require "study_engine/form"
require "study_engine/assessment"
require "study_engine/config"

module StudyEngine
  class BeginAssessmentForm < Form
    wraps "study_engine/assessment"

    attributes :study_id, :event, :method_applied, :coordinator

    attr_accessor :restart

    delegate :study, :site, :id, to: :study_id, prefix: true
    delegate :study=, :site=, :id=, to: :study_id, prefix: true

    validate :presence_of_event
    validate :format_of_study_id
    validate :uniqueness_of_study_id_and_event, unless: :restart
    validate :presence_of_previous_events

    def study_id_study
      study_options.one? ? study_options.first : study_id.study
    end

    def study_id_site
      site_options.one? ? site_options.first : study_id.site
    end

    def study_id_id
      id_options.one? ? id_options.first : study_id.id
    end

    def study_id
      @study_id ||= StudyID.new
    end

    def method_applied
      @method_applied || "In-person"
    end

    def existing_assessment
      if study_id and new_record?
        @existing_assessment ||= Assessment.by_study_id(study_id).where(event: event).last
      end
    end

    def restartable?
      existing_assessment.try(:incomplete?)
    end

    def study_options
      StudyID::Bank.studies_grouped_by_site.fetch(coordinator.try(:site_id)) { StudyID::Bank.studies }
    end

    def site_options
      coordinator.try(:site_id).present? ? [coordinator.site_id] : StudyID::Bank.sites
    end

    def id_options
      ids_grouped_by_study_and_site[study_id_study.to_s + study_id_site.to_s]
    end

    def ids_grouped_by_study_and_site
      StudyID::Bank.ids_grouped_by_study_and_site
    end

    delegate :by_url?, :by_mail?, :group_index_name, :created_at, :assessment_updated_at, to: :@model

    private

    def format_of_study_id
      if study_id.present?
        unless study_id.valid?
          errors.add :base, "METRC study ID must be in the following format: XXX-XXX-####"
        end
      else
        errors.add :base, "METRC study ID can not be blank.  Enter ID in the following format: XXX-XXX-####"
      end
    end

    def presence_of_event
      if event.blank?
        events = StudyEngine.events.dup
        events.map!(&:titleize)
        events.last.prepend("or ")
        events = events.join(", ")
        errors.add :base, "Study event can not be blank.  Choose #{events} assessment."
      end
    end

    def uniqueness_of_study_id_and_event
      if existing_assessment
        errors.add :base, "Assessment data has already been collected for this ID number and event.  Please check these fields to confirm you are beginning an assessment for the correct ID and event."
      end
    end

    def presence_of_previous_events
      index = StudyEngine.events.index(event)
      return if index.nil? || index.zero?
      previous_events = StudyEngine.events[0...index]

      previous_events.each do |previous_event|
        if Assessment.by_study_id(study_id).by_event(previous_event).none?
          errors.add :base, "#{previous_event.capitalize} assessment must already exist to administer #{event} assessment"
        end
      end
    end
  end
end