package daemon

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"reflect"

	"isle/bootstrap"
	"isle/garage/garagesrv"
	"isle/jsonutil"
	"isle/secrets"
)

// JoiningBootstrap wraps a normal Bootstrap to include extra data which a host
// might need while joining a network.
type JoiningBootstrap struct {
	Bootstrap bootstrap.Bootstrap
	Secrets   map[secrets.ID]json.RawMessage
}

func writeBootstrapToStateDir(
	stateDirPath string, hostBootstrap bootstrap.Bootstrap,
) error {
	var (
		path    = bootstrap.StateDirPath(stateDirPath)
		dirPath = filepath.Dir(path)
	)

	if err := os.MkdirAll(dirPath, 0700); err != nil {
		return fmt.Errorf("creating directory %q: %w", dirPath, err)
	}

	if err := jsonutil.WriteFile(hostBootstrap, path, 0600); err != nil {
		return fmt.Errorf("writing bootstrap to %q: %w", path, err)
	}

	return nil
}

func coalesceDaemonConfigAndBootstrap(
	daemonConfig Config, hostBootstrap bootstrap.Bootstrap,
) (
	bootstrap.Bootstrap, error,
) {
	host := bootstrap.Host{
		HostAssigned: hostBootstrap.HostAssigned,
		HostConfigured: bootstrap.HostConfigured{
			Nebula: bootstrap.NebulaHost{
				PublicAddr: daemonConfig.VPN.PublicAddr,
			},
		},
	}

	if allocs := daemonConfig.Storage.Allocations; len(allocs) > 0 {

		for i, alloc := range allocs {

			id, rpcPort, err := garagesrv.InitAlloc(alloc.MetaPath, alloc.RPCPort)
			if err != nil {
				return bootstrap.Bootstrap{}, fmt.Errorf(
					"initializing alloc at %q: %w", alloc.MetaPath, err,
				)
			}

			host.Garage.Instances = append(host.Garage.Instances, bootstrap.GarageHostInstance{
				ID:        id,
				RPCPort:   rpcPort,
				S3APIPort: alloc.S3APIPort,
			})

			allocs[i].RPCPort = rpcPort
		}
	}

	hostBootstrap.Hosts[host.Name] = host

	return hostBootstrap, nil
}

type bootstrapDiff struct {
	hostsChanged  bool
	nebulaChanged bool
	dnsChanged    bool
}

func calcBootstrapDiff(
	daemonConfig Config,
	prevBootstrap, nextBootstrap bootstrap.Bootstrap,
) (
	diff bootstrapDiff, err error,
) {
	{
		prevHash, prevErr := bootstrap.HostsHash(prevBootstrap.Hosts)
		nextHash, nextErr := bootstrap.HostsHash(nextBootstrap.Hosts)
		if err = errors.Join(prevErr, nextErr); err != nil {
			err = fmt.Errorf("calculating host hashes: %w", err)
			return
		}

		diff.hostsChanged = !bytes.Equal(prevHash, nextHash)
	}

	{
		prevNebulaConfig, prevErr := nebulaConfig(daemonConfig, prevBootstrap)
		nextNebulaConfig, nextErr := nebulaConfig(daemonConfig, nextBootstrap)
		if err = errors.Join(prevErr, nextErr); err != nil {
			err = fmt.Errorf("calculating nebula config: %w", err)
			return
		}

		diff.nebulaChanged = !reflect.DeepEqual(
			prevNebulaConfig, nextNebulaConfig,
		)
	}

	{
		diff.dnsChanged = !reflect.DeepEqual(
			dnsmasqConfig(daemonConfig, prevBootstrap),
			dnsmasqConfig(daemonConfig, nextBootstrap),
		)
	}

	return
}