#include "pagetable.h"
#include "pageframealloc.h"
#include "../utils/string.h"

void load_cr3( void* cr3_value ) {
    asm volatile("mov %0, %%cr3" :: "r"((uint64_t)cr3_value) : "memory");
}

void write_identity_map(pagetable_t* identity_table, uint64_t size){
    for(uintptr_t i=0; i<size/4096; i++){
        identity_table[i/512].entries[i%512] = {
            .present = 1,
            .write = 1,
            .user = 0,
            .address = i,
        };
    }
}

void create_basic_page_table(four_lvl_paging_t* table, pagetable_t* kernel_identity){

    assert(table);
    assert(kernel_identity);

    table->l4 = (pagetable_t*)PageFrameAllocator::alloc(true);
    table->l3 = (pagetable_t*)PageFrameAllocator::alloc(true);
    table->l2 = (pagetable_t*)PageFrameAllocator::alloc(true);

    //memset(table, 0, sizeof(four_lvl_paging_t));
    table->l4->entries[0] = {
        .present = 1,
        .write = 1,
        .user = 1,
        .address = ((uintptr_t)(table->l3)) >> 12,
    };

    table->l3->entries[0] = {
        .present = 1,
        .write = 1,
        .user = 1,
        .address = ((uintptr_t)(table->l2)) >> 12,
    };

    //kernel memory
    for(uint32_t i=0; i<KERNEL_MEMORY_BORDER/4096/512; i++){
        table->l2->entries[i] = {
            .present = 1,
            .write = 1,
            .user = 1,
            .address = (uintptr_t)(&kernel_identity[i]) >> 12,
        };
    }

    //write_identity_map(table->l1, KERNEL_MEMORY_BORDER);
    //for(uintptr_t i=0; i<KERNEL_MEMORY_BORDER/4096; i++){
    //    table->l1[i/512].entries[i%512] = {
    //        .present = 1,
    //        .write = 1,
    //        .user = 0,
    //        .address = i,
    //    };
    //}

    //add ioapic address to pagetable
    table->l2_apic = (pagetable_t*)PageFrameAllocator::alloc(true);
    table->ioapic = (pagetable_t*)PageFrameAllocator::alloc(true);
    table->lapic = (pagetable_t*)PageFrameAllocator::alloc(true);

    table->l3->entries[3] = {
        .present = 1,
        .write = 1,
        .user = 1,
        .address = (uintptr_t)(table->l2_apic) >> 12,
    };
    table->l2_apic->entries[502] = {
        .present = 1,
        .write = 1,
        .user = 1,
        .address = (uintptr_t)(table->ioapic) >> 12,
    };
    table->ioapic->entries[0] = {
        .present = 1,
        .write = 1,
        .user = 0,
        .address = 0xFEC00,
    };

    //lapic
    table->l2_apic->entries[503] = {
        .present = 1,
        .write = 1,
        .user = 1,
        .address = (uintptr_t)(table->lapic) >> 12,
    };
    table->lapic->entries[0] = {
        .present = 1,
        .write = 1,
        .user = 0,
        .address = 0xFEE00,
    };

    //unmap 0 page
    kernel_identity[0].entries[0].present = 0;
}