#ifndef VM_PAGE_H
#define VM_PAGE_H

#include "threads/thread.h"
#include "threads/synch.h"
#include "filesys/off_t.h"

enum page_type {
  PAGE_FILE,
  PAGE_MMAP
};

struct page_entry {
  enum page_type type; /* Type of Data that should go into the page */
  void *upage;         /* Start Address of the User Page (Key of hash table). */

  /* Data for swapped pages */
  struct lock lock;    /* Enforces mutual exclusion in accessing the page
                          referenced by the entry between its owning process
                          and any thread performing page eviction. */

  /* File Data */
  struct file *file;   /* Pointer to the file for executables. */
  off_t offset;        /* Offset of the page content within the file. */
  uint32_t read_bytes; /* Number of bytes to read within the page. */
  uint32_t zero_bytes; /* Number of bytes to zero within the page. */
  bool writable;       /* Flag for whether this page is writable or not. */

  struct hash_elem elem; /* An elem for the hash table. */
};

unsigned page_hash (const struct hash_elem *e, void *aux);
bool page_less (const struct hash_elem *a_, const struct hash_elem *b_,
                void *aux);
struct page_entry *page_insert_swapped (void *upage, void* kpage,
                                        struct thread *owner);
struct page_entry *page_insert_file (struct file *file, off_t ofs, void *upage,
                                     uint32_t read_bytes, uint32_t zero_bytes,
                                     bool writable, enum page_type);
struct page_entry *page_get (struct thread *thread, void *upage);
bool page_load_file (struct page_entry *page, bool writable);
void page_cleanup (struct hash_elem *e, void *aux);

bool page_in_swap (struct thread *, void *);
size_t page_get_swap (struct thread *owner, void *upage);

#endif /* vm/frame.h */