#include <limits.h>
#include <string.h>

#include <dlfcn.h>
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#if CPUINFO_MOCK
#include <cpuinfo-mock.h>
#endif
#include <arm/linux/api.h>
#include <cpuinfo.h>
#include <cpuinfo/log.h>

#if CPUINFO_ARCH_ARM64 ||                                                     \
	CPUINFO_ARCH_ARM && defined(__GLIBC__) && defined(__GLIBC_MINOR__) && \
		(__GLIBC__ > 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ >= 16)
#include <sys/auxv.h>
#else
#define AT_HWCAP 16
#define AT_HWCAP2 26
#endif

#if CPUINFO_MOCK
static uint32_t mock_hwcap = 0;
void cpuinfo_set_hwcap(uint32_t hwcap) {
	mock_hwcap = hwcap;
}

static uint64_t mock_hwcap2 = 0;
void cpuinfo_set_hwcap2(uint64_t hwcap2) {
	mock_hwcap2 = hwcap2;
}
#endif

#if CPUINFO_ARCH_ARM
typedef unsigned long (*getauxval_function_t)(unsigned long);

bool cpuinfo_arm_linux_hwcap_from_getauxval(uint32_t hwcap[restrict static 1], uint64_t hwcap2[restrict static 1]) {
#if CPUINFO_MOCK
	*hwcap = mock_hwcap;
	*hwcap2 = mock_hwcap2;
	return true;
#elif defined(__ANDROID__)
	/* Android: dynamically check if getauxval is supported */
	void* libc = NULL;
	getauxval_function_t getauxval = NULL;

	dlerror();
	libc = dlopen("libc.so", RTLD_LAZY);
	if (libc == NULL) {
		cpuinfo_log_warning("failed to load libc.so: %s", dlerror());
		goto cleanup;
	}

	getauxval = (getauxval_function_t)dlsym(libc, "getauxval");
	if (getauxval == NULL) {
		cpuinfo_log_info("failed to locate getauxval in libc.so: %s", dlerror());
		goto cleanup;
	}

	*hwcap = getauxval(AT_HWCAP);
	*hwcap2 = getauxval(AT_HWCAP2);

cleanup:
	if (libc != NULL) {
		dlclose(libc);
		libc = NULL;
	}
	return getauxval != NULL;
#elif defined(__GLIBC__) && defined(__GLIBC_MINOR__) && (__GLIBC__ > 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ >= 16)
	/* GNU/Linux: getauxval is supported since glibc-2.16 */
	*hwcap = getauxval(AT_HWCAP);
	*hwcap2 = getauxval(AT_HWCAP2);
	return true;
#else
	return false;
#endif
}

#ifdef __ANDROID__
bool cpuinfo_arm_linux_hwcap_from_procfs(uint32_t hwcap[restrict static 1], uint64_t hwcap2[restrict static 1]) {
#if CPUINFO_MOCK
	*hwcap = mock_hwcap;
	*hwcap2 = mock_hwcap2;
	return true;
#else
	uint64_t hwcaps[2] = {0, 0};
	bool result = false;
	int file = -1;

	file = open("/proc/self/auxv", O_RDONLY);
	if (file == -1) {
		cpuinfo_log_warning("failed to open /proc/self/auxv: %s", strerror(errno));
		goto cleanup;
	}

	ssize_t bytes_read;
	do {
		Elf32_auxv_t elf_auxv;
		bytes_read = read(file, &elf_auxv, sizeof(Elf32_auxv_t));
		if (bytes_read < 0) {
			cpuinfo_log_warning("failed to read /proc/self/auxv: %s", strerror(errno));
			goto cleanup;
		} else if (bytes_read > 0) {
			if (bytes_read == sizeof(elf_auxv)) {
				switch (elf_auxv.a_type) {
					case AT_HWCAP:
						hwcaps[0] = (uint32_t)elf_auxv.a_un.a_val;
						break;
					case AT_HWCAP2:
						hwcaps[1] = (uint64_t)elf_auxv.a_un.a_val;
						break;
				}
			} else {
				cpuinfo_log_warning(
					"failed to read %zu bytes from /proc/self/auxv: %zu bytes available",
					sizeof(elf_auxv),
					(size_t)bytes_read);
				goto cleanup;
			}
		}
	} while (bytes_read == sizeof(Elf32_auxv_t));

	/* Success, commit results */
	*hwcap = hwcaps[0];
	*hwcap2 = hwcaps[1];
	result = true;

cleanup:
	if (file != -1) {
		close(file);
		file = -1;
	}
	return result;
#endif
}
#endif /* __ANDROID__ */
#elif CPUINFO_ARCH_ARM64
void cpuinfo_arm_linux_hwcap_from_getauxval(uint32_t hwcap[restrict static 1], uint64_t hwcap2[restrict static 1]) {
#if CPUINFO_MOCK
	*hwcap = mock_hwcap;
	*hwcap2 = mock_hwcap2;
#else
	*hwcap = (uint32_t)getauxval(AT_HWCAP);
	*hwcap2 = (uint64_t)getauxval(AT_HWCAP2);
	return;
#endif
}
#endif