#include <inttypes.h>
#include <stdbool.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

#include "config.h"
#include "vmap.h"

VMap* vmap_init() {
    VMap* vmap = (VMap*)malloc(sizeof(VMap));
    vmap->mmap = mmap_init();
    vmap->pages = createLinkedList();
    vmap->index = 0;

    return vmap;
}

PageMapInfo* vmap_new_page(VMap* vmap) {
    PageMapInfo* page = (PageMapInfo*)malloc(sizeof(PageMapInfo));
    
    bool moved;
    page->key = page_create(vmap->mmap, &moved)->key;
    page->start = vmap->index;
    page->cursor = 0;
    page->nb_allocs = 0;
    page->swapped = moved;

    vmap->index += PAGE_SIZE;

    insertFirst(vmap->pages, page->start, page);

    return page;
}

int page_map_available_size(PageMapInfo* page) {
    int avail = page->start + PAGE_SIZE - page->cursor;
    assert(avail >= 0);
    return avail;
}


void vmap_free_page(VMap* vmap, PageMapInfo* page) {
    deleteElement(vmap->pages, page->key);
    page_remove(vmap->mmap, page->key);
    free(page);
}

PageMapInfo* vmap_get_page(VMap* vmap, void* ptr) {
    node* current = vmap->pages->head;
    while (current) {
        PageMapInfo* page = current->data;
        if (page->start <= (int64_t)ptr && page->start+PAGE_SIZE > (int64_t)ptr) {
            return page;
        }
        current = current->next;
    }
    return NULL;
}

void vmap_unswap(VMap* vmap, PageMapInfo* page) {
    if (!page->swapped)
        return;

    read_from_swap(vmap->mmap, page_lookup(vmap->mmap, page->key));
    page->swapped = false;
}


void* my_malloc(VMap* vmap, int size) {
    if (size > PAGE_SIZE) {
        fprintf(stderr, "my_malloc: Requesting too much space: %d > %d\n", size, PAGE_SIZE);
        exit(1);
    }

    // Parcours de la liste pour trouver un candidat. Sinon, nouvelle page
    node* current = vmap->pages->head;
    while (current) {
        PageMapInfo* page = current->data;
        if (page_map_available_size(page) >= size) {
            void* ptr = (void*)((uint64_t)page->start+page->cursor);
            page->cursor += size;
            page->nb_allocs++;

            return ptr;
        }
        current = current->next;
    }

    PageMapInfo* page = vmap_new_page(vmap);

    void* ptr = (void*)((uint64_t)page->start+page->cursor);
    page->cursor += size;
    page->nb_allocs++;

    return ptr;
}

void my_free(VMap* vmap, void* ptr) {
    PageMapInfo* page = vmap_get_page(vmap, ptr);

    if (!page) {
        fprintf(stderr, "my_free: Double free or memory corrupted\n");
        exit(1);
    }

    page->nb_allocs--;       
    if (page->nb_allocs == 0) {
        vmap_free_page(vmap, page);
    }
}

void my_copy(VMap* vmap, void* src, void* dst, int size) {
    PageMapInfo* page_map_src =  vmap_get_page(vmap, src);
    PageMapInfo* page_map_dst =  vmap_get_page(vmap, dst);

    if (((int64_t)src % PAGE_SIZE) + size >= PAGE_SIZE) {
        fprintf(stderr, "my_copy: size not available in this src page\n");
        exit(1);
    }

    if (((int64_t)dst % PAGE_SIZE) + size >= PAGE_SIZE) {
        fprintf(stderr, "my_copy: size not available in this dst page\n");
        exit(1);
    }

    if (page_map_src->swapped) {
        vmap_unswap(vmap, page_map_src);
    }
    if (page_map_dst->swapped) {
        vmap_unswap(vmap, page_map_dst);
    }

    PageInfo* page_src = page_lookup(vmap->mmap, page_map_src->key);
    PageInfo* page_dst = page_lookup(vmap->mmap, page_map_dst->key);

    memcpy(page_dst->data+((int64_t)src % PAGE_SIZE), page_src->data+((int64_t)dst % PAGE_SIZE), size);
}

void vmap_copy_to_memory(struct VMap *vmap, void *src, void *dst, int size) {
    PageMapInfo* page_map = vmap_get_page(vmap, src);
    PageInfo* page = page_lookup(vmap->mmap, page_map->key);

    if (!page) {
        fprintf(stderr, "vmap_copy_to_memory: page not found\n");
        exit(1);
    }
    
    memcpy(page->data + ((int64_t)src % PAGE_SIZE), dst, size);
}

void vmap_copy_from_memory(struct VMap *vmap, void *src, void *dst, int size) {
    PageMapInfo* page_map = vmap_get_page(vmap, dst);
    PageInfo* page = page_lookup(vmap->mmap, page_map->key);

    if (!page) {
        fprintf(stderr, "vmap_copy_to_memory: page not found\n");
        exit(1);
    }
    
    memcpy(src, page->data + ((int64_t)dst % PAGE_SIZE), size);
}