#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_ARRAY_SIZE 255

typedef struct product {
  char* description;
  char* name;
  double price;
  int quantity;
} product;

//Function prototypes
void buyProduct();
int checkInputData(char* data);
int deleteProductFromCart(FILE* fp,int row);
char* dgets();
void displayAllContent(FILE* fp);
void displayCart();
void displayCategory(char* category);
void displayCheckup(char* productName);
void displayDeleteMenu(FILE* fp);
void displayError();
void displayFormatedName(char * productName);
void displayMenu();
int findAndReplaceInCart(FILE* fp, product pdt);
char* getFileName(FILE* fp, char* str);
int getFileRowNumber(FILE *fp);
product getProductFromRow(char* rowStr, int cat);
char* getRowInFile(FILE* fp, int row);
int replaceRowInFile(FILE* fp, product pdt, int row);
int sendToCart(product pdt);
void writeFormatedName(FILE* fp, char* productName);



void buyProduct(FILE* category, int productNumber) {

}

int checkInputData(char* data) { //Checks whether the data entered is correct or not
  int i;
  for (i = 0; i < strlen(data); i++)
    if ( !(isdigit(data[i])) )
      if (data[i] != '\0')
        return -1;
      else
        break;
  return atoi(data);
}

int deleteProductFromCart(FILE* fp,int row) {
  int status = 0;
  int rowNum = getFileRowNumber(fp);
  product pdt[rowNum-2];
  int i;
  int j = 0;
  char* rowStr;
  for (i = 1; i < rowNum;i++) {
    if (i != row) {
      rowStr = getRowInFile(fp,i);
      pdt[i-1-j] = getProductFromRow(rowStr,1);
    } else
      j++;
  }
  fclose(fp);
  FILE* newCartFile = fopen("carrito.txt","w");
  fprintf(newCartFile,"Num\tProducto\t\t\tCantidad\tPrecio");
  for (i = 1; i < rowNum-1;i++) {
      fprintf(newCartFile,"\n%i.\t",i);
      writeFormatedName(newCartFile,pdt[i-1].name);
      fprintf(newCartFile,"%i\t\t$%.2f",pdt[i-1].quantity,pdt[i-1].price);
  }
  fclose(newCartFile);
  status = 1;
  return status;
}

void displayAllContent(FILE* fp) {
  //fscanf(fp,"%*[^\n]\n");
  fseek(fp, 0, SEEK_SET);
  char c = fgetc(fp);
  while (c != EOF) {
    printf("%c",c);
    c = fgetc(fp);
  }
  printf("\n");
}

void displayCart() {
  FILE* cartFile = fopen("carrito.txt","r");
  int opt = -1;
  char* input;
  do {
    system("CLS");
    displayAllContent(cartFile);
    printf("Que desea realizar?\n0. Regresar al menu principal\n1. Proceder a compra\n");
    printf("2. Eliminar elementos del carrito\n");
    input = dgets();
    opt = checkInputData(input);
    switch(opt) {
      case 0:
        break;
      case 1:
        break;
      case 2:
        displayDeleteMenu(cartFile);
        cartFile = fopen("carrito.txt","r");
        break;
      default:
        displayError();
    }
  } while (opt != 0);
  fclose(cartFile);
}

void displayCategory(char* category) {
  int opt = -1;
  char* input;
  FILE* catMenu = fopen(category,"r");
  do {
    displayAllContent(catMenu);
    printf("0. Regresar al menu principal\n");
    input = dgets();
    opt = checkInputData(input);
    system("CLS");
    if (opt <= 0 || opt > getFileRowNumber(catMenu) - 1) {
      if (opt != 0)
        displayError();
    }

    else {
      displayCheckup(getRowInFile(catMenu, opt));
    }
  } while (opt != 0);
  fclose(catMenu);
}

void displayCheckup(char* productInfo) {
  int opt = -1;
  product pdt = getProductFromRow(productInfo,0);
  pdt.quantity = -1;
  char* input;
  do {
    printf("El siguiente producto ha sido seleccionado:\n");
    printf("Producto\t\t\tPrecio\t\tDescripcion\n");
    displayFormatedName(pdt.name);
    printf("$%.2f\t\t%s\n",pdt.price,pdt.description);
    printf("Seleccione la cantidad que desea comprar o digite 0 para salir del checkup\n");
    input = dgets();
    pdt.quantity = checkInputData(input);
    system("CLS");
    if (pdt.quantity <= 0)
      if (pdt.quantity != 0)
        displayError();
      else
        opt = 0;
    else {
      pdt.price *= pdt.quantity;
      do {
        printf("Resumen de compra:\n");
        printf("Producto\t\t\tCantidad\tPrecio total\n");
        displayFormatedName(pdt.name);
        printf("%i\t\t$%.2f\n",pdt.quantity,pdt.price);
        printf("0. Descartar compra y regresar al menu\n1. Comprar\n2. Mandar al carrito de compras\n");
        input = dgets();
        opt = checkInputData(input);
        system("CLS");
        switch(opt) {
          case 0:
            break;
          case 1:
            printf("Compra realizada!\n");
            break;
          case 2:
            if (sendToCart(pdt))
              printf("Articulos enviados al carrito exitosamente!\n");
            else
              printf("Hubo un error al enviar los articulos al carrito, intentelo mas tarde\n");
              break;
          default:
              displayError();
        }
      } while (!(opt >= 0 && opt <= 2));
      break;
    }
  } while (opt != 0);
}

void displayDeleteMenu(FILE* fp) {
  int opt = -1;
  char* input;
  do {
    system("CLS");
    displayAllContent(fp);
    printf("Seleccione el producto que desea eliminar o digite 0 para salir al menu.\n");
    input = dgets();
    opt = checkInputData(input);
    if(opt <= 0 || opt > getFileRowNumber(fp) - 1) {
      if (opt != 0)
        displayError();
    } else {
       if (deleteProductFromCart(fp,opt)) {
         printf("Articulo eliminado exitosamente!\n");
         fclose(fp);
         opt = 0;
       } else {
         printf("El articulo no pudo ser eliminado, intente mas tarde\n");
         fclose(fp);
       }
    }
  } while (opt != 0);

}

void displayError() {
  printf("El dato ingresado no es valido, por favor ingrese un dato valido\n");
}

void displayFormatedName(char * productName) {
  int productNameLength = strlen(productName);
  int i;
  printf("%s",productName);
  for (i = 0; i < 4 - productNameLength / 8; i++)
    printf("\t");
}

void displayMenu() {
  int opt = -1;
  char* input;
  char* fileName;
  FILE* menu = fopen("Menu.txt","r");
  do {
    displayAllContent(menu);
    input = dgets();
    opt = checkInputData(input);
    system("CLS");
    if(opt <= 0 || opt > getFileRowNumber(menu) - 1) {
      if (opt != 0)
        displayError();
    }
    else {
      fileName = getFileName(menu,input);
      if (fileName != NULL) {
        strcat(fileName,".txt");
        displayCategory(fileName);
      }
    }
  } while (opt != 0);
  free(input);
  fclose(menu);
}

char* dgets() {
  char input[MAX_ARRAY_SIZE];
  if (gets(input) == NULL)
    return NULL;
  char* str = malloc(sizeof(char));
  int i;
  for(i = 0; i < MAX_ARRAY_SIZE; i++) {
    if (input[i] != '\0') {
      str[i] = input[i];
      str = realloc(str,sizeof(char) * i + 2);
    } else {
      str[i] = '\0';
      break;
    }
  }
  return str;
}

int findAndReplaceInCart(FILE* fp, product pdt) {
  char* rowStr;
  char* match;
  int status = 0;
  int rowNum = getFileRowNumber(fp);
  int i, j;
  for (i = 0; i < rowNum; i++) {
    rowStr = getRowInFile(fp,i);
    match = strstr(rowStr, pdt.name);
    if (match == NULL)
      continue;
    product oldProduct = getProductFromRow(rowStr,1);
    pdt.quantity += oldProduct.quantity;
    pdt.price += oldProduct.price;
    replaceRowInFile(fp,pdt,i);
    status = 1;
    break;
  }
  return status;
}

/*char* dgets() {
  char c = getchar();
  if(c == '\n')
    return NULL;
  char* str = malloc(sizeof(char));
  int strSize = 0;
  do {
    printf("c:%c\n",c);
    str[strSize] = c;
    str = realloc(str, sizeof(char) * (++strSize) + 1);
  } while (c = getchar() != '\n');
  str[strSize] = '\0';
  return str;
}*/

char* getFileName(FILE* fp, char* str) {
  int rowNum = getFileRowNumber(fp);
  int i;
  char* rowStr;
  char* match;
  for (i = 0; i < rowNum;i++) {
    rowStr = getRowInFile(fp,i);
    match = strstr(rowStr, str);
    if (match == NULL)
      continue;
    match = strstr(match, " ");
    return match + 1;
    break;
  }
  return NULL;
}

int getFileRowNumber(FILE *fp) {
  fseek(fp, 0, SEEK_SET);
  char c = fgetc(fp);
  int num = 1;
  while (c != EOF) {
    if (c == '\n')
    num++;
    c = fgetc(fp);
  }
  return num;
}

product getProductFromRow(char* rowStr, int cat) {
  product pdt;
  int i,j;
  char* name = strstr(rowStr, "	");
  name++;
  for(i = 0; i < strlen(name); i++)
    if(name[i] == '\t')
      break;
  pdt.name = malloc(sizeof(char) * (i + 1));
  for(j = 0; j < i; j++)
    pdt.name[j] = name[j];
  pdt.name[i] = '\0';
  char* price = strstr(rowStr, "$");
  char* description;
  pdt.price = strtod(price+1, &description);
  if (cat == 0) {
    pdt.description = description + 2;
  } else {
    char* quantity = strstr(rowStr, name);
    quantity += strlen(pdt.name) + 4 - strlen(pdt.name) / 8;
    pdt.quantity = atoi(quantity);
  }
  return pdt;
}

char* getRowInFile(FILE* fp, int row) {
  fseek(fp, 0, SEEK_SET);
  int i;
  for(i = 0; i < row; i++)
    fscanf(fp,"%*[^\n]\n");
  i = 0;
  int strSize = 20;
  char* str = malloc(sizeof(char) * strSize);
  char c = fgetc(fp);
  while(c != '\n' && c != EOF) {
    if(i >= strSize) {
      str = realloc(str, strSize * 2);
      strSize *= 2;
    }
    str[i] = c;
    c = fgetc(fp);
    i++;
  }
  str[i] = '\0';
  return str;
}

int replaceRowInFile(FILE* fp, product pdt, int row) {
  fseek(fp, 0, SEEK_SET);
  fprintf(fp,"Num"); // If this line is remove, the cart doesn't update anything. WTF??
  int i;
  for (i = 0; i < row; i++)
    fscanf(fp,"%*[^\n]\n");
  fprintf(fp,".\t");
  writeFormatedName(fp,pdt.name);
  fprintf(fp,"%i\t\t$%.2f",pdt.quantity,pdt.price);
}

int sendToCart(product pdt) {
  FILE* cartFile = fopen("carrito.txt","r+");
  if (cartFile == NULL)
    return 0;
  if (! (findAndReplaceInCart(cartFile, pdt)) ) {
    fseek(cartFile, 0, SEEK_SET);
    int itemNum = getFileRowNumber(cartFile);
    int i;
    for(i = 0; i < itemNum; i++)
      fscanf(cartFile,"%*[^\n]\n");
    itemNum;
    fprintf(cartFile, "\n%i.\t",itemNum);
    writeFormatedName(cartFile, pdt.name);
    fprintf(cartFile, "%i\t\t$%.2f",pdt.quantity,pdt.price);
  }
  fclose(cartFile);
  return 1;
}

void writeFormatedName(FILE* fp, char* productName) {
  int productNameLength = strlen(productName);
  int i;
  fprintf(fp,"%s",productName);
  for (i = 0; i < 4 - productNameLength / 8;i++)
  fprintf(fp,"\t");
}

int main() {
  int opt = -1;
  char* input;
  system("COLOR A");
  do {
    printf("*** No me acuerdo ***\n");
    printf("Bienvenido a la cooperativa escolar \"No me acuerdo\", que desea realizar?\n");
    printf("0. Salir de la aplicacion\n1. Buscar productos\n2. Consultar carrito de compras\n3. Consultar saldo\n4.\n");
    //scanf("%[^\n]%*c", input);
    input = dgets();
    fflush(stdin);
    opt = checkInputData(input);
    system("CLS");
    switch(opt) {
      case 0:
        break;
      case 1:
        displayMenu();
        break;
      case 2:
        printf("*** Carrito de compras ***\n");
        displayCart();
        break;
      case 3:
        break;
      case 4:
        break;
      default:
      displayError();
    }
  } while (opt != 0);
  free(input);
}