new windows types

lib/bbs/markdown.rb

@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+require_relative 'frame_buffer'
+
+module BBS
+  # Markdown → ANSI line array renderer.
+  #
+  #   BBS::Markdown.to_lines(text, width:, theme:)
+  #
+  # Returns an array of strings (one per terminal line) with embedded ANSI SGR
+  # codes — suitable for BBS::Widgets::ScrollView. Each inline span ends with
+  # the theme :text SGR so that trailing text keeps the right background.
+  module Markdown
+    module_function
+
+    def to_lines(text, width:, theme:)
+      styles = {
+        base:   theme[:text],
+        h1:     theme[:text_bright],
+        h2:     theme[:accent],
+        h3:     theme[:label],
+        bold:   theme[:text_bright],
+        italic: theme[:text_dim],
+        code:   theme[:label],
+        link:   theme[:accent],
+        quote:  theme[:text_dim],
+        bullet: theme[:accent],
+        rule:   theme[:label],
+      }
+      result    = []
+      paragraph = []
+      in_code   = false
+      base      = styles[:base]
+
+      flush_paragraph = lambda do
+        next if paragraph.empty?
+        joined = paragraph.join(' ').gsub(/\s+/, ' ').strip
+        FrameBuffer.wrap_ansi(inline(joined, styles, base), width).each { |l| result << l }
+        paragraph.clear
+      end
+
+      text.to_s.split(/\r?\n/).each do |line|
+        if line.lstrip.start_with?('```')
+          flush_paragraph.call
+          in_code = !in_code
+          next
+        end
+
+        if in_code
+          flush_paragraph.call
+          clipped = FrameBuffer.clip_ansi(line, width)
+          result << "#{styles[:code]}#{clipped}#{base}"
+          next
+        end
+
+        if line.strip.empty?
+          flush_paragraph.call
+          result << ''
+          next
+        end
+
+        if (m = line.match(/\A([#]{1,6})\s+(.+?)\s*#*\s*\z/))
+          level   = m[1].length
+          heading = m[2].strip
+          flush_paragraph.call
+          style = level == 1 ? styles[:h1] : (level == 2 ? styles[:h2] : styles[:h3])
+          FrameBuffer.wrap_ansi(inline(heading, styles, base), width).each do |l|
+            result << "#{style}#{l}#{base}"
+          end
+          next
+        end
+
+        if line.match?(/\A\s*([-*_])\1{2,}\s*\z/)
+          flush_paragraph.call
+          result << "#{styles[:rule]}#{'─' * width}#{base}"
+          next
+        end
+
+        if (m = line.match(/\A\s*>\s?(.*)/))
+          content = m[1]
+          flush_paragraph.call
+          inner_w = [width - 2, 1].max
+          FrameBuffer.wrap_ansi(inline(content, styles, base), inner_w).each do |l|
+            result << "#{styles[:quote]}│ #{base}#{l}"
+          end
+          next
+        end
+
+        if (m = line.match(/\A(\s*)[-*+]\s+(.+)/))
+          indent = m[1].length
+          body   = m[2]
+          flush_paragraph.call
+          prefix_w = indent + 2
+          inner_w  = [width - prefix_w, 1].max
+          wrapped  = FrameBuffer.wrap_ansi(inline(body, styles, base), inner_w)
+          wrapped.each_with_index do |l, i|
+            pad = ' ' * indent
+            result << if i.zero?
+                        "#{pad}#{styles[:bullet]}•#{base} #{l}"
+                      else
+                        "#{' ' * prefix_w}#{l}"
+                      end
+          end
+          next
+        end
+
+        if (m = line.match(/\A(\s*)(\d+)\.\s+(.+)/))
+          indent = m[1].length
+          num    = m[2]
+          body   = m[3]
+          flush_paragraph.call
+          prefix  = "#{' ' * indent}#{num}. "
+          inner_w = [width - prefix.length, 1].max
+          wrapped = FrameBuffer.wrap_ansi(inline(body, styles, base), inner_w)
+          wrapped.each_with_index do |l, i|
+            result << if i.zero?
+                        "#{' ' * indent}#{styles[:bullet]}#{num}.#{base} #{l}"
+                      else
+                        "#{' ' * prefix.length}#{l}"
+                      end
+          end
+          next
+        end
+
+        paragraph << line.strip
+      end
+
+      flush_paragraph.call
+      result
+    end
+
+    def inline(text, styles, base_sgr)
+      s = text.to_s
+      s = s.gsub(/\[([^\]]+)\]\(([^)]+)\)/) { "#{styles[:link]}#{::Regexp.last_match(1)}#{base_sgr}" }
+      s = s.gsub(/`([^`]+)`/) { "#{styles[:code]}#{::Regexp.last_match(1)}#{base_sgr}" }
+      s = s.gsub(/\*\*([^*]+)\*\*/) { "#{styles[:bold]}#{::Regexp.last_match(1)}#{base_sgr}" }
+      s = s.gsub(/(?<![A-Za-z0-9*])\*([^*\s][^*]*?[^*\s]|\S)\*(?![A-Za-z0-9*])/) do
+        "#{styles[:italic]}#{::Regexp.last_match(1)}#{base_sgr}"
+      end
+      s = s.gsub(/(?<![A-Za-z0-9_])_([^_\s][^_]*?[^_\s]|\S)_(?![A-Za-z0-9_])/) do
+        "#{styles[:italic]}#{::Regexp.last_match(1)}#{base_sgr}"
+      end
+      s.gsub(/\\([\\`*_{}\[\]()#+\-.!>])/) { ::Regexp.last_match(1) }
+    end
+  end
+end