class User < Struct.new(:nickname)
end

class Question < Struct.new(:asker_id, :title, :body)
end

class Answer < Struct.new(:question_id, :responder_id, :body)
end

class QuestionVote < Struct.new(:user_id, :question_id, :vote)
end

class AnswerVote < Struct.new(:user_id, :answer_id, :vote)
end

@users = { 1 => User.new("Warrior"),
           2 => User.new("EtherealCereal"),
           3 => User.new("AgentSmith"),
           4 => User.new("WeaponX"),
           5 => User.new("ManOnTheRun"),
           6 => User.new("ButtersFromSouthPark"),
           7 => User.new("Avenger") }

@questions = { 1 => Question.new(4, "Iterating Over an Array in Ruby", "How to do it?"),
               2 => Question.new(7, "Substituting Variables Into Strings in Ruby", "How to do it?"),
               3 => Question.new(1, "Generating Random Numbers in Ruby", "How to do it?"),
               4 => Question.new(2, "Validating an Email Address in Ruby", "How to do it?"),
               5 => Question.new(4, "Generating Prime Numbers in Ruby", "How to do it?"),
               6 => Question.new(5, "Performing Date Arithmetic in Ruby", "How to do it?"),
               7 => Question.new(1, "Removing Duplicate Elements from an Array in Ruby", "How to do it?"),
               8 => Question.new(6, "Using Symbols as Hash Keys in Ruby", "How to do it?"),
               9 => Question.new(4, "Writing an Infinite Loop in Ruby", "How to do it?") }

@answers = { 10 => Answer.new(1, 5, "Try this: your_array.each { |x| ... }"),
             11 => Answer.new(2, 3, "Try this: \#{variable_to_interpolate}"),
             12 => Answer.new(5, 1, "You need the mathn gem."),
             14 => Answer.new(9, 7, "Try this: loop do ... end") }

@q_votes = [ QuestionVote.new(1, 1,  1),
             QuestionVote.new(2, 1,  1),
             QuestionVote.new(3, 1,  1),
             QuestionVote.new(5, 1,  1),
             QuestionVote.new(7, 1,  1),
             QuestionVote.new(1, 2,  1),
             QuestionVote.new(2, 2,  1),
             QuestionVote.new(3, 2,  1),
             QuestionVote.new(4, 2,  1),
             QuestionVote.new(2, 3,  1),
             QuestionVote.new(3, 3,  1),
             QuestionVote.new(4, 3,  1),
             QuestionVote.new(5, 3,  1),
             QuestionVote.new(6, 3,  1),
             QuestionVote.new(7, 3,  1),
             QuestionVote.new(1, 9, -1),
             QuestionVote.new(2, 9, -1),
             QuestionVote.new(3, 9, -1),
             QuestionVote.new(5, 9, -1),
             QuestionVote.new(6, 9, -1),
             QuestionVote.new(7, 9, -1) ]

@a_votes = [ AnswerVote.new(1, 10,  1),
             AnswerVote.new(2, 10,  1),
             AnswerVote.new(3, 10,  1),
             AnswerVote.new(1, 11,  1),
             AnswerVote.new(4, 11,  1),
             AnswerVote.new(5, 11,  1),
             AnswerVote.new(7, 11,  1),
             AnswerVote.new(2, 12,  1),
             AnswerVote.new(3, 12,  1),
             AnswerVote.new(4, 12,  1),
             AnswerVote.new(5, 12,  1),
             AnswerVote.new(6, 12,  1),
             AnswerVote.new(4, 14, -1),
             AnswerVote.new(5, 14, -1) ]

def vote_question(uid,qid,which_way)
  return if @questions[qid].asker_id == uid
  ok_to_append_vote = true
  @q_votes.each_with_index do |qv,i|
    if qv.user_id == uid and qv.question_id == qid
      @q_votes[i].vote = which_way
      ok_to_append_vote = false
    end
  end
  if ok_to_append_vote
    @q_votes << QuestionVote.new(uid,qid,which_way)
  end
end

def vote_answer(uid,aid,which_way)
  return if @answers[aid].responder_id == uid
  ok_to_append_vote = true
  @a_votes.each_with_index do |av,i|
    if av.user_id == uid and av.answer_id == aid
      @a_votes[i].vote = which_way
      ok_to_append_vote = false
    end
  end
  if ok_to_append_vote
    @a_votes << AnswerVote.new(uid,aid,which_way)
  end
end

def content(navst)
  c = []
  if navst == :single_question
    c = []
    c << "Title:    #{@questions[@selected_qid].title}"
    c << "Body:     #{@questions[@selected_qid].body}"
    q_votes = @q_votes.select do |qvote|
                         qvote.question_id == @selected_qid
                       end.reduce(0) do |sum,qvote|
                             sum + qvote.vote
                           end
    c << "Votes:    #{q_votes}"
    q_author = @users[@questions[@selected_qid].asker_id].nickname
    c << "Asked by: #{q_author}"
    @answers.select { |k,v| v.question_id == @selected_qid }.each do |k,v|
      c << ""
      c << "#{k}) Answer:"
      c << "#{v.body}"
      a_author = @users[@answers[k].responder_id].nickname
      a_votes = @a_votes.select do |avote|
                           avote.answer_id == k
                         end.reduce(0) do |sum,avote|
                               sum + avote.vote
                             end
      c << "Votes: #{a_votes} (answer provided by #{a_author})"
    end
  end
  c
end

# questions.select { |k,v| v.title.include?("aria") }

@menu_options = { :main_menu       => ["1) Show all questions",
                                       "2) Ask a question"],
                  :single_question => ["1) Upvote the question   (not possible if you authored it)",
                                       "2) Downvote the question (not possible if you authored it)",
                                       "3) Provide an answer",
                                       "4) Select an answer to upvote/downvote"] }

system("clear")
@prompt_with = "Hello there! Choose a nickname:"
puts @prompt_with
@my_nickname = gets.chomp
@my_user_id = @users.count + 1
@users[@my_user_id] = User.new(@my_nickname)
@banner_text = "Main menu"
@navigation_state = :main_menu
@selected_qid = 0
@selected_aid = 0
loop do
  system("clear")
  puts "Logged in as: #{@my_nickname}"
  puts
  puts @banner_text
  puts
  content(@navigation_state).each { |line| puts line }
  puts
  @menu_options[@navigation_state].each { |option| puts option }
  puts
  puts "m) Main menu" unless @navigation_state == :main_menu
  puts "q) Quit"
  puts
  @prompt_with = "Select an option:"
  puts @prompt_with
  @keyboard_input = gets.chomp
  if @navigation_state == :main_menu and @keyboard_input == "1"
    @banner_text = "Showing all questions"
    @navigation_state = :all_questions
    @menu_options[@navigation_state] = @questions.map { |k,v| "#{k}) #{v.title}" }
    next
  end
  if @navigation_state == :main_menu and @keyboard_input == "2"
    system("clear")
    @prompt_with = "Ask a question:"
    puts @prompt_with
    @keyboard_input = gets.chomp
    @questions[@questions.count + 1] = Question.new(@my_user_id, @keyboard_input, "Any ideas?")
    next
  end
  if @navigation_state == :all_questions
    aux_int = @keyboard_input.to_i
    if @questions.has_key?(aux_int)
      @selected_qid = aux_int
      @banner_text = "Showing single question (and its answers, if there are any)"
      @navigation_state = :single_question
      next
    end
  end
  if @navigation_state == :single_question and @keyboard_input == "1"
    vote_question(@my_user_id,@selected_qid,1)
  end
  if @navigation_state == :single_question and @keyboard_input == "2"
    vote_question(@my_user_id,@selected_qid,-1)
  end
  if @navigation_state == :single_question and @keyboard_input == "3"
    @prompt_with = "Provide an answer:"
    puts @prompt_with
    @keyboard_input = gets.chomp
    @answers[@answers.count + 11] = Answer.new(@selected_qid, @my_user_id, @keyboard_input)
    next
  end
  if @navigation_state == :single_question and @keyboard_input == "4"
    @prompt_with = "Select an answer:"
    puts @prompt_with
    @keyboard_input = gets.chomp
    aux_int = @keyboard_input.to_i
    if @answers.has_key?(aux_int)
      @selected_aid = aux_int
      puts "1) Upvote the selected answer   (not possible if you authored it)"
      puts "2) Downvote the selected answer (not possible if you authored it)"
      @keyboard_input = gets.chomp
      if @keyboard_input == "1"
        vote_answer(@my_user_id,@selected_aid,1)
      end
      if @keyboard_input == "2"
        vote_answer(@my_user_id,@selected_aid,-1)
      end
    end
  end
  if @keyboard_input == "m"
    @banner_text = "Main menu"
    @navigation_state = :main_menu
    @selected_qid = 0
    @selected_aid = 0
    next
  end
  if @keyboard_input == "q"
    exit
  end
end