#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#define TECH_LIST \
    X("System Principles") \
    X("Infrastructure") \
    X("Low-level C/C++")\
    X("Backend dev golang")

#define HOBBY_LIST \
    X("Running ") \
    X("Guitar ") \
    X("Animals ") \
    X("Photography ")

typedef struct {
    const char *target;
} Dream;

typedef struct {
    const char *job;
    const char *task;
} Reality;

typedef struct {
    const char **tech;
    size_t tech_count;
    const char **life;
    size_t life_count;
} Interest;

typedef struct Me Me;

struct Me {
    Dream dream;
    Reality reality;
    Interest interest;
    const char *(*whoami)(Me *self);
    void (*show)(Me *self);
    const char *(*pursuit)(Me *self);
};

#define NEW(type, ...) ((type*)memcpy(malloc(sizeof(type)), &(type)__VA_ARGS__, sizeof(type)))
#define ARRAY(...) (const char*[]){__VA_ARGS__}, sizeof((const char*[]){__VA_ARGS__})/sizeof(char*)

const char *whoami_impl(Me *self) {
    (void)self;
    return "A backend developer who dreams of being a geek.";
}

void show_impl(Me *self) {
    printf("hi %s\n\n", self->whoami(self));
    printf("== Reality ==\nJob: %s\nTask: %s\n\n", self->reality.job, self->reality.task);
    printf("== Dream ==\n%s\n\n", self->dream.target);
    printf("== Tech Interests ==\n");
    for (size_t i = 0; i < self->interest.tech_count; i++) {
        printf(" - %s\n", self->interest.tech[i]);
    }
    printf("\n== Life Hobbies ==\n");
    for (size_t i = 0; i < self->interest.life_count; i++) {
        printf(" - %s\n", self->interest.life[i]);
    }
}

const char *pursuit_impl(Me *self) {
    return self->dream.target && strlen(self->dream.target)
        ? self->dream.target
        : self->reality.task;
}

Me *new_me() {
    const char *tech[] = {
    #define X(item) item,
        TECH_LIST
    #undef X
    };

    const char *hobbies[] = {
    #define X(item) item,
        HOBBY_LIST
    #undef X
    };

    return NEW(Me, {
        .dream = {"Contribute to Redis & Linux Kernel"},
        .reality = {"Backend Engineer", "Write business code"},
        .interest = {ARRAY(tech[0], tech[1], tech[2]),
                     ARRAY(hobbies[0], hobbies[1], hobbies[2], hobbies[3])},
        .whoami = whoami_impl,
        .show = show_impl,
        .pursuit = pursuit_impl
    });
}

int main() {
    Me *me = new_me();
    me->show(me);
    printf("\n Pursuing: %s\n", me->pursuit(me));
    __asm__ volatile ("nop");
    free(me);
    return 0;
}