<?php

// Configuration
const SECURITY_TOKEN = '';
const API_BASE_URL = 'https://web-api.tp.entsoe.eu/api';
const IN_OUT_DOMAIN = '10YNL----------L'; // Netherlands


/**
 * Downloads day-ahead hourly price data (raw XML) for a given day and saves it.
 *
 * @param string $day YYYYMMDD format (e.g., 20240101)
 * @return string|false The path to the saved XML file on success, or false on failure.
 */
function downloadAndSaveRawXml(string $day): string|false
{
    // Request a 25-hour window from 23:00 UTC of the previous day to 00:00 UTC of the day after
    // to reliably capture the full 24 hours of the target day's market data (A44).
    try {
        $dateTimeStart = new DateTimeImmutable("$day 00:00:00", new DateTimeZone('UTC'));
        $periodStart = $dateTimeStart->format('YmdH00');

        $dateTimeEnd = $dateTimeStart->modify('+23 hours');
        $periodEnd = $dateTimeEnd->format('YmdH00');
    } catch (Exception $e) {
        echo "Error creating date objects: " . $e->getMessage() . "\n";
        return false;
    }

    $apiUrl = API_BASE_URL . '?' . http_build_query([
        'securityToken' => SECURITY_TOKEN,
        'documentType' => 'A44', // Price Document
        'in_Domain' => IN_OUT_DOMAIN,
        'out_Domain' => IN_OUT_DOMAIN,
        'periodStart' => $periodStart,
        'periodEnd' => $periodEnd,
    ]);

    echo "Fetching raw XML data from ENTSO-E API for $day...\n";
    // echo "API URL: $apiUrl\n"; // Uncomment for debugging

    // Initialize cURL
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $apiUrl);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HEADER, false);

    $xmlResponse = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($httpCode !== 200 || !$xmlResponse) {
        echo "Error: HTTP Code $httpCode or failed to get response.\n";
        return false;
    }
    
    // Check for Acknowledge document (error/no data)
    if (str_contains($xmlResponse, '<Acknowledgement_MarketDocument>')) {
        echo "Error: The API returned an Acknowledge document (often indicating missing data or an error).\n";
        echo "Check the XML content for details before proceeding.\n";
    }

    // Save to XML file
    $filename = "prices_{$day}.xml";
    if (file_put_contents($filename, $xmlResponse) === false) {
        echo "Error: Could not save data to file: $filename\n";
        return false;
    }

    echo "Successfully saved raw XML response to **$filename**.\n";
    return $filename;
}

// --- Main Execution ---
if ($argc < 2) {
    echo "Usage: php Collector.php YYYYMMDD\n";
    exit(1);
}

$targetDay = $argv[1];

if (!preg_match('/^\d{8}$/', $targetDay)) {
    echo "Invalid date format. Please use YYYYMMDD (e.g., 20240101).\n";
    exit(1);
}

downloadAndSaveRawXml($targetDay);

?>