#include "common/sysctl.h"

#include <stdlib.h>

#ifdef __OpenBSD__
const char* ffSysctlGetString(int mib1, int mib2, FFstrbuf* result) {
    size_t neededLength;
    if (sysctl((int[]) { mib1, mib2 }, 2, NULL, &neededLength, NULL, 0) != 0 || neededLength == 1) { // neededLength is 1 for empty strings, because of the null terminator
        return "sysctl() length query failed";
    }

    ffStrbufEnsureFree(result, (uint32_t) neededLength - 1);

    if (sysctl((int[]) { mib1, mib2 }, 2, result->chars + result->length, &neededLength, NULL, 0) != 0) {
        return "sysctl() failed to retrieve string data";
    }

    result->length += (uint32_t) neededLength - 1;
    result->chars[result->length] = '\0';

    return NULL;
}

int ffSysctlGetInt(int mib1, int mib2, int defaultValue) {
    int result;
    size_t neededLength = sizeof(result);
    if (sysctl((int[]) { mib1, mib2 }, 2, &result, &neededLength, NULL, 0) != 0) {
        return defaultValue;
    }
    return result;
}

int64_t ffSysctlGetInt64(int mib1, int mib2, int64_t defaultValue) {
    int64_t result;
    size_t neededLength = sizeof(result);
    if (sysctl((int[]) { mib1, mib2 }, 2, &result, &neededLength, NULL, 0) != 0) {
        return defaultValue;
    }
    return result;
}
#else
const char* ffSysctlGetString(const char* propName, FFstrbuf* result) {
    size_t neededLength;
    if (sysctlbyname(propName, NULL, &neededLength, NULL, 0) != 0 || neededLength == 1) { // neededLength is 1 for empty strings, because of the null terminator
        return "sysctlbyname() failed";
    }

    ffStrbufEnsureFree(result, (uint32_t) neededLength - 1);

    if (sysctlbyname(propName, result->chars + result->length, &neededLength, NULL, 0) != 0) {
        return "sysctlbyname() failed to retrieve string data";
    }

    result->length += (uint32_t) neededLength - 1;

    result->chars[result->length] = '\0';

    return NULL;
}

int ffSysctlGetInt(const char* propName, int defaultValue) {
    int result;
    size_t neededLength = sizeof(result);
    if (sysctlbyname(propName, &result, &neededLength, NULL, 0) != 0) {
        return defaultValue;
    }
    return result;
}

int64_t ffSysctlGetInt64(const char* propName, int64_t defaultValue) {
    int64_t result;
    size_t neededLength = sizeof(result);
    if (sysctlbyname(propName, &result, &neededLength, NULL, 0) != 0) {
        return defaultValue;
    }
    return result;
}
#endif // OpenBSD

void* ffSysctlGetData(int* request, u_int requestLength, size_t* resultLength) {
    if (sysctl(request, requestLength, NULL, resultLength, NULL, 0) != 0) {
        return NULL;
    }

    void* data = malloc(*resultLength);

    if (sysctl(request, requestLength, data, resultLength, NULL, 0) != 0) {
        free(data);
        return NULL;
    }

    return data;
}
