#!/usr/bin/ruby
SERIES_DIR = "lists"
APP_NAME = "The Ultimate Star Trek Slash Pairing Generator"
SHOW_ADS = true

SERIES = [ ["TOS", "Star Trek: The Original Series"],
  ["TNG", "Star Trek: The Next Generation"],
  ["DS9", "Star Trek: Deep Space Nine"],
  ["VOY", "Star Trek: Voyager"],
  ["ENT", "Star Trek: Enterprise"]]
any = SERIES.collect { |x| x[0] }.join("|")
SERIES.insert(0, [any, "every Star Trek series"])

class WeightedList < Hash
  def choose
    sum = inject(0) do |sum, item_and_weight| 
      sum += item_and_weight[1] 
    end
    target = rand(sum)
    each do |item, weight|
      return item if target <= weight
      target -= weight
    end
    return nil
  end
end

require 'cgi'
class SlashCGI

  @@max_commands = 5
  @@max_nsome_per_command = 3

  #Build weighted list of story lengths
  @@story_lengths = WeightedList.new
  @@story_lengths["story"] = 5
  ["short story", "epic", "short-short"].each do |i|
    @@story_lengths[i] = 3
  end
  (2..14).each { |i| @@story_lengths["#{i}-part serial"] = 1 }

  #Build non-weighted list of story types.
  @@story_types = ["the romantic entanglements %s", 
    "the torrid love affair %s", "the Platonic friendship %s",
    "the kinky depravity of", "the star-crossed love %s", 
    "the angst-filled soul-searching of", "the innermost secrets of", 
    "the playful bickering %s", "the unresolved sexual tension %s", 
    "the shocking perversions of", "the troubled relationship %s",
    "the forbidden love %s"]

  #List of genders.
  @@genders = [["A", "(any gender)"], ["M", "male"], 
    ["F", "female"], ["N", "ungendered/other"] ]

  #List of character tiers
  @@tiers = [["0", "primary"], 
    ["1", "primary or secondary"],
    ["2", "primary, secondary, or tertiary"]]

  def initialize
    @cgi = CGI.new("html4")
    valid = true
    begin
      commands = gather
    rescue UnsatisfiableException
      valid = false
      commands = []
    end
    @cgi.out do
      @cgi.html do
        @cgi.head do @cgi.title { APP_NAME } end +
        @cgi.body do
          a = do_ads
          a << @cgi.h1 { APP_NAME }
          unless commands.empty?            
            begin
              a << make_choices(commands)
              a << @cgi.p { "Care to try again?" }
            rescue UnsatisfiableException
              a << "Sorry, I couldn't find a set of characters that matched your query. Try expanding your search to include more character types or more genders; or ask for fewer people."
            end
          end
          a << @cgi.hr            
          a << form(commands)
          a << @cgi.hr
          a << @cgi.p { @cgi.small { %{<i>Star Trek</i> and related names are trademarks of Paramount Pictures, and are used under "fair use" guidelines. #{APP_NAME} is not affiliated with or sponsored by the <A href="http://www.memoryalpha.org/">Memory Alpha</a> wiki or Paramount Pictures. Hoo, boy, is it not affiliated with or sponsored by Paramount Pictures. } } }
          a
        end
      end
    end
  end

  # Plaster ads on every flat surface.
  def do_ads
    return SHOW_ADS ? "" : ""
  end

  # Gather commands from CGI input
  def gather
    commands = []
    0.upto(@@max_commands) do |i|
      number = @cgi["#{i}-number"].to_i
      gender = @cgi["#{i}-gender"]
      series = @cgi["#{i}-series"].split("|")
      tier = @cgi["#{i}-tier"]
      # error checking: max number, bad series/gender/tier 
      raise UnsatisfiableException if number > @@max_nsome_per_command
      raise UnsatisfiableException if series.detect { |x| !SERIES.detect { |y| y[0] == x }}
      if !series.empty? and number != "" and gender != "" and  tier != ""
        commands << [series, number, gender, tier.to_i] if number > 0
      end
    end	
    return commands
  end

  def make_choices(commands)
    first = true
    choices = choose(commands)
    story_type = @@story_types[rand(@@story_types.size)]
    total = 0
    # between or among?
    choices.each do |series, people|
      total += people.length
      break if total > 2
    end
    if total > 2
      commas = true
      story_type = story_type % "between" if story_type.index("%s")
    else        
      commas = false
      story_type = story_type % "among" if story_type.index("%s")
    end
    a = @cgi.a({"href"=>"./"}) { APP_NAME } + " has spoken!</p> <p>The Internet eagerly awaits your #{@@story_lengths.choose} about "
    if total == 1
      choices.each do |series, people|
        a << series.link(*people[0])
      end
      a << "."
    else
      a << story_type << " "
      choices.each_with_index do |sp, i|
        series, people = sp
        people.each_with_index do |p, j|
          last = (i == choices.size-1) && (j == people.size-1)
          if first
            first = false
          else
            a << "and " if last
          end
          a << series.link(*p) << (last ? "." : (commas ? ", " : " "))
        end
      end
    end
    return a
  end
  
  def form(commands)
    return @cgi.form("get", "slash.cgi") do
      possible_nsomes = (0..@@max_nsome_per_command).collect { |x| x.to_s }
      o = " Pair "
      @@max_commands.times do |i|
        tiers = @@tiers.dup
        if commands.size > i
          series_ids, number, gender, tier = commands[i]
          selected_series = series_ids.join('|')
          series = SERIES.inject([]) do |build, series|
            if series[0] == selected_series
              build << (series.dup << true)
            else
              build << series
            end
          end

          nsomes = possible_nsomes.dup
          nsomes[number] = [nsomes[number], true]

          genders = @@genders.inject([]) do |build, g|
            if g[0] == gender
              build << (g.dup << true)
            else
              build << g
            end
          end
          
          tiers[tier] = (tiers[tier].dup << true)
        else
          series = SERIES
          tiers[1] = (@@tiers[1].dup << true)
          genders = @@genders
          nsomes = possible_nsomes
          # By default, only the first pairing argument is actually set.
          if i==0
            nsomes = possible_nsomes.dup
            nsomes[2] = [nsomes[2], true]
          end
        end
#        puts "Series #{series.inspect}"
#        puts "nsomes #{nsomes.inspect}"
#        puts "genders #{genders.inspect}"
#        puts "tiers #{tiers.inspect}"
        o << ((i == 0) ? "" : @cgi.br + "and ") +
          @cgi.popup_menu("#{i}-number", *nsomes) +
          " of the " + @cgi.popup_menu("#{i}-gender", *genders) + 
          @cgi.popup_menu("#{i}-tier", *tiers) +
          " characters from " + @cgi.popup_menu("#{i}-series", *series)	
      end    
      o + @cgi.br + @cgi.submit("/")
    end
  end
  
  def choose(selections, series_dir=SERIES_DIR)
    @series = {}
    choices_by_series = {}
    selections.each do |series_names, number, gender, bottom_tier|
      tiers = nil
      old_series = series = nil
      number.times do
        series_name = series_names[rand(series_names.size)-1]	
        if old_series != series_name and SERIES.detect { |x| x[0] == series_name }:
          @series[series_name] ||= Series.new(open(File.join(series_dir, 
                                                             series_name)))
          old_series = series_name
          series = @series[series_name]
          tiers = series.gather_tiers(gender, bottom_tier)
          else
        end

        tier = tiers.choose
        raise UnsatisfiableException unless tier
        choice = tier.choose!(choices_by_series, gender)
        (choices_by_series[series] ||= []) << choice
        tiers.delete(tier) unless tier.can_satisfy(gender)
      end
    end

    choices_by_series
  end  
end

class UnsatisfiableException  < Exception
end

class Tier
  attr_accessor :people, :people_by_gender, :totals_by_gender
  def initialize
    @people_by_gender = {}
  end
  
  def add(person, sexes)
    if sexes.respond_to? :each
      sexes.each do |s|
        p = [person[0] % Series.genders[s].downcase, person[1]]
        (@people_by_gender[s] ||= []) << p
        (@people_by_gender["A"] ||= []) << p
      end
    else
      (@people_by_gender[sexes] ||= []) << person
      (@people_by_gender["A"] ||= []) << person
    end
  end

  # Chooses a person of the given gender from this tier, and removes them
  # from the tier.
  def choose!(choices, gender)
    raise UnsatisfiableException unless can_satisfy(gender)
    people = @people_by_gender[gender]
    i = rand(people.size)
    choice = nil
    while !choice or choices.detect { |series| choices[series] and choices[series].detect { |x| x[0] == choice[0] } }
        choice = people.slice!(i)
    end
    return choice
  end

  def can_satisfy(gender)
    return @people_by_gender[gender] && !@people_by_gender[gender].empty?
  end
end

class Series
  def Series.genders
    @@genders
  end

  def wikify(person, page)
    page = person.gsub(" ", "_") unless page
    if page.strip.size > 0
      return @base_url % page
    else
      return nil
    end
  end

  def link(person, page)
    link = wikify(person, page)
    if link != @base_url
      person = %{<a href="#{link}">#{person}</a>}
    end
    return person
  end

  @@probabilities = [45, 33, 22]
  @@genders = { "M" => "Male", "F" => "Female", "N" => "Other" }
  def initialize(file)
    @base_url = file.readline.chomp

    @tiers = []
    working_gender = nil
    @tiers << (working_tier = Tier.new())
    file.each do |line|
      line = line.chomp
      if line.size == 0
        @tiers << (working_tier = Tier.new()) 
     else
        g = line[0].chr
        if line[1] == ?\s and (@@genders[g] || g == "E")
          working_gender = g == "E" ? ["M", "F"] : g
          line = line[2..line.size]
        end
        l = line.split("|")
        page = l.size > 1 ? l[1] : nil
        working_tier.add([l[0], page], working_gender)
      end
    end
  end

  def gather_tiers(must_have_gender, bottom)
    list = WeightedList.new
    found = 0
    0.upto([bottom,@tiers.size-1].min) do |i|
      tier = @tiers[i]
      if tier.can_satisfy(must_have_gender)
        list[tier] = @@probabilities[found] 
        found += 1
      end
    end
    return list
  end
end

SlashCGI.new