cache

type Cache[Key comparable, Value any] interface {
	// SetEvictionCallback sets the eviction callback to the provided hook.
	SetEvictionCallback(hook func(Key, Value))

	// SetInvalidateCallback sets the invalidate callback to the provided hook.
	SetInvalidateCallback(hook func(Key, Value))

	// Get fetches the value with key from the cache, extending its TTL.
	Get(key Key) (value Value, ok bool)

	// Add attempts to place the value at key in the cache, doing nothing if a value with this key already exists. Returned bool is success state. Calls invalidate callback on success.
	Add(key Key, value Value) bool

	// Set places the value at key in the cache. This will overwrite any existing value. Existing values will have their TTL extended upon update. Always calls invalidate callback.
	Set(key Key, value Value)

	// CAS will attempt to perform a CAS operation on 'key', using provided old and new values, and comparator function. Returned bool is success.
	CAS(key Key, old, new Value, cmp func(Value, Value) bool) bool

	// Swap will attempt to perform a swap on 'key', replacing the value there and returning the existing value. If no value exists for key, this will set the value and return the zero value for V.
	Swap(key Key, swp Value) Value

	// Has checks the cache for a value with key, this will not update TTL.
	Has(key Key) bool

	// Invalidate deletes a value from the cache, calling the invalidate callback.
	Invalidate(key Key) bool

	// InvalidateAll is equivalent to multiple Invalidate calls.
	InvalidateAll(keys ...Key) bool

	// Clear empties the cache, calling the invalidate callback on each entry.
	Clear()

	// Len returns the current length of the cache.
	Len() int

	// Cap returns the maximum capacity of the cache.
	Cap() int
}

type TTLCache[Key comparable, Value any] interface {
	// Start will start the cache background eviction routine with given sweep frequency. If already running or a freq <= 0 provided, this is a no-op. This will block until the eviction routine has started.
	Start(freq time.Duration) bool

	// Stop will stop cache background eviction routine. If not running this is a no-op. This will block until the eviction routine has stopped.
	Stop() bool

	// SetTTL sets the cache item TTL. Update can be specified to force updates of existing items in the cache, this will simply add the change in TTL to their current expiry time.
	SetTTL(ttl time.Duration, update bool)

	// implements base cache.
	Cache[Key, Value]
}