package extypes

import (
	"errors"
	"sync"
)

var QueueFullErr = errors.New("queue full")

type Queue[T any] struct {
	size  uint64
	mu    sync.RWMutex
	queue Slice[T]
}

func CreateQueue[T any](size uint64) *Queue[T] {
	return &Queue[T]{queue: make(Slice[T], 0, size), size: size}
}

func (q *Queue[T]) Len() uint64 {
	q.mu.RLock()
	defer q.mu.RUnlock()
	return uint64(q.queue.Len())
}
func (q *Queue[T]) IsEmpty() bool { return q.Len() == 0 }
func (q *Queue[T]) IsFull() bool  { return q.Len() == q.size }
func (q *Queue[T]) Size() uint64  { return q.size }

func (q *Queue[T]) Enqueue(el T) error {
	if q.IsFull() {
		return QueueFullErr
	}
	q.queue = q.queue.Push(el)
	return nil
}

func (q *Queue[T]) Dequeue() T {
	q.mu.RLock()
	el := q.queue.Get(0)
	q.mu.RUnlock()

	if q.Len() == 1 {
		q.mu.Lock()
		q.queue = make(Slice[T], 0)
		q.mu.Unlock()
		return el
	}

	q.mu.Lock()
	q.queue = q.queue.Pop(0)
	q.mu.Unlock()
	return el
}

func (q *Queue[T]) Peak() T {
	q.mu.RLock()
	defer q.mu.RUnlock()
	return q.queue.Get(0)
}

func (q *Queue[T]) Raw() Slice[T] {
	return q.queue
}