class Reline::ANSI

def self.clear_screen
  @@output.write "\e[2J"
  @@output.write "\e[1;1H"
end

def self.cursor_pos
  begin
    res = +''
    m = nil
    @@input.raw do |stdin|
      @@output << "\e[6n"
      @@output.flush
      loop do
        c = stdin.getc
        next if c.nil?
        res << c
        m = res.match(/\e\[(?<row>\d+);(?<column>\d+)R/)
        break if m
      end
      (m.pre_match + m.post_match).chars.reverse_each do |ch|
        stdin.ungetc ch
      end
    end
    column = m[:column].to_i - 1
    row = m[:row].to_i - 1
  rescue Errno::ENOTTY
    begin
      buf = @@output.pread(@@output.pos, 0)
      row = buf.count("\n")
      column = buf.rindex("\n") ? (buf.size - buf.rindex("\n")) - 1 : 0
    rescue Errno::ESPIPE
      # Just returns column 1 for ambiguous width because this I/O is not
      # tty and can't seek.
      row = 0
      column = 1
    end
  end
  Reline::CursorPos.new(column, row)
end

def self.deprep(otio)
  Signal.trap('WINCH', @@old_winch_handler) if @@old_winch_handler
end

def self.empty_buffer?
  unless @@buf.empty?
    return false
  end
  !@@input.wait_readable(0)
end

def self.encoding: () -> Encoding

def self.encoding
  Encoding.default_external
end

def self.erase_after_cursor: () -> Integer

def self.erase_after_cursor
  @@output.write "\e[K"
end

def self.get_screen_size
  s = @@input.winsize
  return s if s[0] > 0 && s[1] > 0
  s = [ENV["LINES"].to_i, ENV["COLUMNS"].to_i]
  return s if s[0] > 0 && s[1] > 0
  [24, 80]
rescue Errno::ENOTTY
  [24, 80]
end

def self.getc
  if Reline.core.config.enable_bracketed_paste
    getc_with_bracketed_paste
  else
    inner_getc
  end
end

def self.getc_with_bracketed_paste
  buffer = String.new(encoding: Encoding::ASCII_8BIT)
  buffer << inner_getc
  while START_BRACKETED_PASTE.start_with?(buffer) or END_BRACKETED_PASTE.start_with?(buffer) do
    if START_BRACKETED_PASTE == buffer
      @@in_bracketed_paste_mode = true
      return inner_getc
    elsif END_BRACKETED_PASTE == buffer
      @@in_bracketed_paste_mode = false
      ungetc(-1)
      return inner_getc
    end
    begin
      succ_c = nil
      Timeout.timeout(Reline.core.config.keyseq_timeout * 100) {
        succ_c = inner_getc
      }
    rescue Timeout::Error
      break
    else
      buffer << succ_c
    end
  end
  buffer.bytes.reverse_each do |ch|
    ungetc ch
  end
  inner_getc
end

def self.hide_cursor
  if Reline::Terminfo.enabled?
    begin
      @@output.write Reline::Terminfo.tigetstr('civis')
    rescue Reline::Terminfo::TerminfoError
      # civis is undefined
    end
  else
    # ignored
  end
end

def self.in_pasting?
  @@in_bracketed_paste_mode or (not empty_buffer?)
end

def self.inner_getc
  unless @@buf.empty?
    return @@buf.shift
  end
  until c = @@input.raw(intr: true) { @@input.wait_readable(0.1) && @@input.getbyte }
    Reline.core.line_editor.resize
  end
  (c == 0x16 && @@input.raw(min: 0, time: 0, &:getbyte)) || c
rescue Errno::EIO
  # Maybe the I/O has been closed.
  nil
rescue Errno::ENOTTY
  nil
end

def self.input=(val)
  @@input = val
end

def self.move_cursor_column: (Integer x) -> Integer

def self.move_cursor_column(x)
  @@output.write "\e[#{x + 1}G"
end

def self.move_cursor_down: (Integer x) -> Integer

def self.move_cursor_down(x)
  if x > 0
    @@output.write "\e[#{x}B"
  elsif x < 0
    move_cursor_up(-x)
  end
end

def self.move_cursor_up: (Integer x) -> Integer

def self.move_cursor_up(x)
  if x > 0
    @@output.write "\e[#{x}A"
  elsif x < 0
    move_cursor_down(-x)
  end
end

def self.output=(val)
  @@output = val
end

def self.prep
  retrieve_keybuffer
  nil
end

def self.retrieve_keybuffer
  begin
    return unless @@input.wait_readable(0.001)
    str = @@input.read_nonblock(1024)
    str.bytes.each do |c|
      @@buf.push(c)
    end
  rescue EOFError
  end
end

def self.scroll_down(x)
  return if x.zero?
  # We use `\n` instead of CSI + S because CSI + S would cause https://github.com/ruby/reline/issues/576
  @@output.write "\n" * x
end

def self.set_default_key_bindings(config, allow_terminfo: true)
  set_default_key_bindings_ansi_cursor(config)
  if allow_terminfo && Reline::Terminfo.enabled?
    set_default_key_bindings_terminfo(config)
  else
    set_default_key_bindings_comprehensive_list(config)
  end
  {
    [27, 91, 90] => :completion_journey_up, # S-Tab
  }.each_pair do |key, func|
    config.add_default_key_binding_by_keymap(:emacs, key, func)
    config.add_default_key_binding_by_keymap(:vi_insert, key, func)
  end
  {
    # default bindings
    [27, 32] => :em_set_mark,             # M-<space>
    [24, 24] => :em_exchange_mark,        # C-x C-x
  }.each_pair do |key, func|
    config.add_default_key_binding_by_keymap(:emacs, key, func)
  end
end

def self.set_default_key_bindings_ansi_cursor(config)
  ANSI_CURSOR_KEY_BINDINGS.each do |char, (default_func, modifiers)|
    bindings = [["\e[#{char}", default_func]] # CSI + char
    if modifiers[:ctrl]
      # CSI + ctrl_key_modifier + char
      bindings << ["\e[1;5#{char}", modifiers[:ctrl]]
    end
    if modifiers[:meta]
      # CSI + meta_key_modifier + char
      bindings << ["\e[1;3#{char}", modifiers[:meta]]
      # Meta(ESC) + CSI + char
      bindings << ["\e\e[#{char}", modifiers[:meta]]
    end
    bindings.each do |sequence, func|
      key = sequence.bytes
      config.add_default_key_binding_by_keymap(:emacs, key, func)
      config.add_default_key_binding_by_keymap(:vi_insert, key, func)
      config.add_default_key_binding_by_keymap(:vi_command, key, func)
    end
  end
end

def self.set_default_key_bindings_comprehensive_list(config)
  {
    # Console (80x25)
    [27, 91, 49, 126] => :ed_move_to_beg, # Home
    [27, 91, 52, 126] => :ed_move_to_end, # End
    [27, 91, 51, 126] => :key_delete,     # Del
    # KDE
    # Del is 0x08
    [27, 71, 65] => :ed_prev_history,     # ↑
    [27, 71, 66] => :ed_next_history,     # ↓
    [27, 71, 67] => :ed_next_char,        # →
    [27, 71, 68] => :ed_prev_char,        # ←
    # urxvt / exoterm
    [27, 91, 55, 126] => :ed_move_to_beg, # Home
    [27, 91, 56, 126] => :ed_move_to_end, # End
    # GNOME
    [27, 79, 72] => :ed_move_to_beg,      # Home
    [27, 79, 70] => :ed_move_to_end,      # End
    # Del is 0x08
    # Arrow keys are the same of KDE
    [27, 79, 65] => :ed_prev_history,     # ↑
    [27, 79, 66] => :ed_next_history,     # ↓
    [27, 79, 67] => :ed_next_char,        # →
    [27, 79, 68] => :ed_prev_char,        # ←
  }.each_pair do |key, func|
    config.add_default_key_binding_by_keymap(:emacs, key, func)
    config.add_default_key_binding_by_keymap(:vi_insert, key, func)
    config.add_default_key_binding_by_keymap(:vi_command, key, func)
  end
end

def self.set_default_key_bindings_terminfo(config)
  key_bindings = CAPNAME_KEY_BINDINGS.map do |capname, key_binding|
    begin
      key_code = Reline::Terminfo.tigetstr(capname)
      [ key_code.bytes, key_binding ]
    rescue Reline::Terminfo::TerminfoError
      # capname is undefined
    end
  end.compact.to_h
  key_bindings.each_pair do |key, func|
    config.add_default_key_binding_by_keymap(:emacs, key, func)
    config.add_default_key_binding_by_keymap(:vi_insert, key, func)
    config.add_default_key_binding_by_keymap(:vi_command, key, func)
  end
end

def self.set_screen_size(rows, columns)
  @@input.winsize = [rows, columns]
  self
rescue Errno::ENOTTY
  self
end

def self.set_winch_handler(&handler)
  @@old_winch_handler = Signal.trap('WINCH', &handler)
end

def self.show_cursor
  if Reline::Terminfo.enabled?
    begin
      @@output.write Reline::Terminfo.tigetstr('cnorm')
    rescue Reline::Terminfo::TerminfoError
      # cnorm is undefined
    end
  else
    # ignored
  end
end

def self.ungetc(c)
  @@buf.unshift(c)
end

def self.win?
  false
end

def self.with_raw_input
  @@input.raw { yield }
end