Class: TUI::InputBuffer

Inherits:
Object
  • Object
show all
Defined in:
lib/tui/input_buffer.rb

Overview

Manages editable text with cursor position tracking. Supports multiline input with newline insertion, cursor navigation across physical lines, and standard text editing operations.

Pure logic object with no rendering or framework dependencies.

Constant Summary collapse

MAX_LENGTH = 
10_000

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ InputBuffer

Returns a new instance of InputBuffer.



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# File 'lib/tui/input_buffer.rb', line 14

def initialize
  @text = ""
  @cursor_pos = 0
end

Instance Attribute Details

#cursor_pos ⇒ Object (readonly)

Returns the value of attribute cursor_pos.



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# File 'lib/tui/input_buffer.rb', line 12

def cursor_pos
  @cursor_pos
end

#text ⇒ Object (readonly)

Returns the value of attribute text.



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# File 'lib/tui/input_buffer.rb', line 12

def text
  @text
end

Instance Method Details

#backspace ⇒ Boolean

Deletes the character before the cursor.

Returns:

  • (Boolean) —

    true if a character was deleted



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# File 'lib/tui/input_buffer.rb', line 71

def backspace
  return false if @cursor_pos == 0

  @text = "#{@text[0...@cursor_pos - 1]}#{@text[@cursor_pos..]}"
  @cursor_pos -= 1
  true
end

#clamp_cursor ⇒ void

This method returns an undefined value.

Ensures cursor stays within valid bounds after external state changes.



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# File 'lib/tui/input_buffer.rb', line 46

def clamp_cursor
  @cursor_pos = @cursor_pos.clamp(0, @text.length)
end

#clear ⇒ void

This method returns an undefined value.

Resets the buffer to empty state.



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# File 'lib/tui/input_buffer.rb', line 21

def clear
  @text = ""
  @cursor_pos = 0
end

#consume ⇒ String

Returns stripped text and clears the buffer for message submission.

Returns:

  • (String) —

    the trimmed input text



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# File 'lib/tui/input_buffer.rb', line 28

def consume
  content = @text.strip
  clear
  content
end

#cursor_location ⇒ Array(Integer, Integer)

Returns [line_index, column] for current cursor position.

Returns:

  • (Array(Integer, Integer)) —
    line_index, column

    for current cursor position



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# File 'lib/tui/input_buffer.rb', line 157

def cursor_location
  return [0, 0] if @text.empty?

  lines = @text.split("\n", -1)
  pos = 0
  lines.each_with_index do |line, index|
    len = line.length
    return [index, @cursor_pos - pos] if @cursor_pos <= pos + len
    pos += len + 1
  end
  [lines.length - 1, lines.last.length]
end

#delete ⇒ Boolean

Deletes the character at the cursor (forward delete).

Returns:

  • (Boolean) —

    true if a character was deleted



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# File 'lib/tui/input_buffer.rb', line 81

def delete
  return false if @cursor_pos >= @text.length

  @text = "#{@text[0...@cursor_pos]}#{@text[@cursor_pos + 1..]}"
  true
end

#full? ⇒ Boolean

Returns whether the buffer has reached MAX_LENGTH.

Returns:

  • (Boolean) —

    whether the buffer has reached MAX_LENGTH



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# File 'lib/tui/input_buffer.rb', line 40

def full?
  @text.length >= MAX_LENGTH
end

#insert(char) ⇒ Boolean

Returns true if inserted, false if result would exceed MAX_LENGTH.

Parameters:

  • char (String) —

    character(s) to insert at cursor

Returns:

  • (Boolean) —

    true if inserted, false if result would exceed MAX_LENGTH



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# File 'lib/tui/input_buffer.rb', line 52

def insert(char)
  return false if @text.length + char.length > MAX_LENGTH

  @text = "#{@text[0...@cursor_pos]}#{char}#{@text[@cursor_pos..]}"
  @cursor_pos += char.length
  true
end

#line_start_positions ⇒ Array<Integer>

Maps each physical line to its starting offset within the text buffer. Position after each newline marks the start of the next line.

Returns:

  • (Array<Integer>) —

    start position of each physical line



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# File 'lib/tui/input_buffer.rb', line 173

def line_start_positions
  positions = [0]
  @text.each_char.with_index do |char, offset|
    positions << (offset + 1) if char == "\n"
  end
  positions
end

#move_down ⇒ Boolean

Moves cursor down one physical line, preserving column position. Clamps column to the target line’s length when the next line is shorter.

Returns:

  • (Boolean) —

    true if cursor moved



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# File 'lib/tui/input_buffer.rb', line 145

def move_down
  lines = @text.split("\n", -1)
  line_idx, col = cursor_location
  return false if line_idx >= lines.length - 1

  next_idx = line_idx + 1
  target_col = [col, lines[next_idx].length].min
  @cursor_pos = line_start_positions[next_idx] + target_col
  true
end

#move_end ⇒ Boolean

Moves cursor to the end of the current physical line.

Returns:

  • (Boolean) —

    true if cursor moved



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# File 'lib/tui/input_buffer.rb', line 119

def move_end
  newline_pos = @text.index("\n", @cursor_pos)
  target = newline_pos || @text.length
  return false if @cursor_pos == target

  @cursor_pos = target
  true
end

#move_home ⇒ Boolean

Moves cursor to the start of the current physical line.

Returns:

  • (Boolean) —

    true if cursor moved



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# File 'lib/tui/input_buffer.rb', line 106

def move_home
  return false if @cursor_pos == 0

  last_newline = @text.rindex("\n", @cursor_pos - 1)
  target = last_newline ? last_newline + 1 : 0
  return false if @cursor_pos == target

  @cursor_pos = target
  true
end

#move_left ⇒ Boolean

Returns true if cursor moved.

Returns:

  • (Boolean) —

    true if cursor moved



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# File 'lib/tui/input_buffer.rb', line 89

def move_left
  return false if @cursor_pos == 0

  @cursor_pos -= 1
  true
end

#move_right ⇒ Boolean

Returns true if cursor moved.

Returns:

  • (Boolean) —

    true if cursor moved



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# File 'lib/tui/input_buffer.rb', line 97

def move_right
  return false if @cursor_pos >= @text.length

  @cursor_pos += 1
  true
end

#move_up ⇒ Boolean

Moves cursor up one physical line, preserving column position. Clamps column to the target line’s length when the previous line is shorter.

Returns:

  • (Boolean) —

    true if cursor moved



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# File 'lib/tui/input_buffer.rb', line 131

def move_up
  line_idx, col = cursor_location
  return false if line_idx == 0

  lines = @text.split("\n", -1)
  prev_idx = line_idx - 1
  target_col = [col, lines[prev_idx].length].min
  @cursor_pos = line_start_positions[prev_idx] + target_col
  true
end

#multiline? ⇒ Boolean

Returns whether the buffer contains any newline characters.

Returns:

  • (Boolean) —

    whether the buffer contains any newline characters



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# File 'lib/tui/input_buffer.rb', line 35

def multiline?
  @text.include?("\n")
end

#newline ⇒ Boolean

Returns true if a newline was inserted.

Returns:

  • (Boolean) —

    true if a newline was inserted



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# File 'lib/tui/input_buffer.rb', line 61

def newline
  return false if full?

  @text = "#{@text[0...@cursor_pos]}\n#{@text[@cursor_pos..]}"
  @cursor_pos += 1
  true
end