module GitTrend
  module Rendering
    def self.included(base)
      base.extend(self)
    end
    HEADER_COLUMNS = %w(no. name lang star description)
    DEFAULT_COLUMNS_SIZES = [3, 40, 10, 6, 20]

    def render(projects, enable_description = false)
      @enable_description = enable_description
      rule_columns_sizes(projects)
      render_header
      render_body(projects)
      render_footer
    end

    def render_languages(languages)
      puts languages
      puts
      puts "#{languages.size} languages"
      puts "you can get only selected language list with '-l' option."
      puts "if languages is unknown, you can specify 'unkown'."
      puts
    end

    private

    def rule_columns_sizes(projects)
      @columns_sizes = DEFAULT_COLUMNS_SIZES.dup
      rule_max_column_size(projects, :name)
      rule_max_column_size(projects, :lang)
      rule_max_description_size if @enable_description
      @columns_sizes.pop unless @enable_description
    end

    def rule_max_description_size
      terminal_width, _terminal_height = detect_terminal_size
      description_width = terminal_width - @columns_sizes[0..-2].inject(&:+) - (@columns_sizes.size - 1)
      if description_width >= DEFAULT_COLUMNS_SIZES.last
        @columns_sizes[-1] = description_width
      else
        @enable_description = false
      end
    end

    def rule_max_column_size(projects, attr)
      index = HEADER_COLUMNS.index(attr.to_s)
      max_size = max_size_of(projects, attr)
      @columns_sizes[index] = max_size if max_size > @columns_sizes[index]
    end

    def max_size_of(projects, attr)
      projects.max_by { |project| project.send(attr).size }.send(attr).size
    end

    def render_header
      header = HEADER_COLUMNS.map(&:capitalize)
      header.pop unless @enable_description
      f = @columns_sizes
      fmt = "%#{f[0]}s %-#{f[1]}s %-#{f[2]}s %#{f[3]}s"
      fmt << " %-#{f[4]}s" if @enable_description

      puts fmt % header
      puts fmt % @columns_sizes.map { |column| '-' * column }
    end

    def render_body(projects)
      f = @columns_sizes
      fmt = "%#{f[0]}s %-#{f[1]}s %-#{f[2]}s %#{f[3]}s"
      fmt << " %-#{f[4]}s" if @enable_description
      projects.each_with_index do |project, i|
        data = [i + 1, project.to_a].flatten
        data << project.description.mb_truncate(f.last) if @enable_description
        result = fmt % data
        puts result
      end
    end

    def render_footer
      puts
    end

    # https://github.com/cldwalker/hirb/blob/master/lib/hirb/util.rb#L61-71
    def detect_terminal_size
      if (ENV['COLUMNS'] =~ /^\d+$/) && (ENV['LINES'] =~ /^\d+$/)
        [ENV['COLUMNS'].to_i, ENV['LINES'].to_i]
      elsif (RUBY_PLATFORM =~ /java/ || (!STDIN.tty? && ENV['TERM'])) && command_exists?('tput')
        [`tput cols`.to_i, `tput lines`.to_i]
      elsif STDIN.tty? && command_exists?('stty')
        `stty size`.scan(/\d+/).map {  |s| s.to_i }.reverse
      else
        nil
      end
    rescue
      nil
    end

    def command_exists?(command)
      ENV['PATH'].split(File::PATH_SEPARATOR).any? { |d| File.exist? File.join(d, command) }
    end
  end
end