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

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

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