package repository

import (
	"database/sql"
	"fmt"
	"time"

	domain "github.com/haydenhargreaves/Potion/internal/domain/engagement"
	_ "github.com/lib/pq"
)

type EngagementRepository struct {
	db *sql.DB
}

// Compile-time check to ensure the EngagementRepository implements domain.EngagementRepository
var _ domain.EngagementRepository = (*EngagementRepository)(nil)

// NewUserRepository creates a user repository object which is used by the user service to access
// the database. Any user related database operations will take place in this repository.
func NewEngagementRepository(db *sql.DB) domain.EngagementRepository {
	return &EngagementRepository{db: db}
}

// AddUserEngagement creates an engagement record in the database with the user ID provided. This
// function does not accept an entity ID as it should be used when there is no need to reference
// an entity. The message should be provided, but a blank string ("") is acceptable. The engagement
// type parameter determines the labeling of the engagement in the database. Any errors will be
// bubbled to the caller.
func (r *EngagementRepository) AddUserEngagement(userId int, message string, engagementType domain.EngagementType) (domain.Engagement, error) {
	tx, err := r.db.Begin()
	if err != nil {
		tx.Rollback()
		return domain.Engagement{}, err
	}

	query := `
		INSERT INTO Engagements (
			type, message, entity, userid, created
		) VALUES  (
			$1, $2, NULL, $3, $4
		) RETURNING *;
	`

	var engagement domain.Engagement
	if err := tx.QueryRow(query, engagementType, message, userId, time.Now()).Scan(
		&engagement.Id,
		&engagement.Type,
		&engagement.Message,
		&engagement.Entity,
		&engagement.UserId,
		&engagement.Created,
	); err != nil {
		tx.Rollback()
		return domain.Engagement{}, fmt.Errorf("Failed to insert engagement into database. %s", err.Error())
	}

	if err := tx.Commit(); err != nil {
		tx.Rollback()
		return domain.Engagement{}, err
	}

	return engagement, nil
}

// AddUserEngagement creates an engagement record in the database with the user ID provided. This
// function requires an entity ID as it should be used when there is a reference to external an
// entity. The message should be provided, but a blank string ("") is acceptable. The engagement
// type parameter determines the labeling of the engagement in the database. Any errors will be
// bubbled to the caller.
func (r *EngagementRepository) AddUserEntityEngagement(userId, entityId int, message string, engagementType domain.EngagementType) (domain.Engagement, error) {
	tx, err := r.db.Begin()
	if err != nil {
		tx.Rollback()
		return domain.Engagement{}, err
	}

	query := `
		INSERT INTO Engagements (
			type, message, entity, userid, created
		) VALUES  (
			$1, $2, $3, $4, $5
		) RETURNING *;
	`

	var engagement domain.Engagement
	if err := tx.QueryRow(query, engagementType, message, entityId, userId, time.Now()).Scan(
		&engagement.Id,
		&engagement.Type,
		&engagement.Message,
		&engagement.Entity,
		&engagement.UserId,
		&engagement.Created,
	); err != nil {
		tx.Rollback()
		return domain.Engagement{}, fmt.Errorf("Failed to insert engagement into database. %s", err.Error())
	}

	if err := tx.Commit(); err != nil {
		tx.Rollback()
		return domain.Engagement{}, err
	}

	return engagement, nil
}

// GetUserEngagement returns a list of the users most recent engagement entries. The number of records
// is determined by the limit passed into this function. The results are sorted, newest-to-oldest.
func (r *EngagementRepository) GetUserEngagement(userId, limit int) ([]domain.Engagement, error) {
	tx, err := r.db.Begin()
	if err != nil {
		tx.Rollback()
		return []domain.Engagement{}, err
	}

	query := `
		SELECT * FROM Engagements
		WHERE Userid = $1
		ORDER BY created DESC LIMIT $2;
	`

	rows, err := tx.Query(query, userId, limit)
	if err != nil {
		tx.Rollback()
		return []domain.Engagement{}, fmt.Errorf("Failed to get user engagements. %s", err.Error())
	}
	defer rows.Close()

	var engagements []domain.Engagement
	for rows.Next() {
		var engagement domain.Engagement
		if err := rows.Scan(
			&engagement.Id,
			&engagement.Type,
			&engagement.Message,
			&engagement.Entity,
			&engagement.UserId,
			&engagement.Created,
		); err != nil {
			tx.Rollback()
			return []domain.Engagement{}, fmt.Errorf("Failed to scan user engagement. %s", err.Error())
		}

		engagements = append(engagements, engagement)
	}

	if err := tx.Commit(); err != nil {
		tx.Rollback()
		return []domain.Engagement{}, err
	}

	return engagements, err
}