#import <Foundation/Foundation.h>

#pragma mark - Macros Based API

/**
 * A macro for wrapping the return type of the swizzled method.
 */
#define SentrySWReturnType(type) type

/**
 * A macro for wrapping arguments of the swizzled method.
 */
#define SentrySWArguments(arguments...) _SentrySWArguments(arguments)

/**
 * A macro for wrapping the replacement code for the swizzled method.
 */
#define SentrySWReplacement(code...) code

/**
 * A macro for casting and calling original implementation.
 * @note May be used only in @c SentrySwizzleInstanceMethod or @c SentrySwizzleClassMethod macros.
 */
#define SentrySWCallOriginal(arguments...) _SentrySWCallOriginal(arguments)

#pragma mark └ Swizzle Instance Method

/**
 * Swizzles the instance method of the class with the new implementation.
 *
 * Example for swizzling @c -(int)calculate:(int)number; method:
 *
 * @code
 *
 *    SentrySwizzleInstanceMethod(classToSwizzle,
 *                            @selector(calculate:),
 *                            SentrySWReturnType(int),
 *                            SentrySWArguments(int number),
 *                            SentrySWReplacement(
 *    {
 *        // Calling original implementation.
 *        int res = SentrySWCallOriginal(number);
 *        // Returning modified return value.
 *        return res + 1;
 *    }), 0, NULL);
 *
 * @endcode
 *
 * Swizzling frequently goes along with checking whether this particular class (or
 * one of its superclasses) has been already swizzled. Here the
 * @c SentrySwizzleMode and @c key parameters can help.
 * @see @code +[SentrySwizzle swizzleInstanceMethod:inClass:newImpFactory:mode:key:] @endcode
 *
 * Swizzling is fully thread-safe.
 *
 * @param classToSwizzle The class with the method that should be swizzled.
 *
 * @param selector Selector of the method that should be swizzled.
 *
 * @param SentrySWReturnType The return type of the swizzled method wrapped in the
 * @c SentrySWReturnType macro.
 *
 * @param SentrySWArguments The arguments of the swizzled method wrapped in the
 * @c SentrySWArguments macro.
 *
 * @param SentrySWReplacement The code of the new implementation of the swizzled
 * method wrapped in the @c SentrySWReplacement macro.
 *
 * @param SentrySwizzleMode The mode is used in combination with the key to
 * indicate whether the swizzling should be done for the given class. You can pass
 * @c 0 for @c SentrySwizzleModeAlways.
 *
 * @param key The key is used in combination with the mode to indicate whether the
 * swizzling should be done for the given class. May be @c NULL if the mode is
 * @c SentrySwizzleModeAlways.
 *
 * @return @c YES if successfully swizzled and @c NO if swizzling has been already done
 * for given key and class (or one of superclasses, depends on the mode).
 */
#define SentrySwizzleInstanceMethod(classToSwizzle, selector, SentrySWReturnType,                  \
    SentrySWArguments, SentrySWReplacement, SentrySwizzleMode, key)                                \
    _SentrySwizzleInstanceMethod(classToSwizzle, selector, SentrySWReturnType,                     \
        _SentrySWWrapArg(SentrySWArguments), _SentrySWWrapArg(SentrySWReplacement),                \
        SentrySwizzleMode, key)

#if TEST || TESTCI
/**
 * Unswizzles the instance method of the class.
 *
 * @warning To reduce the risk of breaking functionality with unswizzling, this method is not
 * considered safe-to-use in production and only available in test targets.
 *
 * @param classToUnswizzle The class with the method that should be unswizzled.
 * @param selector Selector of the method that should be unswizzled.
 * @param key The key to unswizzle the method with.
 *
 * @return @c YES if successfully unswizzled and @c NO if the method was not swizzled.
 */
#    define SentryUnswizzleInstanceMethod(classToUnswizzle, selector, key)                         \
        _SentryUnswizzleInstanceMethod(classToUnswizzle, selector, key)
#endif // TEST || TESTCI

#pragma mark └ Swizzle Class Method

/**
 * Swizzles the class method of the class with the new implementation.
 *
 * Example for swizzling @c +(int)calculate:(int)number; method:
 *
 * @code
 *
 *    SentrySwizzleClassMethod(classToSwizzle,
 *                         @selector(calculate:),
 *                         SentrySWReturnType(int),
 *                         SentrySWArguments(int number),
 *                         SentrySWReplacement(
 *    {
 *        // Calling original implementation.
 *        int res = SentrySWCallOriginal(number);
 *        // Returning modified return value.
 *        return res + 1;
 *    }));
 *
 * @endcode
 *
 * Swizzling is fully thread-safe.
 *
 * @param classToSwizzle The class with the method that should be swizzled.
 *
 * @param selector Selector of the method that should be swizzled.
 *
 * @param SentrySWReturnType The return type of the swizzled method wrapped in the
 * SentrySWReturnType macro.
 *
 * @param SentrySWArguments The arguments of the swizzled method wrapped in the
 * SentrySWArguments macro.
 *
 * @param SentrySWReplacement The code of the new implementation of the swizzled
 * method wrapped in the SentrySWReplacement macro.
 */
#define SentrySwizzleClassMethod(                                                                  \
    classToSwizzle, selector, SentrySWReturnType, SentrySWArguments, SentrySWReplacement)          \
    _SentrySwizzleClassMethod(classToSwizzle, selector, SentrySWReturnType,                        \
        _SentrySWWrapArg(SentrySWArguments), _SentrySWWrapArg(SentrySWReplacement))

#pragma mark - Main API

/**
 * A function pointer to the original implementation of the swizzled method.
 */
typedef void (*SentrySwizzleOriginalIMP)(void /* id, SEL, ... */);

/**
 * @c SentrySwizzleInfo is used in the new implementation block to get and call
 * original implementation of the swizzled method.
 */
@interface SentrySwizzleInfo : NSObject

/**
 * Returns the original implementation of the swizzled method.
 *
 * It is actually either an original implementation if the swizzled class
 * implements the method itself; or a super implementation fetched from one of the
 * superclasses.
 *
 * @note You must always cast returned implementation to the appropriate function
 * pointer when calling.
 *
 * @return A function pointer to the original implementation of the swizzled
 * method.
 */
- (SentrySwizzleOriginalIMP)getOriginalImplementation;

/**
 * The selector of the swizzled method.
 */
@property (nonatomic, readonly) SEL selector;

#if defined(TEST) || defined(TESTCI)
/**
 * A flag to check whether the original implementation was called.
 */
@property (nonatomic) BOOL originalCalled;
#endif // defined(TEST) || defined(TESTCI) || defined(DEBUG)

@end

/**
 * A factory block returning the block for the new implementation of the swizzled
 * method.
 *
 * You must always obtain original implementation with @c swizzleInfo and call it
 * from the new implementation.
 *
 * @param swizzleInfo An info used to get and call the original implementation of
 * the swizzled method.
 *
 * @return A block providing an implementation for the swizzled method. The selector is not
 * available as a parameter to this block. Its signature should be: @code method_return_type ^(id
 * self, method_args...) @endcode
 */
typedef id (^SentrySwizzleImpFactoryBlock)(SentrySwizzleInfo *swizzleInfo);

typedef NS_ENUM(NSUInteger, SentrySwizzleMode) {
    /**
     * @c SentrySwizzle always does swizzling.
     */
    SentrySwizzleModeAlways = 0,
    /**
     * @c SentrySwizzle does not do swizzling if the same class has been swizzled
     * earlier with the same key.
     */
    SentrySwizzleModeOncePerClass = 1,
    /**
     * @c SentrySwizzle does not do swizzling if the same class or one of its
     * superclasses have been swizzled earlier with the same key.
     * @note There is no guarantee that your implementation will be called only
     * once per method call. If the order of swizzling is: first inherited
     * class, second superclass, then both swizzlings will be done and the new
     * implementation will be called twice.
     */
    SentrySwizzleModeOncePerClassAndSuperclasses = 2
};

@interface SentrySwizzle : NSObject

#pragma mark └ Swizzle Instance Method

/**
 * Swizzles the instance method of the class with the new implementation.
 *
 * Original implementation must always be called from the new implementation. And
 * because of the the fact that for safe and robust swizzling original
 * implementation must be dynamically fetched at the time of calling and not at
 * the time of swizzling, swizzling API is a little bit complicated.
 *
 * You should pass a factory block that returns the block for the new
 * implementation of the swizzled method. And use swizzleInfo argument to retrieve
 * and call original implementation.
 *
 * Example for swizzling @c -(int)calculate:(int)number; method:
 *
 * @code
 *
 *    SEL selector = @selector(calculate:);
 *    [SentrySwizzle
 *     swizzleInstanceMethod:selector
 *     inClass:classToSwizzle
 *     newImpFactory:^id(SentrySwizzleInfo *swizzleInfo) {
 *         // This block will be used as the new implementation.
 *         return ^int(__unsafe_unretained id self, int num){
 *             // You MUST always cast implementation to the correct function
 * pointer. int (*originalIMP)(__unsafe_unretained id, SEL, int); originalIMP =
 * (__typeof(originalIMP))[swizzleInfo getOriginalImplementation];
 *             // Calling original implementation.
 *             int res = originalIMP(self,selector,num);
 *             // Returning modified return value.
 *             return res + 1;
 *         };
 *     }
 *     mode:SentrySwizzleModeAlways
 *     key:NULL];
 *
 * @endcode
 *
 * Swizzling frequently goes along with checking whether this particular class (or
 * one of its superclasses) has been already swizzled. Here the @c mode and @c key
 * parameters can help.
 *
 * Here is an example of swizzling @c -(void)dealloc; only in case when neither
 * class and no one of its superclasses has been already swizzled with our key.
 * However "Deallocating ..." message still may be logged multiple times per
 * method call if swizzling was called primarily for an inherited class and later
 * for one of its superclasses.
 *
 * @code
 *
 *    static const void *key = &key;
 *    SEL selector = NSSelectorFromString(@"dealloc");
 *    [SentrySwizzle
 *     swizzleInstanceMethod:selector
 *     inClass:classToSwizzle
 *     newImpFactory:^id(SentrySwizzleInfo *swizzleInfo) {
 *         return ^void(__unsafe_unretained id self){
 *             NSLog(@"Deallocating %@.",self);
 *
 *             void (*originalIMP)(__unsafe_unretained id, SEL);
 *             originalIMP = (__typeof(originalIMP))[swizzleInfo
 * getOriginalImplementation]; originalIMP(self,selector);
 *         };
 *     }
 *     mode:SentrySwizzleModeOncePerClassAndSuperclasses
 *     key:key];
 *
 * @endcode
 *
 * Swizzling is fully thread-safe.
 *
 * @param selector Selector of the method that should be swizzled.
 *
 * @param classToSwizzle The class with the method that should be swizzled.
 *
 * @param factoryBlock The factory block returning the block for the new
 * implementation of the swizzled method.
 *
 * @param mode The mode is used in combination with the key to indicate whether
 * the swizzling should be done for the given class.
 *
 * @param key The key is used in combination with the mode to indicate whether the
 * swizzling should be done for the given class. May be @c NULL if the mode is
 * SentrySwizzleModeAlways.
 *
 * @return @c YES if successfully swizzled and @c NO if swizzling has been already done
 * for given key and class (or one of superclasses, depends on the mode).
 */
+ (BOOL)swizzleInstanceMethod:(SEL)selector
                      inClass:(Class)classToSwizzle
                newImpFactory:(SentrySwizzleImpFactoryBlock)factoryBlock
                         mode:(SentrySwizzleMode)mode
                          key:(const void *)key;

#if TEST || TESTCI
/**
 * Unswizzles the instance method of the class.
 *
 * @warning To reduce the risk of breaking functionality with unswizzling, this method is not
 * considered safe-to-use in production and only available in test targets.
 *
 * @param selector Selector of the method that should be unswizzled.
 * @param classToUnswizzle The class with the method that should be unswizzled.
 * @param key The key is used in combination with the mode to indicate whether the
 * swizzling should be done for the given class.
 *
 * @return @c YES if successfully unswizzled and @c NO if the method was not swizzled.
 */
+ (BOOL)unswizzleInstanceMethod:(SEL)selector inClass:(Class)classToUnswizzle key:(const void *)key;
#endif // TEST || TESTCI

#pragma mark └ Swizzle Class method

/**
 * Swizzles the class method of the class with the new implementation.
 *
 * Original implementation must always be called from the new implementation. And
 * because of the the fact that for safe and robust swizzling original
 * implementation must be dynamically fetched at the time of calling and not at
 * the time of swizzling, swizzling API is a little bit complicated.
 *
 * You should pass a factory block that returns the block for the new
 * implementation of the swizzled method. And use @c swizzleInfo argument to retrieve
 * and call original implementation.
 *
 * Example for swizzling @c +(int)calculate:(int)number; method:
 *
 * @code
 *
 *    SEL selector = @selector(calculate:);
 *    [SentrySwizzle
 *     swizzleClassMethod:selector
 *     inClass:classToSwizzle
 *     newImpFactory:^id(SentrySwizzleInfo *swizzleInfo) {
 *         // This block will be used as the new implementation.
 *         return ^int(__unsafe_unretained id self, int num){
 *             // You MUST always cast implementation to the correct function
 * pointer. int (*originalIMP)(__unsafe_unretained id, SEL, int); originalIMP =
 * (__typeof(originalIMP))[swizzleInfo getOriginalImplementation];
 *             // Calling original implementation.
 *             int res = originalIMP(self,selector,num);
 *             // Returning modified return value.
 *             return res + 1;
 *         };
 *     }];
 *
 * @endcode
 *
 * Swizzling is fully thread-safe.
 *
 * @param selector Selector of the method that should be swizzled.
 *
 * @param classToSwizzle The class with the method that should be swizzled.
 *
 * @param factoryBlock The factory block returning the block for the new
 * implementation of the swizzled method.
 */
+ (void)swizzleClassMethod:(SEL)selector
                   inClass:(Class)classToSwizzle
             newImpFactory:(SentrySwizzleImpFactoryBlock)factoryBlock;

@end

#pragma mark - Implementation details
// Do not write code that depends on anything below this line.

// Wrapping arguments to pass them as a single argument to another macro.
#define _SentrySWWrapArg(args...) args

#define _SentrySWDel2Arg(a1, a2, args...) a1, ##args
#define _SentrySWDel3Arg(a1, a2, a3, args...) a1, a2, ##args

// To prevent comma issues if there are no arguments we add one dummy argument
// and remove it later.
#define _SentrySWArguments(arguments...) DEL, ##arguments

#if defined(TEST) || defined(TESTCI)
#    define _SentrySWReplacement(code...)                                                          \
        @try {                                                                                     \
            code                                                                                   \
        } @finally {                                                                               \
            if (!swizzleInfo.originalCalled)                                                       \
                @throw([NSException exceptionWithName:@"SwizzlingError"                            \
                                               reason:@"Original method not called"                \
                                             userInfo:nil]);                                       \
        }
#else
#    define _SentrySWReplacement(code...) code
#endif // defined(TEST) || defined(TESTCI) || defined(DEBUG)

#define _SentrySwizzleInstanceMethod(classToSwizzle, selector, SentrySWReturnType,                 \
    SentrySWArguments, SentrySWReplacement, SentrySwizzleMode, KEY)                                \
    [SentrySwizzle                                                                                 \
        swizzleInstanceMethod:selector                                                             \
                      inClass:[classToSwizzle class]                                               \
                newImpFactory:^id(SentrySwizzleInfo *swizzleInfo) {                                \
                    SentrySWReturnType (*originalImplementation_)(                                 \
                        _SentrySWDel3Arg(__unsafe_unretained id, SEL, SentrySWArguments));         \
                    SEL selector_ = selector;                                                      \
                    return ^SentrySWReturnType(_SentrySWDel2Arg(__unsafe_unretained id self,       \
                        SentrySWArguments)) { _SentrySWReplacement(SentrySWReplacement) };         \
                }                                                                                  \
                         mode:SentrySwizzleMode                                                    \
                          key:KEY];

#if TEST || TESTCI
/**
 * Macro to unswizzle an instance method.
 *
 * @warning To reduce the risk of breaking functionality with unswizzling, this macro is not
 * considered safe-to-use in production and only available in test targets.
 *
 * @param classToUnswizzle The class to unswizzle the method from.
 * @param selector The selector of the method to unswizzle.
 * @param KEY The key to unswizzle the method with.
 * @return @c YES if the method was successfully unswizzled, @c NO otherwise.
 */
#    define _SentryUnswizzleInstanceMethod(classToUnswizzle, selector, KEY)                        \
        [SentrySwizzle unswizzleInstanceMethod:selector inClass:[classToUnswizzle class] key:KEY]
#endif // TEST || TESTCI

#define _SentrySwizzleClassMethod(                                                                 \
    classToSwizzle, selector, SentrySWReturnType, SentrySWArguments, SentrySWReplacement)          \
    [SentrySwizzle                                                                                 \
        swizzleClassMethod:selector                                                                \
                   inClass:[classToSwizzle class]                                                  \
             newImpFactory:^id(SentrySwizzleInfo *swizzleInfo) {                                   \
                 SentrySWReturnType (*originalImplementation_)(                                    \
                     _SentrySWDel3Arg(__unsafe_unretained id, SEL, SentrySWArguments));            \
                 SEL selector_ = selector;                                                         \
                 return ^SentrySWReturnType(_SentrySWDel2Arg(__unsafe_unretained id self,          \
                     SentrySWArguments)) { _SentrySWReplacement(SentrySWReplacement) };            \
             }];

#define _SentrySWCallOriginal(arguments...)                                                        \
    ((__typeof(originalImplementation_))[swizzleInfo getOriginalImplementation])(                  \
        self, selector_, ##arguments)
