<?php
// reproduce datastore 409 error: too much contention on these datastore entities
// 1. run: php datastore409.php
// 2. run: php datastore409.php update
// 3. you will see error:

// Fatal error: Uncaught exception 'Google\Cloud\Core\Exception\ConflictException' with message '{
//   "error": {
//     "code": 409,
//     "message": "too much contention on these datastore entities. please try again.",
//     "status": "ABORTED"
//   }
// }
// Includes the autoloader for libraries installed with composer
require __DIR__ . '/vendor/autoload.php';

// Imports the Google Cloud client library
use Google\Cloud\Datastore\DatastoreClient;

// Instantiates a client
$datastore = new DatastoreClient([
    'keyFilePath' =>  __DIR__ . '/config/gcloud_key.json',
    'namespaceId' => 'test',
]);


if (count($argv) == 1) {
    // The kind for the new entity
    $kind = 'Task';

    // The name/ID for the new entity
    $name = 'sampleTask';

    // The Cloud Datastore key for the new entity
    $taskKey = $datastore->key($kind, $name);

    // Prepares the new entity
    $task = $datastore->entity($taskKey, ['description' => 'Buy milk']);

    // Saves the entity
    $datastore->upsert($task);

    echo 'Saved ' . $task->key() . ': ' . $task['description'] . PHP_EOL;


    $transaction = $datastore->transaction();
    $key = $datastore->key('Task', 'sampleTask');
    $task = $transaction->lookup($key);
    var_dump($task);
    echo 'now you should open another terminal and run: ' . "\n\n";
    echo '          php datastore409.php update' . "\n\n";
    echo 'then come back here to see result:' . "\n";
    sleep(10);
    $task['priority'] = 'slow' . time();
    try {
        $transaction->upsert($task);
        $transaction->commit();
    } catch (Google\Cloud\Core\Exception\ConflictException $e) {
        echo $e->getMessage() . "\n";
        $task_in_datastore = $datastore->lookup($key);
        echo 'datastore entity version: ' . $task_in_datastore->baseVersion() . "\n";
        echo 'php       entity version: ' . $task->baseVersion() . "\n";
        echo 'your data version is older than datastore, so 409 error happened' . "\n";
    }
} elseif (!empty($argv[1]) && $argv[1] == 'update') {
    $transaction = $datastore->transaction();
    $key = $datastore->key('Task', 'sampleTask');
    $task = $transaction->lookup($key);
    $task['priority'] = 'fast' . time();
    $transaction->upsert($task);
    $transaction->commit();
    echo 'I have updated the entity before you.' . "\n";
}