queue.go

package queue

import (
	"encoding/json"
	"fmt"
	"os"
)

type Queue struct {
	Elements []string
	FilePath string
}

func NewQueue(filePath string) (*Queue, error) {
	q := &Queue{
		Elements: make([]string, 0),
		FilePath: filePath,
	}

	// Load state from file
	if _, err := os.Stat(filePath); err == nil {
		data, err := os.ReadFile(filePath)
		if err != nil {
			return nil, fmt.Errorf("error reading state file: %w", err)
		}
		if err := json.Unmarshal(data, &q.Elements); err != nil {
			return nil, fmt.Errorf("error parsing state file: %w", err)
		}
	}
	return q, nil
}

func (q *Queue) Enqueue(element string) {
	q.Elements = append(q.Elements, element)
}

func (q *Queue) Dequeue() (string, error) {
	if len(q.Elements) == 0 {
		return "", fmt.Errorf("queue is empty")
	}
	element := q.Elements[0]
	q.Elements = q.Elements[1:]
	return element, nil
}

func (q *Queue) Save() error {
	data, err := json.Marshal(q.Elements)
	if err != nil {
		return fmt.Errorf("error serializing state: %w", err)
	}
	if err := os.WriteFile(q.FilePath, data, 0644); err != nil {
		return fmt.Errorf("error writing state to file: %w", err)
	}
	return nil
}