#!/usr/bin/env php
<?php
/**
 * Analytics Verification Script
 * 
 * This script helps verify the accuracy of analytics data by:
 * - Comparing raw visit counts with summary totals
 * - Identifying potential issues (bots, duplicates, etc.)
 * - Validating data integrity
 * - Showing discrepancies
 */

// Timezone: where reality meets server configuration
date_default_timezone_set('UTC'); // Adjust to your server's actual timezone

$dataDir = '/var/www/data/analytics';
$date = isset($argv[1]) ? $argv[1] : date('Y-m-d');

echo "=== Analytics Verification for {$date} ===\n\n";

// Load summary
$summaryFile = $dataDir . '/summary_' . $date . '.json';
$summary = [];
if (file_exists($summaryFile)) {
    $summary = json_decode(file_get_contents($summaryFile), true) ?: [];
} else {
    echo "ERROR: Summary file not found: {$summaryFile}\n";
    exit(1);
}

// Load raw visits
$visitsFile = $dataDir . '/visits_' . $date . '.json';
$visits = [];
if (file_exists($visitsFile)) {
    $visits = json_decode(file_get_contents($visitsFile), true) ?: [];
} else {
    echo "ERROR: Visits file not found: {$visitsFile}\n";
    exit(1);
}

// 1. Count pageviews from raw data
$pageviews = array_filter($visits, function($v) { return $v['type'] === 'pageview'; });
$pageviewCount = count($pageviews);

// 2. Count new vs returning from raw data
$newVisitors = [];
$returningVisitors = [];
foreach ($pageviews as $visit) {
    if ($visit['isNew']) {
        $newVisitors[$visit['visitorId']] = true;
    } else {
        $returningVisitors[$visit['visitorId']] = true;
    }
}
$newCount = count($newVisitors);
$returningCount = count($returningVisitors);

// 3. Recalculate hourly distribution
$byHour = array_fill(0, 24, 0);
foreach ($pageviews as $visit) {
    if (isset($visit['timestamp'])) {
        $hour = (int)date('H', $visit['timestamp']);
        if ($hour >= 0 && $hour < 24) {
            $byHour[$hour]++;
        }
    }
}

// 4. Count shares
$shares = ['mastodon' => 0, 'bluesky' => 0, 'copy' => 0];
foreach ($visits as $visit) {
    if ($visit['type'] === 'share' && isset($visit['platform'])) {
        $platform = $visit['platform'];
        if (isset($shares[$platform])) {
            $shares[$platform]++;
        }
    }
}

// 5. Count RSS clicks
$rssClicks = 0;
foreach ($visits as $visit) {
    if ($visit['type'] === 'rss_click') {
        $rssClicks++;
    }
}

// 6. Identify potential issues
$issues = [];

// Check for duplicate pageviews (same visitor, same page, within 5 seconds)
$duplicates = [];
foreach ($pageviews as $i => $visit1) {
    foreach ($pageviews as $j => $visit2) {
        if ($i < $j && 
            $visit1['visitorId'] === $visit2['visitorId'] &&
            $visit1['page'] === $visit2['page'] &&
            abs($visit1['timestamp'] - $visit2['timestamp']) < 5) {
            $duplicates[] = [
                'visitor' => $visit1['visitorId'],
                'page' => $visit1['page'],
                'time1' => date('H:i:s', $visit1['timestamp']),
                'time2' => date('H:i:s', $visit2['timestamp'])
            ];
        }
    }
}

if (count($duplicates) > 0) {
    $issues[] = "Found " . count($duplicates) . " potential duplicate pageviews (same visitor, same page, <5s apart)";
}

// Check for suspicious user agents (common bots)
$botPatterns = [
    '/bot/i', '/crawler/i', '/spider/i', '/scraper/i',
    '/google/i', '/bing/i', '/yahoo/i', '/duckduckbot/i',
    '/facebookexternalhit/i', '/twitterbot/i', '/linkedinbot/i'
];
$botCount = 0;
$botVisitors = [];
foreach ($visits as $visit) {
    $ua = $visit['userAgent'] ?? '';
    foreach ($botPatterns as $pattern) {
        if (preg_match($pattern, $ua)) {
            $botCount++;
            $botVisitors[$visit['visitorId']] = true;
            break;
        }
    }
}

if ($botCount > 0) {
    $issues[] = "Found {$botCount} visits from potential bots/crawlers (" . count($botVisitors) . " unique visitors)";
}

// Check for rapid-fire visits (potential scripted access)
$rapidVisits = [];
$visitorTimestamps = [];
foreach ($pageviews as $visit) {
    $vid = $visit['visitorId'];
    if (!isset($visitorTimestamps[$vid])) {
        $visitorTimestamps[$vid] = [];
    }
    $visitorTimestamps[$vid][] = $visit['timestamp'];
}

foreach ($visitorTimestamps as $vid => $timestamps) {
    sort($timestamps);
    for ($i = 1; $i < count($timestamps); $i++) {
        $diff = $timestamps[$i] - $timestamps[$i-1];
        if ($diff < 2) { // Less than 2 seconds between pageviews
            $rapidVisits[$vid] = ($rapidVisits[$vid] ?? 0) + 1;
        }
    }
}

if (count($rapidVisits) > 0) {
    $issues[] = "Found " . count($rapidVisits) . " visitors with rapid-fire pageviews (<2s apart)";
}

// Check summary vs raw data discrepancies
$discrepancies = [];

if ($summary['total'] != $pageviewCount) {
    $discrepancies[] = sprintf(
        "Total visits mismatch: Summary=%d, Raw count=%d (diff: %+d)",
        $summary['total'], $pageviewCount, $summary['total'] - $pageviewCount
    );
}

if ($summary['new'] != $newCount) {
    $discrepancies[] = sprintf(
        "New visitors mismatch: Summary=%d, Raw count=%d (diff: %+d)",
        $summary['new'], $newCount, $summary['new'] - $newCount
    );
}

if ($summary['returning'] != $returningCount) {
    $discrepancies[] = sprintf(
        "Returning visitors mismatch: Summary=%d, Raw count=%d (diff: %+d)",
        $summary['returning'], $returningCount, $summary['returning'] - $returningCount
    );
}

// Compare hourly data
$hourlyDiff = false;
for ($h = 0; $h < 24; $h++) {
    if ($summary['byHour'][$h] != $byHour[$h]) {
        $hourlyDiff = true;
        break;
    }
}
if ($hourlyDiff) {
    $discrepancies[] = "Hourly distribution differs between summary and raw data";
}

// Compare shares
foreach (['mastodon', 'bluesky', 'copy'] as $platform) {
    $summaryShares = $summary['shares'][$platform] ?? 0;
    $rawShares = $shares[$platform] ?? 0;
    if ($summaryShares != $rawShares) {
        $discrepancies[] = sprintf(
            "Shares ({$platform}) mismatch: Summary=%d, Raw count=%d (diff: %+d)",
            $summaryShares, $rawShares, $summaryShares - $rawShares
        );
    }
}

// Compare RSS
$summaryRss = $summary['rss'] ?? 0;
if ($summaryRss != $rssClicks) {
    $discrepancies[] = sprintf(
        "RSS clicks mismatch: Summary=%d, Raw count=%d (diff: %+d)",
        $summaryRss, $rssClicks, $summaryRss - $rssClicks
    );
}

// Display results
echo "SUMMARY DATA:\n";
echo "  Total visits: " . ($summary['total'] ?? 0) . "\n";
echo "  New visitors: " . ($summary['new'] ?? 0) . "\n";
echo "  Returning visitors: " . ($summary['returning'] ?? 0) . "\n";
echo "  RSS clicks: " . ($summary['rss'] ?? 0) . "\n";
echo "  Shares: Mastodon=" . ($summary['shares']['mastodon'] ?? 0) . 
      ", Bluesky=" . ($summary['shares']['bluesky'] ?? 0) . 
      ", Copy=" . ($summary['shares']['copy'] ?? 0) . "\n\n";

echo "RAW DATA COUNT:\n";
echo "  Total pageviews: {$pageviewCount}\n";
echo "  Unique new visitors: {$newCount}\n";
echo "  Unique returning visitors: {$returningCount}\n";
echo "  RSS clicks: {$rssClicks}\n";
echo "  Shares: Mastodon={$shares['mastodon']}, Bluesky={$shares['bluesky']}, Copy={$shares['copy']}\n";
echo "  Total visits (all types): " . count($visits) . "\n\n";

if (count($discrepancies) > 0) {
    echo "⚠️  DISCREPANCIES FOUND:\n";
    foreach ($discrepancies as $disc) {
        echo "  - {$disc}\n";
    }
    echo "\n";
} else {
    echo "✓ Summary and raw data match!\n\n";
}

if (count($issues) > 0) {
    echo "⚠️  POTENTIAL ISSUES:\n";
    foreach ($issues as $issue) {
        echo "  - {$issue}\n";
    }
    echo "\n";
} else {
    echo "✓ No obvious issues detected.\n\n";
}

// Show top visitors
echo "TOP VISITORS (by pageview count):\n";
$visitorCounts = [];
foreach ($pageviews as $visit) {
    $vid = $visit['visitorId'];
    $visitorCounts[$vid] = ($visitorCounts[$vid] ?? 0) + 1;
}
arsort($visitorCounts);
$topVisitors = array_slice($visitorCounts, 0, 10, true);
foreach ($topVisitors as $vid => $count) {
    $firstVisit = null;
    foreach ($pageviews as $v) {
        if ($v['visitorId'] === $vid) {
            $firstVisit = $v;
            break;
        }
    }
    $ua = substr($firstVisit['userAgent'] ?? 'Unknown', 0, 50);
    echo sprintf("  %s: %d pageviews (UA: %s...)\n", substr($vid, 0, 30), $count, $ua);
}

echo "\n";

// Show hourly breakdown
echo "HOURLY BREAKDOWN (from raw data):\n";
for ($h = 0; $h < 24; $h++) {
    $count = $byHour[$h];
    $bar = str_repeat('█', min(50, (int)($count / max(1, max($byHour)) * 50)));
    echo sprintf("  %02d:00 %5d %s\n", $h, $count, $bar);
}

echo "\n";

// Accuracy notes
echo "ACCURACY CONSIDERATIONS:\n";
echo "  ✓ Data is recalculated from raw timestamps (hourly stats are accurate)\n";
echo "  ⚠  Bot traffic is NOT filtered (may inflate numbers)\n";
echo "  ⚠  Ad blockers may prevent tracking (may deflate numbers)\n";
echo "  ⚠  Self-visits are NOT filtered\n";
echo "  ⚠  JavaScript-disabled browsers won't be tracked\n";
echo "  ⚠  Privacy tools may block localStorage (affects visitor ID)\n";
echo "  ⚠  New/Returning is calculated per-day, not across days\n";
echo "  ⚠  Multiple tabs/devices = multiple visitors\n";
echo "\n";

?>