
        if ($epoch === false) throw new RuntimeException('Capture timestamp missing');
        $file = $directory . '/raw-' . gmdate('Ymd', $epoch) . '.jsonl';
        $lockPath = $directory . '/.writer.lock';
        if (is_link($lockPath) || is_link($file)) throw new RuntimeException('Symbolic link refused');
        $lock = fopen($lockPath, 'c+b');
        if ($lock === false) throw new RuntimeException('Capture lock unavailable');
        try {
            if (!flock($lock, LOCK_EX | LOCK_NB)) throw new RuntimeException('Capture writer busy');
            clearstatcache(); $used = 0; $files = glob($directory . '/raw-*.jsonl');
            if ($files === false || count($files) > 400) throw new RuntimeException('Data directory bounds exceeded');
            foreach ($files as $p) {
                if (is_link($p)) throw new RuntimeException('Symbolic journal refused');
                $size = filesize($p); if ($size === false) throw new RuntimeException('Cannot size journal');
                $used += $size;
            }
            if ($used + strlen($json) > $quota) throw new RuntimeException('Capture quota reached; no data deleted');
            $free = disk_free_space($directory);
            if ($free === false || $free < 104857600 + strlen($json)) throw new RuntimeException('Insufficient free disk; capture paused');
            $h = fopen($file, 'c+b');
            if ($h === false) throw new RuntimeException('Cannot open capture journal');
            try {
                fseek($h, 0, SEEK_END); $old = ftell($h);
                if ($old === false || $old + strlen($json) > 67108864) throw new RuntimeException('Daily capture bounds exceeded');
                if ($old > 0) {
                    fseek($h, -1, SEEK_END);
                    if (fread($h, 1) !== "\n") throw new RuntimeException('Incomplete journal tail; preserve for review');
                }
                fseek($h, 0, SEEK_END); $n = 0;
                try {
                    while ($n < strlen($json)) {
                        $written = fwrite($h, substr($json, $n));
                        if ($written === false || $written === 0) throw new RuntimeException('Capture write incomplete');
                        $n += $written;
                    }
                    if (!fflush($h)) throw new RuntimeException('Capture flush failed');
                } catch (Throwable $e) { ftruncate($h, $old); fflush($h); throw $e; }
                if (!chmod($file, 0640)) throw new RuntimeException('Cannot restrict journal permissions');
            } finally { fclose($h); }
            return $file;
        } finally { flock($lock, LOCK_UN); fclose($lock); }
    }
}