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

#include "../memory/config.h"
#include "../arch/lapic.h"
#include "../arch/apic.h"

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

void mark_pageframes(uintptr_t start, uintptr_t end, bool available){
    DBG << "start: " << hex << start << " end: " << end;
    start = Page::floor(start);
    end = Page::ceil(end);
    DBG << " page start: " << hex << start << " end: " << end << endl;

    for(uint64_t i = start; i < end; i += 4096){
        uint64_t pg = i/4096;

        PageFrameAllocator::PageFrames[pg].available = available;
        //if(available)
        //    PageFrameAllocator::bitmap[pg/8] |= (1 << pg%8);
        //else
        //    PageFrameAllocator::bitmap[pg/8] &= ~(1 << pg%8);
    }
}

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

    //mark as available
    while(memory_map_entry != 0){
        uintptr_t start =  (uintptr_t)memory_map_entry->getStartAddress();
        uintptr_t end =  (uintptr_t)memory_map_entry->getEndAddress();
        bool available = memory_map_entry->isAvailable();

        if(available)
            mark_pageframes(start, end, true);

        memory_map_entry = memory_map_entry->getNext();
    }

    //mark as unavailable
    memory_map_entry = memory_map_start;
    while(memory_map_entry != 0){
        uintptr_t start =  (uintptr_t)memory_map_entry->getStartAddress();
        uintptr_t end =  (uintptr_t)memory_map_entry->getEndAddress();
        bool available = memory_map_entry->isAvailable();

        if(!available)
            mark_pageframes(start, end, false);

        memory_map_entry = memory_map_entry->getNext();
    }

    //mark other known regions as unavailable
    DBG << "kernel image ";
    mark_pageframes((uintptr_t)&___KERNEL_START___, (uintptr_t)&___KERNEL_END___, false);

    DBG << "ISA adresses ";
    mark_pageframes(0x00F00000, 0x00FFFFFF, false);

    DBG << "LAPIC ";
    mark_pageframes(0xfee00000, 0xfee003f0, false);

    DBG << "IO APIC ";
    mark_pageframes(APIC::getIOAPICAddress(), APIC::getIOAPICAddress()+0x10, false);

    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();
        DBG << "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(PageFrames)/sizeof(PageFrames[0]));i++){
        if(PageFrames[i].available)
        //if(bitmap[i/8] & (1<<i%8))
            pages_available++;
    }
    for(uint64_t i=0; i < 0x2000000/4096/8; i++){
        if(i%64 == 0){
            DBG << endl << hex << i * 8 * 4096 << " " << flush;
            int x,y;
            dout.getPos(x,y);
            for(uint8_t j=x; j<10; j++){
                DBG<<" ";
            }
        }

        if(PageFrames[i].available)
            DBG << '#';
        else
            DBG << '.';
    }
    DBG << "\npages available: " << dec << pages_available << endl;
}

PageFrame* PageFrameAllocator::alloc(bool kernel){
    uintptr_t search_start;
    uintptr_t search_end;
    if(kernel){
        search_start = Page::ceil((uintptr_t)&___KERNEL_END___);
        search_end = 0x4000000;
    }
    else{
        search_start = 0x4000000;
        search_end = 0x8000000;
    }

    uint64_t free_pageframe=0;
    //TODO make this more efficent
    for(uint64_t i=search_start/4096; i < search_end/4096; i++){
        if(PageFrames[i].available){
            free_pageframe = i;
            break;
        }
    }

    if(!free_pageframe)
        return 0;

    mark_pageframes(free_pageframe*4096, free_pageframe*4096, false);
    return &PageFrames[free_pageframe];
}

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

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