#include "arena.h"
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>

ArenaResult arena_init(size_t size) {

    void *buffer = malloc(size);
    if (buffer == NULL) {
        ArenaResult err = {
            .is_valid = false,
            .err = ARENA_BAD_ALLOC,
        };
        return err;
    }

    if (size < 1) {
        ArenaResult err = {
            .is_valid = false,
            .err = ARENA_INVALID_SIZE,
        };
        return err;
    }

    Arena new_arena = {
        .data = buffer,
        .size = size,
        .offset = 0,
    };
    ArenaResult val = {
        .is_valid = true,
        .arena = new_arena,
    };

    return val;
}

void arena_destroy(Arena *arena) {
    if (arena == NULL) {
        return;
    }

    arena->offset = 0;
    arena->size = 0;
    free(arena->data);
}

ArenaPointer arena_alloc(Arena *arena, size_t size, size_t alignment) {
    if (arena == NULL) {
        ArenaPointer err = {
            .is_valid = false,
            .err = ARENA_NULL_ARG,
        };
        return err;
    }

    size_t new_offset = align_arena_offset(arena, alignment);
    if (new_offset + size >= arena->size) {
        ArenaPointer err = {
            .is_valid = false,
            .err = ARENA_OUT_OF_SPACE,
        };
        return err;
    }

    arena->offset = new_offset;

    ArenaPointer val = {
        .is_valid = true,
        .pointer = arena->data + arena->offset,
    };
    return val;
}