class Doctor
  attr_reader :id
  attr_accessor :name, :age, :specialty

  def initialize(attributes={})
    @id = attributes[:id]
    @name = attributes[:name]
    @age = attributes[:age]
    @specialty = attributes[:specialty]
  end

  def save
    @id.nil? ? insert : update
  end

  def destroy
    DB.execute('DELETE FROM doctors WHERE id = ?', @id)
  end

  def self.find(id)
    DB.results_as_hash = true
    row = DB.execute('SELECT * FROM doctors WHERE id = ?', id).first
    Doctor.new(name: row['name'], id: row['id'] , age: row['age'], specialty: row['specialty'])
  end

  def self.all
    DB.results_as_hash = true
    rows = DB.execute('SELECT * FROM doctors')
    result = []
    rows.each do |row|
      result << Doctor.new(name: row['name'], id: row['id'] , age: row['age'], specialty: row['specialty'])
    end
    result
  end

  private
  def insert
    DB.execute("INSERT INTO doctors (name, age, specialty) VALUES (?,?,?)", @name, @age, @specialty)
    @id = DB.last_insert_row_id
  end

  def update
    DB.execute("UPDATE doctors SET name=?, age=?, specialty=? WHERE id=?", @name, @age, @specialty, @id)
  end


end