<?php
require_once __DIR__ . '/config.php';

$errors = load_json(ERRORS_FILE);
$sessions = load_json(SESSIONS_FILE);

$total = count($errors);
$byType = [];
$bySeverity = [];
$byCategory = [];
$byModule = [];
$byDay = [];
$topErrors = [];

foreach ($errors as $e) {
    $t = $e['type'] ?? 'unknown';
    $byType[$t] = ($byType[$t] ?? 0) + ($e['count'] ?? 1);
    
    $s = $e['severity'] ?? 'error';
    $bySeverity[$s] = ($bySeverity[$s] ?? 0) + ($e['count'] ?? 1);
    
    $c = $e['category'] ?? 'runtime';
    $byCategory[$c] = ($byCategory[$c] ?? 0) + ($e['count'] ?? 1);
    
    $m = $e['module'] ?? 'unknown';
    $byModule[$m] = ($byModule[$m] ?? 0) + ($e['count'] ?? 1);
    
    $day = substr($e['ingested_at'] ?? $e['last_seen'], 0, 10);
    $byDay[$day] = ($byDay[$day] ?? 0) + ($e['count'] ?? 1);
    
    $hash = $e['hash'] ?? '';
    if ($hash) {
        if (!isset($topErrors[$hash])) {
            $topErrors[$hash] = ['hash' => $hash, 'message' => $e['message'] ?? '', 'count' => 0, 'type' => $t];
        }
        $topErrors[$hash]['count'] += $e['count'] ?? 1;
    }
}

$totalOccurrences = 0;
foreach ($errors as $e) { $totalOccurrences += (int)($e['count'] ?? 1); }

usort($topErrors, fn($a, $b) => $b['count'] - $a['count']);
$topErrors = array_slice($topErrors, 0, 20);
ksort($byDay);

json_response([
    'success' => true,
    // total_errors = OCCURRENCES (sum of counts); unique_errors = distinct signatures.
    // Before 2026-10-23 the key held the record count while by_type held occurrences,
    // so two numbers on the same screen disagreed by ~3,500x.
    'total_errors' => $totalOccurrences,
    'unique_errors' => $total,
    'total_sessions' => count($sessions),
    'by_type' => $byType,
    'by_severity' => $bySeverity,
    'by_category' => $byCategory,
    'by_module' => $byModule,
    'by_day' => $byDay,
    'top_errors' => $topErrors,
    'generated_at' => date('c'),
]);