<?php // phpcs:ignoreFile
/**
 * Report Data API
 * 
 * Fetches aggregated data from SQL Server archive for reporting
 */

header('Content-Type: application/json');
header('Cache-Control: no-cache, must-revalidate');

require __DIR__ . '/../config.php';

$response = ['success' => false, 'error' => null, 'data' => []];

try {
    $pdo = getReportDbConnection();
    if (!$pdo) {
        throw new Exception('Database connection failed');
    }

    // Parameters
    $tags = isset($_GET['tags']) ? explode(',', $_GET['tags']) : [];
    $startDate = $_GET['start_date'] ?? null;
    $endDate = $_GET['end_date'] ?? null;
    $aggregation = $_GET['aggregation'] ?? 'hourly'; // hourly, daily, raw
    $statsOnly = isset($_GET['stats_only']); // Return only min/max/avg

    if (empty($tags)) {
        throw new Exception('No tags specified');
    }

    if (!$startDate || !$endDate) {
        throw new Exception('Start and end dates required');
    }

    // Validate aggregation
    $validAggregations = ['hourly', 'daily', 'raw'];
    if (!in_array($aggregation, $validAggregations)) {
        $aggregation = 'hourly';
    }

    // Build results for each tag
    $results = [];

    foreach ($tags as $tagName) {
        $tagName = trim($tagName);
        if (empty($tagName)) continue;

        // Use JOIN pattern like trends/live/realtime_data.php
        // No separate lookup - join archive with id_names directly

        if ($statsOnly) {
            // Return summary statistics only (fast)
            // CAST Value to FLOAT since it's stored as VARCHAR
            $sql = "SELECT 
                        MIN(CAST(a.Value AS FLOAT)) as min_val,
                        MAX(CAST(a.Value AS FLOAT)) as max_val,
                        AVG(CAST(a.Value AS FLOAT)) as avg_val,
                        COUNT(*) as sample_count,
                        MIN(a.TimeStamp) as first_sample,
                        MAX(a.TimeStamp) as last_sample
                    FROM dbo.archive a
                    INNER JOIN dbo.id_names n ON a.ID = n.idnumber
                    WHERE n.name = :tag_name
                      AND a.TimeStamp BETWEEN :start_date AND :end_date";

            $stmt = $pdo->prepare($sql);
            $stmt->execute([
                ':tag_name' => $tagName,
                ':start_date' => $startDate,
                ':end_date' => $endDate
            ]);
            $stats = $stmt->fetch();

            if (!$stats || $stats['sample_count'] == 0) {
                $results[$tagName] = ['error' => 'No data found for this tag/date range'];
                continue;
            }

            $results[$tagName] = [
                'min' => $stats['min_val'] !== null ? round((float)$stats['min_val'], 2) : null,
                'max' => $stats['max_val'] !== null ? round((float)$stats['max_val'], 2) : null,
                'avg' => $stats['avg_val'] !== null ? round((float)$stats['avg_val'], 2) : null,
                'samples' => (int)$stats['sample_count'],
                'first' => $stats['first_sample'],
                'last' => $stats['last_sample']
            ];

        } elseif ($aggregation === 'hourly') {
            // Hourly aggregation
            $sql = "SELECT 
                        DATEADD(HOUR, DATEDIFF(HOUR, 0, a.TimeStamp), 0) as time_bucket,
                        MIN(CAST(a.Value AS FLOAT)) as min_val,
                        MAX(CAST(a.Value AS FLOAT)) as max_val,
                        AVG(CAST(a.Value AS FLOAT)) as avg_val,
                        COUNT(*) as samples
                    FROM dbo.archive a
                    INNER JOIN dbo.id_names n ON a.ID = n.idnumber
                    WHERE n.name = :tag_name
                      AND a.TimeStamp BETWEEN :start_date AND :end_date
                    GROUP BY DATEADD(HOUR, DATEDIFF(HOUR, 0, a.TimeStamp), 0)
                    ORDER BY time_bucket";

            $stmt = $pdo->prepare($sql);
            $stmt->execute([
                ':tag_name' => $tagName,
                ':start_date' => $startDate,
                ':end_date' => $endDate
            ]);

            $results[$tagName] = $stmt->fetchAll();

        } elseif ($aggregation === 'daily') {
            // Daily aggregation
            $sql = "SELECT 
                        CAST(a.TimeStamp AS DATE) as time_bucket,
                        MIN(CAST(a.Value AS FLOAT)) as min_val,
                        MAX(CAST(a.Value AS FLOAT)) as max_val,
                        AVG(CAST(a.Value AS FLOAT)) as avg_val,
                        COUNT(*) as samples
                    FROM dbo.archive a
                    INNER JOIN dbo.id_names n ON a.ID = n.idnumber
                    WHERE n.name = :tag_name
                      AND a.TimeStamp BETWEEN :start_date AND :end_date
                    GROUP BY CAST(a.TimeStamp AS DATE)
                    ORDER BY time_bucket";

            $stmt = $pdo->prepare($sql);
            $stmt->execute([
                ':tag_name' => $tagName,
                ':start_date' => $startDate,
                ':end_date' => $endDate
            ]);

            $results[$tagName] = $stmt->fetchAll();

        } else {
            // Raw data (limited)
            $sql = "SELECT a.TimeStamp, a.Value
                    FROM dbo.archive a
                    INNER JOIN dbo.id_names n ON a.ID = n.idnumber
                    WHERE n.name = :tag_name
                      AND a.TimeStamp BETWEEN :start_date AND :end_date
                    ORDER BY a.TimeStamp
                    OFFSET 0 ROWS FETCH NEXT :limit ROWS ONLY";

            $stmt = $pdo->prepare($sql);
            $stmt->bindValue(':tag_name', $tagName);
            $stmt->bindValue(':start_date', $startDate);
            $stmt->bindValue(':end_date', $endDate);
            $stmt->bindValue(':limit', REPORT_MAX_ROWS, PDO::PARAM_INT);
            $stmt->execute();

            $results[$tagName] = $stmt->fetchAll();
        }
    }

    $response['success'] = true;
    $response['data'] = $results;
    $response['params'] = [
        'start_date' => $startDate,
        'end_date' => $endDate,
        'aggregation' => $aggregation,
        'stats_only' => $statsOnly
    ];

} catch (Exception $e) {
    $response['error'] = $e->getMessage();
}

echo json_encode($response, JSON_PRETTY_PRINT);