/*
This is part of WHY2
Copyright (C) 2022 Václav Šmejkal

This program 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
(at your option) any later version.

This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
*/

/*
    bro this whole file is fucked up af...

    ...or maybe I am...
*/

#include <why2/memory.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>

#include <why2/flags.h>

//LOCAL
enum POINTER_TYPES
{
    ALLOCATION,
    FOPEN,
    OPENDIR
};

typedef struct node
{
    void *pointer;
    char *identifier;
    enum POINTER_TYPES type;
    struct node *next;
} node_t; //SINGLE LINKED LIST

node_t *head = NULL;

void push_to_list(void *pointer, enum POINTER_TYPES type)
{
    //CREATE NODE
    node_t *new_node = malloc(sizeof(node_t));
    node_t *buffer = head;

    new_node -> pointer = pointer;
    new_node -> identifier = why2_get_memory_identifier();
    new_node -> type = type;
    new_node -> next = NULL;

    if (head == NULL) //INIT LIST
    {
        head = new_node;
    } else
    {
        while (buffer -> next != NULL) buffer = buffer -> next; //GET TO THE END OF LIST

        buffer -> next = new_node; //LINK
    }
}

void remove_node(node_t *node)
{
    if (node == NULL) return; //NULL NODE

    node_t *buffer_1 = head;
    node_t *buffer_2;

    while (buffer_1 -> next != NULL) //GO TROUGH EVERY ELEMENT IN LIST
    {
        if (buffer_1 == node) break; //FOUND (IF THE WHILE GOES TROUGH THE WHOLE LIST WITHOUT THE break, I ASSUME THE LAST NODE IS THE CORRECT ONE)

        buffer_1 = buffer_1 -> next;
    }

    if (node != buffer_1) return; //node WASN'T FOUND

    if (buffer_1 == head) //node WAS THE FIRST NODE IN THE LIST
    {
        //UNLINK
        head = buffer_1 -> next;
    } else //wdyt
    {
        //GET THE NODE BEFORE node
        buffer_2 = head;

        while (buffer_2 -> next != buffer_1) buffer_2 = buffer_2 -> next;

        //UNLINK
        buffer_2 -> next = buffer_1 -> next;
    }

    //DEALLOCATION
    free(node);
}

node_t *get_node(void *pointer)
{
    if (head == NULL || pointer == NULL) return NULL; //EMPTY LIST

    node_t *buffer = head;
    while (buffer -> next != NULL)
    {
        if (buffer -> pointer == pointer) return buffer;

        buffer = buffer -> next;
    }

    if (pointer != buffer -> pointer) buffer = NULL; //PREVENT FROM RETURNING INVALID NODE

    return buffer;
}

//GLOBAL
void *why2_malloc(unsigned long size)
{
    void *allocated = malloc(size);

    push_to_list(allocated, ALLOCATION);

    return allocated;
}

void *why2_calloc(unsigned long element, unsigned long size)
{
    void *allocated = calloc(element, size);

    push_to_list(allocated, ALLOCATION);

    return allocated;
}

void *why2_realloc(void *pointer, unsigned long size)
{
    if (pointer != NULL) why2_deallocate(pointer);

    void *allocated = malloc(size);

    push_to_list(allocated, ALLOCATION);

    return allocated;
}

void *why2_recalloc(void *pointer, unsigned long size, unsigned long block_size)
{
    if (pointer != NULL) why2_deallocate(pointer);

    void *allocated = calloc(size, block_size);

    push_to_list(allocated, ALLOCATION);

    return allocated;
}

char *why2_strdup(char *string)
{
    if (string == NULL) return NULL;

    char *allocated = strdup(string);

    push_to_list(allocated, ALLOCATION);

    return allocated;
}

void *why2_fopen(char *name, char *modes)
{
    void *opened = fopen(name, modes);

    push_to_list(opened, FOPEN);

    return opened;
}

void *why2_fdopen(int file, char *modes)
{
    void *opened = fdopen(file, modes);

    push_to_list(opened, FOPEN);

    return opened;
}

void *why2_opendir(char *name)
{
    void *opened = opendir(name);

    push_to_list(opened, OPENDIR);

    return opened;
}

void why2_deallocate(void *pointer)
{
    if (pointer == NULL) return; //DEALLOCATING NULL

    //VARIABLES
    node_t *node = get_node(pointer);

    if (node == NULL) return;

	switch (node -> type) //DEALLOCATE BY THE CORRECT WAY
    {
        case ALLOCATION: //STANDARD MALLOC, CALLOC OR REALLOC
            free(pointer);
            break;

        case FOPEN: //FOPEN OR FDOPEN
            fclose(pointer);
            break;

        case OPENDIR: //OPENDIR SYSTEM CALL
            closedir(pointer);
            break;
    }

	remove_node(node); //REMOVE FROM LIST IF FOUND
}

void why2_clean_memory(char *identifier)
{
    if (head == NULL) return; //LIST IS EMPTY

    node_t *buffer = head;
    void *pointer_buffer = NULL;
    why2_bool force_deallocating = identifier == why2_get_default_memory_identifier();

    while (buffer -> next != NULL) //GO TROUGH LIST
    {
        if (buffer -> identifier == identifier || force_deallocating) pointer_buffer = buffer -> pointer;

        buffer = buffer -> next;

        if (pointer_buffer != NULL)
        {
            why2_deallocate(pointer_buffer);
            pointer_buffer = NULL;
        }
    }

    if (buffer -> identifier == identifier || force_deallocating) why2_deallocate(buffer -> pointer); //LAST NODE

    why2_reset_memory_identifier(); //THIS WILL CAUSE SEGFAULT IF YOU DIDN'T USE why2_set_memory_identifier
}

why2_bool why2_allocated(void *pointer)
{
    return get_node(pointer) != NULL;
}