new framework

lib/bbs/statusbar.rb

@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+require_relative 'widget'
+
+module BBS
+  # A status bar at the bottom of the screen. Render a list of hotkey hints
+  # like "F1=Help F2=Save Esc=Cancel". Optionally a right-aligned status text.
+  class Statusbar < Widget
+    Hint = Struct.new(:key, :label, :on_activate, keyword_init: true)
+
+    attr_accessor :hints, :right_text
+
+    def initialize(hints: [], right_text: nil, **kw)
+      super(**kw)
+      @hints      = hints
+      @right_text = right_text
+    end
+
+    def add_hint(key, label, &on_activate)
+      @hints << Hint.new(key: key, label: label, on_activate: on_activate)
+    end
+
+    def render(frame)
+      sgr = style(:statusbar)
+      key_sgr = style(:statusbar_key)
+      frame.move(bounds.x, bounds.y)
+      frame.write(' ' * bounds.width, sgr: sgr)
+
+      cx = bounds.x + 1
+      @hints.each do |hint|
+        text_key = hint.key.to_s
+        text_lbl = " #{hint.label} "
+        break if cx + text_key.length + text_lbl.length > bounds.x + bounds.width - 1
+        frame.move(cx, bounds.y)
+        frame.write(text_key, sgr: key_sgr)
+        frame.write(text_lbl, sgr: sgr)
+        cx += text_key.length + text_lbl.length + 1
+      end
+
+      if @right_text
+        txt = @right_text.to_s
+        rx  = bounds.x + bounds.width - txt.length - 1
+        if rx >= cx
+          frame.move(rx, bounds.y)
+          frame.write(txt, sgr: sgr)
+        end
+      end
+    end
+
+    def handle_event(event)
+      if event.key?
+        hint = match_key(event.key)
+        return hint.on_activate&.call || :handled if hint
+        return nil
+      end
+
+      return nil unless event.mouse? && event.mouse.kind == :press &&
+                        event.mouse.button == :left && event.y == bounds.y
+      cx = bounds.x + 1
+      @hints.each do |hint|
+        text_key = hint.key.to_s
+        text_lbl = " #{hint.label} "
+        width    = text_key.length + text_lbl.length
+        if event.x >= cx && event.x < cx + width
+          return hint.on_activate&.call || :handled
+        end
+        cx += width + 1
+      end
+      nil
+    end
+
+    private
+
+    def match_key(key)
+      key_str = key.to_s
+      @hints.find do |hint|
+        label = hint.key.to_s
+        case label
+        when /\AF(\d+)\z/i  then key == :"f#{::Regexp.last_match(1)}"
+        when /\AAlt-(.)\z/i then key == :"alt_#{::Regexp.last_match(1).downcase}"
+        when /\AEsc\z/i     then key == :escape
+        when /\ATab\z/i     then key == :tab
+        else                     key_str.casecmp?(label)
+        end
+      end
+    end
+  end
+end