#!/usr/bin/env ruby
# -*- ruby -*-
#
# Reads an RSS feed from the given website, e.g.
#
#  % read digg
#  % read digg.com
#  % read http://digg.com
#  % read http://digg.com/rss/index.xml
#
# All the same...
#

require 'net/http'

# --------------------------------------------------
# Classes
# --------------------------------------------------

class Entry

  attr_reader :title, :url, :description

  def initialize(title,url,description)
    @title = title
    @url = url
    @description = description
  end
end

# --------------------------------------------------
# Functions
# --------------------------------------------------

def log(msg)
  STDERR.puts "*** " + msg if $verbose
end

def display(name,host,page)

  # EEEEK!!! This is the grossest, nastiest RSS parser ever 
  #          (just saying!)

  # if we start with http:// change the host and page
  if page.match /^http\:\/\//
    new_host = page.gsub /^http\:\/\//, ""
    new_page = new_host.gsub /^[^\/]+\//, "/"
    new_host = new_host.gsub /\/.*$/, ""
    host = new_host
    page = new_page
  end

  log host + ":" + page
  
  h = Net::HTTP.new host, 80
  resp, data = h.get page, nil
  if resp.message == "OK"
    data = data.gsub /\n/, ""
    lines = data.split /</
    entries = []
    title = nil
    url = nil
    description = nil

    # Find the entries
    lines.each do |x|
      x.scan /^title>(.*)/ do |res|
        title = res[0]
      end
      x.scan /^link>(.*)/ do |res|
        url = res[0]
      end
      x.scan /^description>(.*)/ do |res|
        description = res[0]
      end
      if title and url and description
        e = Entry.new title, url, description
        entries.push e
        title = nil
        url = nil
        description = nil
      end
    end

    # Display the results
    show_entries entries
  else
    puts "ERROR: #{resp}"
  end
end

def show_entries(entries)
  done = false
  while !done
    i = 1
    entries.each do |e|
      s = ""
      s += " " if i<10
      tab = "     "
      tab += " " if i<10
      puts "[" + i.to_s + "] " + e.title
      puts tab + "( " + e.url + " )"
      puts
      i += 1
    end
    entry = nil
    while true
      print "Please choose a number between 1 and " + (i-1).to_s + " or 'q' to quit> "
      STDOUT.flush
      num = STDIN.readline
      if num.match /^q/
        done = true
        break
      end
      begin
        n = num.to_i
        if n<1
          STDERR.puts "!!! " + n.to_s + " must be > 0"
        elsif n>i
          STDERR.puts "!!! " + n.to_s + " must be < " + i.to_s
        else
          entry = entries[n-1]
          break
        end
      rescue
      end
    end

    # open the URL
    "Openning " + entry.title + "..."
    exec "open", entry.url

  end
end

def process(s)

  host = s
  page = "/"

  # maybe remove http://
  host = host.gsub /^http\:\/\//, ""

  # maybe add an extension
  host += ".com" if !host.match /\.\w\w\w\/?$/ 

  # maybe add www
  host = "www." + host if !host.match /^www\./

  # try to find the RSS feed
  log host + ":" + page
  h = Net::HTTP.new host, 80
  resp, data = h.get page, nil
  if resp.message == "OK"
    lines = data.split /</
    lines.each do |x|
      if x.match /type="application\/rss\+xml"/
        x.scan /href=\"([^\"]+)\"/ do |res|
          display s, host, res[0]
        end
      end
    end
  else
    puts "ERROR: #{resp}"
  end

end

def main(args)

  # Parse the command line
  sites = []
  args.each do |arg|
    if arg == "-v" or arg == "-verbose"
      $verbose = true
    else
      sites.push arg
    end
  end

  # Now process all the sites
  sites.each do |site|
    process site
  end
end

# Options
$verbose = false

main ARGV