<?php
require_once __DIR__ . '/../helpers.php';
runAuth();

global $businessId;

$data = readJsonBody();
$bizId = $businessId;
if ($bizId <= 0) $bizId = (int) ($data['BusinessID'] ?? 0);
if ($bizId <= 0) {
    apiAbort(['OK' => false, 'ERROR' => 'missing_business_id', 'MESSAGE' => 'BusinessID is required']);
}

try {
    $qBiz = queryOne("SELECT ID, BeaconShardID, BeaconMajor FROM Businesses WHERE ID = ? LIMIT 1", [$bizId]);
    if (!$qBiz) {
        apiAbort(['OK' => false, 'ERROR' => 'invalid_business', 'MESSAGE' => 'Business not found']);
    }

    // Already allocated
    if ((int) ($qBiz['BeaconShardID'] ?? 0) > 0 && $qBiz['BeaconMajor'] !== null) {
        $qShard = queryOne("SELECT UUID FROM BeaconShards WHERE ID = ?", [(int) $qBiz['BeaconShardID']]);
        jsonResponse([
            'OK' => true,
            'BusinessID' => $bizId,
            'BeaconShardUUID' => $qShard['UUID'],
            'BeaconMajor' => (int) $qBiz['BeaconMajor'],
            'ShardID' => (int) $qBiz['BeaconShardID'],
            'AlreadyAllocated' => true,
        ]);
    }

    // Find shard with lowest utilization
    $qShard = queryOne("
        SELECT ID, UUID, BusinessCount FROM BeaconShards
        WHERE IsActive = 1 AND BusinessCount < MaxBusinesses
        ORDER BY BusinessCount ASC LIMIT 1
    ", []);

    if (!$qShard) {
        apiAbort(['OK' => false, 'ERROR' => 'no_available_shards', 'MESSAGE' => 'All beacon shards are at capacity']);
    }

    $shardId = (int) $qShard['ID'];
    $shardUUID = $qShard['UUID'];

    $qMaxMajor = queryOne("
        SELECT COALESCE(MAX(BeaconMajor), -1) AS MaxMajor FROM Businesses WHERE BeaconShardID = ?
    ", [$shardId]);
    $nextMajor = (int) $qMaxMajor['MaxMajor'] + 1;

    if ($nextMajor > 65535) {
        apiAbort(['OK' => false, 'ERROR' => 'shard_full', 'MESSAGE' => 'Shard has reached maximum major value']);
    }

    queryTimed("
        UPDATE Businesses SET BeaconShardID = ?, BeaconMajor = ?
        WHERE ID = ? AND (BeaconShardID IS NULL OR BeaconMajor IS NULL)
    ", [$shardId, $nextMajor, $bizId]);

    queryTimed("UPDATE BeaconShards SET BusinessCount = BusinessCount + 1 WHERE ID = ?", [$shardId]);

    jsonResponse([
        'OK' => true,
        'BusinessID' => $bizId,
        'BeaconShardUUID' => $shardUUID,
        'BeaconMajor' => $nextMajor,
        'ShardID' => $shardId,
        'AlreadyAllocated' => false,
    ]);

} catch (Exception $e) {
    jsonResponse(['OK' => false, 'ERROR' => 'server_error', 'MESSAGE' => $e->getMessage()]);
}