const db = require("../");
const Course = db.Course;
const Op = db.Sequelize.Op;

// Create and Save a new Course
exports.create = (req, res) => {
  // Validate
  if (!req.body) {
    res.status(400).send({
      message: "Body content can not be empty!"
    });
    return;
  }

  // Create
  const courses = []

  if (Array.isArray(req.body)) {
    courses.push(...req.body)
  } else {
    courses.push(req.body)
  }

  // Save
  const promises = []
  courses.forEach(course => {
    promises.push(Course.create(course))
  });

  const successes = []
  const failures = []
  Promise.allSettled(promises)
    .then(data => {
      if (data.every(result => result.status === 'fulfilled')) {
        res.status(201).send({
          message: "All courses were created successfully.",
          successes: data.map(result => result.value),
          failures: [],
        })
        return;
      }

      data.forEach(result => {
        if (result.status === 'fulfilled') {
          successes.push(result.value)
        } else {
          failures.push(result.reason)
        }
      })
      res.status(207).send({
        message: "Some courses were created successfully.",
        successes: successes,
        failures: failures,
      })
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while creating the Course.",

      });
    });
};

// Retrieve all Courses from the database.
exports.findAll = (req, res) => {
  const name = req.query.name;
  var condition = name ? { name: { [Op.like]: `%${name}%` } } : null;

  Course.findAll({ where: condition, include: ['trainingsHeld'] })
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while retrieving courses."
      });
    });
};

// Find a single Course with an id
exports.findOne = (req, res) => {
  const id = req.params.id;

  Course.findByPk(id)
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message: "Error retrieving Course with id=" + id
      });
    });
};

// Update a Course by the id in the request
exports.update = (req, res) => {
  const id = req.params.id;

  Course.update(req.body, {
    where: { id: id }
  })
    .then(num => {
      if (num == 1) {
        res.send({
          message: "Course was updated successfully."
        });
      } else {
        res.send({
          message: `Cannot update Course with id=${id}. Maybe Course was not found or req.body is empty!`
        });
      }
    })
    .catch(err => {
      res.status(500).send({
        message: "Error updating Course with id=" + id
      });
    });
};

// Delete a Course with the specified id in the request
exports.delete = (req, res) => {
  const id = req.params.id;

  Course.destroy({
    where: { id: id }
  })
    .then(num => {
      if (num == 1) {
        res.send({
          message: "Course was deleted successfully!"
        });
      } else {
        res.send({
          message: `Cannot delete Course with id=${id}. Maybe Course was not found!`
        });
      }
    })
    .catch(err => {
      res.status(500).send({
        message: "Could not delete Course with id=" + id
      });
    });
};

// Delete all Courses from the database.
exports.deleteAll = (req, res) => {
  Course.destroy({
    where: {},
    truncate: false
  })
    .then(nums => {
      res.send({ message: `${nums} Courses were deleted successfully!` });
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while removing all courses."
      });
    });
};

// Find all published Courses
exports.findAllPublished = (req, res) => {
  Course.findAll({ where: { published: true } })
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while retrieving courses."
      });
    });
};