class GekanatorQuestionsController < ApplicationController
  def index
    return head :not_found unless current_user&.admin?

    questions =
        GekanatorQuestion
        .accepted
        .includes(:gekanator_question_examples)
        .order(priority_weight: :desc, id: :asc)

    render json: {
      questions: questions.map { |question| question_json(question) }
    }
  end

  private

  def question_json question
    condition = condition_json(question.condition).deep_symbolize_keys
    json = {
      id: question_id_for(question, condition),
      text: question_text_for(question, condition),
      kind: question.kind,
      condition: condition,
      source: question.source,
      priority_weight: question.priority_weight
    }
    if question.kind == 'post_similarity'
      json[:example_answers] = example_answers_json(question)
    end
    json
  end

  def question_id_for question, condition
    case condition[:type]
    when 'tag'
      "tag:#{ condition[:key] }"
    when 'source'
      "source:#{ condition[:host] }"
    when 'original-year'
      "original-year:#{ condition[:year] }"
    when 'original-month'
      "original-month:#{ condition[:month] }"
    when 'original-month-day'
      "original-month-day:#{ condition[:monthDay] || condition[:month_day] }"
    when 'title-length-at-least'
      "title:length-at-least:#{ condition[:length] }"
    when 'title-length-greater-than'
      "title:length-at-least:#{ condition[:length].to_i + 1 }"
    when 'title-has-ascii'
      'title:ascii'
    when 'post-similarity'
      "post-similarity:#{ question.id }"
    else
      "catalog:#{ question.id }"
    end
  end

  def condition_json condition
    json = condition.deep_dup.as_json

    if json['type'] == 'original-month-day' && json['monthDay'].blank?
      json['monthDay'] = json.delete('month_day')
    end

    if json['type'] == 'title-length-greater-than'
      json['type'] = 'title-length-at-least'
      json['length'] = json['length'].to_i + 1
    end

    json
  end

  def question_text_for question, condition
    return question.text unless question.kind == 'title'

    case condition[:type]
    when 'title-length-at-least'
      "タイトルは #{ condition[:length] } 文字以上?"
    else
      question.text
    end
  end

  def example_answers_json question
    question
        .gekanator_question_examples
        .group_by(&:post_id)
        .transform_values { |examples| aggregate_answer(examples) }
  end

  def aggregate_answer examples
    examples
        .group_by(&:answer)
        .map { |answer, grouped| [answer, grouped.sum(&:weight), grouped.max_by(&:updated_at)&.updated_at] }
        .sort_by { |(_answer, weight, updated_at)| [-weight, -(updated_at&.to_f || 0)] }
        .first
        &.first
  end
end