package nuapi

import (
	"context"
)

type Cursor[T any] struct {
	ctx        context.Context
	cancelFunc context.CancelFunc
	Chan       <-chan *T
}

func (c *Cursor[T]) First() *T {
	defer c.cancelFunc()
	return <-c.Chan
}

func (c *Cursor[T]) Close() {
	c.cancelFunc()
}

func (c *Cursor[T]) Next() (*T, bool) {
	if c.ctx.Err() != nil {
		return nil, false
	}

	value, ok := <-c.Chan
	return value, ok
}

func (c *Cursor[T]) Slice() []T {
	s := make([]T, 0)
	for value, ok := c.Next(); ok; value, ok = c.Next() {
		s = append(s, *value)
	}
	return s
}