module ChainGame

# File lib/chain_game.rb, line 42
def add_words(game:, user:, text:)
  return { error: "No active chain." } unless game && game["stage"] == "active"
  return { error: "Not your turn." } unless GameStore.same_nick?(user, game["turn"])

  words = count_words(text)
  return { error: "Add exactly #{WORDS_PER_TURN} words (got #{words.length})." } unless words.length == WORDS_PER_TURN

  game = game.dup
  line = words.join(" ")
  game["lines"] = Array(game["lines"]) + [line]
  game["round"] = game["round"].to_i + 1

  if game["round"] >= MAX_ROUNDS
    game["stage"] = "done"
    { game: game, message: format_story(game), done: true }
  else
    game["turn"] = AsyncDuel.opponent(game, user)
    { game: game, message: "Line #{game['round']} added. #{game['turn']}: your #{WORDS_PER_TURN} words." }
  end
end

# File lib/chain_game.rb, line 26
def count_words(text)
  text.to_s.strip.split(/\s+/).reject(&:empty?)
end

# File lib/chain_game.rb, line 72
def format_header(title)
  IrcFormat.report_header(tag: "CHAIN", title: title, style: STYLE_TITLE)
end

# File lib/chain_game.rb, line 76
def format_status(game)
  return format_header("No game") + "\nNo echo chain active." unless game

  lines = [format_header("#{game['challenger']} vs #{game['target']}")]
  lines << "Round #{game['round']}/#{MAX_ROUNDS} · turn: #{game['turn']}"
  Array(game["lines"]).each_with_index { |l, i| lines << "#{i + 1}. #{l}" }
  lines << IrcFormat.report_footer("echo chain")
  lines.join("\n")
end

# File lib/chain_game.rb, line 63
def format_story(game)
  story = Array(game["lines"]).join(" ")
  word_count = story.split.length
  lines = [format_header("Echo Chain complete")]
  lines << story
  lines << IrcFormat.report_footer("#{word_count} words", "#{game['round']} rounds")
  lines.join("\n")
end

# File lib/chain_game.rb, line 19
def parse_command(text)
  base = AsyncDuel.parse_base(text, usage: usage_message)
  return base unless base[:action] == :unknown

  { action: :add, text: base[:tail].join(" ") }
end

# File lib/chain_game.rb, line 30
def start_game(game, rand: ->(max) { Random.rand(0...max) })
  game = game.dup
  game["stage"] = "active"
  game["lines"] = []
  game["round"] = 0
  game["turn"] = game["challenger"]
  {
    game: game,
    message: "#{format_header('Echo Chain')}\n#{game['challenger']}: add exactly #{WORDS_PER_TURN} words with !chain <words>"
  }
end

# File lib/chain_game.rb, line 15
def usage_message
  "Usage: !chain challenge <nick> | accept | decline | <six words> | status"
end