package com.freecoders.server;

import com.freecoders.server.entites.Availability;

import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TimeService {

        public static List<LocalDateTime> divideTasks(List<Availability> availabilities, int numTasks, LocalDateTime deadline) {
            LocalDateTime now = LocalDateTime.now();
            List<LocalDateTime> startTimes = new ArrayList<>();
            for (Availability availability : availabilities) {
                if (availability.getFromDate().isAfter(now) && availability.getFromDate().isBefore(deadline)) {
                    startTimes.add(availability.getFromDate());
                }
            }

            if (startTimes.size() >= numTasks) {
                return startTimes.subList(0, numTasks);
            } else {
                int index = 0;
                List<LocalDateTime> dividedTasks = new ArrayList<>();
                for (int i = 0; i < numTasks; i++) {
                    dividedTasks.add(startTimes.get(index));
                    index = (index + 1) % startTimes.size();
                }
                return dividedTasks;
            }
        }

        public static boolean checkForOverlappingTasks(List<LocalDateTime> tasks) {
            Map<LocalDateTime, Integer> taskCount = new HashMap<>();
            for (LocalDateTime task : tasks) {
                if (!taskCount.containsKey(task)) {
                    taskCount.put(task, 1);
                } else {
                    taskCount.put(task, taskCount.get(task) + 1);
                }
            }
            for (LocalDateTime task : tasks) {
                if (taskCount.get(task) > 1) {
                    return true;
                }
            }
            return false;
        }

        public static List<LocalDateTime> divideTasksWithUniqueStartTimes(List<Availability> availabilities, int numTasks, LocalDateTime deadline) {
            List<LocalDateTime> tasks = divideTasks(availabilities, numTasks, deadline);
            while (checkForOverlappingTasks(tasks)) {
                tasks = divideTasks(availabilities, numTasks, deadline);
            }
            return tasks;
        }


}