<?php
/**
 * Simple OAI-PMH 2.0 Data Provider
 * Copyright (C) 2005 Heinrich Stamerjohanns <stamer@uni-oldenburg.de>
 * Copyright (C) 2011 Jianfeng Li <jianfeng.li@adelaide.edu.au>
 * Copyright (C) 2013 Daniel Neis Araujo <danielneis@gmail.com>
 * Copyright (C) 2017 Sebastian Meyer <sebastian.meyer@opencultureconsulting.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

use OCC\OAI2\Exception;
use OCC\OAI2\Server;

// Register PSR-4 autoloader
require __DIR__.'/vendor/autoload.php';

// Load configuration
require __DIR__.'/Configuration/Main.php';

// Get all available records and their respective status and timestamps
$records = [];
$deleted = [];
$timestamps = [];
$earliest = time();

foreach ($config['metadataPrefix'] as $prefix => $uris) {
    $files = glob(rtrim($config['dataDirectory'], '/').'/'.$prefix.'/*.xml');
    foreach ($files as $file) {
        $records[$prefix][pathinfo($file, PATHINFO_FILENAME)] = $file;
        $deleted[$prefix][pathinfo($file, PATHINFO_FILENAME)] = !filesize($file);
        $timestamps[$prefix][filemtime($file)][] = pathinfo($file, PATHINFO_FILENAME);
        if (filemtime($file) < $earliest) {
            $earliest = filemtime($file);
        }
    }
    ksort($records[$prefix]);
    reset($records[$prefix]);
    ksort($timestamps[$prefix]);
    reset($timestamps[$prefix]);
}

// Get current base URL
$baseURL = $_SERVER['HTTP_HOST'].parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);
if (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off') {
    $baseURL = 'https://'.$baseURL;
} else {
    $baseURL = 'http://'.$baseURL;
}

// Build the Identify response
$identifyResponse = [
    'repositoryName' => $config['repositoryName'],
    'baseURL' => $baseURL,
    'protocolVersion' => '2.0',
    'adminEmail' => $config['adminEmail'],
    'earliestDatestamp' => gmdate('Y-m-d\TH:i:s\Z', $earliest),
    'deletedRecord' => $config['deletedRecord'],
    'granularity' => 'YYYY-MM-DDThh:mm:ssZ'
];

$oai2 = new Server(
    $baseURL,
    $_GET,
    $identifyResponse,
    [
        'GetRecord' => function ($identifier, $metadataPrefix) {
            global $records, $deleted;
            if (empty($records[$metadataPrefix][$identifier])) {
                return [];
            } else {
                return [
                    'identifier' => $identifier,
                    'timestamp' => filemtime($records[$metadataPrefix][$identifier]),
                    'deleted' => $deleted[$metadataPrefix][$identifier],
                    'metadata' => $records[$metadataPrefix][$identifier]
                ];
            }
        },
        'ListRecords' => function ($metadataPrefix, $from = null, $until = null, $count = false, $deliveredRecords = 0, $maxItems = 100) {
            global $records, $deleted, $timestamps;
            $resultSet = [];
            foreach ($timestamps[$metadataPrefix] as $timestamp => $identifiers) {
                if ((is_null($from) || $timestamp >= $from) && (is_null($until) || $timestamp <= $until)) {
                    foreach ($identifiers as $identifier) {
                        $resultSet[] = [
                            'identifier' => $identifier,
                            'timestamp' => filemtime($records[$metadataPrefix][$identifier]),
                            'deleted' => $deleted[$metadataPrefix][$identifier],
                            'metadata' => $records[$metadataPrefix][$identifier]
                        ];
                    }
                }
            }
            if ($count) {
                return count($resultSet);
            } else {
                return array_slice($resultSet, $deliveredRecords, $maxItems);
            }
        },
        'ListMetadataFormats' => function ($identifier = '') {
            global $config, $records;
            if (!empty($identifier)) {
                $formats = [];
                foreach ($records as $format => $record) {
                    if (!empty($record[$identifier])) {
                        $formats[$format] = $config['metadataPrefix'][$format];
                    }
                }
                if (!empty($formats)) {
                    return $formats;
                } else {
                    throw new Exception('idDoesNotExist');
                }
            } else {
                return $config['metadataPrefix'];
            }
        }
    ],
    $config
);

$response = $oai2->response();

if (isset($return)) {
    return $response;
} else {
    $response->formatOutput = true;
    $response->preserveWhiteSpace = false;
    header('Content-Type: text/xml');
    echo $response->saveXML();
}