require 'cli/ui'
require 'readline'
module CLI
module UI
module Prompt
autoload :InteractiveOptions, 'cli/ui/prompt/interactive_options'
autoload :OptionsHandler, 'cli/ui/prompt/options_handler'
private_constant :InteractiveOptions, :OptionsHandler
class << self
# Ask a user a question with either free form answer or a set of answers (multiple choice)
# Can use arrows, y/n, numbers (1/2), and vim bindings to control multiple choice selection
# Do not use this method for yes/no questions. Use +confirm+
#
# * Handles free form answers (options are nil)
# * Handles default answers for free form text
# * Handles file auto completion for file input
# * Handles interactively choosing answers using +InteractiveOptions+
#
# https://user-images.githubusercontent.com/3074765/33799822-47f23302-dd01-11e7-82f3-9072a5a5f611.png
#
# ==== Attributes
#
# * +question+ - (required) The question to ask the user
#
# ==== Options
#
# * +:options+ - Options that the user may select from. Will use +InteractiveOptions+ to do so.
# * +:default+ - The default answer to the question (e.g. they just press enter and don't input anything)
# * +:is_file+ - Tells the input to use file auto-completion (tab completion)
# * +:allow_empty+ - Allows the answer to be empty
#
# Note:
# * +:options+ or providing a +Block+ conflicts with +:default+ and +:is_file+, you cannot set options with either of these keywords
# * +:default+ conflicts with +:allow_empty:, you cannot set these together
# * +:options+ conflicts with providing a +Block+ , you may only set one
#
# ==== Block (optional)
#
# * A Proc that provides a +OptionsHandler+ and uses the public +:option+ method to add options and their
# respective handlers
#
# ==== Return Value
#
# * If a +Block+ was not provided, the selected option or response to the free form question will be returned
# * If a +Block+ was provided, the evaluted value of the +Block+ will be returned
#
# ==== Example Usage:
#
# Free form question
# CLI::UI::Prompt.ask('What color is the sky?')
#
# Free form question with a file answer
# CLI::UI::Prompt.ask('Where is your Gemfile located?', is_file: true)
#
# Free form question with a default answer
# CLI::UI::Prompt.ask('What color is the sky?', default: 'blue')
#
# Free form question when the answer can be empty
# CLI::UI::Prompt.ask('What is your opinion on this question?', allow_empty: true)
#
# Interactive (multiple choice) question
# CLI::UI::Prompt.ask('What kind of project is this?', options: %w(rails go ruby python))
#
# Interactive (multiple choice) question with defined handlers
# CLI::UI::Prompt.ask('What kind of project is this?') do |handler|
# handler.option('rails') { |selection| selection }
# handler.option('go') { |selection| selection }
# handler.option('ruby') { |selection| selection }
# handler.option('python') { |selection| selection }
# end
#
def ask(question, options: nil, default: nil, is_file: nil, allow_empty: true, &options_proc)
if ((options || block_given?) && (default || is_file))
raise(ArgumentError, 'conflicting arguments: options provided with default or is_file')
end
if options || block_given?
ask_interactive(question, options, &options_proc)
else
ask_free_form(question, default, is_file, allow_empty)
end
end
# Asks the user a yes/no question.
# Can use arrows, y/n, numbers (1/2), and vim bindings to control
#
# ==== Example Usage:
#
# Confirmation question
# CLI::UI::Prompt.confirm('Is the sky blue?')
#
def confirm(question)
ask_interactive(question, %w(yes no)) == 'yes'
end
private
def ask_free_form(question, default, is_file, allow_empty)
raise(ArgumentError, 'conflicting arguments: default enabled but allow_empty is false') if (default && !allow_empty)
if default
puts_question("#{question} (empty = #{default})")
else
puts_question(question)
end
# Ask a free form question
loop do
line = readline(is_file: is_file)
if line.empty? && default
write_default_over_empty_input(default)
return default
end
if !line.empty? || allow_empty
return line
end
end
end
def ask_interactive(question, options = nil)
raise(ArgumentError, 'conflicting arguments: options and block given') if options && block_given?
options ||= if block_given?
handler = OptionsHandler.new
yield handler
handler.options
end
raise(ArgumentError, 'insufficient options') if options.nil? || options.size < 2
puts_question("#{question} {{yellow:(choose with ↑ ↓ ⏎)}}")
resp = interactive_prompt(options)
# Clear the line, and reset the question to include the answer
print(ANSI.previous_line + ANSI.end_of_line + ' ')
print(ANSI.cursor_save)
print(' ' * CLI::UI::Terminal.width)
print(ANSI.cursor_restore)
puts_question("#{question} (You chose: {{italic:#{resp}}})")
return handler.call(resp) if block_given?
resp
end
# Useful for stubbing in tests
def interactive_prompt(options)
InteractiveOptions.call(options)
end
def write_default_over_empty_input(default)
CLI::UI.raw do
STDERR.puts(
CLI::UI::ANSI.cursor_up(1) +
"\r" +
CLI::UI::ANSI.cursor_forward(4) + # TODO: width
default +
CLI::UI::Color::RESET.code
)
end
end
def puts_question(str)
CLI::UI.with_frame_color(:blue) do
STDOUT.puts(CLI::UI.fmt('{{?}} ' + str))
end
end
def readline(is_file: false)
if is_file
Readline.completion_proc = Readline::FILENAME_COMPLETION_PROC
Readline.completion_append_character = ""
else
Readline.completion_proc = proc { |*| nil }
Readline.completion_append_character = " "
end
# because Readline is a C library, CLI::UI's hooks into $stdout don't
# work. We could work around this by having CLI::UI use a pipe and a
# thread to manage output, but the current strategy feels like a
# better tradeoff.
prefix = CLI::UI.with_frame_color(:blue) { CLI::UI::Frame.prefix }
prompt = prefix + CLI::UI.fmt('{{blue:> }}{{yellow:')
begin
line = Readline.readline(prompt, true)
line.to_s.chomp
rescue Interrupt
CLI::UI.raw { STDERR.puts('^C' + CLI::UI::Color::RESET.code) }
raise
end
end
end
end
end
end