#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>
#include <errno.h>
#include <dlfcn.h>

#include "binder_ndk.h"

static bool binder_available = false;

bool binder_is_available(void)
{
	return binder_available;
}

AIBinder_Class *(*AIBinder_Class_define)(const char *interfaceDescriptor, AIBinder_Class_onCreate onCreate, AIBinder_Class_onDestroy onDestroy, AIBinder_Class_onTransact onTransact) __attribute__((warn_unused_result)) = NULL;
bool (*AIBinder_associateClass)(AIBinder *binder, const AIBinder_Class *clazz) = NULL;
void (*AIBinder_decStrong)(AIBinder *binder) = NULL;
binder_status_t (*AIBinder_prepareTransaction)(AIBinder *binder, AParcel **in) = NULL;
binder_status_t (*AIBinder_transact)(AIBinder *binder, transaction_code_t code, AParcel **in, AParcel **out, binder_flags_t flags) = NULL;
binder_status_t (*AIBinder_ping)(AIBinder *binder) = NULL;
binder_status_t (*AIBinder_dump)(AIBinder *binder, int fd, const char **args, uint32_t numArgs) = NULL;
binder_status_t (*AParcel_readStatusHeader)(const AParcel *parcel, AStatus **status) = NULL;
binder_status_t (*AParcel_readBool)(const AParcel *parcel, bool *value) = NULL;
void (*AParcel_delete)(AParcel *parcel) = NULL;
binder_status_t (*AParcel_setDataPosition)(const AParcel *parcel, int32_t position) = NULL;
int32_t (*AParcel_getDataPosition)(const AParcel *parcel) = NULL;
binder_status_t (*AParcel_writeInt32)(AParcel *parcel, int32_t value) = NULL;
binder_status_t (*AParcel_writeStringArray)(AParcel *parcel, const void *arrayData, int32_t length, AParcel_stringArrayElementGetter getter) = NULL;
binder_status_t (*AParcel_writeString)(AParcel *parcel, const char *string, int32_t length) = NULL;
bool (*AStatus_isOk)(const AStatus *status) = NULL;
void (*AStatus_delete)(AStatus *status) = NULL;
binder_exception_t (*AStatus_getExceptionCode)(const AStatus *status) = NULL;
int32_t (*AStatus_getServiceSpecificError)(const AStatus *status) = NULL;
const char* (*AStatus_getMessage)(const AStatus *status) = NULL;
binder_status_t (*AStatus_getStatus)(const AStatus *status) = NULL;
AIBinder *(*AServiceManager_getService)(const char *instance) __attribute__((__warn_unused_result__)) = NULL;

static	__attribute__((__constructor__(65535))) void load_symbols(void)
{
	void *handle = NULL;
	if (!(handle = dlopen("libbinder_ndk.so", RTLD_LAZY))) {
		fprintf(stderr, "Warning: libbinder_ndk.so is not available\n");
		binder_available = false;
		return;
	}
	else
		binder_available = true;

#define X(symb) ({							\
			if (!((symb) = (__typeof__(symb))dlsym(handle, #symb)))	{ \
				fprintf(stderr, "Error: unable to import " #symb " from libbinder_ndk.so\n"); \
				exit(ELIBACC);				\
			}						\
		})

	X(AIBinder_Class_define);
	X(AIBinder_associateClass);
	X(AIBinder_decStrong);
	X(AIBinder_prepareTransaction);
	X(AIBinder_transact);
	X(AIBinder_ping);
	X(AIBinder_dump);
	X(AParcel_readStatusHeader);
	X(AParcel_readBool);
	X(AParcel_delete);
	X(AParcel_setDataPosition);
	X(AParcel_getDataPosition);
	X(AParcel_writeInt32);
	X(AParcel_writeStringArray);
	X(AParcel_writeString);
	X(AStatus_isOk);
	X(AStatus_delete);
	X(AStatus_getExceptionCode);
	X(AStatus_getServiceSpecificError);
	X(AStatus_getMessage);
	X(AStatus_getStatus);
	X(AServiceManager_getService);
#undef X
}

void cleanup_binder(AIBinder **binder)
{
	AIBinder_decStrong(*binder);
}

void cleanup_status(AStatus **status)
{
	AStatus_delete(*status);
}

void cleanup_parcel(AParcel **parcel)
{
	AParcel_delete(*parcel);
}

binder_status_t meaningful_binder_status(const AStatus *status_out)
{
	binder_status_t status = STATUS_OK;
	binder_exception_t exc_code;
	int32_t exc_code_service;
	const char *message;

	if (!AStatus_isOk(status_out)) {
		exc_code = AStatus_getExceptionCode(status_out);
		if (exc_code == EX_TRANSACTION_FAILED) {
			status = AStatus_getStatus(status_out);
			fprintf(stderr, "Error: transaction failed: %d\n", status);
		}
		else {
			message = AStatus_getMessage(status_out);

			if (exc_code == EX_SERVICE_SPECIFIC) {
				exc_code_service = AStatus_getServiceSpecificError(status_out);
				fprintf(stderr, "Error: service specific exception code: %d%s%s\n", exc_code_service, message ? ": " : "", message ?: "");
			}
			else
				fprintf(stderr, "Error: exception code: %d%s%s\n", exc_code, message ? ": " : "", message ?: "");

			status = STATUS_FAILED_TRANSACTION;
		}
	}

	return status;
}