new windows types

lib/bbs/windows/button_bar.rb

@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require_relative '../widgets'
+
+module BBS
+  module Windows
+    # Lays out a row of buttons at the bottom of a window.
+    #
+    # Button descriptor:
+    #   { key:, label:, on_click:, primary:, cancel:, align:, keep_open: }
+    #
+    # `on_click` receives the BBS::Window as its only argument and may return
+    # :keep to keep the window open. Any other return value (or nil) causes
+    # the window to be closed after the handler.
+    #
+    # `primary: true` gets initial focus on the button.
+    # `cancel: true` is informational only — ESC closes the window through the
+    # standard Window#close_key path. If you also want a cancel-specific side
+    # effect on ESC, set `window.on_close = ...` manually.
+    # `align: :left | :right | :center` — default is :center for a single
+    # button, :right otherwise. Left-aligned buttons stack from the left edge;
+    # right-aligned buttons stack flush against the right edge in declaration
+    # order (so the last right-aligned button sits closest to the edge).
+    module ButtonBar
+      module_function
+
+      # Returns { widgets:, primary:, by_key: }.
+      def attach(window, app, descriptors)
+        return { widgets: [], primary: nil, by_key: {} } if descriptors.nil? || descriptors.empty?
+
+        widgets = descriptors.map do |d|
+          BBS::Widgets::Button.new(label: d[:label], on_click: build_handler(window, app, d))
+        end
+
+        default_align = descriptors.length == 1 ? :center : :right
+        aligns        = descriptors.map { |d| d[:align] || default_align }
+
+        row_y    = window.bounds.y + window.bounds.height - 2
+        left_x0  = window.bounds.x + 2
+        right_x1 = window.bounds.x + window.bounds.width - 2
+        win_x0   = window.bounds.x
+        win_w    = window.bounds.width
+
+        x = left_x0
+        widgets.each_with_index do |w, i|
+          next unless aligns[i] == :left
+          bw = button_width(w)
+          w.layout(x, row_y, bw, 1)
+          x += bw + 1
+        end
+
+        right_indices = aligns.each_index.select { |i| aligns[i] == :right }
+        total_right   = right_indices.sum { |i| button_width(widgets[i]) + 1 } - 1
+        total_right   = [total_right, 0].max
+        x = right_x1 - total_right + 1
+        right_indices.each do |i|
+          bw = button_width(widgets[i])
+          widgets[i].layout(x, row_y, bw, 1)
+          x += bw + 1
+        end
+
+        center_indices = aligns.each_index.select { |i| aligns[i] == :center }
+        total_center   = center_indices.sum { |i| button_width(widgets[i]) + 1 } - 1
+        total_center   = [total_center, 0].max
+        x = win_x0 + (win_w - total_center) / 2
+        center_indices.each do |i|
+          bw = button_width(widgets[i])
+          widgets[i].layout(x, row_y, bw, 1)
+          x += bw + 1
+        end
+
+        widgets.each { |w| window.add(w) }
+
+        primary_idx = descriptors.index { |d| d[:primary] }
+        primary     = primary_idx ? widgets[primary_idx] : nil
+
+        by_key = {}
+        descriptors.each_with_index { |d, i| by_key[d[:key]] = widgets[i] if d[:key] }
+
+        { widgets: widgets, primary: primary, by_key: by_key }
+      end
+
+      def button_width(button)
+        "[ #{button.display_label} ]".length
+      end
+
+      def build_handler(window, app, descriptor)
+        on_click  = descriptor[:on_click]
+        keep_open = descriptor[:keep_open]
+        lambda do |_btn|
+          result = on_click&.call(window)
+          app.close_window(window) unless keep_open || result == :keep
+          :handled
+        end
+      end
+    end
+  end
+end