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

struct groceryList{
int ID;
float amount;
char grocery[100];
char unit[10];
};

/*funktion som kollar om användaren skriver in chars i "amount".*/
void errorHandling(struct groceryList *pgroceries, int listCounter)
{
    int i, scanString = 0, count;
    char arr[20];
    do{
        fflush(stdin);
        gets(arr);
        scanString = strlen(arr);
        count = 0;

        for(i = 0; i < scanString;)
        {
            if(isdigit(arr[i]) != 0 || arr[i] == '.')   //Om arr:s index inte är alfabetiskt eller är en punkt. Hoppa till nästa index
            {
                i++;
            }
            else
            {
                printf("Wrong input. Try again!");
                count++;
                break;
            }
        }

    }while(count > 0);
    pgroceries[listCounter].amount = atof(arr);         //ger amount arr:s numeriska symboler.
}

/* funktion som listar alla varor och mängden av varan.*/
void listingGroceries(struct groceryList *pgroceries, int listCounter)
{

        fflush(stdin);
        pgroceries[listCounter].ID = listCounter + 1;           //listar varorna
        printf("What grocery do you wanna put in the list? ");
        gets(pgroceries[listCounter].grocery);
        printf("What's the amount? ");
        errorHandling(pgroceries, listCounter);
        printf("What's the unit? ");
        gets(pgroceries[listCounter].unit);
}

/*Skriver ut alla varor med formaterad text.*/
void printGroceries(struct groceryList *pgroceries, int listCounter)
{
    int j;
    if(pgroceries == 0)
    {
        printf("There are no groceries to print.\n");
    }
    else
    {

        for(j = 0; j < listCounter; j++)
        {
            printf("Grocery %2d:", pgroceries[j].ID);           //Skriver ut varorna.
            printf("%-15s:", pgroceries[j].grocery);
            printf("%10.2f:", pgroceries[j].amount);
            printf("%-8s\n", pgroceries[j].unit);

        }
    }
}
int writeToFile(struct groceryList **pgroceries, int listCounter)
{
    char userInput[50];
    FILE *fp = 0;
    printf("What would you like to call the file?\n");              //Funktion som läser in varorna till en fil. Felhantering finns.
    scanf("%s", userInput);
    fp = fopen(userInput,"wb");
        if(fp == NULL)
        {
            printf("Could not write to file, sorry!\n");
            return 0;
        }
    fwrite(*pgroceries, sizeof(struct groceryList), listCounter, fp);
    printf("%d groceries where saved to the file!\n", listCounter);

    fclose(fp);

    fflush(stdin);
return 0;
}

int readFromFile(struct groceryList **pgroceries, int listCounter)
{
    char userInput[50];
    int byteSize = 0;
    FILE *fp = 0;
    printf("What file would you like to open?\n");
    scanf("%s", userInput);
    fp = fopen(userInput,"rb");                                 //funktion som läser in från en fil.
        if(fp == NULL)
        {
            printf("Could not read from file, sorry!\n");
            return 0;
        }
        else
        {
            fseek(fp, 0, SEEK_END);     //letar efter filens slut.
            byteSize = ftell(fp);       //Get bytesize filpekarens antal minnesplatser som en siffra.
            rewind(fp);                 //Sätter filpekaren i början av filen igen.
            *pgroceries = (struct groceryList*)realloc(*pgroceries, sizeof(struct groceryList) * (byteSize/sizeof(struct groceryList))); //allokerar minne
            listCounter = fread(*pgroceries, sizeof(struct groceryList), byteSize/sizeof(struct groceryList), fp); // läser in varorna och ger listcounter
            printf("%d groceries where read from the file!\n", listCounter);                                       //antalet varor som läses in.

            fclose(fp);
        }
    fflush(stdin);
    return listCounter;
}
//funktion som modiferar en vara i listan.
int modifyGrocery(struct groceryList **pgroceries, int listCounter)
{
    printf("Type in the ID of the grocery you would like to modify. ");
    scanf("%d", &listCounter);
    if(*pgroceries == NULL)
        {
            printf("No groceries to modify. Add groceries to the list first!\n");
            fflush(stdin);
            return 0;
        }
    else
    {
        listingGroceries(*pgroceries,listCounter-1);
        printf("ID %d has been modified.", listCounter);
    }
    fflush(stdin);
    return listCounter;
}

void setMemory(struct groceryList **pgroceries, int listCounter)
{
    struct groceryList *tp = (struct groceryList*) realloc(*pgroceries,listCounter*sizeof(struct groceryList)); // Allokerar minne varje gång man lägger till en vara.

    if(tp != NULL)
    {
        *pgroceries = tp;
    }
    else
        printf("Something went wrong");

}


int removeGrocery(struct groceryList **pgroceries, int listCounter)
{
    int pickedElement;


    printf("What grocery would you like to remove? ");
    scanf("%d", &pickedElement);
    if(*pgroceries == NULL)
    {
        printf("No groceries to remove. Add groceries first!\n");
        fflush(stdin);
        return 0;
    }
    else if(pickedElement == 0 || pickedElement > listCounter)
    {
        printf("No grocery with that number.\n");
        fflush(stdin);
        return 0;
    }
    else
    {

        pickedElement--;
        strcpy((*pgroceries)[pickedElement].grocery, (*pgroceries)[listCounter-1].grocery); // tar bort ett element, och lägger sista elementet på dess plats.
        (*pgroceries)[pickedElement].amount = (*pgroceries)[listCounter-1].amount;
        strcpy((*pgroceries)[pickedElement].unit, (*pgroceries)[listCounter-1].unit);
        listCounter--;
        setMemory(pgroceries, listCounter);
        fflush(stdin);
    }

    printf("Grocery %d is annihilated.\n", pickedElement+1);
    fflush(stdin);
    return listCounter;
}

int* menu(struct groceryList **pgroceries)
{
    char menuBrowser[2];
    int listCounter = 0;

    do{

        printf("Menu\nWhat would you like to do?\n");
        printf("\n-----------------------------------\n");
        printf("1. Add grocery\n");
        printf("2. Print your list\n");
        printf("3. Add groceries to file\n");
        printf("4. Read groceries from file\n");
        printf("5. Modify grocery\n");
        printf("6. Remove grocery\n");
        printf("7. Exit the program\n");
        printf("\n-----------------------------------\n");
        gets(menuBrowser);



        switch(menuBrowser[0]){

            case '1':
            {
                listCounter++;
                setMemory(pgroceries, listCounter);
                listingGroceries(*pgroceries, listCounter-1);
                break;
            }
            case '2':
            {
                printGroceries(*pgroceries, listCounter);
                break;
            }
            case '3':
            {
                writeToFile(pgroceries, listCounter);
                break;
            }
            case '4':
            {
                listCounter = readFromFile(pgroceries, listCounter);
                break;
            }
            case '5':
            {

                modifyGrocery(pgroceries, listCounter);
                break;
            }

            case '6':
            {
               listCounter = removeGrocery(pgroceries, listCounter);
                break;
            }
            case '7':
            {
                free(pgroceries);
                return 0;
            }
        }

    }while(1);
}

int main()
{

    char loop = 'y';
    struct groceryList *groceries = NULL;

    do{

        menu(&groceries);


        printf("\nDo you want to play the program again? Y/N ");
        do
        {
            scanf("%c", &loop);
        }
        while(loop != 'y' && loop != 'n');
        fflush(stdin);
    }while(loop == 'y');
    return 0;
}