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

struct data{
  char task[200];
  int priority;
  struct data *next;
  struct data *prev;
} *head, *tail, *curr;

/*--------------------PUSHCODE--------------------------------------*/

void insert(char task[], int priority, int menu){

  struct data *add = (struct data*)malloc(sizeof(struct data));

  strcpy(add->task, task);
  add->priority = priority;

  //IF NO NODES YET
  if(head==NULL){
    head = tail = add;
    head->prev = NULL;
    tail->next = NULL;
  }
  //IF MENU = 1, PUSHFRONT
  else if(menu == 1){
    add->next = head;
    add->prev = NULL;
    head->prev = add;
    head = add;
  }
  //IF MENU = 2, PUSHMID
  else if(menu == 2){
    curr = head;
    while(curr != NULL && curr->priority <= priority){
      curr = curr->next;
    }
    curr->prev->next = add;
    add->prev = curr->prev;
    curr->prev = add;
    add->next = curr;
  }
  //IF MENU = 3, PUSHBACK
  else if(menu == 3){
    add->prev = tail;
    add->next = NULL;
    tail->next = add;
    tail = add;
  }
}

/*-------------------DELETECODE---------------------------------------*/


void newDelete(){
  if(head==NULL) return;
  if(curr==head && curr==tail){
    free(curr);
    head = tail = NULL;
  }
  else if(curr==head){
    head = head->next;
    free(curr);
    head->prev = NULL;
  }
  else if(curr==tail){
    tail = tail->prev;
    free(curr);
    tail->next = NULL;
  }
  else{
    curr->prev->next = curr->next;
    curr->next->prev = curr->prev;
    free(curr);
  }
}

/*---------------------SEARCHCODE------------------------------------*/

void search(int priority){
  curr = head;
  while(curr!=NULL && curr->priority<=priority){
    if(curr->priority==priority)
      printf("    %d  |  %s\n", curr->priority, curr->task);
    curr = curr->next;
  }
}

/*-----------------UPDATECODE----------------------------------------*/
void update(char task[]){
  curr = head;
  while(curr!=NULL && strcmp(task, curr->task)!=0){
    curr = curr->next;
  }
  if(curr==NULL) printf("Task is not in the list!\n");
  else{
    char task[200]; int priority;
    printf("    %d  |  %s\n", curr->priority, curr->task);
    newDelete();
    printf("Enter new task name: ");
    scanf("%[^\n]", task); getchar();
    printf("Enter new priority: ");
    scanf("%d", &priority); getchar();
    insert(task, priority, 2);
  }
}

/*----------------LIST-------------------------------------*/
void list(){
  printf(". . TODO LIST . .\n\n");
  if(head == NULL){
    printf("    No more task left!\n");
  }
  else{
    curr = head;
    while(curr != NULL){
      printf("    %d  |  %s\n", curr->priority, curr->task);
      curr = curr->next;
    }
  }
  puts("");
}

/*-----------------------DRIVERCODE--------------------------------------*/

int main(){

  int choice = 0;
  do{
    list();
    printf("1. Insert New Task\n");
    printf("2. Do Task\n");
    printf("3. Search task on priority\n");
    printf("4. Update Existing Task\n");
    printf("5. Exit\n");
    printf(".. Choice : ");
    scanf("%d", &choice); getchar();

    if(choice == 1){
      int menu = 0;
      char task[200];
      int priority;
      printf("Select priority:\n");
      printf("1. Insert urgent task\n");
      printf("2. Insert task\n");
      printf("3. Insert extra task\n");
      printf(".. Choice : ");
      scanf("%d", &menu); getchar();
      if(menu == 1 || menu == 3){
        printf("Enter task name: ");
        scanf("%[^\n]", task); getchar();
        menu == 1 ? priority = 1 : priority = 99;
        insert(task, priority, menu);
      }
      else if(menu==2){
        printf("Enter task name: ");
        scanf("%[^\n]", task); getchar();
        do{
          printf("Enter priority: ");
          scanf("%d", &priority); getchar();
        }while(priority<=0 || priority >= 100);
        insert(task, priority, menu);
      }
    }

    else if(choice == 2){
      curr = head;
      newDelete();
    }

    else if(choice == 3){
      int priority;
      printf("Enter priority: ");
      scanf("%d", &priority); getchar();
      search(priority);
      puts("");
    }

    else if(choice == 4){
      char task[200];
      printf("Enter task name: ");
      scanf("%[^\n]", task); getchar();
      update(task);
    }


  }while(choice!=5);


  return 0;
}