require 'capistrano/cli'
require 'progressbar'

module Flucti
  module CLI
    extend self
    
    def start
      adjust_environment
      reinterpret_help_option
      Flucti.boot
      
      cli = Capistrano::CLI.new(ARGV)
      cli.parse_options!
      cli.options[:verbose] = Capistrano::Logger::INFO
      cli.execute!
    end
    
    def tasks
      adjust_environment
      config = Capistrano::Configuration.new
      config.load File.dirname(__FILE__) + '/tasks.rb'
      return config
    end
    
  private
    
    def adjust_environment
      expose_constants
      fix_cap_recipe_loading
      fix_cap_tasks_brief_descriptions
      fix_cap_help_messages
      allow_for_lazy_env_var_naming
    end
    
    def expose_constants
      Object.class_eval do
        include Flucti
        include Flucti::Resources
        include Flucti::Utilities
      end
    end
    
    # Force Capistrano::CLI to load the needed recipe files, and only them.
    def fix_cap_recipe_loading
      override 'Capistrano::CLI::Execute#load_recipes' do
        def load_recipes(config)
          config.load(File.dirname(__FILE__) + '/tasks.rb')
        end
      end
    end
    
    # Fix brief description of tasks to allow the first sentence to be spanned
    # over multiple lines.
    def fix_cap_tasks_brief_descriptions
      override 'Capistrano::CLI::Help#output_columns' do
        def output_columns
          Flucti::Utilities::UserInterface.terminal_width - 3
        end
      end
      override 'Capistrano::TaskDefinition#brief_description' do
        def brief_description(max_length=nil)
          brief = (description[/\A.*?\.(?=\s|$)/m] || description).gsub(/\n+/, ' ')
          if max_length && brief.length > max_length
            brief = brief[0,max_length-3] + "..."
          end
          brief
        end
      end
    end
    
    # Make help messages refer to the current command instead of the hard-coded
    # `cap' one.
    def fix_cap_help_messages
      override 'Capistrano::CLI::Help#puts' do
        def puts(*lines)
          super(*lines.map { |line| line.to_s.gsub(/\bcap\b/, Flucti::Utilities::Miscellaneous.command) })
        end
      end
    end
    
    # Fix letter-casing for environment variable assignments.
    def allow_for_lazy_env_var_naming
      ARGV.each_with_index { |arg, pos| ARGV[pos] = arg.sub(/^(\w+)(=)/) { $1.upcase + $2 } }
      ENV.each { |key, value| ENV[key.upcase] ||= value }
    end
    
    # Replace the default help message with a list of tasks.
    def reinterpret_help_option
      if ARGV.empty? || %w(-h --help).map { |opt| ARGV.delete(opt) }.any?
        ARGV.unshift '-vT'
      end
    end
    
  private
  
    def override(fqn, &block)
      name, method = fqn.to_s.split('#', 2)
      if mod = Object.class_eval("#{name} if defined? #{name}") and (Kernel.respond_to?(method) || [:public, :protected, :private].any? { |v| mod.send("#{v}_method_defined?", method) })
        mod.module_eval(&block)
      else
        require 'capistrano/version'
        raise "This library is incompatible with the current version of Capistrano (#{Capistrano::Version::STRING}). Failed to override `#{fqn}'."
      end
    end
  end
end