module Riffer::Rig::Terminal::Markdown::Flow

# File lib/riffer/rig/terminal/markdown/flow.rb, line 13
def lines(spans, theme:, width:)
  wrapper = Riffer::Rig::Terminal::Wrapper.new(width: width, indent: 0)
  wrapped = (wrapper << "#{spans.map(&:text).join}\n").lines(chomp: true)
  # The Wrapper moves, drops and rewrites whitespace but never a visible
  # character, so the nth visible character of its output is the nth one the
  # spans supplied.
  owners = spans.flat_map { |span| [span] * span.text.scan(VISIBLE).size }
  sizes = wrapped.map { |line| line.scan(VISIBLE).size }
  starts = sizes.each_with_object([0]) { |size, sums| sums << (sums.fetch(-1) + size) }
  wrapped.each_with_index.map do |line, index|
    paint(line, owners.slice(starts.fetch(index), sizes.fetch(index)) || [], theme)
  end
end