<?php
require_once __DIR__ . '/db.php';
require_once __DIR__ . '/../version.php';

// ── Node helpers ──────────────────────────────────────────────────────────────

function get_all_nodes(): array {
    return db()->query('SELECT * FROM nodes ORDER BY name')->fetchAll();
}

function get_node(int $id): array|false {
    $s = db()->prepare('SELECT * FROM nodes WHERE id = ?');
    $s->execute([$id]);
    return $s->fetch();
}

function upsert_node(array $data, ?int $id = null): int {
    $pdo = db();
    if ($id) {
        $s = $pdo->prepare(
            'UPDATE nodes SET name=?, api_url=?, username=?, password=?,
             verify_ssl=?, enabled=? WHERE id=?'
        );
        $s->execute([
            $data['name'], $data['api_url'], $data['username'], $data['password'],
            (int)($data['verify_ssl'] ?? 0), (int)($data['enabled'] ?? 1), $id,
        ]);
        return $id;
    }
    $s = $pdo->prepare(
        'INSERT INTO nodes (name, api_url, username, password, verify_ssl, enabled)
         VALUES (?, ?, ?, ?, ?, ?)'
    );
    $s->execute([
        $data['name'], $data['api_url'], $data['username'], $data['password'],
        (int)($data['verify_ssl'] ?? 0), (int)($data['enabled'] ?? 1),
    ]);
    return (int)$pdo->lastInsertId();
}

function delete_node(int $id): void {
    $s = db()->prepare('DELETE FROM nodes WHERE id = ?');
    $s->execute([$id]);
}

// ── Fetch helpers ─────────────────────────────────────────────────────────────

/**
 * Call the portspoof_py JSON API on a node.
 * Returns decoded JSON on success, or false on failure.
 */
function fetch_node_api(array $node, string $path): mixed {
    $url = rtrim($node['api_url'], '/') . $path;
    $ch  = curl_init($url);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT        => FETCH_TIMEOUT,
        CURLOPT_USERPWD        => $node['username'] . ':' . $node['password'],
        CURLOPT_HTTPAUTH       => CURLAUTH_BASIC,
        CURLOPT_SSL_VERIFYPEER => (bool)$node['verify_ssl'],
        CURLOPT_SSL_VERIFYHOST => $node['verify_ssl'] ? 2 : 0,
        CURLOPT_HTTPHEADER     => ['Accept: application/json'],
    ]);
    $body = curl_exec($ch);
    $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($body === false || $code !== 200) {
        return false;
    }
    return json_decode($body, true);
}

/**
 * Ingest connection events from portspoof_py that are strictly newer than
 * $last_event_at (ISO 8601 string, or null to ingest everything).
 *
 * Returns ['inserted' => int, 'new_max_ts' => string|null]
 * where new_max_ts is the DATETIME(6) of the newest row inserted, or null if
 * nothing new was inserted.
 */
function ingest_connections(int $node_id, array $events, ?string $last_event_at): array {
    $inserted   = 0;
    $new_max_ts = null;

    $s = db()->prepare(
        'INSERT INTO connections
         (node_id, occurred_at, src_ip, src_port, dst_port, banner_hex, banner_len)
         VALUES (?, ?, ?, ?, ?, ?, ?)'
    );

    foreach ($events as $ev) {
        $raw_ts = $ev['timestamp'] ?? null;
        if ($raw_ts === null) {
            continue;
        }

        // Normalise to MySQL DATETIME(6)
        $ts = date('Y-m-d H:i:s.u', strtotime($raw_ts));

        // Skip events already ingested
        if ($last_event_at !== null && $ts <= $last_event_at) {
            continue;
        }

        $s->execute([
            $node_id,
            $ts,
            $ev['src_ip']   ?? '',
            (int)($ev['src_port']  ?? 0),
            (int)($ev['dst_port']  ?? 0),
            $ev['banner_hex'] ?? null,
            (int)($ev['banner_len'] ?? 0),
        ]);
        $inserted++;

        if ($new_max_ts === null || $ts > $new_max_ts) {
            $new_max_ts = $ts;
        }
    }

    return ['inserted' => $inserted, 'new_max_ts' => $new_max_ts];
}

/**
 * Poll every enabled node, ingest new events, and advance each node's cursor.
 *
 * Returns an array of per-node result maps:
 *   ['node_id', 'name', 'fetched', 'inserted', 'last_event_at', 'error']
 */
function run_fetch(): array {
    $nodes   = get_all_nodes();
    $enabled = array_filter($nodes, fn($n) => (bool)$n['enabled']);
    $results = [];

    foreach ($enabled as $node) {
        $entry = [
            'node_id'       => (int)$node['id'],
            'name'          => $node['name'],
            'fetched'       => 0,
            'inserted'      => 0,
            'last_event_at' => $node['last_event_at'],
            'error'         => null,
        ];

        $events = fetch_node_api($node, '/api/connections?limit=' . FETCH_LIMIT);

        if ($events === false) {
            $entry['error'] = 'could not reach API';
            $results[] = $entry;
            continue;
        }

        if (!is_array($events)) {
            $entry['error'] = 'unexpected API response';
            $results[] = $entry;
            continue;
        }

        $entry['fetched'] = count($events);
        $result = ingest_connections((int)$node['id'], $events, $node['last_event_at']);
        $entry['inserted'] = $result['inserted'];

        $s = db()->prepare(
            'UPDATE nodes SET last_fetched_at = NOW()'
            . ($result['new_max_ts'] !== null ? ', last_event_at = ?' : '')
            . ' WHERE id = ?'
        );
        $params = $result['new_max_ts'] !== null
            ? [$result['new_max_ts'], $node['id']]
            : [$node['id']];
        $s->execute($params);

        if ($result['new_max_ts'] !== null) {
            $entry['last_event_at'] = $result['new_max_ts'];
        }

        $results[] = $entry;
    }

    return $results;
}

// ── Settings ──────────────────────────────────────────────────────────────────

function get_setting(string $key, string $default = ''): string {
    $s = db()->prepare('SELECT value FROM settings WHERE key_name = ?');
    $s->execute([$key]);
    $row = $s->fetchColumn();
    return $row !== false ? $row : $default;
}

function set_setting(string $key, string $value): void {
    $s = db()->prepare(
        'INSERT INTO settings (key_name, value) VALUES (?, ?)
         ON DUPLICATE KEY UPDATE value = VALUES(value)'
    );
    $s->execute([$key, $value]);
}

// ── Purge ─────────────────────────────────────────────────────────────────────

/**
 * Delete connections older than retention_days setting.
 * Returns the number of rows deleted.
 */
function purge_old_connections(): int {
    $days = max(1, (int)get_setting('retention_days', '7'));
    $s = db()->prepare(
        'DELETE FROM connections WHERE occurred_at < NOW() - INTERVAL ? DAY'
    );
    $s->execute([$days]);
    return $s->rowCount();
}

// ── Upstream version check ────────────────────────────────────────────────────

define('UPSTREAM_VERSION_URL', 'https://git.ny.daprogs.com/api/v1/repos/DAProgs/portspoof_concentrator/raw/version.php?ref=main');
define('UPSTREAM_VERSION_CACHE', __DIR__ . '/../upstream_version.cache');
define('UPSTREAM_VERSION_TTL', 3600); // seconds

/**
 * Fetch the upstream version string from the git repo, with a 1-hour file cache.
 * Returns null silently on any failure so the page always loads.
 */
function fetch_upstream_version(): ?string {
    // Return cached value if still fresh
    if (file_exists(UPSTREAM_VERSION_CACHE)) {
        $cached = json_decode(file_get_contents(UPSTREAM_VERSION_CACHE), true);
        if (isset($cached['version'], $cached['checked_at'])
            && (time() - $cached['checked_at']) < UPSTREAM_VERSION_TTL) {
            return $cached['version'];
        }
    }

    $ch = curl_init(UPSTREAM_VERSION_URL);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT        => 5,
        CURLOPT_FOLLOWLOCATION => true,
    ]);
    $body = curl_exec($ch);
    $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($body === false || $code !== 200) {
        return null;
    }

    if (!preg_match("/define\s*\(\s*'APP_VERSION'\s*,\s*'([^']+)'\s*\)/", $body, $m)) {
        return null;
    }

    $version = $m[1];
    file_put_contents(
        UPSTREAM_VERSION_CACHE,
        json_encode(['version' => $version, 'checked_at' => time()]),
        LOCK_EX
    );
    return $version;
}

/**
 * Returns true if $upstream is a newer version than $local.
 * Format: YYMM.N  e.g. 2603.4
 */
function is_newer_version(string $upstream, string $local): bool {
    $parse = fn($v) => array_map('intval', explode('.', $v, 2));
    [$um, $un] = $parse($upstream);
    [$lm, $ln] = $parse($local);
    return $um > $lm || ($um === $lm && $un > $ln);
}

// ── API queries ───────────────────────────────────────────────────────────────

/**
 * Return connections from the last $minutes minutes, newest first.
 * Optionally filtered to a single node.
 */
function connections_since(int $minutes = 10, ?int $node_id = null): array {
    $since = date('Y-m-d H:i:s', time() - $minutes * 60);

    if ($node_id !== null) {
        $s = db()->prepare(
            'SELECT c.id, c.occurred_at, c.src_ip, c.src_port, c.dst_port,
                    c.banner_hex, c.banner_len, n.name AS node_name, n.id AS node_id
             FROM connections c JOIN nodes n ON n.id = c.node_id
             WHERE c.node_id = ? AND c.occurred_at >= ?
             ORDER BY c.occurred_at DESC'
        );
        $s->execute([$node_id, $since]);
    } else {
        $s = db()->prepare(
            'SELECT c.id, c.occurred_at, c.src_ip, c.src_port, c.dst_port,
                    c.banner_hex, c.banner_len, n.name AS node_name, n.id AS node_id
             FROM connections c JOIN nodes n ON n.id = c.node_id
             WHERE c.occurred_at >= ?
             ORDER BY c.occurred_at DESC'
        );
        $s->execute([$since]);
    }
    return $s->fetchAll();
}

// ── Dashboard stats ───────────────────────────────────────────────────────────

function global_stats(): array {
    $pdo = db();

    $total = (int)$pdo->query('SELECT COUNT(*) FROM connections')->fetchColumn();

    $since = date('Y-m-d H:i:s', time() - RATE_WINDOW_SECONDS);
    $recent = (int)$pdo->prepare('SELECT COUNT(*) FROM connections WHERE occurred_at >= ?')
                        ->execute([$since]) ? : 0;
    $s = $pdo->prepare('SELECT COUNT(*) FROM connections WHERE occurred_at >= ?');
    $s->execute([$since]);
    $recent = (int)$s->fetchColumn();

    $s = $pdo->query('SELECT MAX(occurred_at) FROM connections');
    $last = $s->fetchColumn() ?: null;

    return compact('total', 'recent', 'last');
}

function top_ips(int $n = TOP_N): array {
    $s = db()->prepare(
        'SELECT src_ip, COUNT(*) AS cnt
         FROM connections
         WHERE occurred_at >= NOW() - INTERVAL 24 HOUR
         GROUP BY src_ip
         ORDER BY cnt DESC
         LIMIT ?'
    );
    $s->execute([$n]);
    return $s->fetchAll();
}

function top_ports(int $n = TOP_N): array {
    $s = db()->prepare(
        'SELECT dst_port, COUNT(*) AS cnt
         FROM connections
         WHERE occurred_at >= NOW() - INTERVAL 24 HOUR
         GROUP BY dst_port
         ORDER BY cnt DESC
         LIMIT ?'
    );
    $s->execute([$n]);
    return $s->fetchAll();
}

function top_ips_by_node(int $node_id, int $n = TOP_N): array {
    $s = db()->prepare(
        'SELECT src_ip, COUNT(*) AS cnt
         FROM connections
         WHERE node_id = ? AND occurred_at >= NOW() - INTERVAL 24 HOUR
         GROUP BY src_ip
         ORDER BY cnt DESC
         LIMIT ?'
    );
    $s->execute([$node_id, $n]);
    return $s->fetchAll();
}

function recent_connections(int $limit = DASH_RECENT_LIMIT, ?int $node_id = null): array {
    if ($node_id !== null) {
        $s = db()->prepare(
            'SELECT c.*, n.name AS node_name
             FROM connections c JOIN nodes n ON n.id = c.node_id
             WHERE c.node_id = ?
             ORDER BY c.occurred_at DESC
             LIMIT ?'
        );
        $s->execute([$node_id, $limit]);
    } else {
        $s = db()->prepare(
            'SELECT c.*, n.name AS node_name
             FROM connections c JOIN nodes n ON n.id = c.node_id
             ORDER BY c.occurred_at DESC
             LIMIT ?'
        );
        $s->execute([$limit]);
    }
    return $s->fetchAll();
}

// ── Misc ──────────────────────────────────────────────────────────────────────

function h(string $s): string {
    return htmlspecialchars($s, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
}

function banner_text(string $hex): string {
    $raw = hex2bin($hex);
    if ($raw === false) return '';
    return mb_convert_encoding($raw, 'UTF-8', 'latin-1');
}