class CustomWizard::Builder
  attr_accessor :wizard, :updater, :submissions

  def initialize(wizard_id, user = nil)
    template = CustomWizard::Template.find(wizard_id)
    return nil if template.blank?

    @wizard = CustomWizard::Wizard.new(template, user)
    @steps = template['steps'] || []
    @actions = template['actions'] || []
    @submissions = @wizard.submissions
  end

  def self.sorted_handlers
    @sorted_handlers ||= []
  end

  def self.step_handlers
    sorted_handlers.map { |h| { wizard_id: h[:wizard_id], block: h[:block] } }
  end

  def self.add_step_handler(priority = 0, wizard_id, &block)
    sorted_handlers << { priority: priority, wizard_id: wizard_id, block: block }
    @sorted_handlers.sort_by! { |h| -h[:priority] }
  end

  def mapper
    CustomWizard::Mapper.new(
      user: @wizard.user,
      data: @submissions.last
    )
  end

  def build(build_opts = {}, params = {})
    return nil if !SiteSetting.custom_wizard_enabled || !@wizard
    return @wizard if !@wizard.can_access?

    build_opts[:reset] = build_opts[:reset] || @wizard.restart_on_revisit

    @steps.each do |step_template|
      @wizard.append_step(step_template['id']) do |step|
        step.permitted = true

        if step_template['required_data']
          step = ensure_required_data(step, step_template)
        end

        if !step.permitted
          if step_template['required_data_message']
            step.permitted_message = step_template['required_data_message']
          end
          next
        end

        step.title = step_template['title'] if step_template['title']
        step.banner = step_template['banner'] if step_template['banner']
        step.key = step_template['key'] if step_template['key']

        if step_template['description']
          step.description = mapper.interpolate(
            step_template['description'],
            user: true,
            value: true
          )
        end

        if permitted_params = step_template['permitted_params']
          save_permitted_params(permitted_params, params)
        end

        if step_template['fields'] && step_template['fields'].length
          step_template['fields'].each_with_index do |field_template, index|
            append_field(step, step_template, field_template, build_opts, index)
          end
        end

        step.on_update do |updater|
          @updater = updater
          user = @wizard.user

          updater.validate

          next if updater.errors.any?

          CustomWizard::Builder.step_handlers.each do |handler|
            if handler[:wizard_id] == @wizard.id
              handler[:block].call(self)
            end
          end

          next if updater.errors.any?

          submission = updater.submission

          if current_submission = @wizard.current_submission
            submission = current_submission.merge(submission)
          end

          final_step = updater.step.next.nil?

          if @actions.present?
            @actions.each do |action|

              if (action['run_after'] === updater.step.id) ||
                 (final_step && (!action['run_after'] || (action['run_after'] === 'wizard_completion')))

                CustomWizard::Action.new(
                  wizard: @wizard,
                  action: action,
                  user: user,
                  data: submission
                ).perform
              end
            end
          end

          if updater.errors.empty?
            if route_to = submission['route_to']
              submission.delete('route_to')
            end

            if @wizard.save_submissions
              save_submissions(submission, final_step)
            end

            if final_step
              if @wizard.id == @wizard.user.custom_fields['redirect_to_wizard']
                @wizard.user.custom_fields.delete('redirect_to_wizard')
                @wizard.user.save_custom_fields(true)
              end

              redirect_url = route_to || submission['redirect_on_complete'] || submission["redirect_to"]
              updater.result[:redirect_on_complete] = redirect_url
            elsif route_to
              updater.result[:redirect_on_next] = route_to
            end

            true
          else
            false
          end
        end
      end
    end

    @wizard
  end

  def append_field(step, step_template, field_template, build_opts, index)
    params = {
      id: field_template['id'],
      type: field_template['type'],
      required: field_template['required'],
      number: index + 1
    }

    params[:label] = field_template['label'] if field_template['label']
    params[:description] = field_template['description'] if field_template['description']
    params[:image] = field_template['image'] if field_template['image']
    params[:key] = field_template['key'] if field_template['key']
    params[:validations] = field_template['validations'] if field_template['validations']
    params[:min_length] = field_template['min_length'] if field_template['min_length']
    params[:max_length] = field_template['max_length'] if field_template['max_length']
    params[:char_counter] = field_template['char_counter'] if field_template['char_counter']
    params[:value] = prefill_field(field_template, step_template)

    if !build_opts[:reset] && (submission = @wizard.current_submission)
      params[:value] = submission[field_template['id']] if submission[field_template['id']]
    end

    if field_template['type'] === 'group' && params[:value].present?
      params[:value] = params[:value].first
    end

    if field_template['type'] === 'checkbox'
      params[:value] = standardise_boolean(params[:value])
    end

    if field_template['type'] === 'upload'
      params[:file_types] = field_template['file_types']
    end

    if ['date', 'time', 'date_time'].include?(field_template['type'])
      params[:format] = field_template['format']
    end

    if field_template['type'] === 'category' || field_template['type'] === 'tag'
      params[:limit] = field_template['limit']
    end

    if field_template['type'] === 'category'
      params[:property] = field_template['property']
    end

    if field_template['type'] === 'category' || (
          field_template['validations'] &&
          field_template['validations']['similar_topics'] &&
          field_template['validations']['similar_topics']['categories'].present?
        )
      @wizard.needs_categories = true
    end

    if field_template['type'] === 'group'
      @wizard.needs_groups = true
    end

    if (content_inputs = field_template['content']).present?
      content = CustomWizard::Mapper.new(
        inputs: content_inputs,
        user: @wizard.user,
        data: @submissions.last,
        opts: {
          with_type: true
        }
      ).perform

      if content.present? &&
         content[:result].present?

        if content[:type] == 'association'
          content[:result] = content[:result].map do |item|
            {
              id: item[:key],
              name: item[:value]
            }
          end
        end

        if content[:type] == 'assignment' && field_template['type'] === 'dropdown'
          content[:result] = content[:result].map do |item|
            {
              id: item,
              name: item
            }
          end
        end

        params[:content] = content[:result]
      end
    end

    field = step.add_field(params)
  end

  def prefill_field(field_template, step_template)
    if (prefill = field_template['prefill']).present?
      CustomWizard::Mapper.new(
        inputs: prefill,
        user: @wizard.user,
        data: @submissions.last
      ).perform
    end
  end

  def standardise_boolean(value)
    ActiveRecord::Type::Boolean.new.cast(value)
  end

  def save_submissions(submission, final_step)
    if final_step
      submission['submitted_at'] = Time.now.iso8601
    end

    if submission.present?
      @submissions.pop(1) if @wizard.unfinished?
      @submissions.push(submission)
      @wizard.set_submissions(@submissions)
    end
  end

  def save_permitted_params(permitted_params, params)
    permitted_data = {}

    permitted_params.each do |pp|
      pair = pp['pairs'].first
      params_key = pair['key'].to_sym
      submission_key = pair['value'].to_sym
      permitted_data[submission_key] = params[params_key] if params[params_key]
    end

    if permitted_data.present?
      current_data = @submissions.last || {}
      save_submissions(current_data.merge(permitted_data), false)
    end
  end

  def ensure_required_data(step, step_template)
    step_template['required_data'].each do |required|
      pairs = required['pairs'].select do |pair|
        pair['key'].present? && pair['value'].present?
      end

      if pairs.any? && !@submissions.last
        step.permitted = false
        break
      end

      pairs.each do |pair|
        pair['key'] = @submissions.last[pair['key']]
      end

      if !mapper.validate_pairs(pairs)
        step.permitted = false
        break
      end
    end

    step
  end
end