#-- encoding: UTF-8

#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2018 the OpenProject Foundation (OPF)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
# Copyright (C) 2006-2017 Jean-Philippe Lang
# Copyright (C) 2010-2013 the ChiliProject Team
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
# See docs/COPYRIGHT.rdoc for more details.
#++

require 'model_contract'

module WorkPackages
  class BaseContract < ::ModelContract
    include ::Attachments::ValidateReplacements
    include ::Concerns::AssignableValuesContract

    attribute :subject
    attribute :description
    attribute :status_id,
              writeable: ->(*) {
                # If we did not change into the status,
                # mark unwritable if status and version is closed
                model.status_id_change || !closed_version_and_status?
              }
    attribute :type_id
    attribute :priority_id
    attribute :category_id
    attribute :fixed_version_id,
              permission: :assign_versions do
      validate_fixed_version_is_assignable
    end

    validate :validate_no_reopen_on_closed_version

    attribute :project_id

    attribute :done_ratio,
              writeable: ->(*) {
                model.leaf? && Setting.work_package_done_ratio == 'field'
              }

    attribute :estimated_hours
    attribute :derived_estimated_hours, writeable: false

    attribute :parent_id,
              permission: :manage_subtasks

    attribute :assigned_to_id do
      next unless model.project

      validate_people_visible :assigned_to,
                              'assigned_to_id',
                              model.project.possible_assignee_members
    end

    attribute :responsible_id do
      next unless model.project

      validate_people_visible :responsible,
                              'responsible_id',
                              model.project.possible_responsible_members
    end

    attribute :start_date,
              writeable: ->(*) {
                model.leaf?
              } do
      if start_before_soonest_start?
        message = I18n.t('activerecord.errors.models.work_package.attributes.start_date.violates_relationships',
                         soonest_start: model.soonest_start)

        errors.add :start_date, message, error_symbol: :violates_relationships
      end
    end

    attribute :due_date,
              writeable: ->(*) {
                model.leaf?
              }

    validates :due_date,
              date: { after_or_equal_to: :start_date,
                      message: :greater_than_or_equal_to_start_date,
                      allow_blank: true },
              unless: Proc.new { |wp| wp.start_date.blank? }

    validate :validate_enabled_type
    validate :validate_type_exists

    validate :validate_milestone_constraint
    validate :validate_parent_not_milestone

    validate :validate_parent_exists
    validate :validate_parent_in_same_project
    validate :validate_parent_not_subtask

    validate :validate_status_exists
    validate :validate_status_transition

    validate :validate_active_priority
    validate :validate_priority_exists

    validate :validate_category
    validate :validate_estimated_hours

    validate :validate_assigned_to_exists

    def initialize(work_package, user, options: {})
      super

      @can = WorkPackagePolicy.new(user)
    end

    def writable_attributes
      ret = super

      # If we're in a readonly status and did not move into that status right now
      # only allow other status transitions
      if model.readonly_status? && !model.status_id_change
        ret &= %w(status status_id)
      end

      ret
    end

    def assignable_statuses(include_default = false)
      # Do not allow skipping statuses without intermediately saving the work package.
      # We therefore take the original status of the work_package, while preserving all
      # other changes to it (e.g. type, assignee, etc.)
      status = if model.persisted? && model.status_id_changed?
                 Status.find_by(id: model.status_id_was)
               else
                 model.status
               end

      statuses = new_statuses_allowed_from(status)

      statuses = statuses.or(Status.where_default) if include_default

      statuses.order_by_position
    end

    def assignable_types
      scope = if model.project.nil?
                Type
              else
                model.project.types.includes(:color)
              end

      scope.includes(:color)
    end

    def assignable_categories
      model.project.categories if model.project.respond_to?(:categories)
    end

    def assignable_priorities
      IssuePriority.active
    end

    def assignable_versions
      model.try(:assignable_versions) if model.project
    end

    private

    attr_reader :can

    def validate_estimated_hours
      if !model.estimated_hours.nil? && model.estimated_hours < 0
        errors.add :estimated_hours, :only_values_greater_or_equal_zeroes_allowed
      end
    end

    def validate_enabled_type
      # Checks that the issue can not be added/moved to a disabled type
      if type_context_changed?
        errors.add :type_id, :inclusion unless model.project.types.include?(model.type)
      end
    end

    def validate_assigned_to_exists
      errors.add :assigned_to, :does_not_exist if model.assigned_to&.is_a?(User::InexistentUser)
    end

    def validate_type_exists
      errors.add :type, :does_not_exist if type_inexistent?
    end

    def validate_milestone_constraint
      if model.is_milestone? && model.due_date && model.start_date && model.start_date != model.due_date
        errors.add :due_date, :not_start_date
      end
    end

    def validate_parent_not_milestone
      if model.parent&.is_milestone?
        errors.add :parent, :cannot_be_milestone
      end
    end

    def validate_parent_exists
      if model.parent&.is_a?(WorkPackage::InexistentWorkPackage)

        errors.add :parent, :does_not_exist
      end
    end

    def validate_parent_in_same_project
      if parent_in_different_project?
        errors.add :parent, :cannot_be_in_another_project
      end
    end

    # have to validate ourself as the parent relation is created after saving
    def validate_parent_not_subtask
      if model.parent_id_changed? && model.parent && invalid_relations_with_new_hierarchy.exists?
        errors.add :base, :cant_link_a_work_package_with_a_descendant
      end
    end

    def validate_status_exists
      errors.add :status, :does_not_exist if model.status && !status_exists?
    end

    def validate_status_transition
      if status_changed? && status_exists? && !(model.type_id_changed? || status_transition_exists?)
        errors.add :status_id, :status_transition_invalid
      end
    end

    def validate_active_priority
      if model.priority && !model.priority.active? && model.priority_id_changed?
        errors.add :priority_id, :only_active_priorities_allowed
      end
    end

    def validate_priority_exists
      errors.add :priority, :does_not_exist if model.priority&.is_a?(Priority::InexistentPriority)
    end

    def validate_category
      if inexistent_category?
        errors.add :category, :does_not_exist
      elsif category_not_of_project?
        errors.add :category, :only_same_project_categories_allowed
      end
    end

    def validate_fixed_version_is_assignable
      if model.fixed_version_id && !model.assignable_versions.map(&:id).include?(model.fixed_version_id)
        errors.add :fixed_version_id, :inclusion
      end
    end

    def validate_no_reopen_on_closed_version
      if model.fixed_version_id && model.reopened? && model.fixed_version.closed?
        errors.add :base, I18n.t(:error_can_not_reopen_work_package_on_closed_version)
      end
    end

    def validate_people_visible(attribute, id_attribute, list)
      id = model[id_attribute]

      return if id.nil? || !model.changed.include?(id_attribute)

      unless principal_visible?(id, list)
        errors.add attribute,
                   I18n.t('api_v3.errors.validation.invalid_user_assigned_to_work_package',
                          property: I18n.t("attributes.#{attribute}"))
      end
    end

    def principal_visible?(id, list)
      list.exists?(user_id: id)
    end

    def start_before_soonest_start?
      model.start_date &&
        model.soonest_start &&
        model.start_date < model.soonest_start
    end

    def parent_in_different_project?
      model.parent &&
        model.parent.project != model.project &&
        !Setting.cross_project_work_package_relations? &&
        !model.parent.is_a?(WorkPackage::InexistentWorkPackage)
    end

    def inexistent_category?
      model.category_id.present? && !model.category
    end

    def category_not_of_project?
      model.category && !model.project.categories.include?(model.category)
    end

    def status_changed?
      model.status_id_was != 0 && model.status_id_changed?
    end

    def status_exists?
      model.status_id && model.status && !model.status.is_a?(Status::InexistentStatus)
    end

    def status_transition_exists?
      assignable_statuses.exists?(model.status_id)
    end

    def invalid_relations_with_new_hierarchy
      query = Relation.from_parent_to_self_and_descendants(model)
                      .or(Relation.from_self_and_descendants_to_ancestors(model))
                      .direct

      # Ignore the immediate relation from the old parent to the model
      # since that will still exist before saving.
      old_parent_id = model.parent_id_was

      if old_parent_id.present?
        query
          .where.not(hierarchy: 1)
          .where.not(from_id: old_parent_id)
          .where.not(to_id: model.id)
      else
        query
      end
    end

    def type_context_changed?
      model.project && !type_inexistent? && (model.type_id_changed? || model.project_id_changed?)
    end

    def type_inexistent?
      model.type.is_a?(Type::InexistentType)
    end

    # Returns a scope of status the user is able to apply
    def new_statuses_allowed_from(status)
      return Status.where('1=0') if status.nil?

      current_status = Status.where(id: status.id)

      return current_status if closed_version_and_status?(status)

      statuses = new_statuses_by_workflow(status)
                   .or(current_status)

      statuses = statuses.where(is_closed: false) if model.blocked?

      statuses
    end

    def closed_version_and_status?(status = model.status)
      model.fixed_version&.closed? && status.is_closed?
    end

    def new_statuses_by_workflow(status)
      workflows = Workflow
                  .from_status(status.id,
                               model.type_id,
                               users_roles_in_project.map(&:id),
                               user_is_author?,
                               user_was_or_is_assignee?)

      Status.where(id: workflows.select(:new_status_id))
    end

    def user_was_or_is_assignee?
      model.assigned_to_id_changed? ? model.assigned_to_id_was == user.id : model.assigned_to_id == user.id
    end

    def user_is_author?
      model.author == user
    end

    def users_roles_in_project
      user.roles_for_project(model.project)
    end
  end
end