<?php
/**
 * Peer Class
 * 
 * Manages BGP peer configurations with full Pathvector options support
 */

require_once __DIR__ . '/FlatFileDB.php';
require_once __DIR__ . '/Logger.php';
require_once __DIR__ . '/Validator.php';

class Peer {
    private FlatFileDB $db;
    private Logger $logger;
    private Validator $validator;
    
    /**
     * Constructor
     * 
     * @param string $dataFile Path to peers JSON file
     * @param Logger $logger Logger instance
     */
    public function __construct(string $dataFile, Logger $logger) {
        $this->db = new FlatFileDB($dataFile);
        $this->logger = $logger;
        $this->validator = new Validator();
        
        if (!$this->db->exists('peers')) {
            $this->db->set('peers', []);
        }
    }
    
    /**
     * Get all peers
     * 
     * @return array
     */
    public function getAll(): array {
        return $this->db->get('peers') ?? [];
    }
    
    /**
     * Get peers by ASN
     * 
     * @param int $asn
     * @return array
     */
    public function getByAsn(int $asn): array {
        $peers = $this->db->get('peers') ?? [];
        return array_filter($peers, fn($peer) => ($peer['asn'] ?? 0) === $asn);
    }
    
    /**
     * Get peers by node
     * 
     * @param string $nodeId
     * @return array
     */
    public function getByNode(string $nodeId): array {
        $peers = $this->db->get('peers') ?? [];
        return array_filter($peers, fn($peer) => ($peer['node'] ?? '') === $nodeId);
    }
    
    /**
     * Get peer by ID
     * 
     * @param string $id
     * @return array|null
     */
    public function get(string $id): ?array {
        $peers = $this->db->get('peers') ?? [];
        return $peers[$id] ?? null;
    }
    
    /**
     * Create new peer
     * 
     * @param array $data
     * @return array
     */
    public function create(array $data): array {
        $this->validator->clear();
        
        // Validate required fields
        if (empty($data['id'])) {
            return [
                'success' => false,
                'message' => 'Peer ID is required',
                'errors' => ['id' => 'Peer ID is required'],
            ];
        }
        
        if (empty($data['asn'])) {
            return [
                'success' => false,
                'message' => 'Local ASN is required',
                'errors' => ['asn' => 'Local ASN is required'],
            ];
        }
        
        if (empty($data['remote_asn'])) {
            return [
                'success' => false,
                'message' => 'Remote ASN is required',
                'errors' => ['remote_asn' => 'Remote ASN is required'],
            ];
        }
        
        if (!$this->validator->validateAsn($data['asn'], 'asn') ||
            !$this->validator->validateAsn($data['remote_asn'], 'remote_asn')) {
            return [
                'success' => false,
                'message' => 'Invalid ASN',
                'errors' => $this->validator->getErrors(),
            ];
        }
        
        $peers = $this->db->get('peers') ?? [];
        $id = $this->sanitizeId($data['id']);
        
        if (isset($peers[$id])) {
            return [
                'success' => false,
                'message' => "Peer $id already exists",
                'errors' => ['id' => 'Peer ID already exists'],
            ];
        }
        
        // Validate neighbors
        $neighbors = $data['neighbors'] ?? [];
        if (!is_array($neighbors)) {
            $neighbors = array_filter(array_map('trim', explode("\n", $neighbors)));
        }
        
        foreach ($neighbors as $neighbor) {
            if (!$this->validator->validateIP($neighbor, 'neighbors')) {
                return [
                    'success' => false,
                    'message' => "Invalid neighbor IP: $neighbor",
                    'errors' => $this->validator->getErrors(),
                ];
            }
        }
        
        $peerData = $this->buildPeerData($id, $data, $neighbors);
        $peers[$id] = $peerData;
        
        if ($this->db->set('peers', $peers)) {
            $this->logger->success('peer', "Created peer: $id (AS{$peerData['remote_asn']}) on node {$peerData['node']}");
            return [
                'success' => true,
                'message' => "Peer $id created successfully",
                'data' => $peerData,
            ];
        }
        
        return [
            'success' => false,
            'message' => 'Failed to save peer',
            'errors' => ['database' => 'Failed to save peer'],
        ];
    }
    
    /**
     * Update peer
     * 
     * @param string $id
     * @param array $data
     * @return array
     */
    public function update(string $id, array $data): array {
        $peers = $this->db->get('peers') ?? [];
        
        if (!isset($peers[$id])) {
            return [
                'success' => false,
                'message' => "Peer $id not found",
                'errors' => ['id' => 'Peer not found'],
            ];
        }
        
        $peerData = $peers[$id];
        
        // Handle neighbors
        if (isset($data['neighbors'])) {
            $neighbors = $data['neighbors'];
            if (!is_array($neighbors)) {
                $neighbors = array_filter(array_map('trim', explode("\n", $neighbors)));
            }
            
            foreach ($neighbors as $neighbor) {
                if (!$this->validator->validateIP($neighbor, 'neighbors')) {
                    return [
                        'success' => false,
                        'message' => "Invalid neighbor IP: $neighbor",
                        'errors' => $this->validator->getErrors(),
                    ];
                }
            }
            $peerData['neighbors'] = array_values($neighbors);
        }
        
        // Update Pathvector options
        if (isset($data['pathvector'])) {
            $peerData['pathvector'] = $this->buildPathvectorOptions(
                array_merge($peerData['pathvector'], $data['pathvector'])
            );
        }
        
        // Update basic fields
        $basicFields = [
            'name', 'description', 'remote_asn', 'node', 'template',
            'afi', 'templates', 'is_active', 'tags'
        ];
        
        foreach ($basicFields as $field) {
            if (isset($data[$field])) {
                $peerData[$field] = $data[$field];
            }
        }
        
        $peerData['updated_at'] = date('c');
        $peers[$id] = $peerData;
        
        if ($this->db->set('peers', $peers)) {
            $this->logger->info('peer', "Updated peer: $id");
            return [
                'success' => true,
                'message' => "Peer $id updated successfully",
                'data' => $peerData,
            ];
        }
        
        return [
            'success' => false,
            'message' => 'Failed to update peer',
            'errors' => ['database' => 'Failed to save peer'],
        ];
    }
    
    /**
     * Delete peer
     * 
     * @param string $id
     * @return array
     */
    public function delete(string $id): array {
        $peers = $this->db->get('peers') ?? [];
        
        if (!isset($peers[$id])) {
            return [
                'success' => false,
                'message' => "Peer $id not found",
            ];
        }
        
        $peerName = $peers[$id]['name'];
        $peerAsn = $peers[$id]['remote_asn'];
        unset($peers[$id]);
        
        if ($this->db->set('peers', $peers)) {
            $this->logger->warning('peer', "Deleted peer: $id ($peerName - AS$peerAsn)");
            return [
                'success' => true,
                'message' => "Peer $id deleted successfully",
            ];
        }
        
        return [
            'success' => false,
            'message' => 'Failed to delete peer',
        ];
    }
    
    /**
     * Build peer data structure
     * 
     * @param string $id
     * @param array $data
     * @param array $neighbors
     * @return array
     */
    private function buildPeerData(string $id, array $data, array $neighbors): array {
        return [
            'id' => $id,
            'name' => $data['name'] ?? $id,
            'description' => $data['description'] ?? '',
            'asn' => (int) $data['asn'],
            'remote_asn' => (int) $data['remote_asn'],
            'node' => $data['node'] ?? '',
            'neighbors' => array_values($neighbors),
            'afi' => $data['afi'] ?? ['ipv4', 'ipv6'],
            'template' => $data['template'] ?? '',
            'templates' => $data['templates'] ?? [],
            'tags' => $data['tags'] ?? [],
            'pathvector' => $this->buildPathvectorOptions($data['pathvector'] ?? []),
            'is_active' => $data['is_active'] ?? true,
            'created_at' => date('c'),
            'updated_at' => date('c'),
        ];
    }
    
    /**
     * Build Pathvector options structure with ALL supported options
     * 
     * @param array $data
     * @return array
     */
    private function buildPathvectorOptions(array $data): array {
        return [
            // Session control
            'disabled' => $data['disabled'] ?? false,
            'import' => $data['import'] ?? true,
            'export' => $data['export'] ?? true,
            
            // BGP attributes
            'local_asn' => $data['local_asn'] ?? null,
            'prepends' => $data['prepends'] ?? 0,
            'prepend_path' => $data['prepend_path'] ?? [],
            'clear_path' => $data['clear_path'] ?? false,
            'local_pref' => $data['local_pref'] ?? 100,
            'local_pref4' => $data['local_pref4'] ?? null,
            'local_pref6' => $data['local_pref6'] ?? null,
            'set_local_pref' => $data['set_local_pref'] ?? false,
            'multihop' => $data['multihop'] ?? null,
            
            // Listening
            'listen4' => $data['listen4'] ?? '',
            'listen6' => $data['listen6'] ?? '',
            'local_port' => $data['local_port'] ?? 179,
            'neighbor_port' => $data['neighbor_port'] ?? 179,
            'passive' => $data['passive'] ?? false,
            'direct' => $data['direct'] ?? false,
            
            // Next-hop
            'next_hop_self' => $data['next_hop_self'] ?? false,
            'next_hop_self_ebgp' => $data['next_hop_self_ebgp'] ?? false,
            'next_hop_self_ibgp' => $data['next_hop_self_ibgp'] ?? false,
            'import_next_hop' => $data['import_next_hop'] ?? '',
            'export_next_hop' => $data['export_next_hop'] ?? '',
            'enforce_peer_nexthop' => $data['enforce_peer_nexthop'] ?? true,
            'force_peer_nexthop' => $data['force_peer_nexthop'] ?? false,
            
            // BFD
            'bfd' => $data['bfd'] ?? false,
            
            // Authentication
            'password' => $data['password'] ?? '',
            
            // Route server / reflector
            'rs_client' => $data['rs_client'] ?? false,
            'rr_client' => $data['rr_client'] ?? false,
            
            // AS path manipulation
            'remove_private_asns' => $data['remove_private_asns'] ?? true,
            'allow_local_as' => $data['allow_local_as'] ?? false,
            'enforce_first_as' => $data['enforce_first_as'] ?? true,
            
            // Multi-protocol
            'mp_unicast_46' => $data['mp_unicast_46'] ?? false,
            
            // Add-path
            'add_path_tx' => $data['add_path_tx'] ?? false,
            'add_path_rx' => $data['add_path_rx'] ?? false,
            
            // Confederation
            'confederation' => $data['confederation'] ?? null,
            'confederation_member' => $data['confederation_member'] ?? false,
            
            // TTL Security
            'ttl_security' => $data['ttl_security'] ?? false,
            
            // Timers and limits
            'receive_limit4' => $data['receive_limit4'] ?? null,
            'receive_limit6' => $data['receive_limit6'] ?? null,
            'receive_limit_violation' => $data['receive_limit_violation'] ?? 'disable',
            'export_limit4' => $data['export_limit4'] ?? null,
            'export_limit6' => $data['export_limit6'] ?? null,
            'export_limit_violation' => $data['export_limit_violation'] ?? 'disable',
            
            // Session options
            'interpret_communities' => $data['interpret_communities'] ?? true,
            'default_local_pref' => $data['default_local_pref'] ?? null,
            'advertise_hostname' => $data['advertise_hostname'] ?? false,
            'disable_after_error' => $data['disable_after_error'] ?? false,
            'prefer_older_routes' => $data['prefer_older_routes'] ?? false,
            
            // IRR
            'irr_accept_child_prefixes' => $data['irr_accept_child_prefixes'] ?? false,
            
            // Communities
            'add_on_import' => $data['add_on_import'] ?? [],
            'add_on_export' => $data['add_on_export'] ?? [],
            'announce' => $data['announce'] ?? [],
            'remove_communities' => $data['remove_communities'] ?? [],
            'remove_all_communities' => $data['remove_all_communities'] ?? null,
            
            // AS preferences
            'as_prefs' => $data['as_prefs'] ?? [],
            'community_prefs' => $data['community_prefs'] ?? [],
            'large_community_prefs' => $data['large_community_prefs'] ?? [],
            
            // AS-SET
            'as_set' => $data['as_set'] ?? '',
            
            // Blackhole
            'allow_blackhole_community' => $data['allow_blackhole_community'] ?? false,
            'blackhole_in' => $data['blackhole_in'] ?? false,
            'blackhole_out' => $data['blackhole_out'] ?? false,
            
            // Filtering
            'filter_irr' => $data['filter_irr'] ?? false,
            'filter_rpki' => $data['filter_rpki'] ?? true,
            'strict_rpki' => $data['strict_rpki'] ?? false,
            'filter_max_prefix' => $data['filter_max_prefix'] ?? true,
            'filter_bogon_routes' => $data['filter_bogon_routes'] ?? true,
            'filter_bogon_asns' => $data['filter_bogon_asns'] ?? true,
            'filter_transit_asns' => $data['filter_transit_asns'] ?? false,
            'filter_prefix_length' => $data['filter_prefix_length'] ?? true,
            'filter_never_via_route_servers' => $data['filter_never_via_route_servers'] ?? false,
            'filter_as_set' => $data['filter_as_set'] ?? false,
            'filter_aspa' => $data['filter_aspa'] ?? false,
            'filter_blocklist' => $data['filter_blocklist'] ?? true,
            
            // Transit lock
            'transit_lock' => $data['transit_lock'] ?? [],
            
            // Announcement control
            'dont_announce' => $data['dont_announce'] ?? [],
            'only_announce' => $data['only_announce'] ?? [],
            'prefix_communities' => $data['prefix_communities'] ?? [],
            
            // Auto-config
            'auto_import_limits' => $data['auto_import_limits'] ?? false,
            'auto_as_set' => $data['auto_as_set'] ?? false,
            'auto_as_set_members' => $data['auto_as_set_members'] ?? false,
            
            // Graceful shutdown
            'honor_graceful_shutdown' => $data['honor_graceful_shutdown'] ?? true,
            
            // Prefixes
            'prefixes' => $data['prefixes'] ?? [],
            'as_set_members' => $data['as_set_members'] ?? [],
            
            // BGP Role (RFC 9234)
            'role' => $data['role'] ?? '',
            'require_roles' => $data['require_roles'] ?? false,
            
            // Export options
            'announce_default' => $data['announce_default'] ?? false,
            'announce_originated' => $data['announce_originated'] ?? true,
            'announce_all' => $data['announce_all'] ?? false,
            
            // Custom config
            'session_global' => $data['session_global'] ?? '',
            'pre_import_filter' => $data['pre_import_filter'] ?? '',
            'post_import_filter' => $data['post_import_filter'] ?? '',
            'pre_import_accept' => $data['pre_import_accept'] ?? '',
            'pre_export' => $data['pre_export'] ?? '',
            'pre_export_final' => $data['pre_export_final'] ?? '',
            
            // Route optimization
            'probe_sources' => $data['probe_sources'] ?? [],
            'optimize_inbound' => $data['optimize_inbound'] ?? false,
        ];
    }
    
    /**
     * Sanitize peer ID
     * 
     * @param string $id
     * @return string
     */
    private function sanitizeId(string $id): string {
        $id = strtolower(trim($id));
        $id = preg_replace('/\s+/', '-', $id);
        $id = preg_replace('/[^a-z0-9-_]/', '', $id);
        return $id;
    }
    
    /**
     * Count peers
     * 
     * @return int
     */
    public function count(): int {
        $peers = $this->db->get('peers') ?? [];
        return count($peers);
    }
    
    /**
     * Search peers
     * 
     * @param string $query
     * @return array
     */
    public function search(string $query): array {
        $peers = $this->db->get('peers') ?? [];
        $query = strtolower($query);
        
        return array_filter($peers, function($peer) use ($query) {
            return strpos(strtolower($peer['id']), $query) !== false ||
                   strpos(strtolower($peer['name']), $query) !== false ||
                   strpos((string) $peer['remote_asn'], $query) !== false ||
                   strpos(strtolower($peer['description'] ?? ''), $query) !== false;
        });
    }
    
    /**
     * Export peer to YAML format
     * 
     * @param string $id
     * @return string|null
     */
    public function exportYaml(string $id): ?string {
        $peer = $this->get($id);
        
        if (!$peer) {
            return null;
        }
        
        $pv = $peer['pathvector'];
        $config = [];
        
        // Required fields
        $config['asn'] = $peer['remote_asn'];
        
        if (!empty($peer['template'])) {
            $config['template'] = $peer['template'];
        }
        
        if (!empty($peer['neighbors'])) {
            $config['neighbors'] = $peer['neighbors'];
        }
        
        // Add description if set
        if (!empty($peer['description'])) {
            $config['description'] = $peer['description'];
        }
        
        // Add all non-default Pathvector options
        $this->addNonDefaultOptions($config, $pv);
        
        // Build YAML with peer name as key
        $peerName = $peer['name'];
        $yaml = "  $peerName:\n";
        
        foreach ($config as $key => $value) {
            $yamlKey = str_replace('_', '-', $key);
            $yaml .= $this->formatYamlEntry($yamlKey, $value, 2);
        }
        
        return $yaml;
    }
    
    /**
     * Add non-default options to config array
     * 
     * @param array &$config
     * @param array $pv
     */
    private function addNonDefaultOptions(array &$config, array $pv): void {
        $defaults = $this->buildPathvectorOptions([]);
        
        foreach ($pv as $key => $value) {
            // Skip if same as default
            if (isset($defaults[$key]) && $defaults[$key] === $value) {
                continue;
            }
            
            // Skip empty values
            if ($value === '' || $value === null || $value === []) {
                continue;
            }
            
            // Skip certain internal fields
            if (in_array($key, ['template', 'neighbors'])) {
                continue;
            }
            
            $config[$key] = $value;
        }
    }
    
    /**
     * Format YAML entry
     * 
     * @param string $key
     * @param mixed $value
     * @param int $indent
     * @return string
     */
    private function formatYamlEntry(string $key, $value, int $indent): string {
        $prefix = str_repeat('  ', $indent);
        
        if (is_array($value)) {
            if (empty($value)) {
                return '';
            }
            
            if (array_keys($value) === range(0, count($value) - 1)) {
                // Sequential array
                $yaml = "$prefix$key:\n";
                foreach ($value as $item) {
                    $yaml .= "$prefix  - " . $this->formatYamlValue($item) . "\n";
                }
                return $yaml;
            } else {
                // Associative array
                $yaml = "$prefix$key:\n";
                foreach ($value as $k => $v) {
                    $yaml .= $this->formatYamlEntry($k, $v, $indent + 1);
                }
                return $yaml;
            }
        }
        
        return "$prefix$key: " . $this->formatYamlValue($value) . "\n";
    }
    
    /**
     * Format value for YAML
     * 
     * @param mixed $value
     * @return string
     */
    private function formatYamlValue($value): string {
        if (is_bool($value)) {
            return $value ? 'true' : 'false';
        }
        
        if (is_numeric($value)) {
            return (string) $value;
        }
        
        if (is_string($value) && (strpos($value, ':') !== false || strpos($value, '#') !== false)) {
            return '"' . addslashes($value) . '"';
        }
        
        return (string) $value;
    }
    
    /**
     * Get peers grouped by type (based on template or ASN type)
     * 
     * @return array
     */
    public function getGroupedByType(): array {
        $peers = $this->db->get('peers') ?? [];
        $grouped = [
            'upstream' => [],
            'downstream' => [],
            'peer' => [],
            'routeserver' => [],
            'ibgp' => [],
            'other' => [],
        ];
        
        foreach ($peers as $id => $peer) {
            $template = strtolower($peer['template'] ?? '');
            
            if (strpos($template, 'upstream') !== false) {
                $grouped['upstream'][$id] = $peer;
            } elseif (strpos($template, 'downstream') !== false) {
                $grouped['downstream'][$id] = $peer;
            } elseif (strpos($template, 'routeserver') !== false || strpos($template, 'rs') !== false) {
                $grouped['routeserver'][$id] = $peer;
            } elseif ($peer['asn'] === $peer['remote_asn']) {
                $grouped['ibgp'][$id] = $peer;
            } elseif (strpos($template, 'peer') !== false) {
                $grouped['peer'][$id] = $peer;
            } else {
                $grouped['other'][$id] = $peer;
            }
        }
        
        return $grouped;
    }
    
    /**
     * Backup peers data
     * 
     * @param string $backupDir
     * @return string|false
     */
    public function backup(string $backupDir): string|false {
        return $this->db->backup($backupDir);
    }
}