class Utils::Grepper

def discover_roots(roots)
  roots ||= []
  roots.inject([]) { |rs, r| rs.concat Dir[r] }
end

def initialize(opts = {})
  @args  = opts[:args] || {}
  @roots = discover_roots(opts[:roots])
  @config = opts[:config] || Utils::ConfigFile.new
  if n = @args.values_at(*%w[A B C]).compact.first
    if n.to_s =~ /\A\d+\Z/ and (n = n.to_i) >= 1
      @queue = Queue.new n
    else
      raise ArgumentError, "needs to be an integer number >= 1"
    end
  end
  @paths  = []
  pattern_opts = opts.subhash(:pattern) | {
    :cset  => @args[?a],
    :icase => @args[?i] != ?n,
  }
  @pattern = choose(@args[?p], pattern_opts, default: ?r)
  @name_pattern =
    if name_pattern = @args[?N]
      RegexpPattern.new(:pattern => name_pattern)
    elsif name_pattern = @args[?n]
      FuzzyPattern.new(:pattern => name_pattern)
    end
  @skip_pattern =
    if skip_pattern = @args[?S]
      RegexpPattern.new(:pattern => skip_pattern)
    elsif skip_pattern = @args[?s]
      FuzzyPattern.new(:pattern => skip_pattern)
    end
end

def match(filename)
  @filename = filename
  @output = []
  bn, s = File.basename(filename), File.stat(filename)
  if !s || s.directory? && @config.search.prune?(bn)
    @args[?v] and warn "Pruning #{filename.inspect}."
    prune
  end
  if s.file? && !@config.search.skip?(bn) &&
    (!@name_pattern || @name_pattern.match(bn))
  then
    File.open(filename, 'rb', encoding: Encoding::UTF_8) do |file|
      @args[?v] and warn "Matching #{filename.inspect}."
      if @args[?f]
        @output << filename
      else
        match_lines file
      end
    end
  else
    @args[?v] and warn "Skipping #{filename.inspect}."
  end
  unless @output.empty?
    case
    when @args[?g]
      @output.uniq!
      @output.each do |l|
        blamer = LineBlamer.for_line(l)
        if blame = blamer.perform
          author = nil
          blame.sub!(/^[0-9a-f^]+/) { Term::ANSIColor.yellow($&) }
          blame.sub!(/\(([^)]+)\)/) { author = $1; "(#{Term::ANSIColor.red($1)})" }
          if !@args[?G] || author&.downcase&.match?(@args[?G].downcase)
            puts "#{blame.chomp} #{Term::ANSIColor.blue(l)}"
          end
        end
      end
    when @args[?l], @args[?e], @args[?E], @args[?r]
      @output.uniq!
      @paths.concat @output
    else
      STDOUT.puts @output
    end
    @output.clear
  end
  self
end

def match_lines(file)
  for line in file
    if m = @pattern.match(line)
      @skip_pattern and @skip_pattern =~ line and next
      line[m.begin(0)...m.end(0)] = black on_white m[0]
      @queue and @queue << line
      case
      when @args[?l]
        @output << @filename
      when @args[?L], @args[?r], @args[?g]
        @output << "#{@filename}:#{file.lineno}"
      when @args[?e], @args[?E]
        @output << "#{@filename}:#{file.lineno}"
        break
      else
        @output << red("#{@filename}:#{file.lineno}")
        if @args[?B] or @args[?C]
          @output.concat @queue.data
        else
          @output << line
        end
        if @args[?A] or @args[?C]
          where = file.tell
          lineno = file.lineno
          @queue.max_size.times do
            file.eof? and break
            line = file.readline
            @queue << line
            @output << line
          end
          file.seek where
          file.lineno = lineno
        end
      end
    else
      @queue and @queue << line
    end
  end
end

def search
  suffixes = Array(@args[?I])
  visit = -> filename {
    s  = filename.lstat
    bn = filename.pathname.basename
    if !s ||
        s.directory? && @config.search.prune?(bn) ||
        (s.file? || s.symlink?) && @config.search.skip?(bn) ||
        @args[?F] && s.symlink?
    then
      @args[?v] and warn "Pruning #{filename.inspect}."
      prune
    elsif suffixes.empty?
      true
    else
      suffixes.include?(filename.suffix)
    end
  }
  find(*@roots, visit: visit) do |filename|
    match(filename)
  end
  @paths = @paths.sort_by(&:source_location)
  self
end