package commondao

import (
	"errors"
	"strings"
)

// MemberGroup defines an interface for a group of members.
type MemberGroup interface {
	// Name returns the name of the group.
	Name() string

	// Members returns the members that belong to the group.
	Members() MemberStorage

	// SetMeta sets any metadata relevant to the group.
	// Metadata can be used to store data which is specific to the group.
	// Usually can be used to store parameter values which would be useful
	// during proposal voting or tallying to resolve things like voting
	// weights or rights for example.
	SetMeta(any)

	// GetMeta returns the group metadata.
	GetMeta() any
}

// NewMemberGroup creates a new group of members.
func NewMemberGroup(name string, members MemberStorage) (MemberGroup, error) {
	if members == nil {
		return nil, errors.New("member storage is required")
	}

	name = strings.TrimSpace(name)
	if name == "" {
		return nil, errors.New("member group name is required")
	}

	return &memberGroup{
		name:    name,
		members: members,
	}, nil
}

// MustNewMemberGroup creates a new group of members or panics on error.
func MustNewMemberGroup(name string, members MemberStorage) MemberGroup {
	g, err := NewMemberGroup(name, members)
	if err != nil {
		panic(err)
	}
	return g
}

type memberGroup struct {
	name    string
	members MemberStorage
	meta    any
}

// Name returns the name of the group.
func (g memberGroup) Name() string {
	return g.name
}

// Members returns the members that belong to the group.
func (g memberGroup) Members() MemberStorage {
	return g.members
}

// SetMeta sets any metadata relevant to the group.
func (g *memberGroup) SetMeta(meta any) {
	g.meta = meta
}

// GetMeta returns the group metadata.
func (g memberGroup) GetMeta() any {
	return g.meta
}

// NewReadonlyMemberGroup creates a new readonly member group.
func NewReadonlyMemberGroup(g MemberGroup) (*ReadonlyMemberGroup, error) {
	if g == nil {
		return nil, errors.New("member group is required")
	}
	return &ReadonlyMemberGroup{g}, nil
}

// MustNewReadonlyMemberGroup creates a new readonly member group or panics on error.
func MustNewReadonlyMemberGroup(g MemberGroup) *ReadonlyMemberGroup {
	group, err := NewReadonlyMemberGroup(g)
	if err != nil {
		panic(err)
	}
	return group
}

// ReadonlyMemberGroup defines a readonly member group.
type ReadonlyMemberGroup struct {
	group MemberGroup
}

// Name returns the name of the group.
func (g ReadonlyMemberGroup) Name() string {
	if g.group == nil {
		return ""
	}
	return g.group.Name()
}

// Members returns the members that belong to the group.
func (g ReadonlyMemberGroup) Members() *ReadonlyMemberStorage {
	if g.group == nil {
		return nil
	}
	return MustNewReadonlyMemberStorage(g.group.Members())
}

// GetMeta returns the group metadata.
func (g ReadonlyMemberGroup) GetMeta() any {
	if g.group == nil {
		return nil
	}
	return g.group.GetMeta()
}