<?php
// Collab bucket routes:
//   POST   /api/collab-buckets         create {uid, name, color, members: [usernames]}
//   GET    /api/collab-buckets         list buckets where the caller is a member
//   PATCH  /api/collab-buckets/{uid}   owner-only: update name / color / members
//   DELETE /api/collab-buckets/{uid}   owner: delete bucket; non-owner: leave
//
// No body encryption on buckets — bucket metadata (name, color) is lightweight
// shared data. Cards inside the buckets (Phase 3) follow the chat decrypt-
// reencrypt-per-recipient pattern so content stays private on the relay.

if (!defined('RELAY_BOOTSTRAPPED')) { http_response_code(404); exit; }

$clientTenant = $clientTenant ?? authClient($db);

// ── POST: create ──────────────────────────────────────────────────

if ($route === '/api/collab-buckets' && $method === 'POST') {
    if (!$clientTenant) jsonResponse(['error' => 'unauthorized'], 401);
    $input = json_decode(file_get_contents('php://input'), true) ?: [];
    $uid = trim((string)($input['uid'] ?? ''));
    $name = trim((string)($input['name'] ?? ''));
    $color = (string)($input['color'] ?? '#38bdf8');
    $memberUsernames = is_array($input['members'] ?? null) ? $input['members'] : [];
    if ($uid === '' || $name === '') jsonResponse(['error' => 'uid and name required'], 400);
    // Prevent collisions (clients generate UUIDs so this is paranoia)
    $exists = $db->prepare('SELECT 1 FROM collab_buckets WHERE uid = :u');
    $exists->execute(['u' => $uid]);
    if ($exists->fetchColumn()) jsonResponse(['error' => 'uid already exists'], 409);

    // Resolve requested members; silently drop unknown usernames
    $resolved = [];
    foreach ($memberUsernames as $u) {
        $u = trim((string)$u);
        if ($u === '') continue;
        $t = getTenantByUsername($db, $u);
        if ($t) $resolved[(int)$t['id']] = $t['username'];
    }
    // Always include the owner
    $resolved[(int)$clientTenant['id']] = $clientTenant['username'];

    try {
        $db->beginTransaction();
        $db->prepare('INSERT INTO collab_buckets (uid, owner_id, owner_username, name, color) VALUES (:uid, :oid, :ou, :n, :c)')
            ->execute(['uid' => $uid, 'oid' => $clientTenant['id'], 'ou' => $clientTenant['username'], 'n' => $name, 'c' => $color]);
        $mstmt = $db->prepare('INSERT INTO collab_bucket_members (bucket_uid, tenant_id, username) VALUES (:b, :t, :u)');
        foreach ($resolved as $tid => $uname) {
            $mstmt->execute(['b' => $uid, 't' => $tid, 'u' => $uname]);
        }
        $db->commit();
    } catch (Throwable $e) {
        if ($db->inTransaction()) $db->rollBack();
        @error_log('[hyprcrd-relay] collab bucket create failed: ' . $e->getMessage());
        jsonResponse(['error' => 'create failed'], 500);
    }
    jsonResponse(['ok' => true, 'uid' => $uid, 'members' => array_values($resolved)]);
}

// ── GET: list buckets I'm a member of ─────────────────────────────

if ($route === '/api/collab-buckets' && $method === 'GET') {
    if (!$clientTenant) jsonResponse(['error' => 'unauthorized'], 401);
    if (isRateLimited($db, 'collab-buckets-get', 120)) jsonResponse(['error' => 'rate limited'], 429);
    $stmt = $db->prepare('
        SELECT b.uid, b.name, b.color, b.owner_username, b.created_at, b.updated_at
        FROM collab_buckets b
        INNER JOIN collab_bucket_members m ON m.bucket_uid = b.uid
        WHERE m.tenant_id = :tid
        ORDER BY b.updated_at DESC
    ');
    $stmt->execute(['tid' => $clientTenant['id']]);
    $buckets = $stmt->fetchAll();
    // Attach member list to each bucket
    $mstmt = $db->prepare('SELECT username FROM collab_bucket_members WHERE bucket_uid = :uid ORDER BY username');
    foreach ($buckets as &$b) {
        $mstmt->execute(['uid' => $b['uid']]);
        $b['members'] = array_column($mstmt->fetchAll(), 'username');
    }
    jsonResponse(['ok' => true, 'buckets' => $buckets]);
}

// ── PATCH: owner updates name / color / members ───────────────────

if (preg_match('#^/api/collab-buckets/([a-zA-Z0-9_-]+)$#', $route, $m) && $method === 'PATCH') {
    if (!$clientTenant) jsonResponse(['error' => 'unauthorized'], 401);
    $uid = $m[1];
    $row = $db->prepare('SELECT owner_id FROM collab_buckets WHERE uid = :u');
    $row->execute(['u' => $uid]);
    $bucket = $row->fetch();
    if (!$bucket) jsonResponse(['error' => 'bucket not found'], 404);
    if ((int)$bucket['owner_id'] !== (int)$clientTenant['id']) jsonResponse(['error' => 'only the owner can update'], 403);

    $input = json_decode(file_get_contents('php://input'), true) ?: [];
    $sets = [];
    $params = ['u' => $uid];
    if (isset($input['name'])) { $sets[] = 'name = :n'; $params['n'] = trim((string)$input['name']); }
    if (isset($input['color'])) { $sets[] = 'color = :c'; $params['c'] = (string)$input['color']; }

    // Ownership transfer: new owner must already be a member of the bucket.
    // We set owner_id/owner_username atomically and keep the current
    // caller in the member list (no implicit leave on transfer).
    if (isset($input['owner'])) {
        $newOwnerName = trim((string)$input['owner']);
        if ($newOwnerName === '') jsonResponse(['error' => 'owner cannot be empty'], 400);
        $newOwner = getTenantByUsername($db, $newOwnerName);
        if (!$newOwner) jsonResponse(['error' => 'user not found'], 404);
        $memCheck = $db->prepare('SELECT 1 FROM collab_bucket_members WHERE bucket_uid = :b AND tenant_id = :t');
        $memCheck->execute(['b' => $uid, 't' => $newOwner['id']]);
        if (!$memCheck->fetchColumn()) {
            jsonResponse(['error' => 'new owner must already be a member of the bucket'], 400);
        }
        $sets[] = 'owner_id = :oid';       $params['oid'] = (int)$newOwner['id'];
        $sets[] = 'owner_username = :oun'; $params['oun'] = (string)$newOwner['username'];
    }

    if ($sets) {
        $sets[] = "updated_at = datetime('now')";
        $db->prepare('UPDATE collab_buckets SET ' . implode(', ', $sets) . ' WHERE uid = :u')->execute($params);
    }

    if (isset($input['members']) && is_array($input['members'])) {
        $resolved = [];
        foreach ($input['members'] as $u) {
            $u = trim((string)$u);
            if ($u === '') continue;
            $t = getTenantByUsername($db, $u);
            if ($t) $resolved[(int)$t['id']] = $t['username'];
        }
        // Caller is always kept (the user editing) + the current effective
        // owner (possibly just transferred in this same request).
        $resolved[(int)$clientTenant['id']] = $clientTenant['username'];
        if (isset($newOwner)) $resolved[(int)$newOwner['id']] = $newOwner['username'];
        $db->prepare('DELETE FROM collab_bucket_members WHERE bucket_uid = :u')->execute(['u' => $uid]);
        $ins = $db->prepare('INSERT INTO collab_bucket_members (bucket_uid, tenant_id, username) VALUES (:b, :t, :u)');
        foreach ($resolved as $tid => $uname) {
            $ins->execute(['b' => $uid, 't' => $tid, 'u' => $uname]);
        }
        $db->prepare("UPDATE collab_buckets SET updated_at = datetime('now') WHERE uid = :u")->execute(['u' => $uid]);
    }

    jsonResponse(['ok' => true]);
}

// ── DELETE: owner wipes; member leaves ────────────────────────────

if (preg_match('#^/api/collab-buckets/([a-zA-Z0-9_-]+)$#', $route, $m) && $method === 'DELETE') {
    if (!$clientTenant) jsonResponse(['error' => 'unauthorized'], 401);
    $uid = $m[1];
    $row = $db->prepare('SELECT owner_id FROM collab_buckets WHERE uid = :u');
    $row->execute(['u' => $uid]);
    $bucket = $row->fetch();
    if (!$bucket) jsonResponse(['error' => 'bucket not found'], 404);

    if ((int)$bucket['owner_id'] === (int)$clientTenant['id']) {
        // Owner: destroy everything
        $db->prepare('DELETE FROM collab_bucket_members WHERE bucket_uid = :u')->execute(['u' => $uid]);
        $db->prepare('DELETE FROM collab_buckets WHERE uid = :u')->execute(['u' => $uid]);
        jsonResponse(['ok' => true, 'action' => 'deleted']);
    } else {
        // Member: remove own membership only
        $del = $db->prepare('DELETE FROM collab_bucket_members WHERE bucket_uid = :u AND tenant_id = :t');
        $del->execute(['u' => $uid, 't' => $clientTenant['id']]);
        // Bump updated_at so remaining members see the member-list change on next poll
        $db->prepare("UPDATE collab_buckets SET updated_at = datetime('now') WHERE uid = :u")->execute(['u' => $uid]);
        jsonResponse(['ok' => true, 'action' => 'left']);
    }
}