package cache

import (
	"sync"
	"time"

	"fergalla.com/dockerbot/internal/docker"
)

type ContainerCache struct {
	mu sync.RWMutex

	data      []docker.ContainerBasicInfo
	expiresAt time.Time
	ttl       time.Duration

	// función para obtener datos frescos
	fetchFunc func() ([]docker.ContainerBasicInfo, error)
}

// Constructor
func NewContainerCache(ttl time.Duration, fetch func() ([]docker.ContainerBasicInfo, error)) *ContainerCache {
	return &ContainerCache{
		ttl:       ttl,
		fetchFunc: fetch,
	}
}

// Get devuelve datos cacheados o refresca si ha expirado
func (c *ContainerCache) Get() ([]docker.ContainerBasicInfo, error) {
	// 🔍 lectura rápida
	c.mu.RLock()
	if time.Now().Before(c.expiresAt) && c.data != nil {
		data := c.data
		c.mu.RUnlock()
		return data, nil
	}
	c.mu.RUnlock()

	// 🔒 lock de escritura (refresco)
	c.mu.Lock()
	defer c.mu.Unlock()

	// ⚠️ doble check (evita refrescos duplicados)
	if time.Now().Before(c.expiresAt) && c.data != nil {
		return c.data, nil
	}

	data, err := c.fetchFunc()
	if err != nil {
		return nil, err
	}

	c.data = data
	c.expiresAt = time.Now().Add(c.ttl)

	return c.data, nil
}

// Invalidate fuerza limpieza de cache
func (c *ContainerCache) Invalidate() {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.data = nil
	c.expiresAt = time.Time{}
}

// ForceRefresh fuerza actualización inmediata
func (c *ContainerCache) ForceRefresh() ([]docker.ContainerBasicInfo, error) {
	c.mu.Lock()
	defer c.mu.Unlock()

	data, err := c.fetchFunc()
	if err != nil {
		return nil, err
	}

	c.data = data
	c.expiresAt = time.Now().Add(c.ttl)

	return c.data, nil
}