#pragma once

#include "memory/pointer.h"
#include "process/process.h"
#include "util/optional.h"
#include "init/multiboot2.h"

constexpr const size_t page_size = 4096;

struct PhysicalAllocator {
public:
    struct allocation_t {
        paddr_t ptr;
        size_t page_count;
    };
    struct entry_t {
        uint64_t page_count;
        pid_t owner;
    };
    static void init(const multiboot::tag_mmap* multiboot_info);
    static PhysicalAllocator& getInstance();
    allocation_t allocPages(size_t page_count, pid_t owner);
    void free(allocation_t ptr);
    void force(allocation_t ptr, pid_t owner);
    entry_t getOwner(paddr_t from);
private:
    struct Page {
        optional<Page*> next;
        entry_t entries[255];
        void forceEntry(entry_t entry);
        void cleanup();
        void compact();
    };
    static_assert(sizeof(Page) == page_size);
    Page* storage;    
};