udemy-go-web-1/internal/repository/dbrepo/postgres.go

package dbrepo

import (
	"context"
	"go-udemy-web-1/internal/models"
	"time"
)

func (m *postgresDBRepo) AllUsers() bool {
	return true
}

// InsertReservation inserts a reservation into the database
func (m *postgresDBRepo) InsertReservation(res models.Reservation) (int, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	var newId int
	// statement
	stmt := `insert into reservations (first_name, last_name, email, phone,
	            start_date, end_date, room_id, created_at, updated_at)
	            values ($1, $2, $3, $4, $5, $6, $7, $8, $9) returning id`

	row := m.DB.QueryRowContext(ctx, stmt,
		res.FirstName,
		res.LastName,
		res.Email,
		res.Phone,
		res.StartDate,
		res.EndDate,
		res.RoomID,
		time.Now(),
		time.Now())

	err := row.Scan(&newId)
	if err != nil {
		return 0, err
	}

	return newId, nil
}

// InsertRoomRestriction inserts a room restriction into the database
func (m *postgresDBRepo) InsertRoomRestriction(r models.RoomRestriction) error {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	stmt := `insert into room_restrictions (
                start_date, end_date, room_id, reservation_id, restriction_id,
                created_at, updated_at)
	            values ($1, $2, $3, $4, $5, $6, $7)`

	_, err := m.DB.ExecContext(ctx, stmt,
		r.StartDate,
		r.EndDate,
		r.RoomID,
		r.ReservationID,
		r.RestrictionID,
		time.Now(),
		time.Now())
	if err != nil {
		return err
	}

	return nil
}

// SearchAvailabilityByDatesByRoomID returns true if availability exists for roomID, and false if no availability
func (m *postgresDBRepo) SearchAvailabilityByDatesByRoomID(start, end time.Time, roomID int) (bool, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	var numRows int
	stmt := `select count(id) from room_restrictions
             where room_id = $1 and
             $2 < end_date and $3> start_date`

	row := m.DB.QueryRowContext(ctx, stmt, roomID, start, end)
	err := row.Scan(&numRows)
	if err != nil {
		return false, err
	}

	if numRows == 0 {
		return true, nil
	}

	return false, nil
}

// SearchAvailabilityForAllRooms returns a slice of rooms, if any, for given date range
func (m *postgresDBRepo) SearchAvailabilityForAllRooms(start, end time.Time) ([]models.Room, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	var rooms []models.Room
	stmt := `select
                r.id, r.room_name
            from
                rooms r
            where r.id not in
                (select
                    room_id
                from
                    room_restrictions rr
                where
                    $1 < rr.end_date and $2> rr.start_date)`

	rows, err := m.DB.QueryContext(ctx, stmt, start, end)
	if err != nil {
		return nil, err
	}
	for rows.Next() {
		var room models.Room

		err := rows.Scan(&room.ID, &room.RoomName)
		if err != nil {
			return rooms, err
		}
		rooms = append(rooms, room)
	}

	if err = rows.Err(); err != nil {
		return rooms, err
	}

	return rooms, nil
}

// GetRoomById gets a room by id
func (m *postgresDBRepo) GetRoomById(id int) (models.Room, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	var room models.Room
	stmt := `select
                id, room_name, created_at, updated_at
            from
                rooms
            where id = $1`

	row := m.DB.QueryRowContext(ctx, stmt, id)
	err := row.Scan(&room.ID, &room.RoomName, &room.CreatedAt, &room.UpdatedAt)
	if err != nil {
		return room, err
	}
	return room, nil
}