//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:         Page allocator related functions                            //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2019 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K is free software: you can redistribute it and/or modify              //
//  it under the terms of the GNU General Public License as published by      //
//  the Free Software Foundation, either version 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K is distributed in the hope that it will be useful,                   //
//  but WITHOUT ANY WARRANTY//without even the implied warranty of            //
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             //
//  GNU General Public License for more details.                              //
//                                                                            //
//  You should have received a copy of the GNU General Public License         //
//  along with OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#include <kernel.h>
#include <init/boot.h>
#include <ex/malloc.h>
#include <mm/paging.h>
#include <mm/palloc.h>
#include <io/vga.h>

//---------

enum
{
    Whatever           = 1UL << 52,
    Whatever2          = 1UL << 62
};

static AllocatedPage_t busyPagesList = { (void*)0, 0, (AllocatedPage_t*)0 };

//---------

static bool isPageBusy(void *phyPageAddr) {
    AllocatedPage_t *busyPage = &busyPagesList;
    bool isBusy = false;

    while(busyPage->next) {
        busyPage = busyPage->next;
        DebugLog("Busy page at %p\n", busyPage->phyAddress);

        if (phyPageAddr == busyPage->phyAddress) {
            isBusy = true;
            break;
        }
    }

    return isBusy;
}

static void addPageToBusyList(void *phyPageAddr, ulong id) {
    AllocatedPage_t *busyPage = &busyPagesList;

    while(busyPage->next) {
        busyPage = busyPage->next;
    }

    AllocatedPage_t *newBusyPage = (AllocatedPage_t*)malloc(sizeof(AllocatedPage_t));
    newBusyPage->phyAddress = phyPageAddr;
    newBusyPage->id = id;
    busyPage->next = newBusyPage;
}

static void removePageFromBusyList(void *phyPageAddr) {
    AllocatedPage_t *busyPage = &busyPagesList;
    AllocatedPage_t *prevBusyPage = NULL;

    while(busyPage->next) {
        prevBusyPage = busyPage;
        busyPage = busyPage->next;

        if (phyPageAddr == busyPage->phyAddress) {
            prevBusyPage->next = busyPage->next;
            free(busyPage);
            break;
        }
    }
}

//
// Returns a structure that describes a pageframe
//
error_t MmGetFreePageFrame(void **framePtr, size_t *pageNumber, size_t size) {
    *pageNumber = (ulong)size / KPAGESIZE;

    return EOK;
}

error_t MmTestBusyPage(void) {

    DebugLog("Adding pages \n");
    addPageToBusyList((void*)0x123456789, 56);
    addPageToBusyList((void*)0x555666666, 69);
    addPageToBusyList((void*)0x454545454, 5);

    DebugLog("\nVerifying busy 1\n");
    isPageBusy((void*)0x123456789);
    DebugLog("\nVerifying busy 2\n");
    isPageBusy((void*)0);
    DebugLog("\nVerifying busy 3\n");
    isPageBusy((void*)0x1234567894);

    DebugLog("\nRemoving first\n");
    removePageFromBusyList((void*)0x123456789);
    isPageBusy((void*)0x1234567894);
    DebugLog("\nRemoving others\n");
    removePageFromBusyList((void*)0x555666666);
    removePageFromBusyList((void*)0x454545454);

    isPageBusy((void*)0x1234567894);

    return EOK;
}