package store

import (
	"fmt"

	"github.com/containerd/containerd/platforms"
	"github.com/docker/buildx/util/platformutil"
	specs "github.com/opencontainers/image-spec/specs-go/v1"
	"github.com/pkg/errors"
)

type NodeGroup struct {
	Name   string
	Driver string
	Nodes  []Node
}

type Node struct {
	Name       string
	Endpoint   string
	Platforms  []specs.Platform
	Flags      []string
	ConfigFile string
	DriverOpts map[string]string
}

func (ng *NodeGroup) Leave(name string) error {
	i := ng.findNode(name)
	if i == -1 {
		return errors.Errorf("node %q not found for %s", name, ng.Name)
	}
	if len(ng.Nodes) == 1 {
		return errors.Errorf("can not leave last node, do you want to rm instance instead?")
	}
	ng.Nodes = append(ng.Nodes[:i], ng.Nodes[i+1:]...)
	return nil
}

func (ng *NodeGroup) Update(name, endpoint string, platforms []string, endpointsSet bool, actionAppend bool, flags []string, configFile string, do map[string]string) error {
	i := ng.findNode(name)
	if i == -1 && !actionAppend {
		if len(ng.Nodes) > 0 {
			return errors.Errorf("node %s not found, did you mean to append?", name)
		}
		ng.Nodes = nil
	}

	pp, err := platformutil.Parse(platforms)
	if err != nil {
		return err
	}

	if i != -1 {
		n := ng.Nodes[i]
		if endpointsSet {
			n.Endpoint = endpoint
		}
		if len(platforms) > 0 {
			n.Platforms = pp
		}
		if flags != nil {
			n.Flags = flags
		}
		ng.Nodes[i] = n
		if err := ng.validateDuplicates(endpoint, i); err != nil {
			return err
		}
		return nil
	}

	if name == "" {
		name = ng.nextNodeName()
	}

	name, err = ValidateName(name)
	if err != nil {
		return err
	}

	n := Node{
		Name:       name,
		Endpoint:   endpoint,
		Platforms:  pp,
		ConfigFile: configFile,
		Flags:      flags,
		DriverOpts: do,
	}
	ng.Nodes = append(ng.Nodes, n)

	if err := ng.validateDuplicates(endpoint, len(ng.Nodes)-1); err != nil {
		return err
	}
	return nil
}

func (ng *NodeGroup) validateDuplicates(ep string, idx int) error {
	i := 0
	for _, n := range ng.Nodes {
		if n.Endpoint == ep {
			i++
		}
	}
	if i > 1 {
		return errors.Errorf("invalid duplicate endpoint %s", ep)
	}

	m := map[string]struct{}{}
	for _, p := range ng.Nodes[idx].Platforms {
		m[platforms.Format(p)] = struct{}{}
	}

	for i := range ng.Nodes {
		if i == idx {
			continue
		}
		ng.Nodes[i].Platforms = filterPlatforms(ng.Nodes[i].Platforms, m)
	}

	return nil
}

func (ng *NodeGroup) findNode(name string) int {
	for i, n := range ng.Nodes {
		if n.Name == name {
			return i
		}
	}
	return -1
}

func (ng *NodeGroup) nextNodeName() string {
	i := 0
	for {
		name := fmt.Sprintf("%s%d", ng.Name, i)
		if ii := ng.findNode(name); ii != -1 {
			i++
			continue
		}
		return name
	}
}

func filterPlatforms(in []specs.Platform, m map[string]struct{}) []specs.Platform {
	out := make([]specs.Platform, 0, len(in))
	for _, p := range in {
		if _, ok := m[platforms.Format(p)]; !ok {
			out = append(out, p)
		}
	}
	return out
}
