<?php
define('CYBERCHAT_API', true);
require_once __DIR__ . '/../bootstrap.php';
sendCorsHeaders();

$user = authRequired();
$action = $_POST['action'] ?? $_GET['action'] ?? 'list';

if (!groupsEnabled()) {
    if ($action === 'list') {
        jsonResponse(['groups' => [], 'member_limit' => 0, 'enabled' => false]);
    }
    jsonResponse(['error' => 'Private groups are currently disabled', 'groups_enabled' => false], 403);
}

switch ($action) {
    case 'list':
        jsonResponse([
            'groups' => userGroups((int)$user['id']),
            'member_limit' => (int)featureValue($user, 'group_member_limit', 2),
            'enabled' => true,
        ]);

    case 'create':
        $name = trim((string)($_POST['name'] ?? ''));
        $names = array_values(array_unique(array_filter(array_map('trim', explode(',', (string)($_POST['members'] ?? ''))))));
        if ($name === '' || strlen($name) > 40) jsonResponse(['error' => 'Group name must be 1-40 characters'], 400);
        $limit = max(2, (int)featureValue($user, 'group_member_limit', 2));
        if (count($names) + 1 > $limit) jsonResponse(['error' => "Your plan allows $limit group members including you"], 403);
        $memberIds = [];
        $lookup = getDB()->prepare("SELECT id FROM users WHERE username=? COLLATE NOCASE");
        foreach ($names as $username) {
            if (strcasecmp($username, $user['username']) === 0) continue;
            $lookup->execute([$username]);
            $id = (int)$lookup->fetchColumn();
            if (!$id) jsonResponse(['error' => "User '$username' was not found"], 404);
            $memberIds[$id] = $id;
        }
        if (!$memberIds) jsonResponse(['error' => 'Add at least one other user to create a group'], 400);
        if (count($memberIds) + 1 > $limit) jsonResponse(['error' => "Your plan allows $limit group members including you"], 403);
        $db = getDB();
        $db->beginTransaction();
        $db->prepare("INSERT INTO chat_groups (owner_id,name,created_at,updated_at) VALUES (?,?,?,?)")
            ->execute([$user['id'], $name, time(), time()]);
        $groupId = (int)$db->lastInsertId();
        $insert = $db->prepare("INSERT INTO group_members (group_id,user_id,role,joined_at) VALUES (?,?,?,?)");
        $insert->execute([$groupId, $user['id'], 'owner', time()]);
        foreach ($memberIds as $id) $insert->execute([$groupId, $id, 'member', time()]);
        $db->commit();
        jsonResponse(['success' => true, 'groups' => userGroups((int)$user['id'])]);

    case 'add_member':
        $groupId = normalizeGroupId($_POST['group_id'] ?? null);
        $username = trim((string)($_POST['username'] ?? ''));
        $groupStmt = getDB()->prepare("SELECT * FROM chat_groups WHERE id=? AND owner_id=?");
        $groupStmt->execute([$groupId, $user['id']]);
        $group = $groupStmt->fetch();
        if (!$group) jsonResponse(['error' => 'Only the group owner can add members'], 403);
        $limit = max(2, (int)featureValue($user, 'group_member_limit', 2));
        $countStmt = getDB()->prepare("SELECT COUNT(*) FROM group_members WHERE group_id=?");
        $countStmt->execute([$groupId]);
        if ((int)$countStmt->fetchColumn() >= $limit) jsonResponse(['error' => "This group has reached your $limit-member limit"], 403);
        $lookup = getDB()->prepare("SELECT id FROM users WHERE username=? COLLATE NOCASE");
        $lookup->execute([$username]);
        $memberId = (int)$lookup->fetchColumn();
        if (!$memberId) jsonResponse(['error' => 'User not found'], 404);
        getDB()->prepare("INSERT OR IGNORE INTO group_members (group_id,user_id,role,joined_at) VALUES (?,?,'member',?)")
            ->execute([$groupId, $memberId, time()]);
        getDB()->prepare("UPDATE chat_groups SET updated_at=? WHERE id=?")->execute([time(), $groupId]);
        jsonResponse(['success' => true, 'groups' => userGroups((int)$user['id'])]);

    case 'remove_member':
        $groupId = normalizeGroupId($_POST['group_id'] ?? null);
        $memberId = (int)($_POST['user_id'] ?? 0);
        $stmt = getDB()->prepare("SELECT owner_id FROM chat_groups WHERE id=?");
        $stmt->execute([$groupId]);
        $ownerId = (int)$stmt->fetchColumn();
        if (!$ownerId) jsonResponse(['error' => 'Group not found'], 404);
        if ($ownerId !== (int)$user['id'] && $memberId !== (int)$user['id']) jsonResponse(['error' => 'Not allowed'], 403);
        if ($memberId === $ownerId) jsonResponse(['error' => 'The owner must delete the group instead'], 400);
        getDB()->prepare("DELETE FROM group_members WHERE group_id=? AND user_id=?")->execute([$groupId, $memberId]);
        jsonResponse(['success' => true, 'groups' => userGroups((int)$user['id'])]);

    case 'delete':
        $groupId = normalizeGroupId($_POST['group_id'] ?? null);
        $db = getDB();
        $owner = $db->prepare("SELECT 1 FROM chat_groups WHERE id=? AND owner_id=?");
        $owner->execute([$groupId, $user['id']]);
        if (!$owner->fetchColumn()) jsonResponse(['error' => 'Only the group owner can delete this group'], 403);
        $voice = $db->prepare("SELECT voice_file FROM messages WHERE group_id=? AND voice_file IS NOT NULL");
        $voice->execute([$groupId]);
        $voiceFiles = $voice->fetchAll();
        $db->beginTransaction();
        try {
            $db->prepare("DELETE FROM recording_status WHERE group_key=?")->execute([groupKey($groupId)]);
            $db->prepare("DELETE FROM messages WHERE group_id=?")->execute([$groupId]);
            $db->prepare("DELETE FROM group_members WHERE group_id=?")->execute([$groupId]);
            $db->prepare("DELETE FROM chat_groups WHERE id=?")->execute([$groupId]);
            $db->commit();
        } catch (Throwable $e) {
            if ($db->inTransaction()) $db->rollBack();
            throw $e;
        }
        foreach ($voiceFiles as $row) deleteVoiceFile($row['voice_file'] ?? null);
        jsonResponse(['success' => true, 'groups' => userGroups((int)$user['id'])]);

    default:
        jsonResponse(['error' => 'Unknown action'], 400);
}