package two

import "sync"

type antiNodeCache struct {
	mu   sync.RWMutex
	data map[coords]struct{}
}

func newAntiNodeCache() antiNodeCache {
	return antiNodeCache{
		data: make(map[coords]struct{}),
	}
}

func (c *antiNodeCache) len() int {
	return len(c.data)
}

func (c *antiNodeCache) contains(coords coords) bool {
	c.mu.RLock()
	defer c.mu.RUnlock()

	_, ok := c.data[coords]
	return ok
}

func (c *antiNodeCache) insert(coords coords) {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.data[coords] = struct{}{}
}