# tty layer as opposed to a future window management server bullshit thingy
# this is just tty0 it adds nice shit like ^B and stuff
# also has history and shit

global tty = {
  line = "", cursor = 0, esc = 0,
  history = {}, hist_index = 0,

  back = fn(self, n) do
    let i = 0
    while i < n do puts("\x08") i += 1 end
  end,
  blanks = fn(self, n) do
    let i = 0
    while i < n do puts(" ") i += 1 end
  end,

  insert = fn(self, ch) do
    const pre = self.line[0..self.cursor]
    const post = self.line[self.cursor..]
    self.line = pre ~ ch ~ post
    puts(ch ~ post)
    self:back(post:len())
    self.cursor += 1
  end,

  backspace = fn(self) do
    if self.cursor == 0 return :nil
    const pre = self.line[0..(self.cursor - 1)]
    const post = self.line[self.cursor..]
    self.line = pre ~ post
    self.cursor -= 1
    puts("\x08")
    puts(post ~ " ")
    self:back(post:len() + 1)
  end,

  move_left = fn(self) do
    if self.cursor > 0 do puts("\x08") self.cursor -= 1 end
  end,
  move_right = fn(self) do
    if self.cursor < self.line:len() do puts(self.line[self.cursor]) self.cursor += 1 end
  end,
  home = fn(self) do
    self:back(self.cursor)
    self.cursor = 0
  end,
  to_end = fn(self) do
    puts(self.line[self.cursor..])
    self.cursor = self.line:len()
  end,

  kill = fn(self) do
    self:back(self.cursor)
    self:blanks(self.line:len())
    self:back(self.line:len())
    self.line = ""
    self.cursor = 0
  end,

  erase_word = fn(self) do
    if self.cursor == 0 return :nil
    let at = self.cursor
    while (at > 0 and self.line[at - 1] == " ") do at -= 1 end
    while (at > 0 and self.line[at - 1] != " ") do at -= 1 end
    let count = self.cursor - at
    while count > 0 do self:backspace() count -= 1 end
  end,

  replace_line = fn(self, text) do
    self:kill()
    self.line = text
    puts(text)
    self.cursor = text:len()
  end,

  history_prev = fn(self) do
    if self.history:len() == 0 return :nil
    if self.hist_index > 0 do self.hist_index -= 1 end
    self:replace_line(self.history[self.hist_index])
  end,
  history_next = fn(self) do
    if self.history:len() == 0 return :nil
    if self.hist_index < self.history:len() - 1 do
      self.hist_index += 1
      self:replace_line(self.history[self.hist_index])
    end
    else do
      self.hist_index = self.history:len()
      self:replace_line("")
    end
  end,

  submit = fn(self) do
    puts("\n")
    const entered = self.line
    if entered:len() > 0 do self.history:push(entered) end
    self.hist_index = self.history:len()
    self.line = ""
    self.cursor = 0
    run(entered)
  end,

  cancel = fn(self) do
    puts("^C\n")
    self.line = ""
    self.cursor = 0
    self.hist_index = self.history:len()
    puts(prompt())
  end,

  clear_screen = fn(self) do
    console:clear()
    puts(prompt())
    puts(self.line)
    self:back(self.line:len() - self.cursor)
  end,

  feed = fn(self, byte) do
    if stdin_deliver(byte) return :nil

    if self.esc == 1 do
      if byte == 91 do self.esc = 2 end
      else do self.esc = 0 end
      return :nil
    end
    if self.esc == 2 do
      self.esc = 0
      if byte == 65 do self:history_prev() end       # up
      else if byte == 66 do self:history_next() end  # down
      else if byte == 67 do self:move_right() end    # right
      else if byte == 68 do self:move_left() end     # left
      else if byte == 72 do self:home() end          # home
      else if byte == 70 do self:to_end() end        # end
      return :nil
    end
    if byte == 27 do self.esc = 1 return :nil end    # ESC, start a sequence

    if byte == 10 do self:submit() return :nil end       # enter
    if byte == 8 or byte == 127 do self:backspace() return :nil end # bs / del
    if byte == 1 do self:home() return :nil end          # ctrl-a
    if byte == 5 do self:to_end() return :nil end        # ctrl-e
    if byte == 3 do self:cancel() return :nil end        # ctrl-c
    if byte == 12 do self:clear_screen() return :nil end # ctrl-l
    if byte == 21 do self:kill() return :nil end         # ctrl-u
    if byte == 23 do self:erase_word() return :nil end   # ctrl-w
    if byte < 32 return :nil                             # ctrl-d and other ctrls: ignore
    if byte > 126 return :nil
    self:insert(string.of_ascii(byte))
  end,
}