#ifndef CORE_HPP
#define CORE_HPP

#include <string.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/mman.h>

// ### Types ###
typedef int8_t int8;
typedef int16_t int16;
typedef int32_t int32;
typedef int64_t int64;
typedef uint8_t uint8;
typedef uint16_t uint16;
typedef uint32_t uint32;
typedef uint64_t uint64;

typedef uint8_t byte;

typedef float real32;
typedef double real64;

// ### Sizes and Numbers ###
#define Bytes(n) (n)
#define Kilobytes(n) (n << 10)
#define Megabytes(n) (n << 20)
#define Gigabytes(n) (((uint64)n) << 30)
#define Terabytes(n) (((uint64)n) << 40)

#define Thousand(n) ((n)*1000)
#define Million(n)  ((n)*1000000)
#define Billion(n)  ((n)*1000000000LL)

#define ArrayCount(arr) (sizeof(arr) / sizeof((arr)[0]))

// ### Arenas ###
struct Arena {
    void *memory;
    size_t capacity;
    size_t head;
};

void *pushSize(Arena *arena, size_t bytes) {
    if (arena->capacity - arena->head >= bytes) {
        void *ptr = (char *)arena->memory + arena->head;
        arena->head += bytes;
        return ptr;
    }
    return 0;
}

#define PushArray(arena, type, size) (type *)pushSize(arena, sizeof(type) * (size))
#define PushStruct(arena, type, size) (type *)pushSize(arena, sizeof(type))

Arena createArena(size_t capacity) {
    Arena result = {};
    result.memory = mmap(0, capacity, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
    result.capacity = capacity;
    result.head = 0;
    return result;
}

// ### Lists ###
template <typename T>
struct list {
    T* data;
    size_t capacity;
    size_t length;
};

#define PushList(arena, type, size) ((list<type>){ PushArray(arena, type, size), size, 0 })

template <typename T>
T *appendList(list<T> *list, T element) {
    if (list->length < list->capacity) {
        list->data[list->length] = element;
        list->length++;
        return &(list->data[list->length - 1]);
    } else {
        return 0;
    }
}

template <typename T>
void zeroList(list<T> *list) {
    list->length = 0;
    memset(list->data, 0, list->capacity * sizeof(T));
}

#define foreach(it, list, type) for (size_t __i = 0; __i < list.length; __i++) { type it = list.data[__i];
#define foreach_end() }

// ### Strings ###
#define strlit(lit) ((string){(char *)(lit), sizeof(lit) - 1})

struct string {
    char *str;
    size_t len;
};

#define PushString(arena, length) ((string){ (char *)pushSize(arena, length), (length) })

const char *cstring(Arena *arena, list<char> buf) {
    char *arr = PushArray(arena, char, buf.length + 1);
    memmove(arr, buf.data, buf.length);
    arr[buf.length] = '\0';
    return arr;
}

const char *cstring(Arena *arena, string str) {
    char *arr = PushArray(arena, char, str.len + 1);
    memmove(arr, str.str, str.len);
    arr[str.len] = '\0';
    return arr;
}

bool strEql(string s1, string s2) {
    if (s1.len != s2.len) {
        return false;
    }
    for (size_t i = 0; i < s1.len; i++) {
        if (s1.str[i] != s2.str[i]) {
            return false;
        }
    }
    return true;
}

string strReverse(Arena *arena, string str) {
    string reversed = PushString(arena, str.len);
    for (
        int mainIndex = str.len - 1, reversedIndex = 0; 
        mainIndex < str.len; 
        mainIndex--, reversedIndex++
    ) {
        reversed.str[reversedIndex] = str.str[mainIndex];
    }
    return reversed;
}

string strSlice(char *data, size_t start, size_t stop) {
    return {
        data + start,
        stop - start,
    };
}

// ### File IO ###
size_t getFileSize(string file) {
    struct stat st;
    stat((char *)file.str, &st);
    return st.st_size;
}

list<char> readEntireFile(Arena *arena, string file) {
    FILE *input = fopen((char *)file.str, "r");
    size_t filesize = getFileSize(file);
    list<char> readBuffer = PushList(arena, char, filesize);
    readBuffer.length = filesize;
    fread(readBuffer.data, sizeof(byte), filesize, input);
    fclose(input);
    return readBuffer;
}

int cmpint(const void *a, const void *b) {
    int *x = (int *)a;
    int *y = (int *)b;
    return (*x > *y) - (*x < *y);
}

#endif