/* Create a database and handel it
 * Created by Jan on 13.12.2024.
 * INPUT: query for previous state
 *        linked list of tasks to store
 *
 * OUTPUT:
 *        linked list of tasks from file
 *        OK
 *
 *
 */

#include "llist.h"
#include "planner.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

/*
write a complete linkedlist to a task csv file.
 */
void write_linkedlist_to_csv(llist *head, const char *filename) {
  // Open file with write permision
  FILE *file = fopen(filename, "w");
  // if there is no file or a wrong file path you becom an error
  if (file == NULL) {
    fprintf(stderr, "Could not open file %s\n", filename);
    exit(1);

  } else {
    // write the file header
    fprintf(file, "TaskName, Created, Deadline, Priority, Spare\n");

    // Iterate through the linked list and write the data to the CSV
    llist *current = head;
    Task *task;
    while (current != NULL) {
      task = current->data;
      // Write the task data to the CSV file
      fprintf(file, "%s, %llu, %llu, %d, %llu\n", task->name, task->created,
              task->deadline, task->priority, task->spare);

      current = current->next;
    }
    fclose(file); // Close the file
  }
}

/*
read a task csv file and write the data in a linked list
 */

llist *write_csv_to_llist(const char *filename) {
  llist *list = NULL; // list to return
  // Open file with read permision
  FILE *file = fopen(filename, "r");
  if (file == NULL) {
    fprintf(stderr, "Could not open file %s\n", filename);

  } else {
    char line[1024];                 // Line Buffer
    int count = 0;                   // task counter
    fgets(line, sizeof(line), file); // read and ignore file head

    while (fgets(line, sizeof(line), file)) {
      memset(line, 0, sizeof(line));
      count++;
      // remove newline sign
      line[strcspn(line, "\n")] = '\0';

      // column slice
      char *taskname = strtok(line, ",");
      char *taskcreation_dateSTR = strtok(NULL, ",");
      char *taskdeadline_dateSTR = strtok(NULL, ",");
      char *taskprioritySTR = strtok(NULL, ",");
      char *taskspareSTR = strtok(NULL, ",");
      printf(" Der Name des Task ist %s\n",taskname);

      // convert char in integer and date
      unsigned long int taskcreation_date =
          strtoul(taskcreation_dateSTR, NULL, 10);
      unsigned long int taskdeadline_date =
          strtoul(taskdeadline_dateSTR, NULL, 10);
      unsigned long int taskspare = strtoul(taskspareSTR, NULL, 10);
      int priority = atoi(taskprioritySTR);

      // create Task
      Task *task = newTask(taskname, taskcreation_date, taskdeadline_date,
                           priority, taskspare);

      // Insert task into the linked list
      if (list == NULL) {
        // If the list is empty, initialize it with the first task
        list = llistNew(task, cmpTaskN);
      } else {
        // Append the task to the linked list
        llistAppend(list, task);
      }
    }
    fclose(file);
  }
  return list; // null on error
}