/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
#include <iostream>
#include <unistd.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>

#ifndef _Bool
#define _Bool bool
#endif
#include "test_core_extern.skel.h"
#include "struct_ops_module.skel.h"

template <typename T>
class Skeleton {
private:
        T *skel;
public:
        Skeleton(): skel(nullptr) { }

        ~Skeleton() { if (skel) T::destroy(skel); }

        int open(const struct bpf_object_open_opts *opts = nullptr)
        {
                int err;

                if (skel)
                        return -EBUSY;

                skel = T::open(opts);
                err = libbpf_get_error(skel);
                if (err) {
                        skel = nullptr;
                        return err;
                }

                return 0;
        }

        int load() { return T::load(skel); }

        int attach() { return T::attach(skel); }

        void detach() { return T::detach(skel); }

        const T* operator->() const { return skel; }

        T* operator->() { return skel; }

        const T *get() const { return skel; }
};

static void dump_printf(void *ctx, const char *fmt, va_list args)
{
}

static void try_skeleton_template()
{
        Skeleton<test_core_extern> skel;
        std::string prog_name;
        int err;
        LIBBPF_OPTS(bpf_object_open_opts, opts);

        err = skel.open(&opts);
        if (err) {
                fprintf(stderr, "Skeleton open failed: %d\n", err);
                return;
        }

        skel->data->kern_ver = 123;
        skel->data->int_val = skel->data->ushort_val;

        err = skel.load();
        if (err) {
                fprintf(stderr, "Skeleton load failed: %d\n", err);
                return;
        }

        if (!skel->kconfig->CONFIG_BPF_SYSCALL)
                fprintf(stderr, "Seems like CONFIG_BPF_SYSCALL isn't set?!\n");

        err = skel.attach();
        if (err) {
                fprintf(stderr, "Skeleton attach failed: %d\n", err);
                return;
        }

        prog_name = bpf_program__name(skel->progs.handle_sys_enter);
        if (prog_name != "handle_sys_enter")
                fprintf(stderr, "Unexpected program name: %s\n", prog_name.c_str());

        bpf_link__destroy(skel->links.handle_sys_enter);
        skel->links.handle_sys_enter = bpf_program__attach(skel->progs.handle_sys_enter);

        skel.detach();

        /* destructor will destroy underlying skeleton */
}

int main(int argc, char *argv[])
{
        struct btf_dump_opts opts = { };
        struct test_core_extern *skel;
        struct struct_ops_module *skel2;
        struct btf *btf;
        int fd;

        try_skeleton_template();

        /* libbpf.h */
        libbpf_set_print(NULL);

        /* bpf.h */
        bpf_prog_get_fd_by_id(0);

        /* btf.h */
        btf = btf__new(NULL, 0);
        if (!libbpf_get_error(btf))
                btf_dump__new(btf, dump_printf, nullptr, &opts);

        /* BPF skeleton */
        skel = test_core_extern__open_and_load();
        test_core_extern__destroy(skel);

        skel2 = struct_ops_module__open_and_load();
        struct_ops_module__destroy(skel2);

        fd = bpf_enable_stats(BPF_STATS_RUN_TIME);
        if (fd < 0)
                std::cout << "FAILED to enable stats: " << fd << std::endl;
        else
                ::close(fd);

        std::cout << "DONE!" << std::endl;

        return 0;
}