package ucind

import (
	"context"
	"errors"
	"fmt"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/filters"
	"github.com/docker/docker/api/types/network"
	dockerclient "github.com/docker/docker/client"
	"google.golang.org/protobuf/types/known/emptypb"
	"time"
	"uncloud/internal/cli/client"
	"uncloud/internal/cli/client/connector"
	"uncloud/internal/machine"
	"uncloud/internal/machine/api/pb"
	"uncloud/internal/machine/cluster"
)

const (
	ClusterNameLabel = "ucind.cluster.name"
	ManagedLabel     = "ucind.managed"
)

type Cluster struct {
	Name     string
	Machines []Machine
}

type CreateClusterOptions struct {
	Machines int
}

func (p *Provisioner) CreateCluster(ctx context.Context, name string, opts CreateClusterOptions) (Cluster, error) {
	var c Cluster

	_, err := p.InspectCluster(ctx, name)
	if err == nil {
		return c, fmt.Errorf("cluster with name '%s' already exists", name)
	}
	if !errors.Is(err, ErrNotFound) {
		return c, fmt.Errorf("inspect cluster '%s': %w", name, err)
	}

	netOpts := network.CreateOptions{
		Labels: map[string]string{
			ClusterNameLabel: name,
			ManagedLabel:     "",
		},
	}
	// Create a Docker network with the same as the cluster name.
	if _, err = p.client.NetworkCreate(ctx, name, netOpts); err != nil {
		return c, fmt.Errorf("create Docker network '%s': %w", name, err)
	}
	c.Name = name

	// Create machines (containers) in the created cluster network.
	for i := 1; i < opts.Machines+1; i++ {
		mopts := CreateMachineOptions{
			Name: fmt.Sprintf("machine-%d", i),
		}
		m, err := p.CreateMachine(ctx, name, mopts)
		if err != nil {
			return c, fmt.Errorf("create machine '%s': %w", mopts.Name, err)
		}

		c.Machines = append(c.Machines, m)
	}

	if len(c.Machines) == 0 {
		return c, nil
	}

	if err = p.initCluster(ctx, c.Machines); err != nil {
		return c, err
	}

	return c, nil
}

func (p *Provisioner) initCluster(ctx context.Context, machines []Machine) error {
	// TODO: properly wait for the API to respond.
	time.Sleep(2 * time.Second) // Wait for the machines to be up and running.

	// Init a new cluster on the first machine.
	initMachine := machines[0]
	initClient, err := client.New(ctx, connector.NewTCPConnector(initMachine.APIAddress))
	if err != nil {
		return fmt.Errorf("create machine client over TCP '%s': %w", initMachine.APIAddress, err)
	}
	defer initClient.Close()

	req := &pb.InitClusterRequest{
		MachineName: initMachine.Name,
		Network:     pb.NewIPPrefix(cluster.DefaultNetwork),
	}
	initResp, err := initClient.InitCluster(ctx, req)
	if err != nil {
		return fmt.Errorf("init cluster: %w", err)
	}
	fmt.Printf("Cluster %q initialised with machine %q\n", initMachine.ClusterName, initResp.Machine.Name)

	// Join the rest of the machines to the cluster.
	for _, m := range machines[1:] {
		mcli, err := client.New(ctx, connector.NewTCPConnector(m.APIAddress))
		if err != nil {
			return fmt.Errorf("create machine client over TCP '%s': %w", m.APIAddress, err)
		}
		//goland:noinspection GoDeferInLoop
		defer mcli.Close()

		tokenResp, err := mcli.Token(ctx, &emptypb.Empty{})
		if err != nil {
			return fmt.Errorf("get machine token: %w", err)
		}
		token, err := machine.ParseToken(tokenResp.Token)
		if err != nil {
			return fmt.Errorf("parse machine token: %w", err)
		}

		// Register the machine in the cluster using its public key and endpoints from the token.
		endpoints := make([]*pb.IPPort, len(token.Endpoints))
		for i, addrPort := range token.Endpoints {
			endpoints[i] = pb.NewIPPort(addrPort)
		}
		addReq := &pb.AddMachineRequest{
			Name: m.Name,
			Network: &pb.NetworkConfig{
				Endpoints: endpoints,
				PublicKey: token.PublicKey,
			},
		}
		addResp, err := initClient.AddMachine(ctx, addReq)
		if err != nil {
			return fmt.Errorf("add machine to cluster: %w", err)
		}

		// Configure the machine to join the cluster.
		joinReq := &pb.JoinClusterRequest{
			Machine:       addResp.Machine,
			OtherMachines: []*pb.MachineInfo{initResp.Machine},
		}
		if _, err = mcli.JoinCluster(ctx, joinReq); err != nil {
			return fmt.Errorf("join cluster: %w", err)
		}

		fmt.Printf("Machine %q added to cluster\n", addResp.Machine.Name)
	}

	return nil
}

func (p *Provisioner) InspectCluster(ctx context.Context, name string) (Cluster, error) {
	var c Cluster

	// Docker network name is the same as the cluster name.
	net, err := p.client.NetworkInspect(ctx, name, network.InspectOptions{})
	if err != nil {
		if dockerclient.IsErrNotFound(err) {
			return c, ErrNotFound
		}
		return c, fmt.Errorf("inspect Docker network '%s': %w", name, err)
	}

	if _, ok := net.Labels[ManagedLabel]; !ok {
		// The network with the cluster name exists, but it's not managed by ucind.
		return c, ErrNotFound
	}

	c.Name = name
	// TODO: list containers (machines) with the cluster name label and include them in the cluster struct.

	return c, nil
}

func (p *Provisioner) RemoveCluster(ctx context.Context, name string) error {
	if _, err := p.InspectCluster(ctx, name); err != nil {
		return err
	}

	// Remove all containers (machines) with the cluster name label.
	opts := container.ListOptions{
		All: true,
		Filters: filters.NewArgs(
			filters.Arg("label", ClusterNameLabel+"="+name),
			filters.Arg("label", ManagedLabel),
		),
	}
	containers, err := p.client.ContainerList(ctx, opts)
	if err != nil {
		return fmt.Errorf("list Docker containers with cluster name '%s': %w", name, err)
	}
	for _, c := range containers {
		if err = p.client.ContainerRemove(ctx, c.ID, container.RemoveOptions{Force: true}); err != nil {
			return fmt.Errorf("remove Docker container '%s': %w", c.ID, err)
		}
	}

	if err = p.client.NetworkRemove(ctx, name); err != nil {
		return fmt.Errorf("remove Docker network '%s': %w", name, err)
	}
	return nil
}