package daemon

import (
	"context"
	"strings"

	"banger/internal/system"
	"banger/internal/vmdns"
)

const vmResolverRouteDomain = "~vm"

var (
	lookupExecutableFunc = system.LookupExecutable
	vmDNSAddrFunc        = func(server *vmdns.Server) string { return server.Addr() }
)

func (d *Daemon) syncVMDNSResolverRouting(ctx context.Context) error {
	if d == nil || d.vmDNS == nil {
		return nil
	}
	if strings.TrimSpace(d.config.BridgeName) == "" {
		return nil
	}
	if _, err := lookupExecutableFunc("resolvectl"); err != nil {
		return nil
	}
	if _, err := d.runner.Run(ctx, "ip", "link", "show", d.config.BridgeName); err != nil {
		return nil
	}
	serverAddr := strings.TrimSpace(vmDNSAddrFunc(d.vmDNS))
	if serverAddr == "" {
		return nil
	}
	if _, err := d.runner.RunSudo(ctx, "resolvectl", "dns", d.config.BridgeName, serverAddr); err != nil {
		return err
	}
	if _, err := d.runner.RunSudo(ctx, "resolvectl", "domain", d.config.BridgeName, vmResolverRouteDomain); err != nil {
		return err
	}
	_, err := d.runner.RunSudo(ctx, "resolvectl", "default-route", d.config.BridgeName, "no")
	return err
}

func (d *Daemon) clearVMDNSResolverRouting(ctx context.Context) error {
	if d == nil || strings.TrimSpace(d.config.BridgeName) == "" {
		return nil
	}
	if _, err := lookupExecutableFunc("resolvectl"); err != nil {
		return nil
	}
	if _, err := d.runner.Run(ctx, "ip", "link", "show", d.config.BridgeName); err != nil {
		return nil
	}
	_, err := d.runner.RunSudo(ctx, "resolvectl", "revert", d.config.BridgeName)
	return err
}

func (d *Daemon) ensureVMDNSResolverRouting(ctx context.Context) {
	if err := d.syncVMDNSResolverRouting(ctx); err != nil && d.logger != nil {
		d.logger.Warn("vm dns resolver route sync failed", "bridge", d.config.BridgeName, "error", err.Error())
	}
}