module Gnomika

# File lib/gnomikologikon/web_processing.rb, line 13
def self.fetch_category_info
  response = HTTParty.get('https://www.gnomikologikon.gr/categ.php', {
    headers: {"User-Agent" => "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36"},
  })

  doc = Nokogiri::HTML.parse(response.body)
  # Each "big" category is stored in a table with class "authrst"
  category_tables = doc.xpath("//table[@class='authrst']")

  categories = []

  category_tables.each do |table|
    # Get category name. Category names are stored in td elements with class "authrsh"
    category_name = table.xpath("tr/td[@class='authrsh']").text

    # Get the subcategories of each category
    subcategories = []
    # Subcategories of each category are a elements in a list
    subcategory_elements = table.xpath("tr//ul//li//a")
    subcategory_elements.each do |element|
      subcategory_name = element.content
      # Need to prefix category URLs with the website URL
      subcategory_url = "https://www.gnomikologikon.gr/#{element[:href]}"
      subcategories << Subcategory.new(subcategory_name,subcategory_url)
    end

    categories << Category.new(category_name,subcategories: subcategories)
  end
  categories
end

# File lib/gnomikologikon/web_processing.rb, line 49
def self.get_quotes_for_categories(subcategories)
  quotes = {}
  subcategories.each do |subcategory|
    response = HTTParty.get(subcategory.url, {
      headers: {"User-Agent" => "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36"},
    })
    quotes[subcategory] = get_quotes_from_html(response.body)
    yield if block_given?
    # Throttle the connection because processing is fast
    sleep 1
  end
  quotes
end

# File lib/gnomikologikon/web_processing.rb, line 67
def self.get_quotes_from_html(page_body)
  doc = Nokogiri::HTML.parse(page_body)
  quotes_tables = doc.xpath("//table[@class='quotes']//td[@class='quote']")
  quotes = []
  quotes_tables.each do |quote|
    # Get quote contents
    content = quote.at_xpath("./text()").text
    # Check if there is an explanation
    explanation = quote.xpath("./table[@class='expth']//td")
    unless explanation.empty?
      # If an explanation exists, there are two td elements
      # Remove pavla
      explanation = explanation.reject{|element| element["class"] == "pavla"}
      # Keep the explanation td element
      explanation = explanation[0]
      content << "\n(#{explanation.text})"
    end
    # Check if there is a comment
    comment = quote.xpath("./p[contains(@class, 'comnt')]")
    unless comment.nil?
      # Do not add comment if it does not contain text
      content << "\n#{comment.text}" unless comment.text.empty?
    end
    # HTML p elements with class auth0-auth4 contain quote author and additional information (e.g. book)
    # Get the text of all auth p elements and combine them in a string
    author = quote.xpath(".//p[contains(@class, 'auth')]")
    author = author.map{|el| el.text}.join(' ')
    quotes << Quote.new(content,author)
  end
  quotes
end

# File lib/gnomika.rb, line 12
def self.main
  # Parse command line arguments
  options = ArgParser.parse(ARGV)
  # Get available categories
  available_categories = Gnomika.fetch_category_info
  # Prompt user to select a category
  selected_category = select_category(available_categories)
  # Prompt user to select subcategories
  selected_subcategories = select_subcategories(selected_category)
  # Create a progress bar
  progressbar = ProgressBar.create(total: selected_subcategories.length, title: "Download Progress")
  # Get the quotes and display progress
  quotes =  Gnomika.get_quotes_for_categories(selected_subcategories){
    progressbar.increment
  }
  # Create quote files with the options given as parameters
  begin
    write_files(options, quotes)
  rescue StandardError => e
    STDERR.puts e.message
  end
end

# File lib/gnomikologikon/ui.rb, line 6
def self.select_category(categories)
  # Index starting from 1
  categories.each_with_index { |category, index| puts "#{index+1}. #{category.name}" }
  ok = false
  num = -1
  until ok
    print "Select a category: "
    STDOUT.flush
    input =  STDIN.gets
    begin
      # Remove 1 because display indexes starting from 1.
      num = Integer(input) - 1
      break unless num < 0 || num > categories.length-1
      # Input was number but out of bounds
      puts "Invalid selection!"
    rescue ArgumentError
      # Input could not be converted to integer
      puts "Invalid selection!"
    end
  end
  # Return Category object chosen by the user
  categories[num]
end

# File lib/gnomikologikon/ui.rb, line 35
def self.select_subcategories(category)
  subcategories = category.subcategories
  # Index starting from 1
  subcategories.each_with_index { |subcategory, index| puts "#{index+1}. #{subcategory.name}" }
  puts "You can select multiple categories separated by ',' or a range of categories with '-'."

  # Contains indexes of all subcategories specified by the user
  selected_indexes = []
  ok = false
  until ok
    print "Select subcategories: "
    # On each loop we assume input is ok until an error is encountered
    ok = true
    # Empty the indexes array, in case of leftovers from previous loop
    selected_indexes = []
    input = STDIN.gets
    # Split the input
    input = input.split(",")
    # Check each selection
    input.each do |selection|
      begin
        # We need to remove 1 from each because during selection category numbers started from 1
        selected_indexes += selection_to_array(selection, subcategories.length).map{|it| it - 1}
      rescue => error
        ok = false
        puts error.message
        break
      end
    end
  end
  # Remove any duplicate indexes
  selected_indexes.uniq!
  # Create an array with the corresponding Subcategory objects and return it
  selected_indexes.map { |index| subcategories[index]}
end

# File lib/gnomikologikon/file_writer.rb, line 7
def self.write_files(options, quotes)
  # If no custom directory is specified, use the current directory
  output_directory = Dir.pwd
  if options.custom_output_dir_set
    custom_dir = options.custom_output_dir_value
    begin
      unless Dir.exist? custom_dir
        Dir.mkdir custom_dir
      end
      output_directory = custom_dir
    rescue StandardError => e
      raise e
    end
  end
  file_writer = FileWriter.new(output_directory, options.single_file, single_file_name: options.single_file_name)
  quotes.each_pair do |subcategory,subcategory_quotes|
    file_writer.write_quotes(subcategory.name,subcategory_quotes)
  end
  # Must generate strfiles for fortune command to work
  file_writer.generate_strfiles
end

# File lib/gnomikologikon/ui.rb, line 80
def self.selection_to_array(selection, max_available_index)
  # Check if selection is a range
  if selection.include?("-")
    # Try to process it as a range
    range_start, range_end = selection.split("-")
    begin
      range_start = Integer(range_start)
      range_end = Integer(range_end)
      # Check if range is correct. Start must be smaller or equal than end and end must be smaller or equal
      # to max_available index
      if range_start > range_end || range_end > max_available_index || range_start < 1
        raise ArgumentError
      end
      return (range_start..range_end).to_a
    rescue ArgumentError
      raise ArgumentError.new "Invalid range! (#{selection.strip})"
    end
  else
    # Assume selection is an integer
    begin
      number = Integer(selection)
      # Check limits
      if number < 1 || number > max_available_index
        raise ArgumentError
      end
      return [number]
    rescue
      raise ArgumentError.new "Invalid selection! (#{selection.strip})"
    end
  end
end