class Pry
  # rubocop:disable Metrics/ClassLength
  class Slop
    require_relative 'slop/option'
    require_relative 'slop/commands'
    include Enumerable
    VERSION = '3.4.0'.freeze

    # The main Error class, all Exception classes inherit from this class.
    class Error < StandardError; end

    # Raised when an option argument is expected but none are given.
    class MissingArgumentError < Error; end

    # Raised when an option is expected/required but not present.
    class MissingOptionError < Error; end

    # Raised when an argument does not match its intended match constraint.
    class InvalidArgumentError < Error; end

    # Raised when an invalid option is found and the strict flag is enabled.
    class InvalidOptionError < Error; end

    # Raised when an invalid command is found and the strict flag is enabled.
    class InvalidCommandError < Error; end

    # Returns a default Hash of configuration options this Slop instance uses.
    DEFAULT_OPTIONS = {
      strict: false,
      help: false,
      banner: nil,
      ignore_case: false,
      autocreate: false,
      arguments: false,
      optional_arguments: false,
      multiple_switches: true,
      longest_flag: 0
    }.freeze

    class << self
      # items  - The Array of items to extract options from (default: ARGV).
      # config - The Hash of configuration options to send to Slop.new().
      # block  - An optional block used to add options.
      #
      # Examples:
      #
      #   Slop.parse(ARGV, :help => true) do
      #     on '-n', '--name', 'Your username', :argument => true
      #   end
      #
      # Returns a new instance of Slop.
      def parse(items = ARGV, config = {}, &block)
        parse! items.dup, config, &block
      end

      # items  - The Array of items to extract options from (default: ARGV).
      # config - The Hash of configuration options to send to Slop.new().
      # block  - An optional block used to add options.
      #
      # Returns a new instance of Slop.
      def parse!(items = ARGV, config = {}, &block)
        if items.is_a?(Hash) && config.empty?
          config = items
          items = ARGV
        end
        slop = Pry::Slop.new config, &block
        slop.parse! items
        slop
      end

      # Build a Slop object from a option specification.
      #
      # This allows you to design your options via a simple String rather
      # than programatically. Do note though that with this method, you're
      # unable to pass any advanced options to the on() method when creating
      # options.
      #
      # string - The optspec String
      # config - A Hash of configuration options to pass to Slop.new
      #
      # Examples:
      #
      #   opts = Slop.optspec(<<-SPEC)
      #   ruby foo.rb [options]
      #   ---
      #   n,name=     Your name
      #   a,age=      Your age
      #   A,auth      Sign in with auth
      #   p,passcode= Your secret pass code
      #   SPEC
      #
      #   opts.fetch_option(:name).description #=> "Your name"
      #
      # Returns a new instance of Slop.
      def optspec(string, config = {})
        config[:banner], optspec = string.split(/^--+$/, 2) if string[/^--+$/]
        lines = optspec.split("\n").reject(&:empty?)
        opts  = Slop.new(config)

        lines.each do |line|
          opt, description = line.split(' ', 2)
          short, long = opt.split(',').map { |s| s.sub(/\A--?/, '') }
          opt = opts.on(short, long, description)

          if long && long.end_with?('=')
            long.sub!(/\=$/, '')
            opt.config[:argument] = true
          end
        end

        opts
      end
    end

    # The Hash of configuration options for this Slop instance.
    attr_reader :config

    # The Array of Slop::Option objects tied to this Slop instance.
    attr_reader :options

    # Create a new instance of Slop and optionally build options via a block.
    #
    # config - A Hash of configuration options.
    # block  - An optional block used to specify options.
    def initialize(config = {}, &block)
      @config = DEFAULT_OPTIONS.merge(config)
      @options = []
      @commands = {}
      @trash = []
      @triggered_options = []
      @unknown_options = []
      @callbacks = {}
      @separators = {}
      @runner = nil

      if block_given?
        block.arity == 1 ? yield(self) : instance_eval(&block)
      end

      return unless config[:help]

      on('-h', '--help', 'Display this help message.', tail: true) do
        warn help
      end
    end

    # Is strict mode enabled?
    #
    # Returns true if strict mode is enabled, false otherwise.
    def strict?
      config[:strict]
    end

    # Set the banner.
    #
    # banner - The String to set the banner.
    def banner=(banner)
      config[:banner] = banner
    end

    # Get or set the banner.
    #
    # banner - The String to set the banner.
    #
    # Returns the banner String.
    def banner(banner = nil)
      config[:banner] = banner if banner
      config[:banner]
    end

    # Set the description (used for commands).
    #
    # desc - The String to set the description.
    def description=(desc)
      config[:description] = desc
    end

    # Get or set the description (used for commands).
    #
    # desc - The String to set the description.
    #
    # Returns the description String.
    def description(desc = nil)
      config[:description] = desc if desc
      config[:description]
    end

    # Add a new command.
    #
    # command - The Symbol or String used to identify this command.
    # options - A Hash of configuration options (see Slop::new)
    #
    # Returns a new instance of Slop mapped to this command.
    def command(command, options = {}, &block)
      @commands[command.to_s] = Pry::Slop.new(options, &block)
    end

    # Parse a list of items, executing and gathering options along the way.
    #
    # items - The Array of items to extract options from (default: ARGV).
    # block - An optional block which when used will yield non options.
    #
    # Returns an Array of original items.
    def parse(items = ARGV, &block)
      parse! items.dup, &block
      items
    end

    # Parse a list of items, executing and gathering options along the way.
    # unlike parse() this method will remove any options and option arguments
    # from the original Array.
    #
    # items - The Array of items to extract options from (default: ARGV).
    # block - An optional block which when used will yield non options.
    #
    # Returns an Array of original items with options removed.
    def parse!(items = ARGV, &block)
      if items.empty? && @callbacks[:empty]
        @callbacks[:empty].each { |cb| cb.call(self) }
        return items
      end

      if (cmd = @commands[items[0]])
        return cmd.parse! items[1..-1]
      end

      items.each_with_index do |item, index|
        @trash << index && break if item == '--'
        autocreate(items, index) if config[:autocreate]
        process_item(items, index, &block) unless @trash.include?(index)
      end
      items.reject!.with_index { |_item, index| @trash.include?(index) }

      missing_options = options.select { |opt| opt.required? && opt.count < 1 }
      if missing_options.any?
        raise MissingOptionError,
              "Missing required option(s): #{missing_options.map(&:key).join(', ')}"
      end

      if @unknown_options.any?
        raise InvalidOptionError, "Unknown options #{@unknown_options.join(', ')}"
      end

      if @triggered_options.empty? && @callbacks[:no_options]
        @callbacks[:no_options].each { |cb| cb.call(self) }
      end

      @runner.call(self, items) if @runner.respond_to?(:call)

      items
    end

    # Add an Option.
    #
    # objects - An Array with an optional Hash as the last element.
    #
    # Examples:
    #
    #   on '-u', '--username=', 'Your username'
    #   on :v, :verbose, 'Enable verbose mode'
    #
    # Returns the created instance of Slop::Option.
    def on(*objects, &block)
      option = build_option(objects, &block)
      options << option
      option
    end
    alias option on
    alias opt on

    # Fetch an options argument value.
    #
    # key - The Symbol or String option short or long flag.
    #
    # Returns the Object value for this option, or nil.
    def [](key)
      option = fetch_option(key)
      option.value if option
    end
    alias get []

    # Returns a new Hash with option flags as keys and option values as values.
    #
    # include_commands - If true, merge options from all sub-commands.
    def to_hash(include_commands = false)
      hash = Hash[options.map { |opt| [opt.key.to_sym, opt.value] }]
      if include_commands
        @commands.each { |cmd, opts| hash.merge!(cmd.to_sym => opts.to_hash) }
      end
      hash
    end
    alias to_h to_hash

    # Enumerable interface. Yields each Slop::Option.
    def each(&block)
      options.each(&block)
    end

    # Specify code to be executed when these options are parsed.
    #
    # callable - An object responding to a call method.
    #
    # yields - The instance of Slop parsing these options
    #          An Array of unparsed arguments
    #
    # Example:
    #
    #   Slop.parse do
    #     on :v, :verbose
    #
    #     run do |opts, args|
    #       puts "Arguments: #{args.inspect}" if opts.verbose?
    #     end
    #   end
    def run(callable = nil, &block)
      @runner = callable || block
      return if @runner.respond_to?(:call)

      raise ArgumentError, "You must specify a callable object or a block to #run"
    end

    # Check for an options presence.
    #
    # Examples:
    #
    #   opts.parse %w( --foo )
    #   opts.present?(:foo) #=> true
    #   opts.present?(:bar) #=> false
    #
    # Returns true if all of the keys are present in the parsed arguments.
    def present?(*keys)
      keys.all? { |key| (opt = fetch_option(key)) && opt.count > 0 }
    end

    # Override this method so we can check if an option? method exists.
    #
    # Returns true if this option key exists in our list of options.
    def respond_to_missing?(method_name, include_all = false)
      options.any? { |o| o.key == method_name.to_s.chop } || super
    end

    # Fetch a list of options which were missing from the parsed list.
    #
    # Examples:
    #
    #   opts = Slop.new do
    #     on :n, :name=
    #     on :p, :password=
    #   end
    #
    #   opts.parse %w[ --name Lee ]
    #   opts.missing #=> ['password']
    #
    # Returns an Array of Strings representing missing options.
    def missing
      (options - @triggered_options).map(&:key)
    end

    # Fetch a Slop::Option object.
    #
    # key - The Symbol or String option key.
    #
    # Examples:
    #
    #   opts.on(:foo, 'Something fooey', :argument => :optional)
    #   opt = opts.fetch_option(:foo)
    #   opt.class #=> Slop::Option
    #   opt.accepts_optional_argument? #=> true
    #
    # Returns an Option or nil if none were found.
    def fetch_option(key)
      options.find { |option| [option.long, option.short].include?(clean(key)) }
    end

    # Fetch a Slop object associated with this command.
    #
    # command - The String or Symbol name of the command.
    #
    # Examples:
    #
    #   opts.command :foo do
    #     on :v, :verbose, 'Enable verbose mode'
    #   end
    #
    #   # ruby run.rb foo -v
    #   opts.fetch_command(:foo).verbose? #=> true
    def fetch_command(command)
      @commands[command.to_s]
    end

    # Add a callback.
    #
    # label - The Symbol identifier to attach this callback.
    #
    # Returns nothing.
    def add_callback(label, &block)
      (@callbacks[label] ||= []) << block
    end

    # Add string separators between options.
    #
    # text - The String text to print.
    def separator(text)
      if @separators[options.size]
        @separators[options.size] << "\n#{text}"
      else
        @separators[options.size] = text
      end
    end

    # Print a handy Slop help string.
    #
    # Returns the banner followed by available option help strings.
    def to_s
      heads  = options.reject(&:tail?)
      tails  = (options - heads)
      opts = (heads + tails).select(&:help).map(&:to_s)
      optstr = opts.each_with_index.map do |o, i|
        (str = @separators[i + 1]) ? [o, str].join("\n") : o
      end.join("\n")

      if @commands.any?
        optstr << "\n" unless optstr.empty?
        optstr << "\nAvailable commands:\n\n"
        optstr << commands_to_help
        optstr << "\n\nSee `<command> --help` for more information on a specific command."
      end

      banner = config[:banner]
      banner ||= "Usage: #{File.basename($PROGRAM_NAME, '.*')}" \
                 "#{' [command]' if @commands.any?} [options]"
      if banner
        "#{banner}\n#{@separators[0] ? "#{@separators[0]}\n" : ''}#{optstr}"
      else
        optstr
      end
    end
    alias help to_s

    private

    # Convenience method for present?(:option).
    #
    # Examples:
    #
    #   opts.parse %( --verbose )
    #   opts.verbose? #=> true
    #   opts.other?   #=> false
    #
    # Returns true if this option is present. If this method does not end
    # with a ? character it will instead call super().
    def method_missing(method, *args, &block)
      meth = method.to_s
      if meth.end_with?('?')
        meth.chop!
        present?(meth) || present?(meth.tr('_', '-'))
      else
        super
      end
    end

    # Process a list item, figure out if it's an option, execute any
    # callbacks, assign any option arguments, and do some sanity checks.
    #
    # items - The Array of items to process.
    # index - The current Integer index of the item we want to process.
    # block - An optional block which when passed will yield non options.
    #
    # Returns nothing.
    def process_item(items, index, &block)
      return unless (item = items[index])

      option, argument = extract_option(item) if item.start_with?('-')

      if option
        option.count += 1 unless item.start_with?('--no-')
        option.count += 1 if option.key[0, 3] == "no-"
        @trash << index
        @triggered_options << option

        if option.expects_argument?
          argument ||= items.at(index + 1)

          if !argument || argument =~ /\A--?[a-zA-Z][a-zA-Z0-9_-]*\z/
            raise MissingArgumentError, "#{option.key} expects an argument"
          end

          execute_option(option, argument, index, item)
        elsif option.accepts_optional_argument?
          argument ||= items.at(index + 1)

          if argument && argument =~ /\A([^\-?]|-\d)+/
            execute_option(option, argument, index, item)
          else
            option.call(nil)
          end
        elsif config[:multiple_switches] && argument
          execute_multiple_switches(option, argument, index)
        else
          option.value = option.count > 0
          option.call(nil)
        end
      else
        @unknown_options << item if strict? && item =~ /\A--?/
        yield(item) if block && !@trash.include?(index)
      end
    end

    # Execute an option, firing off callbacks and assigning arguments.
    #
    # option   - The Slop::Option object found by #process_item.
    # argument - The argument Object to assign to this option.
    # index    - The current Integer index of the object we're processing.
    # item     - The optional String item we're processing.
    #
    # Returns nothing.
    def execute_option(option, argument, index, item = nil)
      unless option
        if config[:multiple_switches] && strict?
          raise InvalidOptionError, "Unknown option -#{item}"
        end

        return
      end

      if argument
        unless item && item.end_with?("=#{argument}")
          @trash << index + 1 unless option.argument_in_value
        end
        option.value = argument
      else
        option.value = option.count > 0
      end

      if option.match? && !argument.match(option.config[:match])
        raise InvalidArgumentError, "#{argument} is an invalid argument"
      end

      option.call(option.value)
    end

    # Execute a `-abc` type option where a, b and c are all options. This
    # method is only executed if the multiple_switches argument is true.
    #
    # option   - The first Option object.
    # argument - The argument to this option. (Split into multiple Options).
    # index    - The index of the current item being processed.
    #
    # Returns nothing.
    def execute_multiple_switches(option, argument, index)
      execute_option(option, nil, index)
      argument.split('').each do |key|
        next unless (opt = fetch_option(key))

        opt.count += 1
        execute_option(opt, nil, index, key)
      end
    end

    # Extract an option from a flag.
    #
    # flag - The flag key used to extract an option.
    #
    # Returns an Array of [option, argument].
    def extract_option(flag)
      option = fetch_option(flag)
      option ||= fetch_option(flag.downcase) if config[:ignore_case]
      option ||= fetch_option(flag.gsub(/([^-])-/, '\1_'))

      unless option
        case flag
        when /\A--?([^=]+)=(.+)\z/, /\A-([a-zA-Z])(.+)\z/, /\A--no-(.+)\z/
          option = fetch_option(Regexp.last_match(1))
          argument = Regexp.last_match(2) || false
          option.argument_in_value = true if option
        end
      end

      [option, argument]
    end

    # Autocreate an option on the fly. See the :autocreate Slop config option.
    #
    # items - The Array of items we're parsing.
    # index - The current Integer index for the item we're processing.
    #
    # Returns nothing.
    def autocreate(items, index)
      flag = items[index]
      return if fetch_option(flag) || @trash.include?(index)

      option = build_option(Array(flag))
      argument = items[index + 1]
      option.config[:argument] = (argument && argument !~ /\A--?/)
      option.config[:autocreated] = true
      options << option
    end

    # Build an option from a list of objects.
    #
    # objects - An Array of objects used to build this option.
    #
    # Returns a new instance of Slop::Option.
    def build_option(objects, &block)
      config = {}
      config[:argument] = true if @config[:arguments]
      config[:optional_argument] = true if @config[:optional_arguments]

      if objects.last.is_a?(Hash)
        config.merge!(objects.last)
        objects.pop
      end
      short = extract_short_flag(objects, config)
      long  = extract_long_flag(objects, config)
      desc  = objects[0].respond_to?(:to_str) ? objects.shift : nil

      Option.new(self, short, long, desc, config, &block)
    end

    # Extract the short flag from an item.
    #
    # objects - The Array of objects passed from #build_option.
    # config  - The Hash of configuration options built in #build_option.
    def extract_short_flag(objects, config)
      flag = clean(objects.first)

      if flag.size == 2 && flag.end_with?('=')
        config[:argument] ||= true
        flag.chop!
      end

      return unless flag.size == 1

      objects.shift
      flag
    end

    # Extract the long flag from an item.
    #
    # objects - The Array of objects passed from #build_option.
    # config  - The Hash of configuration options built in #build_option.
    def extract_long_flag(objects, config)
      flag = objects.first.to_s
      return unless flag =~ /\A(?:--?)?[a-zA-Z][a-zA-Z0-9_-]+\=?\??\z/

      config[:argument] ||= true if flag.end_with?('=')
      config[:optional_argument] = true if flag.end_with?('=?')
      objects.shift
      clean(flag).sub(/\=\??\z/, '')
    end

    # Remove any leading -- characters from a string.
    #
    # object - The Object we want to cast to a String and clean.
    #
    # Returns the newly cleaned String with leading -- characters removed.
    def clean(object)
      object.to_s.sub(/\A--?/, '')
    end

    def commands_to_help
      padding = 0
      @commands.each { |c, _| padding = c.size if c.size > padding }
      @commands.map do |cmd, opts|
        "  #{cmd}#{' ' * (padding - cmd.size)}   #{opts.description}"
      end.join("\n")
    end
  end
  # rubocop:enable Metrics/ClassLength
end