Selects the appropriate input handler based on the active backend mode.

This module bridges the gap between backend selection and input handling, providing a way to choose the correct input handler for the current terminal mode.

The runtime calls select/1 after it has selected a backend. select/0 is a standalone convenience that calls Backend.Selector.select/0; on a capable system that call may activate OTP's Raw shell, so do not use it as a read-only query. Use TermUI.Runtime.backend_mode/0 to query published local runtime context.

Relationship with Backend.Selector

The TermUI.Backend.Selector determines which terminal backend to use (Raw or TTY). This module, TermUI.Input.Selector, then selects the corresponding input handler:

Usage

There are two ways to select an input handler:

Explicit Selection

When you know which mode you want, use select/1:

# Get the Raw input handler
handler = TermUI.Input.Selector.select(:raw)
# => TermUI.Input.Raw

# Get the TTY input handler
handler = TermUI.Input.Selector.select(:tty)
# => TermUI.Input.TTY

Auto-Detection

When you want to match the current backend, use select/0:

# Automatically select based on current backend
handler = TermUI.Input.Selector.select()
# => TermUI.Input.Raw or TermUI.Input.TTY

State-Based Selection

For runtime code that already has a Backend.State struct, you can extract the mode and pass it directly:

backend_state = %TermUI.Backend.State{backend_mode: :tty, ...}
handler = TermUI.Input.Selector.select(backend_state.backend_mode)

Input Handler Contract

Both TermUI.Input.Raw and TermUI.Input.TTY implement the TermUI.Input behaviour, providing a consistent interface:

• new/0 - Create initial handler state
• poll/2 - Poll for input with timeout
• mode/1 - Return the handler's mode (:raw or :tty)

Example Integration

# Typical usage in runtime initialization
case TermUI.Backend.Selector.select() do
  {:raw, backend_state} ->
    input_handler = TermUI.Input.Selector.select(:raw)
    input_state = input_handler.new()
    # ...

  {:tty, capabilities} ->
    input_handler = TermUI.Input.Selector.select(:tty)
    input_state = input_handler.new()
    # ...
end

Note on LineReader

TermUI.Input.LineReader is not included in the selector. LineReader is a specialized module for line-based input (used by TextInput.Line) and does not implement the TermUI.Input behaviour. Use LineReader directly when you need line-based input with shell editing.