class FullscreenTui

# File lib/fullscreen_tui.rb, line 13
def initialize headers:, renderer: nil, enable_jk: true
  @header = Header.new headers
  @footer = Footer.new
  @selection = 0
  @renderer = renderer || Renderer.new
  @up_actions = [:arrow_up, enable_jk ? 'k' : nil].reject(&:nil?)
  @down_actions = [:arrow_down, enable_jk ? 'j' : nil].reject(&:nil?)
end

# File lib/fullscreen_tui.rb, line 84
def go_down
  footer.message = ''
  return if selection >= lines.size - 1

  self.selection += 1
end

# File lib/fullscreen_tui.rb, line 77
def go_up
  footer.message = ''
  return if selection.zero?

  self.selection -= 1
end

# File lib/fullscreen_tui.rb, line 48
def key_press key
  case key
  when *@up_actions then go_up
  when *@down_actions then go_down
  when 'q', "\u0004" then throw :quit # ctrl-d
  else footer.message = "Unknown key: #{key.inspect}"
  end
end

# File lib/fullscreen_tui.rb, line 31
def print_screen
  clear

  rows, columns = TermInfo.screen_size

  header_text = header.output
  rows -= required_lines header_text, columns
  footer_text = footer.output width: columns, lines: lines.size, current_line: selection
  rows -= required_lines footer_text, columns

  renderer.header header_text unless header_text.empty?

  print_lines rows, columns

  renderer.footer footer_text
end

# File lib/fullscreen_tui.rb, line 63
def react
  key = case char = STDIN.getch
  when "\u0003" then exit 1
  when "\e"
    case subchar = STDIN.getch
    when '['
      ARROWS.fetch(STDIN.getch) {|k| "\e[#{k}" }
    else "\e#{subchar}"
    end
  else char
  end
  key_press key
end

# File lib/fullscreen_tui.rb, line 91
def read_full_line message
  puts message
  gets
end

# File lib/fullscreen_tui.rb, line 22
def run
  catch :quit do
    loop do
      print_screen
      react
    end
  end
end

# File lib/fullscreen_tui.rb, line 57
def selected_line
  lines[selection]
end

# File lib/fullscreen_tui.rb, line 129
def clear
  system(Gem.win_platform? ? 'cls' : 'clear')
end

# File lib/fullscreen_tui.rb, line 116
def fill_remaining_lines rows, used_lines
  (rows - used_lines).times { renderer.line '~', selected: false }
end

# File lib/fullscreen_tui.rb, line 120
def height text, columns
  (text.size.to_f / columns).ceil
end

# File lib/fullscreen_tui.rb, line 98
def print_lines rows, columns
  used_lines = 0
  offset = [selection - 5, 0].max
  lines[offset..-1].map(&:to_s).each.with_index do |line, i|
    selected = i + offset == selection
    used_lines += height line, columns
    if used_lines > rows
      renderer.line '...', selected: selected
      break
    end

    renderer.line line, selected: selected
    break if used_lines == rows
  end

  fill_remaining_lines rows, used_lines
end

# File lib/fullscreen_tui.rb, line 124
def required_lines text, columns
  text.split($INPUT_RECORD_SEPARATOR)
    .inject(0) {|sum, line| sum + height(line, columns) }
end