interface Task {
  id: number;
  title: string;
  completed: boolean;
}

class TaskManager {
  private tasks: Task[] = [];

  constructor() {}

  addTask(title: string) {
    const taskId = this.tasks.length + 1;
    const task: Task = {
      id: taskId,
      title,
      completed: false,
    };
    this.tasks.push(task);
  }

  markTaskAsComplete(taskId: number) {
    const task = this.tasks.find((task) => task.id === taskId);
    if (task) {
      task.completed = true;
    }
  }

  markTaskAsIncomplete(taskId: number) {
    const task = this.tasks.find((task) => task.id === taskId);
    if (task) {
      task.completed = false;
    }
  }

  listTasks() {
    console.log('Tasks:');
    this.tasks.forEach((task) => {
      console.log(`${task.id}. [${task.completed ? 'X' : ' '}] ${task.title}`);
    });
  }
}

// Example usage:
const taskManager = new TaskManager();
taskManager.addTask('Buy groceries');
taskManager.addTask('Pay bills');
taskManager.addTask('Clean the house');
taskManager.listTasks();

// Output:
// Tasks:
// 1. [ ] Buy groceries
// 2. [ ] Pay bills
// 3. [ ] Clean the house

function binarySearch(nums: number[], target: number): number {
    let left = 0;
    let right = nums.length - 1;

    while (left <= right) {
        const mid = left + Math.floor((right - left) / 2);

        if (nums[mid] === target) {
            return mid;
        } else if (nums[mid] < target) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }

    return left;
}

function searchInsert(nums: number[], target: number): number {
    return binarySearch(nums, target);
};

function removeElement(nums: number[], val: number): number {
    let zeroStartIndex = 0;
    for(let i = 0; i < nums.length; i++) {
        if(nums[i] !== val) {
            nums[zeroStartIndex] = nums[i];
            zeroStartIndex++;
        }
    }
    return zeroStartIndex;
};

// Print Hello, World!
console.log("Hello, World!");

const getFollowers = async (req: Request, res: Response) => {
  try {
    const username = req.params.username || '';

    const user = await User.findUnique({
      where: { username },
      include: { followedBy: true },
    });

    if (!user) {
      res.status(404).json({
        error: 'User could not be found',
      });
      return;
    }

    const followers = user.followedBy.map(followedBy => {
      return {
        followerId: followedBy.followerId,
      };
    });

    const followersCount = followers.length;

    res.json({ followersCount: followersCount, followers });
  } catch (error) {
    console.error('getFollowers() error: ', error);
    res.status(500).json({
      error: `There was an error fetching followers for user with username "${req.params.username}", please try again later`,
    });
  }
};

const getFollowing = async (req: Request, res: Response) => {
  try {
    const username = req.params.username || '';

    const user = await User.findUnique({
      where: { username },
      include: { following: true },
    });

    if (!user) {
      res.status(404).json({
        error: 'User could not be found',
      });
      return;
    }

    const following = user.following.map(following => {
      return {
        followingId: following.followingId,
      };
    });

    const followingCount = following.length;

    res.json({ followingCount: followingCount, following });
  } catch (error) {
    console.error('getFollowing() error: ', error);
    res.status(500).json({
      error: `There was an error fetching who is following "${req.params.username}", please try again later`,
    });
  }
};

const followUser = async (req: Request, res: Response) => {
  try {
    const username = req.params.username || '';

    const user = await User.findUnique({
      where: { username },
    });

    if (!user) {
      res.status(404).json({
        error: 'User could not be found',
      });
      return;
    }

    // dont allow a user to follow themselves
    if (req.user.id === user.id) {
      res.status(400).json({ error: 'You cannot follow yourself' });
      return;
    }

    //check if a follow relationship already exists
    const followrelationship = await prisma.follows.findUnique({
      where: {
        followerId_followingId: {
          followerId: req.user.id,
          followingId: user.id,
        },
      },
    });

    // check if the follow relationship already exists
    if (followrelationship) {
      res.status(400).json({ error: 'You are already following this user' });
      return;
    }

    // create the follow relationship
    const follow = await prisma.follows.create({
      data: {
        followerId: req.user.id,
        followingId: user.id,
      },
    });

    res.json({ follow });
  } catch (error) {
    console.error('followUser() error: ', error);
    res.status(500).json({
      error: `There was an error following "${req.params.username}", please try again later`,
    });
  }
};

const unfollowUser = async (req: Request, res: Response) => {
  try {
    const username = req.params.username || '';

    const user = await User.findUnique({
      where: { username },
    });

    if (!user) {
      res.status(404).json({
        error: 'User could not be found',
      });
      return;
    }

    // dont allow a user to unfollow themselves
    if (req.user.id === user.id) {
      res.status(400).json({ error: 'You cannot unfollow yourself' });
      return;
    }

    //check if a follow relationship already exists
    const followrelationship = await prisma.follows.findUnique({
      where: {
        followerId_followingId: {
          followerId: req.user.id,
          followingId: user.id,
        },
      },
    });

    // check if the follow relationship already exists
    if (!followrelationship) {
      res.status(400).json({ error: 'You are not following this user' });
      return;
    }

    // delete the follow relationship
    const follow = await prisma.follows.delete({
      where: {
        followerId_followingId: {
          followerId: req.user.id,
          followingId: user.id,
        },
      },
    });

    res.json({ follow });
  } catch (error) {
    console.error('unfollowUser() error: ', error);
    res.status(500).json({
      error: `There was an error unfollowing "${req.params.username}", please try again later`,
    });
  }
};

function removeDuplicates(nums: number[]): number {
    nums.splice(0, nums.length, ...Array.from(new Set(nums)));
    return nums.length;
};