/*
 * This file is part of the SDWebImage package.
 * (c) Olivier Poitrey <rs@dailymotion.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

#import "BU_SDWebImageCompat.h"

@class BU_SDImageCacheConfig;
/**
 A protocol to allow custom disk cache used in SDImageCache.
 */
@protocol BU_SDDiskCache <NSObject>

// All of these method are called from the same global queue to avoid blocking on main queue and thread-safe problem. But it's also recommend to ensure thread-safe yourself using lock or other ways.
@required
/**
 Create a new disk cache based on the specified path. You can check `maxDiskSize` and `maxDiskAge` used for disk cache.
 
 @param cachePath Full path of a directory in which the cache will write data.
 Once initialized you should not read and write to this directory.
 @param config The cache config to be used to create the cache.
 
 @return A new cache object, or nil if an error occurs.
 */
- (nullable instancetype)initWithCachePath:(nonnull NSString *)cachePath config:(nonnull BU_SDImageCacheConfig *)config;

/**
 Returns a boolean value that indicates whether a given key is in cache.
 This method may blocks the calling thread until file read finished.
 
 @param key A string identifying the data. If nil, just return NO.
 @return Whether the key is in cache.
 */
- (BOOL)containsDataForKey:(nonnull NSString *)key;

/**
 Returns the data associated with a given key.
 This method may blocks the calling thread until file read finished.
 
 @param key A string identifying the data. If nil, just return nil.
 @return The value associated with key, or nil if no value is associated with key.
 */
- (nullable NSData *)dataForKey:(nonnull NSString *)key;

/**
 Sets the value of the specified key in the cache.
 This method may blocks the calling thread until file write finished.
 
 @param data The data to be stored in the cache.
 @param key    The key with which to associate the value. If nil, this method has no effect.
 */
- (void)setData:(nullable NSData *)data forKey:(nonnull NSString *)key;

/**
 Removes the value of the specified key in the cache.
 This method may blocks the calling thread until file delete finished.
 
 @param key The key identifying the value to be removed. If nil, this method has no effect.
 */
- (void)removeDataForKey:(nonnull NSString *)key;

/**
 Empties the cache.
 This method may blocks the calling thread until file delete finished.
 */
- (void)removeAllData;

/**
 Removes the expired data from the cache. You can choose the data to remove base on `ageLimit`, `countLimit` and `sizeLimit` options.
 */
- (void)removeExpiredData;

/**
 The cache path for key

 @param key A string identifying the value
 @return The cache path for key. Or nil if the key can not associate to a path
 */
- (nullable NSString *)cachePathForKey:(nonnull NSString *)key;

/**
 Returns the number of data in this cache.
 This method may blocks the calling thread until file read finished.
 
 @return The total data count.
 */
- (NSUInteger)totalCount;

/**
 Returns the total size (in bytes) of data in this cache.
 This method may blocks the calling thread until file read finished.
 
 @return The total data size in bytes.
 */
- (NSUInteger)totalSize;

@end

/**
 The built-in disk cache.
 */
@interface BU_SDDiskCache : NSObject <BU_SDDiskCache>
/**
 Cache Config object - storing all kind of settings.
 */
@property (nonatomic, strong, readonly, nonnull) BU_SDImageCacheConfig *config;

- (nonnull instancetype)init NS_UNAVAILABLE;

@end