package db

import "context"

/*
DDL

CREATE TABLE `courses` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `short_name` varchar(10) NOT NULL,
  `category` varchar(100) NOT NULL,
  `description` varchar(1000) DEFAULT NULL,
  `image_url` varchar(255) DEFAULT NULL,
  `created_at` datetime NOT NULL DEFAULT current_timestamp(),
  `updated_at` datetime NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
  `deleted` tinyint(4) DEFAULT 0,
  `prereq_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `name` (`name`),
  UNIQUE KEY `shortName` (`short_name`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=39 DEFAULT CHARSET=utf8mb4;
*/

type Course struct {
	ObjectBase
	Name        string `json:"name"`
	ShortName   string `json:"short_name"`
	Category    string `json:"category"`
	Description string `json:"description"`
	ImageURL    string `json:"image_url"`

	PassedMembers  []Member        `json:"passed_members" gorm:"many2many:member_courses_pass;"`
	FailedMembers  []Member        `json:"failed_members" gorm:"many2many:member_courses_fail;"`
	Prerequisites  []*Course       `json:"prerequisites" gorm:"many2many:course_prerequisites;"`
	TrainingEvents []TrainingEvent `json:"training_events"`
}

// Get one by id
func (c *Course) GetByID(id int) error {
	db, err := GetDB()
	if err != nil {
		return err
	}

	err = db.First(c, id).Error
	return err
}

// Get one by name
func (c *Course) GetByName(name string) error {
	db, err := GetDB()
	if err != nil {
		return err
	}

	err = db.Where("name = ?", name).First(c).Error
	return err
}

// Get all
func (c *Course) GetAll() ([]Course, error) {
	db, err := GetDB()
	if err != nil {
		return nil, err
	}

	var courses []Course
	err = db.Find(&courses).Error
	return courses, err
}

// Get all training events for a course
func (c *Course) GetTrainingEvents(ctx context.Context, id int) ([]TrainingEvent, error) {
	db, err := GetDB()
	if err != nil {
		return nil, err
	}

	var events []TrainingEvent
	err = db.WithContext(ctx).Where("course_id = ?", id).Find(&events).Error
	if err != nil {
		return nil, err
	}
	return events, nil
}

// Get all prerequisites for a course
func (c *Course) GetPrerequisites(ctx context.Context, id int) ([]Course, error) {
	var prereqs []Course
	db, err := GetDB()
	if err != nil {
		return nil, err
	}
	err = db.WithContext(ctx).Model(c).Where("id = ?", id).Association("Prerequisites").Find(&prereqs)
	if err != nil {
		return nil, err
	}
	return prereqs, nil
}

// Create a new course
func (c *Course) Create(ctx context.Context, course Course) error {
	db, err := GetDB()
	if err != nil {
		return err
	}

	err = db.WithContext(ctx).Create(course).Error
	if err != nil {
		return err
	}
	return nil
}

// Update a course
func (c *Course) Update(ctx context.Context, course Course) error {
	db, err := GetDB()
	if err != nil {
		return err
	}

	err = db.WithContext(ctx).Save(course).Error
	if err != nil {
		return err
	}
	return nil
}

// Delete a course
func (c *Course) Delete(ctx context.Context, course Course) error {
	db, err := GetDB()
	if err != nil {
		return err
	}

	err = db.WithContext(ctx).Delete(course).Error
	if err != nil {
		return err
	}
	return nil
}