#include "allocArea.h"
#include "alloc.h"
#include "assert.h"
#include "kernel.h"
#include "list.h"
#include "mem.h"
#include "stdarg.h"


static struct memArea *freeArea;
static struct memArea *usedArea;

static int areaMergeFreeArea(struct memArea *prev, struct memArea *next);

void areaInit(vaddr_t firstMemUsed, vaddr_t lastUsed)
{
    list_init(freeArea);
    list_init(usedArea);

    vaddr_t areaAddr, descAddr, entryAddr;
    allocSetup(sizeof(struct memArea), &areaAddr, &descAddr, &entryAddr);
    areaAdd(descAddr, 1, FALSE);
    if (entryAddr != descAddr)
        areaAdd(entryAddr, 1, FALSE);
    if (areaAddr != descAddr && areaAddr != entryAddr)
        areaAdd(areaAddr, 1, FALSE);

    int nbPages        = DIV_ROUND_UP((lastUsed - firstMemUsed), PAGE_SIZE);
    areaAdd(ALIGN_DOWN(firstMemUsed, PAGE_SIZE), nbPages, FALSE);
    //TODO: fix the 300 
    areaAdd(ALIGN_DOWN(areaAddr + PAGE_SIZE, PAGE_SIZE), 300 , TRUE);
    allocPopulate();
}

struct memArea *areaFindFit(unsigned int nbPages)
{
    struct memArea *area;
    int count;

    list_foreach(freeArea, area, count)
    {
        if (area->nbPages >= nbPages)
            return area;
    }
    return NULL;
}

static void insertSorted(struct memArea **list, struct memArea *item)
{
    struct memArea *prev, *cur;
    int count;
    prev = NULL;

    list_foreach(*list, cur, count)
    {
        if (cur->startAddr > item->startAddr)
            break;
        prev = cur;
    }
    if (prev)
        list_insert_after(*list, prev, item);
    else
        list_add_tail(*list, item);
}

vaddr_t areaAlloc(unsigned int nbPages, uint32_t flags)
{
    struct memArea *area, *allocated;

    area = areaFindFit(nbPages);
    if (!area)
        return (vaddr_t)NULL;

    if (area->nbPages == nbPages) {
        list_delete(freeArea, area);
        insertSorted(&usedArea, area);
        allocated = area;
    } else {
        struct memArea *newArea = (struct memArea *)malloc(sizeof(struct memArea));
        if (!newArea) {
            pr_devel("Failed to allocated area of %d pages\n", nbPages);
            return (vaddr_t)NULL;
        }

        // Avoid insertSorted(freeArea, newArea) call by modifying area

        newArea->nbPages   = nbPages;
        newArea->startAddr = area->startAddr;

        area->nbPages -= nbPages;
        area->startAddr += nbPages * PAGE_SIZE;

        insertSorted(&usedArea, newArea);

        allocated = newArea;
    }

    if (flags & AREA_PHY_MAP) {
        for (uint i = 0; i < nbPages; i++) {
            paddr_t page = allocPhyPage(1);
            if (page) {
                pageMap(allocated->startAddr + i * PAGE_SIZE, page, PAGING_MEM_WRITE);
            } else {
                // TODO
                assert(1);
            }
        }
    }

    return allocated->startAddr;
}

int areaAdd(vaddr_t addr, uint nbPages, int isFree)
{
    struct memArea **area;

    struct memArea *newArea = (struct memArea *)malloc(sizeof(struct memArea));
    if (!newArea)
        return (vaddr_t)NULL;

    newArea->nbPages   = nbPages;
    newArea->startAddr = addr;

    if (isFree) {
        area = &freeArea;
    } else {
        area = &usedArea;
    }

    insertSorted(area, newArea);

    if (isFree) {
        if (newArea->prev)
            areaMergeFreeArea(newArea->prev, *area);

        if (newArea->next)
            areaMergeFreeArea(*area, newArea->next);
    }

    return 0;
}

static int areaMergeFreeArea(struct memArea *prev, struct memArea *next)
{
    if (prev->startAddr + prev->nbPages * PAGE_SIZE != next->startAddr) {
        return -1;
    }

    prev->nbPages += next->nbPages;
    list_delete(freeArea, next);
    free(next);

    next = prev;

    return 0;
}

static struct memArea *areaFindMemArea(struct memArea *list, vaddr_t addr)
{
    struct memArea *area;
    int count;
    list_foreach(list, area, count)
    {
        if (area->startAddr <= addr && addr < area->startAddr + area->nbPages * PAGE_SIZE)
            return area;
    }

    return NULL;
}

int areaFree(vaddr_t addr)
{
    struct memArea *area;

    area = areaFindMemArea(usedArea, addr);
    if (!area) {
        pr_info("Cannot find memArea associated to %p\n", addr);
        return -1;
    }
    for(uint i = 0; i < area->nbPages; i++){
        pageUnmap( area->startAddr + i * PAGE_SIZE);
    }
    list_delete(usedArea, area);
    insertSorted(&freeArea, area);

    if (area->prev)
        areaMergeFreeArea(area->prev, area);

    if (area->next)
        areaMergeFreeArea(area, area->next);

    return 0;
}