import { NextRequest, NextResponse } from 'next/server';
import { getSetting } from '@/lib/db';
import { applyBackup, fetchBackup, fetchBackupList } from '@/lib/backup-restore';

/**
 * Restore-from-master for the settings page.
 *
 * The browser talks to this route and this route talks to the master with the
 * machine's own stored master_dashboard_url + master_backup_token, so the
 * token never reaches the browser.
 *
 * GET  — the available backups, for the picker.
 * POST { id } — pull that backup and apply it, adopting its identity.
 *               The process must be restarted afterwards; the response says so.
 */

function config(): { masterUrl: string; token: string } | NextResponse {
    const masterUrl = getSetting('master_dashboard_url');
    const token = getSetting('master_backup_token');
    if (!masterUrl) return NextResponse.json({ error: 'master_dashboard_url is not set' }, { status: 400 });
    if (!token) return NextResponse.json({ error: 'master_backup_token is not set' }, { status: 400 });
    return { masterUrl, token };
}

export async function GET() {
    const cfg = config();
    if (cfg instanceof NextResponse) return cfg;

    try {
        const backups = await fetchBackupList(cfg.masterUrl, cfg.token);
        return NextResponse.json({ backups });
    } catch (err) {
        const error = err instanceof Error ? err.message : String(err);
        return NextResponse.json({ error }, { status: 502 });
    }
}

export async function POST(req: NextRequest) {
    const cfg = config();
    if (cfg instanceof NextResponse) return cfg;

    let id = '';
    try {
        const body = await req.json();
        id = typeof body?.id === 'string' ? body.id.trim() : '';
    } catch { /* falls through to the check below */ }
    if (!id) return NextResponse.json({ error: 'id is required' }, { status: 400 });

    try {
        const payload = await fetchBackup(cfg.masterUrl, cfg.token, id);
        const restored = applyBackup(payload);
        return NextResponse.json({
            ok: true,
            restored,
            savedAt: payload.savedAt,
            adopted: {
                name: payload.settings.instance_name ?? '',
                id: payload.settings.instance_id ?? '',
            },
            // Live platform clients, the master link's hello and the proxy all
            // predate the restore — a restart is the only honest way in.
            restartRequired: true,
        });
    } catch (err) {
        const error = err instanceof Error ? err.message : String(err);
        return NextResponse.json({ error }, { status: 502 });
    }
}