package random

import (
	"context"
	"git.diulo.com/mogfee/kit/selector"
	"math/rand"
)

type Option func(o *options)

type options struct {
}
type Balancer struct {
}

func New(opts ...Option) selector.Selector {
	return NewBuilder(opts...).Build()
}
func (b *Balancer) Pick(ctx context.Context, nodes []selector.WeightedNode) (selector.WeightedNode, selector.DoneFunc, error) {
	if len(nodes) == 0 {
		return nil, nil, selector.ErrNoAvailable
	}
	cut := rand.Intn(len(nodes))
	selected := nodes[cut]
	d := selected.Pick()
	return selected, d, nil
}

func NewBuilder(opts ...Option) selector.Builder {
	var option options
	for _, opt := range opts {
		opt(&option)
	}
	return &selector.DefaultBuilder{
		Balancer: &Builder{},
		Node:     &direct.Builder{},
	}
}

// Builder is random builder
type Builder struct{}

func (b *Builder) Builder() selector.Balancer {
	return &Balancer{}
}