#include "../memory/pageframealloc.h"
#include "../boot/multiboot/data.h"
#include "pageframe.h"
#include "../debug/output.h"

#include "../memory/config.h"

uint8_t PageFrameAllocator::bitmap[4294967296 / 4096 / 8];

void PageFrameAllocator::init(){
    Multiboot::Memory* memory_map_entry = Multiboot::getMemoryMap();

    dout << "kernel start: " << ___KERNEL_START___;
    dout << " kernel end: " << ___KERNEL_END___ << endl;
    while(memory_map_entry != 0){
        void* start =  memory_map_entry->getStartAddress();
        void* end =  memory_map_entry->getEndAddress();
        bool available = memory_map_entry->isAvailable();

        //TODO priotity for conflicting regions
        for(uint64_t i = (uint64_t)start; i < (uint64_t)end; i += 4096){
            uint64_t pg = i/4096;
            if(available)
                bitmap[pg/8] |= 1 << pg%8;
            else
                bitmap[pg/8] &= ~(1 << pg%8);
        }

        memory_map_entry = memory_map_entry->getNext();
    }

    for(uint64_t i = (uint64_t)&___KERNEL_START___; i < (uint64_t)&___KERNEL_END___; i += 4096){
        uint64_t pg = i/4096;
        bitmap[pg/8] &= ~(1 << pg%8);
    }

    stats();
}

void PageFrameAllocator::stats(){
    Multiboot::Memory* memory_map_entry = Multiboot::getMemoryMap();
    while(memory_map_entry != 0){
        void* start =  memory_map_entry->getStartAddress();
        void* end =  memory_map_entry->getEndAddress();
        bool available = memory_map_entry->isAvailable();
        dout << "Memory: " << hex << start << " to " << end << " is available: " << available << "." << endl;
        memory_map_entry = memory_map_entry->getNext();
    }

    uint64_t pages_available = 0;
    for(uint64_t i=0; i<sizeof(bitmap)*8;i++)
    {
        if(bitmap[i/8] & (1<<i%8))
            pages_available++;
    }
    dout << "pages available: " << dec << pages_available << endl;

}

PageFrame* PageFrameAllocator::alloc(bool kernel){
    (void) kernel;
    return 0;
}

void PageFrameAllocator::free(PageFrame* frame){
    (void) frame;
}

void PageFrameAllocator::free(uintptr_t addr){
    (void) addr;
}