<?php
/**
 * 数据访问层(全部使用预处理语句)
 */
require_once __DIR__ . DIRECTORY_SEPARATOR . 'db.php';

/* ============================================================
 * 通用工具
 * ============================================================ */
function now_iso()
{
    return date('c');
}

function gen_id($prefix)
{
    return $prefix . bin2hex(random_bytes(8));
}

function db_all($sql, $params = array())
{
    $st = db()->prepare($sql);
    $st->execute($params);
    return $st->fetchAll();
}

function db_one($sql, $params = array())
{
    $st = db()->prepare($sql);
    $st->execute($params);
    $row = $st->fetch();
    return $row === false ? null : $row;
}

function db_val($sql, $params = array())
{
    $st = db()->prepare($sql);
    $st->execute($params);
    return $st->fetchColumn();
}

function db_run($sql, $params = array())
{
    $st = db()->prepare($sql);
    $st->execute($params);
    return $st;
}

function like_param($q)
{
    return '%' . $q . '%';
}

/* ============================================================
 * 用户
 * ============================================================ */
function user_find_by_name($username)
{
    return db_one('SELECT * FROM users WHERE username = ?', array($username));
}

function user_find_by_id($id)
{
    return db_one('SELECT * FROM users WHERE id = ?', array($id));
}

function user_name_map()
{
    $map = array();
    foreach (db_all('SELECT id, username FROM users') as $r) {
        $map[$r['id']] = $r['username'];
    }
    return $map;
}

function user_search($q, $limit, $offset)
{
    $limit = (int) $limit;
    $offset = (int) $offset;
    if ($q === '') {
        return db_all('SELECT * FROM users ORDER BY created_at DESC, username ASC LIMIT ' . $limit . ' OFFSET ' . $offset);
    }
    $p = like_param($q);
    return db_all(
        'SELECT * FROM users WHERE username LIKE ? OR role LIKE ? ORDER BY created_at DESC, username ASC LIMIT ' . $limit . ' OFFSET ' . $offset,
        array($p, $p)
    );
}

function user_count($q)
{
    if ($q === '') {
        return (int) db_val('SELECT COUNT(*) FROM users');
    }
    $p = like_param($q);
    return (int) db_val('SELECT COUNT(*) FROM users WHERE username LIKE ? OR role LIKE ?', array($p, $p));
}

function user_insert($data)
{
    db_run(
        'INSERT INTO users (id, username, password_hash, role, disabled, must_change_password, protected, created_at, last_login_at, login_count)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)',
        array(
            $data['id'],
            $data['username'],
            $data['password_hash'],
            isset($data['role']) ? $data['role'] : 'user',
            !empty($data['disabled']) ? 1 : 0,
            !empty($data['must_change_password']) ? 1 : 0,
            !empty($data['protected']) ? 1 : 0,
            isset($data['created_at']) ? $data['created_at'] : now_iso(),
            isset($data['last_login_at']) ? $data['last_login_at'] : null,
            isset($data['login_count']) ? (int) $data['login_count'] : 0,
        )
    );
    return $data['id'];
}

function user_update($id, $fields)
{
    $allowed = array('username', 'password_hash', 'role', 'disabled', 'must_change_password');
    $sets = array();
    $params = array();
    foreach ($allowed as $f) {
        if (array_key_exists($f, $fields)) {
            $sets[] = $f . ' = ?';
            $params[] = $fields[$f];
        }
    }
    if (!$sets) {
        return false;
    }
    $params[] = $id;
    db_run('UPDATE users SET ' . implode(', ', $sets) . ' WHERE id = ?', $params);
    return true;
}

function user_delete($id)
{
    db_run('DELETE FROM users WHERE id = ?', array($id));
    db_run('DELETE FROM sessions WHERE user_id = ?', array($id));
}

function user_touch_login($id)
{
    db_run('UPDATE users SET last_login_at = ?, login_count = login_count + 1 WHERE id = ?', array(now_iso(), $id));
}

/* ============================================================
 * 用户分组
 * ============================================================ */
function group_list()
{
    return db_all('SELECT * FROM user_groups ORDER BY created_at ASC, name ASC');
}

function group_find($id)
{
    return db_one('SELECT * FROM user_groups WHERE id = ?', array($id));
}

function group_find_by_name($name)
{
    return db_one('SELECT * FROM user_groups WHERE name = ?', array($name));
}

function group_insert($data)
{
    db_run(
        'INSERT INTO user_groups (id, name, description, created_at, updated_at) VALUES (?, ?, ?, ?, ?)',
        array(
            $data['id'],
            $data['name'],
            isset($data['description']) ? $data['description'] : '',
            isset($data['created_at']) ? $data['created_at'] : now_iso(),
            isset($data['updated_at']) ? $data['updated_at'] : now_iso(),
        )
    );
    return $data['id'];
}

function group_update($id, $fields)
{
    $allowed = array('name', 'description');
    $sets = array();
    $params = array();
    foreach ($allowed as $f) {
        if (array_key_exists($f, $fields)) {
            $sets[] = $f . ' = ?';
            $params[] = $fields[$f];
        }
    }
    if (!$sets) {
        return false;
    }
    $sets[] = 'updated_at = ?';
    $params[] = now_iso();
    $params[] = $id;
    db_run('UPDATE user_groups SET ' . implode(', ', $sets) . ' WHERE id = ?', $params);
    return true;
}

function group_delete($id)
{
    db_run('DELETE FROM user_groups WHERE id = ?', array($id));
    db_run('DELETE FROM user_group_members WHERE group_id = ?', array($id));
    db_run("DELETE FROM topo_shares WHERE target_type = 'group' AND target_id = ?", array($id));
}

function group_members($gid)
{
    return db_all(
        'SELECT u.id, u.username FROM user_group_members m JOIN users u ON u.id = m.user_id
         WHERE m.group_id = ? ORDER BY u.username ASC',
        array($gid)
    );
}

function group_member_ids($gid)
{
    $out = array();
    foreach (db_all('SELECT user_id FROM user_group_members WHERE group_id = ?', array($gid)) as $r) {
        $out[] = $r['user_id'];
    }
    return $out;
}

function group_set_members($gid, $userIds)
{
    db_run('DELETE FROM user_group_members WHERE group_id = ?', array($gid));
    $seen = array();
    foreach ((array) $userIds as $uid) {
        $uid = (string) $uid;
        if ($uid === '' || isset($seen[$uid])) {
            continue;
        }
        $seen[$uid] = true;
        db_run(
            'INSERT INTO user_group_members (group_id, user_id, created_at) VALUES (?, ?, ?)',
            array($gid, $uid, now_iso())
        );
    }
}

function group_ids_of_user($uid)
{
    $out = array();
    foreach (db_all('SELECT group_id FROM user_group_members WHERE user_id = ?', array($uid)) as $r) {
        $out[] = $r['group_id'];
    }
    return $out;
}

function group_member_counts()
{
    $map = array();
    foreach (db_all('SELECT group_id, COUNT(*) AS c FROM user_group_members GROUP BY group_id') as $r) {
        $map[$r['group_id']] = (int) $r['c'];
    }
    return $map;
}

/* ============================================================
 * 会话
 * ============================================================ */
function session_create($token, $userId, $expires, $ip, $ua)
{
    db_run(
        'INSERT INTO sessions (token, user_id, created_at, expires_at, ip, user_agent) VALUES (?, ?, ?, ?, ?, ?)',
        array($token, $userId, now_iso(), (int) $expires, $ip, $ua)
    );
}

function session_find($token)
{
    return db_one('SELECT * FROM sessions WHERE token = ?', array($token));
}

function session_delete($token)
{
    db_run('DELETE FROM sessions WHERE token = ?', array($token));
}

function session_delete_by_user($userId)
{
    db_run('DELETE FROM sessions WHERE user_id = ?', array($userId));
}

function session_purge_expired($now)
{
    db_run('DELETE FROM sessions WHERE expires_at < ?', array((int) $now));
}

/* ============================================================
 * 拓扑
 * ============================================================ */
function topo_find($id)
{
    return db_one('SELECT * FROM topologies WHERE id = ?', array($id));
}

function topo_list_for_user($user)
{
    /* 主应用 / 用户后台返回:本人创建的 + 公开的 + 通过成员/分组共享且已开启共享模式的。
       全部拓扑(含他人私有)只能在管理后台查看,见 topo_admin_search()。 */
    return db_all(
        "SELECT DISTINCT t.* FROM topologies t
         LEFT JOIN topo_shares s ON s.topo_id = t.id
         WHERE t.owner_id = ?
            OR t.visibility = 'public'
            OR (t.share_mode = 1 AND (
                 (s.target_type = 'user' AND s.target_id = ?)
                 OR (s.target_type = 'group' AND s.target_id IN (
                       SELECT group_id FROM user_group_members WHERE user_id = ?
                 ))
            ))
         ORDER BY t.updated_at DESC",
        array($user['id'], $user['id'], $user['id'])
    );
}

function topo_admin_search($q, $ownerId, $limit, $offset)
{
    $limit = (int) $limit;
    $offset = (int) $offset;
    $where = array();
    $params = array();
    if ($q !== '') {
        $where[] = 'name LIKE ?';
        $params[] = like_param($q);
    }
    if ($ownerId !== '') {
        $where[] = 'owner_id = ?';
        $params[] = $ownerId;
    }
    $sql = 'SELECT * FROM topologies';
    if ($where) {
        $sql .= ' WHERE ' . implode(' AND ', $where);
    }
    $sql .= ' ORDER BY updated_at DESC LIMIT ' . $limit . ' OFFSET ' . $offset;
    return db_all($sql, $params);
}

function topo_admin_count($q, $ownerId)
{
    $where = array();
    $params = array();
    if ($q !== '') {
        $where[] = 'name LIKE ?';
        $params[] = like_param($q);
    }
    if ($ownerId !== '') {
        $where[] = 'owner_id = ?';
        $params[] = $ownerId;
    }
    $sql = 'SELECT COUNT(*) FROM topologies';
    if ($where) {
        $sql .= ' WHERE ' . implode(' AND ', $where);
    }
    return (int) db_val($sql, $params);
}

function topo_recent($limit)
{
    $limit = (int) $limit;
    return db_all('SELECT * FROM topologies ORDER BY updated_at DESC LIMIT ' . $limit);
}

/* 导出用:根据 id 列表返回完整行;ids 为空时返回全部 */
function topo_export_rows($ids)
{
    if (empty($ids)) {
        return db_all('SELECT * FROM topologies ORDER BY updated_at DESC');
    }
    $ph = implode(',', array_fill(0, count($ids), '?'));
    return db_all('SELECT * FROM topologies WHERE id IN (' . $ph . ') ORDER BY updated_at DESC', $ids);
}

function topo_insert($t)
{
    db_run(
        'INSERT INTO topologies (id, name, owner_id, visibility, data, node_count, edge_count, created_at, updated_at)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)',
        array(
            $t['id'],
            $t['name'],
            $t['owner_id'],
            isset($t['visibility']) ? $t['visibility'] : 'private',
            isset($t['data']) ? $t['data'] : '{"nodes":[],"edges":[]}',
            isset($t['node_count']) ? (int) $t['node_count'] : 0,
            isset($t['edge_count']) ? (int) $t['edge_count'] : 0,
            isset($t['created_at']) ? $t['created_at'] : now_iso(),
            isset($t['updated_at']) ? $t['updated_at'] : now_iso(),
        )
    );
    return $t['id'];
}

function topo_update($id, $data, $nodeCount, $edgeCount, $updatedAt, $name = null)
{
    if ($name !== null && $name !== '') {
        db_run(
            'UPDATE topologies SET data = ?, node_count = ?, edge_count = ?, updated_at = ?, rev = rev + 1, name = ? WHERE id = ?',
            array($data, (int) $nodeCount, (int) $edgeCount, $updatedAt, $name, $id)
        );
    } else {
        db_run(
            'UPDATE topologies SET data = ?, node_count = ?, edge_count = ?, updated_at = ?, rev = rev + 1 WHERE id = ?',
            array($data, (int) $nodeCount, (int) $edgeCount, $updatedAt, $id)
        );
    }
}

function topo_delete($id)
{
    db_run('DELETE FROM topologies WHERE id = ?', array($id));
}

function topo_set_visibility($id, $vis, $updatedAt)
{
    db_run('UPDATE topologies SET visibility = ?, updated_at = ?, rev = rev + 1 WHERE id = ?', array($vis, $updatedAt, $id));
}

function topo_set_name($id, $name, $updatedAt)
{
    db_run('UPDATE topologies SET name = ?, updated_at = ?, rev = rev + 1 WHERE id = ?', array($name, $updatedAt, $id));
}

function topo_set_share_mode($id, $on, $updatedAt)
{
    db_run('UPDATE topologies SET share_mode = ?, updated_at = ?, rev = rev + 1 WHERE id = ?', array($on ? 1 : 0, $updatedAt, $id));
}

/* ============================================================
 * 拓扑共享
 * ============================================================ */
function share_list_by_topo($topoId)
{
    return db_all('SELECT * FROM topo_shares WHERE topo_id = ? ORDER BY created_at ASC', array($topoId));
}

/**
 * 整体替换某拓扑的共享列表(事务)
 */
function share_replace($topoId, $rows, $by)
{
    $pdo = db();
    $pdo->beginTransaction();
    try {
        db_run('DELETE FROM topo_shares WHERE topo_id = ?', array($topoId));
        foreach ((array) $rows as $r) {
            db_run(
                'INSERT INTO topo_shares (id, topo_id, target_type, target_id, permission, created_by, created_at)
                 VALUES (?, ?, ?, ?, ?, ?, ?)',
                array(
                    gen_id('s'),
                    $topoId,
                    $r['target_type'],
                    $r['target_id'],
                    $r['permission'],
                    $by,
                    now_iso(),
                )
            );
        }
        $pdo->commit();
    } catch (Exception $e) {
        if ($pdo->inTransaction()) {
            $pdo->rollBack();
        }
        throw $e;
    }
}

/**
 * 计算用户对拓扑的有效权限:owner | edit | view | none
 */
function topo_permission_for($row, $user)
{
    if (!$row || !$user) {
        return 'none';
    }
    if (isset($user['role']) && $user['role'] === 'admin') {
        return 'owner';
    }
    if ($row['owner_id'] === $user['id']) {
        return 'owner';
    }
    $best = 'none';
    if (!empty($row['share_mode'])) {
        $gids = group_ids_of_user($user['id']);
        foreach (share_list_by_topo($row['id']) as $s) {
            $hit = false;
            if ($s['target_type'] === 'user' && $s['target_id'] === $user['id']) {
                $hit = true;
            } elseif ($s['target_type'] === 'group' && in_array($s['target_id'], $gids, true)) {
                $hit = true;
            }
            if (!$hit) {
                continue;
            }
            if ($s['permission'] === 'edit') {
                return 'edit';
            }
            if ($s['permission'] === 'view') {
                $best = 'view';
            }
        }
    }
    if ($best === 'view') {
        return 'view';
    }
    if ($row['visibility'] === 'public') {
        return 'view';
    }
    return 'none';
}

/* ============================================================
 * 在线状态(协同)
 * ============================================================ */
function presence_touch($topoId, $user)
{
    $now = time();
    $exists = db_one('SELECT topo_id FROM topo_presence WHERE topo_id = ? AND user_id = ?', array($topoId, $user['id']));
    if ($exists) {
        db_run(
            'UPDATE topo_presence SET username = ?, last_seen = ? WHERE topo_id = ? AND user_id = ?',
            array($user['username'], $now, $topoId, $user['id'])
        );
    } else {
        db_run(
            'INSERT INTO topo_presence (topo_id, user_id, username, last_seen) VALUES (?, ?, ?, ?)',
            array($topoId, $user['id'], $user['username'], $now)
        );
    }
}

function presence_list($topoId, $activeWithin)
{
    $cut = time() - (int) $activeWithin;
    return db_all(
        'SELECT user_id, username, last_seen FROM topo_presence WHERE topo_id = ? AND last_seen >= ? ORDER BY last_seen DESC',
        array($topoId, $cut)
    );
}

function presence_remove($topoId, $userId)
{
    db_run('DELETE FROM topo_presence WHERE topo_id = ? AND user_id = ?', array($topoId, $userId));
}

function presence_purge($beforeTs)
{
    db_run('DELETE FROM topo_presence WHERE last_seen < ?', array((int) $beforeTs));
}

function topo_rev($id)
{
    return (int) db_val('SELECT rev FROM topologies WHERE id = ?', array($id));
}

/* ============================================================
 * 操作日志
 * ============================================================ */
function log_add($userId, $username, $action, $target, $detail, $ip)
{
    db_run(
        'INSERT INTO activity_logs (user_id, username, action, target, detail, ip, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)',
        array($userId, $username, $action, $target, $detail, $ip, now_iso())
    );
}

function log_search($q, $limit, $offset)
{
    $limit = (int) $limit;
    $offset = (int) $offset;
    if ($q === '') {
        return db_all('SELECT * FROM activity_logs ORDER BY id DESC LIMIT ' . $limit . ' OFFSET ' . $offset);
    }
    $p = like_param($q);
    return db_all(
        'SELECT * FROM activity_logs WHERE username LIKE ? OR action LIKE ? OR target LIKE ? OR detail LIKE ?
         ORDER BY id DESC LIMIT ' . $limit . ' OFFSET ' . $offset,
        array($p, $p, $p, $p)
    );
}

function log_count($q)
{
    if ($q === '') {
        return (int) db_val('SELECT COUNT(*) FROM activity_logs');
    }
    $p = like_param($q);
    return (int) db_val(
        'SELECT COUNT(*) FROM activity_logs WHERE username LIKE ? OR action LIKE ? OR target LIKE ? OR detail LIKE ?',
        array($p, $p, $p, $p)
    );
}

function log_recent($limit)
{
    $limit = (int) $limit;
    return db_all('SELECT * FROM activity_logs ORDER BY id DESC LIMIT ' . $limit);
}

/* ============================================================
 * 统计
 * ============================================================ */
function stats_overview()
{
    $today = date('Y-m-d') . '%';
    return array(
        'userCount' => (int) db_val('SELECT COUNT(*) FROM users'),
        'adminCount' => (int) db_val("SELECT COUNT(*) FROM users WHERE role = 'admin' AND disabled = 0"),
        'disabledCount' => (int) db_val('SELECT COUNT(*) FROM users WHERE disabled = 1'),
        'topoCount' => (int) db_val('SELECT COUNT(*) FROM topologies'),
        'publicCount' => (int) db_val("SELECT COUNT(*) FROM topologies WHERE visibility = 'public'"),
        'todayTopoCount' => (int) db_val('SELECT COUNT(*) FROM topologies WHERE created_at LIKE ?', array($today)),
        'todayLoginCount' => (int) db_val("SELECT COUNT(*) FROM activity_logs WHERE action = 'login' AND created_at LIKE ?", array($today)),
        'todayLogCount' => (int) db_val('SELECT COUNT(*) FROM activity_logs WHERE created_at LIKE ?', array($today)),
    );
}

/* ============================================================
 * 站点设置(key-value)
 * ============================================================ */
function setting_get($key, $default = null)
{
    $row = db_one('SELECT sval FROM settings WHERE skey = ?', array($key));
    return $row === null ? $default : $row['sval'];
}

function setting_set($key, $val)
{
    $now = now_iso();
    if (db_one('SELECT skey FROM settings WHERE skey = ?', array($key)) !== null) {
        db_run('UPDATE settings SET sval = ?, updated_at = ? WHERE skey = ?', array($val, $now, $key));
    } else {
        db_run('INSERT INTO settings (skey, sval, updated_at) VALUES (?, ?, ?)', array($key, $val, $now));
    }
}

function settings_all()
{
    $out = array();
    foreach (db_all('SELECT skey, sval FROM settings') as $r) {
        $out[$r['skey']] = $r['sval'];
    }
    return $out;
}

/* ============================================================
 * 旧 JSON 数据迁移
 * ============================================================ */
function migrate_legacy_json()
{
    $dir = data_dir();
    $usersFile = $dir . DIRECTORY_SEPARATOR . 'users.json';
    $topoIndexFile = $dir . DIRECTORY_SEPARATOR . 'topologies.json';
    $topoDir = $dir . DIRECTORY_SEPARATOR . 'topologies';

    if (is_file($usersFile) && (int) db_val('SELECT COUNT(*) FROM users') === 0) {
        $data = json_decode(@file_get_contents($usersFile), true);
        if (isset($data['users']) && is_array($data['users'])) {
            foreach ($data['users'] as $u) {
                if (empty($u['id']) || empty($u['username'])) {
                    continue;
                }
                user_insert(array(
                    'id' => $u['id'],
                    'username' => $u['username'],
                    'password_hash' => isset($u['passwordHash']) ? $u['passwordHash'] : '',
                    'role' => isset($u['role']) ? $u['role'] : 'user',
                    'disabled' => !empty($u['disabled']) ? 1 : 0,
                    'must_change_password' => !empty($u['mustChangePassword']) ? 1 : 0,
                    'created_at' => isset($u['createdAt']) ? $u['createdAt'] : now_iso(),
                ));
            }
        }
        @rename($usersFile, $usersFile . '.bak');
    }

    if (is_file($topoIndexFile)) {
        $idx = json_decode(@file_get_contents($topoIndexFile), true);
        if (isset($idx['topologies']) && is_array($idx['topologies'])) {
            foreach ($idx['topologies'] as $t) {
                if (empty($t['id']) || topo_find($t['id'])) {
                    continue;
                }
                $content = array('nodes' => array(), 'edges' => array());
                $cf = $topoDir . DIRECTORY_SEPARATOR . $t['id'] . '.json';
                if (is_file($cf)) {
                    $c = json_decode(@file_get_contents($cf), true);
                    if (is_array($c)) {
                        $content = $c;
                    }
                }
                topo_insert(array(
                    'id' => $t['id'],
                    'name' => isset($t['name']) ? $t['name'] : '未命名',
                    'owner_id' => isset($t['ownerId']) ? $t['ownerId'] : '',
                    'visibility' => isset($t['visibility']) ? $t['visibility'] : 'private',
                    'data' => json_encode($content, JSON_UNESCAPED_UNICODE),
                    'node_count' => isset($content['nodes']) ? count($content['nodes']) : 0,
                    'edge_count' => isset($content['edges']) ? count($content['edges']) : 0,
                    'created_at' => isset($t['createdAt']) ? $t['createdAt'] : now_iso(),
                    'updated_at' => isset($t['updatedAt']) ? $t['updatedAt'] : now_iso(),
                ));
            }
        }
        @rename($topoIndexFile, $topoIndexFile . '.bak');
    }
}

/**
 * 首次初始化:迁移旧数据 + 创建默认管理员
 */
function ensure_seed()
{
    migrate_legacy_json();

    if ((int) db_val('SELECT COUNT(*) FROM users') > 0) {
        protect_configured_admin();
        return;
    }
    $cfg = app_config();
    $admin = isset($cfg['default_admin']) ? $cfg['default_admin'] : array('username' => 'admin', 'password' => 'admin123');
    user_insert(array(
        'id' => gen_id('u'),
        'username' => $admin['username'],
        'password_hash' => password_hash($admin['password'], PASSWORD_DEFAULT),
        'role' => 'admin',
        'disabled' => 0,
        'must_change_password' => 1,
        'created_at' => now_iso(),
        'protected' => 1,
    ));
}

/**
 * 默认管理员(配置文件中的 default_admin)始终置为受保护账号,不可被其他用户改动
 */
function protect_configured_admin()
{
    $cfg = app_config();
    $name = isset($cfg['default_admin']['username']) ? $cfg['default_admin']['username'] : 'admin';
    if ($name !== '' && $name !== null) {
        db_run('UPDATE users SET protected = 1 WHERE username = ?', array($name));
    }
}