move_events_tasks_from_one_day_to_another

manage_calendar.gs

const CALENDAR_IDS = [
  'micorreo@gmail.com',
  'micalendarioID@group.calendar.google.com'//
]
const TASK_LIST_ID = 'milistadetareaID';//

function main() {
  // Format: YYYY-MM-DD
  const ORIGINAL_DATE_STR = '2026-01-17';
  const NEW_DATE_STR = '2026-02-02';
  const originalDate = new Date(ORIGINAL_DATE_STR + 'T00:00:00');
  const newDate = new Date(NEW_DATE_STR + 'T00:00:00');
  
  if (isNaN(originalDate.getTime()) || isNaN(newDate.getTime())) {
    Logger.log('Error: Invalid date format. Please use YYYY-MM-DD for both dates.');
    return;
  }
  let titleFilter = '[ ]'
  CALENDAR_IDS.forEach((calendarId) => {
    moveAllEventsToNewDate(calendarId, titleFilter, originalDate, newDate, true);
  })
  titleFilter = ''
  moveAllTasksToNewDate(titleFilter, originalDate, newDate, true);//use performMove false to simulate
}

/**
 * Moves all events from an original date to a new date, preserving their times.
 * @param {String} titleFilter Filters title.
 * @param {Date} originalDate The date to find events on (at midnight).
 * @param {Date} newDate The date to move events to (at midnight).
 * @param {Boolean} performMove If true, move the tasks. If false, only list
 */
function moveAllEventsToNewDate(calendarId, titleFilter, originalDate, newDate, performMove) {
  const calendar = CalendarApp.getCalendarById(calendarId);
  if (!calendar) {
    Logger.log('Error: Calendar not found with ID: ' + CALENDAR_ID);
    return;
  }

  const startTime = originalDate;
  const endTime = new Date(startTime.getTime());
  endTime.setDate(startTime.getDate() + 1);
  const events = calendar.getEvents(startTime, endTime);
  
  const originalDateStr = originalDate.toLocaleDateString();
  const newDateStr = newDate.toLocaleDateString();

  if (events.length === 0) {
    Logger.log('No events found on ' + originalDateStr + '.');
    return;
  }

  if (performMove) {
    Logger.log('Moving ' + events.length + ' events from ' + originalDateStr + ' to ' + newDateStr + '...');
  } else {
    Logger.log('SIMULATION: Found ' + events.length + ' events on ' + originalDateStr + ' that would be moved to ' + newDateStr + ':');
  }

  events.forEach(function(event) {
    const title = event.getTitle();
    if(!title.startsWith(titleFilter)){
      return
    }
    if (event.isAllDayEvent()) {
      if (performMove) {
        event.moveTo(newDate);
        Logger.log('  Moved (all-day): "' + title + '" to ' + newDateStr);
      } else {
        Logger.log('  [All-day] "' + title + '"');
      }
    } else {
      const originalEventStart = event.getStartTime();
      const newStartDateTime = new Date(newDate.getTime());
      newStartDateTime.setHours(originalEventStart.getHours());
      newStartDateTime.setMinutes(originalEventStart.getMinutes());
      newStartDateTime.setSeconds(originalEventStart.getSeconds());
      
      if (performMove) {
        const originalEventEnd = event.getEndTime();
        const duration = originalEventEnd.getTime() - originalEventStart.getTime();
        const newEndDateTime = new Date(newStartDateTime.getTime() + duration);
        event.setTime(newStartDateTime, newEndDateTime);
        Logger.log('  Moved (timed): "' + title + '" to ' + newStartDateTime.toLocaleString());
      } else {
        Logger.log('  [Timed] "' + title + '" (originally at ' + originalEventStart.toLocaleTimeString() + ')');
      }
    }
  });
  
  if (performMove) {
    Logger.log('Move complete.');
  } else {
    Logger.log('Simulation complete. No events were moved.');
  }
}

/**
 * Moves or lists all incomplete tasks due on an original date to a new due date.
 * * @param {String} titleFilter Filters title.
 * @param {Date} originalDate The exact due date to find tasks on.
 * @param {Date} newDate The new due date to set for those tasks.
 *D* @param {boolean} performMove If true, moves the tasks. If false, only lists them.
 */
function moveAllTasksToNewDate(titleFilter, originalDate, newDate, performMove) {
  
  const originalDateFriendly = originalDate.toLocaleDateString();
  const newDateFriendly = newDate.toLocaleDateString();

  const dueMinStr = originalDate.toISOString();
  
  const endTime = new Date(originalDate.getTime());
  endTime.setDate(originalDate.getDate() + 1);
  const dueMaxStr = endTime.toISOString();

  let tasksResponse;
  try {
    const options = {
      dueMin: dueMinStr,
      dueMax: dueMaxStr,
      showCompleted: false,
      maxResults: 100 // Get up to 100 tasks
    };
    tasksResponse = Tasks.Tasks.list(TASK_LIST_ID, options);

  } catch (e) {
    Logger.log('Error: Could not list tasks. ' + e);
    Logger.log('Check your TASK_LIST_ID and API permissions.');
    return;
  }

  const tasksToMove = tasksResponse.items;

  if (!tasksToMove || tasksToMove.length === 0) {
    Logger.log('No incomplete tasks found due on ' + originalDateFriendly + '.');
    return;
  }

  if (performMove) {
    Logger.log('Moving ' + tasksToMove.length + ' tasks due on ' + originalDateFriendly + ' to ' + newDateFriendly + '...');
  } else {
    Logger.log('SIMULATION: Found ' + tasksToMove.length + ' tasks due on ' + originalDateFriendly + ':');
  }
  
  tasksToMove.forEach(function(task) {
    const title = task.title; // Note: 'task.title', not 'task.getTitle()'
    if(!title.startsWith(titleFilter)){
      return
    }
    if (performMove) {
      const oldDateTime = new Date(task.due)
      const newDateTime = new Date(newDate.getTime());
      newDateTime.setHours(oldDateTime.getHours());
      newDateTime.setMinutes(oldDateTime.getMinutes());
      newDateTime.setSeconds(oldDateTime.getSeconds());
      const newResource = {
        due: newDateTime.toISOString()
      };
      
      // Call the 'patch' method to update the task
      var taskI = Tasks.Tasks.get(TASK_LIST_ID, task.id);

      Tasks.Tasks.patch(newResource, TASK_LIST_ID, task.id);
      
      Logger.log('  Moved: "' + title + '" to be due on ' + newDateTime.toLocaleString());
    } else {
      // This is the simulation.
      Logger.log('  [Task] "' + title + '"');
    }
  });
  
  // Final message
  if (performMove) {
    Logger.log('Task move complete.');
  } else {
    Logger.log('Simulation complete. No tasks were moved.');
  }
}

/**
 * Helper function to format time nicely (e.g., "10:30 AM" or "All-day")
 * @param {Date} date The event's start or end time.
 * @return {string} A formatted time string.
 */
function formatEventTime(date) {
  if (date.getHours() === 0 && date.getMinutes() === 0 && date.getSeconds() === 0) {
    
  }
  return date.toLocaleTimeString(); // Formats as '10:30:00 AM'
}

/**
 * Helper function to find your Task List IDs.
 * Run THIS function once to see all your task lists and their IDs in the log.
 */
function listAllTaskLists() {
  Logger.log('Finding your Task List IDs...');
  let taskListsResponse;
  try {
    // This uses the 'Tasks' advanced service you enabled
    taskListsResponse = Tasks.Tasklists.list();
  } catch (e) {
    Logger.log('Error: Could not access Tasks API. ' + e);
    Logger.log('Please make sure the "Google Tasks API" advanced service is enabled (in Services +).');
    return;
  }
  
  if (!taskListsResponse.items || taskListsResponse.items.length === 0) {
    Logger.log('No task lists found.');
    return;
  }
  
  // The 'items' property holds the array of lists
  taskListsResponse.items.forEach(function(list) {
    Logger.log('  - List Name: "%s", ID: "%s"', list.title, list.id);
  });
  Logger.log('Copy the ID of the list you want to use into the TASK_LIST_ID_TO_USE constant below.');
}