//
// Created by rick on 21-02-21.
//

#include <attributes.h>
#include <stdbool.h>
#include <sys/types.h>

#include <myke/mem/vmm.h>
#include <myke/mem/pm.h>
#include <myke/libk/libk.h>

#define TABLE_ADDR_MASK 0xFFFFF000
#define TABLE_ADDR_IMASK ~TABLE_ADDR_MASK
#define DIRECTORY_SIZE 1024

const uint32_t x = TABLE_ADDR_MASK;
typedef struct {
    union {
        struct {
            bool present: 1;
            bool read_write: 1;
            bool user_mode: 1;
            bool write_through: 1;
            bool cache_disabled: 1;
            bool accessed: 1;
            char: 1;
            bool page_size: 1;
            bool global: 1; // ignored
            uint8_t avail: 3;
        } att_packed;
        uint32_t addr;
    };
} att_packed page_directory_entry;

typedef struct {
    union {
        struct {
            bool present: 1;
            bool read_write: 1;
            bool user_supervisor: 1;
            bool write_through: 1;
            bool cache_disabled: 1;
            bool accessed: 1;
            bool dirty: 1;
            char: 1;
            bool global: 1;
            uint8_t available: 3;
        } att_packed;
        uint32_t addr;
    };
} att_packed page_table_entry;

//#define in_dir(dir, vaddr) ((page_table_entry*)(((page_directory_entry*)((dir)[(vaddr)/4096/1024].addr & TABLE_ADDR_MASK))[(vaddr)/4096%1024]))

#define dir_index(vaddr) (((uint32_t)(vaddr)) / PAGE_SIZE / DIRECTORY_SIZE)
#define page_index(vaddr) (((uint32_t)(vaddr)) / PAGE_SIZE % DIRECTORY_SIZE)

page_directory_entry boot_paging_directory[DIRECTORY_SIZE] att_aligned(4096);
page_table_entry boot_primary_table[DIRECTORY_SIZE] att_aligned(4096);

extern page_directory_entry *vmm_get_current_page_directory();

void vmm_assign_page_one(uint32_t paddr, uint32_t vaddr) {
    page_directory_entry *curr = vmm_get_current_page_directory();

    page_directory_entry *dentry = &curr[dir_index(vaddr)];
    if (!dentry->present || (dentry->addr & TABLE_ADDR_MASK) == 0) {
        // todo allocate table
        k_panics("need to allocate new table");
    }

    page_table_entry *first_entry = (page_table_entry *) (dentry->addr & TABLE_ADDR_MASK);
    page_table_entry *pentry = &first_entry[page_index(vaddr)];
    if (pentry->present) {
        // todo already present
        k_panics("virtual address already in use");
    }

    pentry->addr = (pentry->addr & TABLE_ADDR_IMASK) | paddr;
    pentry->present = true;
    pentry->read_write = true;
}

void vmm_unassign_page_one(uint32_t vaddr) {
    page_directory_entry *curr = vmm_get_current_page_directory();

    page_directory_entry *dentry = &curr[dir_index(vaddr)];
    if (!dentry->present || (dentry->addr & TABLE_ADDR_MASK) == 0) {
        // todo allocate table
        k_panics("need to allocate new table");
    }

    page_table_entry *first_entry = (page_table_entry *) (dentry->addr & TABLE_ADDR_MASK);
    page_table_entry *pentry = &first_entry[page_index(vaddr)];
    if (!pentry->present) {
        // todo already present
        k_panics("virtual address not in use");
    }

    pentry->present = false;
    pentry->read_write = false;
    pentry->addr = pentry->addr & TABLE_ADDR_IMASK;
}

void vmm_assign_page(void *paddr, void *vaddr, size_t number_of_pages) {
    for (size_t i = 0; i < number_of_pages; ++i) {
        vmm_assign_page_one(((uint32_t) paddr) + PAGE_SIZE * i, ((uint32_t) vaddr) + PAGE_SIZE * i);
    }
}

void vmm_unassign_page(void *vaddr, size_t number_of_pages) {
    for (size_t i = 0; i < number_of_pages; ++i) {
        vmm_unassign_page_one(((uint32_t) vaddr) + PAGE_SIZE * i);
    }
}