/*
 * fdb_c.cpp
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define FDB_API_VERSION 610
#define FDB_INCLUDE_LEGACY_TYPES

#include "fdbclient/MultiVersionTransaction.h"
#include "foundationdb/fdb_c.h"

int g_api_version = 0;

/*
 * Our clients might share these ThreadSafe types between threads. It is therefore
 * unsafe to call addRef on them.
 *
 * type mapping:
 *   FDBFuture -> ThreadSingleAssignmentVarBase
 *   FDBDatabase -> IDatabase
 *   FDBTransaction -> ITransaction
 */
#define TSAVB(f) ((ThreadSingleAssignmentVarBase*)(f))
#define TSAV(T, f) ((ThreadSingleAssignmentVar<T>*)(f))

#define DB(d) ((IDatabase*)d)
#define TXN(t) ((ITransaction*)t)

// Legacy (pre API version 610)
#define CLUSTER(c) ((char*)c)

/* 
 * While we could just use the MultiVersionApi instance directly, this #define allows us to swap in any other IClientApi instance (e.g. from ThreadSafeApi)
 */
#define API ((IClientApi*)MultiVersionApi::api)

/* This must be true so that we can return the data pointer of a
   Standalone<RangeResultRef> as an array of FDBKeyValue. */
static_assert( sizeof(FDBKeyValue) == sizeof(KeyValueRef),
			   "FDBKeyValue / KeyValueRef size mismatch" );


#define TSAV_ERROR(type, error) ((FDBFuture*)(ThreadFuture<type>(error())).extractPtr())


extern "C" DLLEXPORT
const char *fdb_get_error( fdb_error_t code ) {
	return Error::fromUnvalidatedCode( code ).what();
}

extern "C" DLLEXPORT
fdb_bool_t fdb_error_predicate( int predicate_test, fdb_error_t code ) {
	if(predicate_test == FDBErrorPredicates::RETRYABLE) {
		return fdb_error_predicate( FDBErrorPredicates::MAYBE_COMMITTED, code ) ||
				fdb_error_predicate( FDBErrorPredicates::RETRYABLE_NOT_COMMITTED, code );
	}
	if(predicate_test == FDBErrorPredicates::MAYBE_COMMITTED) {
		return code == error_code_commit_unknown_result ||
				code == error_code_cluster_version_changed;
	}
	if(predicate_test == FDBErrorPredicates::RETRYABLE_NOT_COMMITTED) {
		return code == error_code_not_committed ||
				code == error_code_transaction_too_old ||
				code == error_code_future_version ||
				code == error_code_database_locked;
	}
	return false;
}

#define RETURN_ON_ERROR(code_to_run)					\
	try { code_to_run }									\
	catch( Error& e) { if (e.code() <= 0) return internal_error().code(); else return e.code(); } \
	catch( ... ) { return error_code_unknown_error; }

#define CATCH_AND_RETURN(code_to_run)			\
	RETURN_ON_ERROR(code_to_run);				\
	return error_code_success;

#define CATCH_AND_DIE(code_to_run)										\
	try { code_to_run }													\
	catch ( Error& e ) { fprintf( stderr, "Unexpected FDB error %d\n", e.code() ); abort(); } \
	catch ( ... ) { fprintf( stderr, "Unexpected FDB unknown error\n" ); abort(); }

extern "C" DLLEXPORT
fdb_error_t fdb_network_set_option( FDBNetworkOption option,
							 uint8_t const* value,
							 int value_length )
{
	CATCH_AND_RETURN(
		API->setNetworkOption( (FDBNetworkOptions::Option)option, value ? StringRef( value, value_length ) : Optional<StringRef>() ); );
}

extern "C"
fdb_error_t fdb_setup_network_impl() {
	CATCH_AND_RETURN( API->setupNetwork(); );
}

extern "C"
fdb_error_t fdb_setup_network_v13( const char* localAddress ) {
	fdb_error_t errorCode = fdb_network_set_option( FDB_NET_OPTION_LOCAL_ADDRESS, (uint8_t const*)localAddress, strlen(localAddress) );
	if(errorCode != 0)
		return errorCode;

	return fdb_setup_network_impl();
}

extern "C" DLLEXPORT
fdb_error_t fdb_run_network() {
	CATCH_AND_RETURN( API->runNetwork(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_stop_network() {
	CATCH_AND_RETURN( API->stopNetwork(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_add_network_thread_completion_hook(void (*hook)(void*), void *hook_parameter) {
	CATCH_AND_RETURN( API->addNetworkThreadCompletionHook(hook, hook_parameter); );
}

extern "C" DLLEXPORT
void fdb_future_cancel( FDBFuture* f ) {
	CATCH_AND_DIE(
		TSAVB(f)->addref();
		TSAVB(f)->cancel();
	);
}

extern "C" DLLEXPORT
void fdb_future_release_memory( FDBFuture* f ) {
	CATCH_AND_DIE( TSAVB(f)->releaseMemory(); );
}

extern "C" DLLEXPORT
void fdb_future_destroy( FDBFuture* f ) {
	CATCH_AND_DIE( TSAVB(f)->cancel(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_block_until_ready( FDBFuture* f ) {
	CATCH_AND_RETURN( TSAVB(f)->blockUntilReady(); );
}

extern "C" DLLEXPORT
fdb_bool_t fdb_future_is_error_v22( FDBFuture* f ) {
	return TSAVB(f)->isError();
}

extern "C" DLLEXPORT
fdb_bool_t fdb_future_is_ready( FDBFuture* f ) {
	return TSAVB(f)->isReady();
}

class CAPICallback : public ThreadCallback {
public:
	CAPICallback(void (*callbackf)(FDBFuture*, void*), FDBFuture* f,
				 void* userdata)
		: callbackf(callbackf), f(f), userdata(userdata) {}

	virtual bool canFire(int notMadeActive) { return true; }
	virtual void fire(const Void& unused, int& userParam) {
		(*callbackf)(f, userdata);
		delete this;
	}
	virtual void error(const Error&, int& userParam) {
		(*callbackf)(f, userdata);
		delete this;
	}

private:
	void (*callbackf)(FDBFuture*, void*);
	FDBFuture* f;
	void* userdata;
};

extern "C" DLLEXPORT
fdb_error_t fdb_future_set_callback( FDBFuture* f,
										 void (*callbackf)(FDBFuture*, void*),
										 void* userdata ) {
	CAPICallback* cb = new CAPICallback(callbackf, f, userdata);
	int ignore;
	CATCH_AND_RETURN( TSAVB(f)->callOrSetAsCallback( cb, ignore, 0 ); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_error_impl( FDBFuture* f ) {
	return TSAVB(f)->getErrorCode();
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_error_v22( FDBFuture* f, const char** description ) {
	if ( !( TSAVB(f)->isError() ) )
		return error_code_future_not_error;
	if (description)
		*description = TSAVB(f)->error.what();
	return TSAVB(f)->error.code();
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_version( FDBFuture* f, int64_t* out_version ) {
	CATCH_AND_RETURN( *out_version = TSAV(Version, f)->get(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_key( FDBFuture* f, uint8_t const** out_key,
								int* out_key_length ) {
	CATCH_AND_RETURN(
		KeyRef key = TSAV(Key, f)->get();
		*out_key = key.begin();
		*out_key_length = key.size(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_cluster_v609( FDBFuture* f, FDBCluster** out_cluster ) {
	CATCH_AND_RETURN(
		*out_cluster = (FDBCluster*)
		( (TSAV( char*, f )->get() ) ); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_database_v609( FDBFuture* f, FDBDatabase** out_database ) {
	CATCH_AND_RETURN(
		*out_database = (FDBDatabase*)
		( (TSAV( Reference<IDatabase>, f )->get() ).extractPtr() ); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_future_get_value( FDBFuture* f, fdb_bool_t* out_present,
								  uint8_t const** out_value, int* out_value_length ) {
	CATCH_AND_RETURN(
		Optional<Value> v = TSAV(Optional<Value>, f)->get();
		*out_present = v.present();
		if (*out_present) {
			*out_value = v.get().begin();
			*out_value_length = v.get().size();
		} );
}

extern "C"
fdb_error_t fdb_future_get_keyvalue_array_impl(
	FDBFuture* f, FDBKeyValue const** out_kv,
	int* out_count, fdb_bool_t* out_more )
{
	CATCH_AND_RETURN(
		Standalone<RangeResultRef> rrr = TSAV(Standalone<RangeResultRef>, f)->get();
		*out_kv = (FDBKeyValue*)rrr.begin();
		*out_count = rrr.size();
		*out_more = rrr.more; );
}

extern "C"
fdb_error_t fdb_future_get_keyvalue_array_v13(
	FDBFuture* f, FDBKeyValue const** out_kv, int* out_count)
{
	CATCH_AND_RETURN(
		Standalone<RangeResultRef> rrr = TSAV(Standalone<RangeResultRef>, f)->get();
		*out_kv = (FDBKeyValue*)rrr.begin();
		*out_count = rrr.size(); );
}

extern "C"
fdb_error_t fdb_future_get_string_array(
	FDBFuture* f, const char*** out_strings, int* out_count)
{
	CATCH_AND_RETURN(
		Standalone<VectorRef<const char*>> na = TSAV(Standalone<VectorRef<const char*>>, f)->get();
		*out_strings = (const char **) na.begin();
		*out_count = na.size();
	);
}

extern "C" DLLEXPORT
FDBFuture* fdb_create_cluster_v609( const char* cluster_file_path ) {
	char *path;
	if(cluster_file_path) {
		path = new char[strlen(cluster_file_path) + 1];
		strcpy(path, cluster_file_path);
	}
	else {
		path = new char[1];
		path[0] = '\0';
	}
	return (FDBFuture*)ThreadFuture<char*>(path).extractPtr();
}

extern "C" DLLEXPORT
fdb_error_t fdb_cluster_set_option_v609( FDBCluster* c,
							 FDBClusterOption option,
							 uint8_t const* value,
							 int value_length )
{
	// There are no cluster options
	return error_code_success;
}

extern "C" DLLEXPORT
void fdb_cluster_destroy_v609( FDBCluster* c ) {
	CATCH_AND_DIE( delete[] CLUSTER(c); );
}

extern "C" DLLEXPORT
FDBFuture* fdb_cluster_create_database_v609( FDBCluster* c, uint8_t const* db_name,
											int db_name_length ) 
{
	if(strncmp((const char*)db_name, "DB", db_name_length) != 0) {
		return (FDBFuture*)ThreadFuture<Reference<IDatabase>>(invalid_database_name()).extractPtr();
	}

	FDBDatabase *db;
	fdb_error_t err = fdb_create_database(CLUSTER(c), &db);
	if(err) {
		return (FDBFuture*)ThreadFuture<Reference<IDatabase>>(Error(err)).extractPtr();
	}

	return (FDBFuture*)ThreadFuture<Reference<IDatabase>>(Reference<IDatabase>(DB(db))).extractPtr();
}

extern "C" DLLEXPORT
fdb_error_t fdb_create_database( const char* cluster_file_path, FDBDatabase** out_database ) {
	CATCH_AND_RETURN(
		*out_database = (FDBDatabase*)API->createDatabase( cluster_file_path ? cluster_file_path : "" ).extractPtr();
	);
}

extern "C" DLLEXPORT
fdb_error_t fdb_database_set_option( FDBDatabase* d,
							  FDBDatabaseOption option,
							  uint8_t const* value,
							  int value_length )
{
	CATCH_AND_RETURN(
		DB(d)->setOption( (FDBDatabaseOptions::Option)option, value ? StringRef( value, value_length ) : Optional<StringRef>() ); );
}

extern "C" DLLEXPORT
void fdb_database_destroy( FDBDatabase* d ) {
	CATCH_AND_DIE( DB(d)->delref(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_database_create_transaction( FDBDatabase* d,
												 FDBTransaction** out_transaction )
{
	CATCH_AND_RETURN(
		Reference<ITransaction> tr = DB(d)->createTransaction();
		if(g_api_version <= 15)
			tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
		*out_transaction = (FDBTransaction*)tr.extractPtr(); );
}


extern "C" DLLEXPORT
void fdb_transaction_destroy( FDBTransaction* tr ) {
	try {
		TXN(tr)->delref();
	} catch ( ... ) { }
}

extern "C" DLLEXPORT
void fdb_transaction_cancel( FDBTransaction* tr ) {
	CATCH_AND_DIE( TXN(tr)->cancel(); );
}

extern "C" DLLEXPORT
void fdb_transaction_set_read_version( FDBTransaction* tr, int64_t version ) {
	CATCH_AND_DIE( TXN(tr)->setVersion( version ); );
}

extern "C" DLLEXPORT
FDBFuture* fdb_transaction_get_read_version( FDBTransaction* tr ) {
	return (FDBFuture*)( TXN(tr)->getReadVersion().extractPtr() );
}

extern "C"
FDBFuture* fdb_transaction_get_impl( FDBTransaction* tr, uint8_t const* key_name,
									 int key_name_length, fdb_bool_t snapshot ) {
	return (FDBFuture*)
		( TXN(tr)->get( KeyRef( key_name, key_name_length ), snapshot ).extractPtr() );
}

extern "C"
FDBFuture* fdb_transaction_get_v13( FDBTransaction* tr, uint8_t const* key_name,
									int key_name_length )
{
	return fdb_transaction_get_impl( tr, key_name, key_name_length, 0 );
}

extern "C"
FDBFuture* fdb_transaction_get_key_impl( FDBTransaction* tr, uint8_t const* key_name,
										 int key_name_length, fdb_bool_t or_equal,
										 int offset, fdb_bool_t snapshot ) {
	return (FDBFuture*)( TXN(tr)->getKey( KeySelectorRef(
											  KeyRef( key_name,
													  key_name_length ),
											  or_equal, offset ),
										  snapshot ).extractPtr() );
}

extern "C"
FDBFuture* fdb_transaction_get_key_v13( FDBTransaction* tr, uint8_t const* key_name,
										int key_name_length, fdb_bool_t or_equal,
										int offset ) {
	return fdb_transaction_get_key_impl( tr, key_name, key_name_length,
										 or_equal, offset, false );
}

extern "C"
FDBFuture* fdb_transaction_get_addresses_for_key( FDBTransaction* tr, uint8_t const* key_name,
									int key_name_length ){
	return (FDBFuture*)( TXN(tr)->getAddressesForKey( KeyRef(key_name, key_name_length) ).extractPtr() );

}

extern "C"
FDBFuture* fdb_transaction_get_range_impl(
		FDBTransaction* tr, uint8_t const* begin_key_name,
		int begin_key_name_length, fdb_bool_t begin_or_equal, int begin_offset,
		uint8_t const* end_key_name, int end_key_name_length,
		fdb_bool_t end_or_equal, int end_offset, int limit, int target_bytes,
		FDBStreamingMode mode, int iteration, fdb_bool_t snapshot,
		fdb_bool_t reverse )
{
	/* This method may be called with a runtime API version of 13, in
	   which negative row limits are a reverse range read */
	if (g_api_version <= 13 && limit < 0) {
		limit = -limit;
		reverse = true;
	}

	/* Zero at the C API maps to "infinity" at lower levels */
	if (!limit)
		limit = CLIENT_KNOBS->ROW_LIMIT_UNLIMITED;
	if (!target_bytes)
		target_bytes = CLIENT_KNOBS->BYTE_LIMIT_UNLIMITED;

	/* Unlimited/unlimited with mode _EXACT isn't permitted */
	if (limit == CLIENT_KNOBS->ROW_LIMIT_UNLIMITED && target_bytes == CLIENT_KNOBS->BYTE_LIMIT_UNLIMITED && mode == FDB_STREAMING_MODE_EXACT)
		return TSAV_ERROR(Standalone<RangeResultRef>, exact_mode_without_limits);

	/* _ITERATOR mode maps to one of the known streaming modes
	   depending on iteration */
	static const int mode_bytes_array[] = {CLIENT_KNOBS->BYTE_LIMIT_UNLIMITED, 256, 1000, 4096, 80000};

	/* The progression used for FDB_STREAMING_MODE_ITERATOR.
	   Goes from small -> medium -> large.  Then 1.5 * previous until serial. */
	static const int iteration_progression[] = { 256, 1000, 4096, 6144, 9216, 13824, 20736, 31104, 46656, 69984, 80000 };

	/* length(iteration_progression) */
	static const int max_iteration = sizeof(iteration_progression) / sizeof(int);

	if(mode == FDB_STREAMING_MODE_WANT_ALL)
		mode = FDB_STREAMING_MODE_SERIAL;

	int mode_bytes;
	if (mode == FDB_STREAMING_MODE_ITERATOR) {
		if (iteration <= 0)
			return TSAV_ERROR(Standalone<RangeResultRef>, client_invalid_operation);

		iteration = std::min(iteration, max_iteration);
		mode_bytes = iteration_progression[iteration - 1];
	}
	else if(mode >= 0 && mode <= FDB_STREAMING_MODE_SERIAL)
		mode_bytes = mode_bytes_array[mode];
	else
		return TSAV_ERROR(Standalone<RangeResultRef>, client_invalid_operation);

	if(target_bytes == CLIENT_KNOBS->BYTE_LIMIT_UNLIMITED)
		target_bytes = mode_bytes;
	else if(mode_bytes != CLIENT_KNOBS->BYTE_LIMIT_UNLIMITED)
		target_bytes = std::min(target_bytes, mode_bytes);

	return (FDBFuture*)( TXN(tr)->getRange(
							 KeySelectorRef(
								 KeyRef( begin_key_name,
										 begin_key_name_length ),
								 begin_or_equal, begin_offset ),
							 KeySelectorRef(
								 KeyRef( end_key_name,
										 end_key_name_length ),
								 end_or_equal, end_offset ),
							 GetRangeLimits(limit, target_bytes),
							 snapshot, reverse ).extractPtr() );
}

extern "C"
FDBFuture* fdb_transaction_get_range_selector_v13(
	FDBTransaction* tr, uint8_t const* begin_key_name, int begin_key_name_length,
	fdb_bool_t begin_or_equal, int begin_offset, uint8_t const* end_key_name,
	int end_key_name_length, fdb_bool_t end_or_equal, int end_offset, int limit )
{
	return fdb_transaction_get_range_impl(
		tr, begin_key_name, begin_key_name_length, begin_or_equal, begin_offset,
		end_key_name, end_key_name_length, end_or_equal, end_offset,
		limit, 0, FDB_STREAMING_MODE_EXACT, 0, false, false);
}

extern "C"
FDBFuture* fdb_transaction_get_range_v13(
	FDBTransaction* tr, uint8_t const* begin_key_name, int begin_key_name_length,
	uint8_t const* end_key_name, int end_key_name_length, int limit )
{
	return fdb_transaction_get_range_selector_v13(
		tr,
		FDB_KEYSEL_FIRST_GREATER_OR_EQUAL(begin_key_name,
										  begin_key_name_length),
		FDB_KEYSEL_FIRST_GREATER_OR_EQUAL(end_key_name,
										  end_key_name_length),
		limit );
}

extern "C" DLLEXPORT
void fdb_transaction_set( FDBTransaction* tr, uint8_t const* key_name,
							  int key_name_length, uint8_t const* value,
							  int value_length ) {
	CATCH_AND_DIE(
		TXN(tr)->set( KeyRef( key_name, key_name_length ),
					  ValueRef( value, value_length ) ); );
}

extern "C" DLLEXPORT
void fdb_transaction_atomic_op( FDBTransaction* tr, uint8_t const* key_name,
								int key_name_length, uint8_t const* param,
								int param_length, FDBMutationType operation_type ) {
	CATCH_AND_DIE(
		TXN(tr)->atomicOp( KeyRef( key_name, key_name_length ),
						   ValueRef( param, param_length ),
						   (FDBMutationTypes::Option) operation_type ); );
}

extern "C" DLLEXPORT
void fdb_transaction_clear( FDBTransaction* tr, uint8_t const* key_name,
								int key_name_length ) {
	CATCH_AND_DIE(
		TXN(tr)->clear( KeyRef( key_name, key_name_length ) ); );
}

extern "C" DLLEXPORT
void fdb_transaction_clear_range(
	FDBTransaction* tr, uint8_t const* begin_key_name, int begin_key_name_length,
	uint8_t const* end_key_name, int end_key_name_length )
{
	CATCH_AND_DIE(
		TXN(tr)->clear( KeyRef( begin_key_name,
								begin_key_name_length ),
						KeyRef( end_key_name,
								end_key_name_length ) ); );
}

extern "C" DLLEXPORT
FDBFuture* fdb_transaction_watch( FDBTransaction *tr, uint8_t const* key_name,
									int key_name_length)
{
	return (FDBFuture*)( TXN(tr)->watch(KeyRef(key_name, key_name_length)).extractPtr() );
}

extern "C" DLLEXPORT
FDBFuture* fdb_transaction_commit( FDBTransaction* tr ) {
	return (FDBFuture*)( TXN(tr)->commit().extractPtr() );
}

extern "C" DLLEXPORT
fdb_error_t fdb_transaction_get_committed_version( FDBTransaction* tr,
													   int64_t* out_version )
{
	CATCH_AND_RETURN(
		*out_version = TXN(tr)->getCommittedVersion(); );
}

extern "C" DLLEXPORT
FDBFuture* fdb_transaction_get_versionstamp( FDBTransaction* tr )
{
	return (FDBFuture*)(TXN(tr)->getVersionstamp().extractPtr());
}

extern "C"
fdb_error_t fdb_transaction_set_option_impl( FDBTransaction* tr,
								 FDBTransactionOption option,
								 uint8_t const* value,
								 int value_length )
{
	CATCH_AND_RETURN(
		TXN(tr)->setOption( (FDBTransactionOptions::Option)option, value ? StringRef( value, value_length ) : Optional<StringRef>() ); );
}

extern "C"
void fdb_transaction_set_option_v13( FDBTransaction* tr,
									 FDBTransactionOption option )
{
	fdb_transaction_set_option_impl( tr, option, NULL, 0 );
}

extern "C" DLLEXPORT
FDBFuture* fdb_transaction_on_error( FDBTransaction* tr, fdb_error_t error ) {
	return (FDBFuture*)( TXN(tr)->onError(
							 Error::fromUnvalidatedCode( error ) ).extractPtr() );
}

extern "C" DLLEXPORT
void fdb_transaction_reset( FDBTransaction* tr ) {
	CATCH_AND_DIE( TXN(tr)->reset(); );
}

extern "C" DLLEXPORT
fdb_error_t fdb_transaction_add_conflict_range( FDBTransaction*tr, uint8_t const* begin_key_name,
												int begin_key_name_length, uint8_t const* end_key_name,
												int end_key_name_length, FDBConflictRangeType type) {
	CATCH_AND_RETURN(
		KeyRangeRef range(KeyRef(begin_key_name, begin_key_name_length), KeyRef(end_key_name, end_key_name_length));
		if(type == FDBConflictRangeType::FDB_CONFLICT_RANGE_TYPE_READ)
			TXN(tr)->addReadConflictRange(range);
		else if(type == FDBConflictRangeType::FDB_CONFLICT_RANGE_TYPE_WRITE)
			TXN(tr)->addWriteConflictRange(range);
		else
			return error_code_client_invalid_operation;
	);

}

#include "fdb_c_function_pointers.g.h"

#define FDB_API_CHANGED(func, ver) if (header_version < ver) fdb_api_ptr_##func = (void*)&(func##_v##ver##_PREV); else if (fdb_api_ptr_##func == (void*)&fdb_api_ptr_unimpl) fdb_api_ptr_##func = (void*)&(func##_impl);

#define FDB_API_REMOVED(func, ver) if (header_version < ver) fdb_api_ptr_##func = (void*)&(func##_v##ver##_PREV); else fdb_api_ptr_##func = (void*)&fdb_api_ptr_removed;

extern "C" DLLEXPORT
fdb_error_t fdb_select_api_version_impl( int runtime_version, int header_version ) {
	/* Can only call this once */
	if (g_api_version != 0)
		return error_code_api_version_already_set;

	/* Caller screwed up, this makes no sense */
	if (runtime_version > header_version)
		return error_code_api_version_invalid;

	/* Caller requested a version we don't speak */
	if (header_version > FDB_API_VERSION)
		return error_code_api_version_not_supported;

	/* No backwards compatibility for earlier versions */
	if (runtime_version < 13)
		return error_code_api_version_not_supported;

	RETURN_ON_ERROR(
		API->selectApiVersion(runtime_version);
	);

	g_api_version = runtime_version;

	platformInit();
	Error::init();

	// Versioned API changes -- descending order by version (new changes at top)
	// FDB_API_CHANGED( function, ver ) means there is a new implementation as of ver, and a function function_(ver-1) is the old implementation
	// FDB_API_REMOVED( function, ver ) means the function was removed as of ver, and function_(ver-1) is the old implementation
	FDB_API_REMOVED( fdb_create_cluster, 610 );
	FDB_API_REMOVED( fdb_cluster_create_database, 610 );
	FDB_API_REMOVED( fdb_cluster_set_option, 610 );
	FDB_API_REMOVED( fdb_cluster_destroy, 610 );
	FDB_API_REMOVED( fdb_future_get_cluster, 610 );
	FDB_API_REMOVED( fdb_future_get_database, 610 );
	FDB_API_CHANGED( fdb_future_get_error, 23 );
	FDB_API_REMOVED( fdb_future_is_error, 23 );
	FDB_API_CHANGED( fdb_future_get_keyvalue_array, 14 );
	FDB_API_CHANGED( fdb_transaction_get_key, 14 );
	FDB_API_CHANGED( fdb_transaction_get_range, 14 );
	FDB_API_REMOVED( fdb_transaction_get_range_selector, 14 );
	FDB_API_CHANGED( fdb_transaction_get, 14 );
	FDB_API_CHANGED( fdb_setup_network, 14 );
	FDB_API_CHANGED( fdb_transaction_set_option, 14 );
	/* End versioned API changes */

	return error_code_success;
}

extern "C" DLLEXPORT
int fdb_get_max_api_version() {
	return FDB_API_VERSION;
}

extern "C" DLLEXPORT
const char* fdb_get_client_version() {
	return API->getClientVersion();
}

#if defined(__APPLE__)
#include <dlfcn.h>
__attribute__((constructor))
static void initialize() {
	//OS X ld doesn't support -z nodelete, so we dlopen to increment the reference count of this module
	Dl_info info;
	int ret = dladdr((void*)&fdb_select_api_version_impl, &info);
	if(!ret || !info.dli_fname)
		return; //If we get here somehow, we face the risk of seg faults if somebody unloads our library

	dlopen(info.dli_fname, RTLD_NOLOAD | RTLD_NODELETE);
}
#endif
