[SOLVED] Discount Shop

module CONSTANT
  DISC_RATE = 1 #nomor variable diskon, ganti aja sama variable yang dimaksud
end

class Window_ShopBuy < Window_Selectable
  def draw_item(index)
    item = @data[index]
    case item
    when RPG::Item
      number = $game_party.item_number(item.id)
    when RPG::Weapon
      number = $game_party.weapon_number(item.id)
    when RPG::Armor
      number = $game_party.armor_number(item.id)
    end
    price = item.price * $game_variables[CONSTANT::DISC_RATE] / 100
    if price <= $game_party.gold and number < 99
      self.contents.font.color = normal_color
    else
      self.contents.font.color = disabled_color
    end
    x = 4
    y = index * 32
    rect = Rect.new(x, y, self.width - 32, 32)
    self.contents.fill_rect(rect, Color.new(0, 0, 0, 0))
    bitmap = RPG::Cache.icon(item.icon_name)
    opacity = self.contents.font.color == normal_color ? 255 : 128
    self.contents.blt(x, y + 4, bitmap, Rect.new(0, 0, 24, 24), opacity)
    self.contents.draw_text(x + 28, y, 212, 32, item.name, 0)
    self.contents.draw_text(x + 240, y, 88, 32, price.to_s, 2)
  end
end

class Scene_Shop
  def update_buy
    # Set status window item
    @status_window.item = @buy_window.item
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Change windows to initial mode
      @command_window.active = true
      @dummy_window.visible = true
      @buy_window.active = false
      @buy_window.visible = false
      @status_window.visible = false
      @status_window.item = nil
      # Erase help text
      @help_window.set_text("")
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # Get item
      @item = @buy_window.item
      @price = @item.price * $game_variables[CONSTANT::DISC_RATE] / 100
      p @price
      # If item is invalid, or price is higher than money possessed
      if @item == nil or @price > $game_party.gold
        # Play buzzer SE
        $game_system.se_play($data_system.buzzer_se)
        return
      end
      # Get items in possession count
      case @item
      when RPG::Item
        number = $game_party.item_number(@item.id)
      when RPG::Weapon
        number = $game_party.weapon_number(@item.id)
      when RPG::Armor
        number = $game_party.armor_number(@item.id)
      end
      # If 99 items are already in possession
      if number == 99
        # Play buzzer SE
        $game_system.se_play($data_system.buzzer_se)
        return
      end
      # Play decision SE
      $game_system.se_play($data_system.decision_se)
      # Calculate maximum amount possible to buy
      max = @price == 0 ? 99 : $game_party.gold / @price
      max = [max, 99 - number].min
      # Change windows to quantity input mode
      @buy_window.active = false
      @buy_window.visible = false
      @number_window.set(@item, max, @price)
      @number_window.active = true
      @number_window.visible = true
    end
  end
  #--------------------------------------------------------------------------
  # * Frame Update (when sell window is active)
  #--------------------------------------------------------------------------
  def update_sell
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Change windows to initial mode
      @command_window.active = true
      @dummy_window.visible = true
      @sell_window.active = false
      @sell_window.visible = false
      @status_window.item = nil
      # Erase help text
      @help_window.set_text("")
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # Get item
      @item = @sell_window.item
      @price = @item.price * $game_variables[CONSTANT::DISC_RATE] / 100
      # Set status window item
      @status_window.item = @item
      # If item is invalid, or item price is 0 (unable to sell)
      if @item == nil or @price == 0
        # Play buzzer SE
        $game_system.se_play($data_system.buzzer_se)
        return
      end
      # Play decision SE
      $game_system.se_play($data_system.decision_se)
      # Get items in possession count
      case @item
      when RPG::Item
        number = $game_party.item_number(@item.id)
      when RPG::Weapon
        number = $game_party.weapon_number(@item.id)
      when RPG::Armor
        number = $game_party.armor_number(@item.id)
      end
      # Maximum quanitity to sell = number of items in possession
      max = number
      # Change windows to quantity input mode
      @sell_window.active = false
      @sell_window.visible = false
      @number_window.set(@item, max, @price / 2)
      @number_window.active = true
      @number_window.visible = true
      @status_window.visible = true
    end
  end
  #--------------------------------------------------------------------------
  # * Frame Update (when quantity input window is active)
  #--------------------------------------------------------------------------
  def update_number
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Set quantity input window to inactive / invisible
      @number_window.active = false
      @number_window.visible = false
      # Branch by command window cursor position
      case @command_window.index
      when 0  # buy
        # Change windows to buy mode
        @buy_window.active = true
        @buy_window.visible = true
      when 1  # sell
        # Change windows to sell mode
        @sell_window.active = true
        @sell_window.visible = true
        @status_window.visible = false
      end
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # Play shop SE
      $game_system.se_play($data_system.shop_se)
      # Set quantity input window to inactive / invisible
      @number_window.active = false
      @number_window.visible = false
      # Branch by command window cursor position
      case @command_window.index
      when 0  # buy
        # Buy process
        $game_party.lose_gold(@number_window.number * @price)
        case @item
        when RPG::Item
          $game_party.gain_item(@item.id, @number_window.number)
        when RPG::Weapon
          $game_party.gain_weapon(@item.id, @number_window.number)
        when RPG::Armor
          $game_party.gain_armor(@item.id, @number_window.number)
        end
        # Refresh each window
        @gold_window.refresh
        @buy_window.refresh
        @status_window.refresh
        # Change windows to buy mode
        @buy_window.active = true
        @buy_window.visible = true
      when 1  # sell
        # Sell process
        $game_party.gain_gold(@number_window.number * (@price / 2))
        case @item
        when RPG::Item
          $game_party.lose_item(@item.id, @number_window.number)
        when RPG::Weapon
          $game_party.lose_weapon(@item.id, @number_window.number)
        when RPG::Armor
          $game_party.lose_armor(@item.id, @number_window.number)
        end
        # Refresh each window
        @gold_window.refresh
        @sell_window.refresh
        @status_window.refresh
        # Change windows to sell mode
        @sell_window.active = true
        @sell_window.visible = true
        @status_window.visible = false
      end
      return
    end
  end
end