#-- 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.
#++

class WorkPackage < ActiveRecord::Base
  include WorkPackage::Validations
  include WorkPackage::SchedulingRules
  include WorkPackage::StatusTransitions
  include WorkPackage::AskBeforeDestruction
  include WorkPackage::TimeEntries
  include WorkPackage::Ancestors
  prepend WorkPackage::Parent
  include WorkPackage::TypedDagDefaults
  include WorkPackage::CustomActions

  include OpenProject::Journal::AttachmentHelper

  DONE_RATIO_OPTIONS = %w(field status disabled).freeze
  ATTRIBS_WITH_VALUES_FROM_CHILDREN =
    %w(start_date due_date estimated_hours done_ratio).freeze

  belongs_to :project
  belongs_to :type
  belongs_to :status, class_name: 'Status', foreign_key: 'status_id'
  belongs_to :author, class_name: 'User', foreign_key: 'author_id'
  belongs_to :assigned_to, class_name: 'Principal', foreign_key: 'assigned_to_id'
  belongs_to :responsible, class_name: 'Principal', foreign_key: 'responsible_id'
  belongs_to :fixed_version, class_name: 'Version', foreign_key: 'fixed_version_id'
  belongs_to :priority, class_name: 'IssuePriority', foreign_key: 'priority_id'
  belongs_to :category, class_name: 'Category', foreign_key: 'category_id'

  has_many :time_entries, dependent: :delete_all

  has_and_belongs_to_many :changesets, -> {
    order("#{Changeset.table_name}.committed_on ASC, #{Changeset.table_name}.id ASC")
  }

  scope :recently_updated, ->() {
    order(updated_at: :desc)
  }

  scope :visible, ->(*args) {
    where(project_id: Project.allowed_to(args.first || User.current, :view_work_packages))
  }

  scope :in_status, ->(*args) do
                      where(status_id: (args.first.respond_to?(:id) ? args.first.id : args.first))
                    end

  scope :for_projects, ->(projects) {
    where(project_id: projects)
  }

  scope :changed_since, ->(changed_since) {
    if changed_since
      where(["#{WorkPackage.table_name}.updated_at >= ?", changed_since])
    end
  }

  scope :with_status_open, ->() {
    includes(:status)
      .where(statuses: { is_closed: false })
  }

  scope :with_status_closed, ->() {
    includes(:status)
      .where(statuses: { is_closed: true })
  }

  scope :with_limit, ->(limit) {
    limit(limit)
  }

  scope :on_active_project, -> {
    includes(:status, :project, :type)
      .where(projects: { status: Project::STATUS_ACTIVE })
  }

  scope :without_version, -> {
    where(fixed_version_id: nil)
  }

  scope :with_query, ->(query) {
    where(query.statement)
  }

  scope :with_author, ->(author) {
    where(author_id: author.id)
  }

  acts_as_watchable

  before_create :default_assign
  before_save :close_duplicates, :update_done_ratio_from_status

  acts_as_customizable

  acts_as_searchable columns: ['subject',
                               "#{table_name}.description",
                               "#{Journal.table_name}.notes"],
                     include: %i(project journals),
                     references: %i(projects journals),
                     date_column: "#{quoted_table_name}.created_at",
                     # sort by id so that limited eager loading doesn't break with postgresql
                     order_column: "#{table_name}.id"

  ##################### WARNING #####################
  # Do not change the order of acts_as_attachable   #
  # and acts_as_journalized!                        #
  #                                                 #
  # This order ensures that no journal entries are  #
  # written after a project is destroyed.           #
  #                                                 #
  # See test/unit/project_test.rb                   #
  # test_destroying_root_projects_should_clear_data #
  # for details.                                    #
  ###################################################
  acts_as_attachable after_remove: :attachments_changed,
                     order: "#{Attachment.table_name}.filename",
                     add_on_new_permission: :add_work_packages,
                     add_on_persisted_permission: :edit_work_packages,
                     modification_blocked: ->(*) { readonly_status? }

  after_validation :set_attachments_error_details,
                   if: lambda { |work_package| work_package.errors.messages.has_key? :attachments }

  associated_to_ask_before_destruction TimeEntry,
                                       ->(work_packages) {
                                         TimeEntry.on_work_packages(work_packages).count > 0
                                       },
                                       method(:cleanup_time_entries_before_destruction_of)

  include WorkPackage::Journalized

  def self.done_ratio_disabled?
    Setting.work_package_done_ratio == 'disabled'
  end

  def self.use_status_for_done_ratio?
    Setting.work_package_done_ratio == 'status'
  end

  def self.use_field_for_done_ratio?
    Setting.work_package_done_ratio == 'field'
  end

  # Returns true if usr or current user is allowed to view the work_package
  def visible?(usr = nil)
    (usr || User.current).allowed_to?(:view_work_packages, project)
  end

  # ACTS AS JOURNALIZED
  def activity_type
    'work_packages'
  end

  # RELATIONS
  # Returns true if this work package is blocked by another work package that is still open
  def blocked?
    blocked_by
      .with_status_open
      .exists?
  end

  def relations
    Relation.of_work_package(self)
  end

  def visible_relations(user)
    # This duplicates chaining
    #  .relations.visible
    # The duplication is made necessary to achive a performant sql query on MySQL.
    # Chaining would result in
    #   WHERE (relations.from_id = [ID] OR relations.to_id = [ID])
    #   AND relations.from_id IN (SELECT [IDs OF VISIBLE WORK_PACKAGES])
    #   AND relations.to_id IN (SELECT [IDs OF VISIBLE WORK_PACKAGES])
    # This performs OK on postgresql but is very slow on MySQL
    # The SQL generated by this method:
    #   WHERE (relations.from_id = [ID] AND relations.to_id IN (SELECT [IDs OF VISIBLE WORK_PACKAGES])
    #   OR (relations.to_id = [ID] AND relations.from_id IN (SELECT [IDs OF VISIBLE WORK_PACKAGES]))
    # is arguably easier to read and performs equally good on both DBs.
    relations_from = Relation
                     .where(from: self)
                     .where(to: WorkPackage.visible(user))

    relations_to = Relation
                   .where(to: self)
                   .where(from: WorkPackage.visible(user))

    relations_from
      .or(relations_to)
  end

  def relation(id)
    Relation.of_work_package(self).find(id)
  end

  def new_relation
    relations_to.build
  end

  def add_time_entry(attributes = {})
    attributes.reverse_merge!(
      project: project,
      work_package: self
    )
    time_entries.build(attributes)
  end

  # Users/groups the work_package can be assigned to
  extend Forwardable
  def_delegator :project, :possible_assignees, :assignable_assignees

  # Users the work_package can be assigned to
  def_delegator :project, :possible_responsibles, :assignable_responsibles

  # Versions that the work_package can be assigned to
  # A work_package can be assigned to:
  #   * any open, shared version of the project the wp belongs to
  #   * the version it was already assigned to
  #     (to make sure, that you can still update closed tickets)
  def assignable_versions
    @assignable_versions ||= begin
      current_version = fixed_version_id_changed? ? Version.find_by(id: fixed_version_id_was) : fixed_version
      (project.assignable_versions + [current_version]).compact.uniq.sort
    end
  end

  def to_s
    "#{type.is_standard ? '' : type.name} ##{id}: #{subject}"
  end

  # Return true if the work_package is closed, otherwise false
  def closed?
    status.nil? || status.is_closed?
  end

  # Return true if the work_package's status is_readonly
  # Careful not to use +readonly?+ which is AR internals!
  def readonly_status?
    status.present? && status.is_readonly?
  end

  # Returns true if the work_package is overdue
  def overdue?
    !due_date.nil? && (due_date < Date.today) && !closed?
  end

  def milestone?
    type && type.is_milestone?
  end
  alias_method :is_milestone?, :milestone?

  # Returns an array of status that user is able to apply
  def new_statuses_allowed_to(user, include_default = false)
    return Status.where('1=0') if status.nil?

    current_status = Status.where(id: status_id)

    statuses = new_statuses_allowed_by_workflow_to(user)
               .or(current_status)

    statuses = statuses.or(Status.where(id: Status.default.id)) if include_default
    statuses = statuses.where(is_closed: false) if blocked?

    statuses.order_by_position
  end

  # Returns users that should be notified
  def recipients
    notified = project.notified_users + attribute_users.select { |u| u.notify_about?(self) }

    notified.uniq!
    # Remove users that can not view the work package
    notified & User.allowed(:view_work_packages, project)
  end

  def notify?(user)
    case user.mail_notification
    when 'selected', 'only_my_events'
      author == user || user.is_or_belongs_to?(assigned_to) || user.is_or_belongs_to?(responsible)
    when 'none'
      false
    when 'only_assigned'
      user.is_or_belongs_to?(assigned_to) || user.is_or_belongs_to?(responsible)
    when 'only_owner'
      author == user
    else
      false
    end
  end

  def done_ratio
    if WorkPackage.use_status_for_done_ratio? && status && status.default_done_ratio
      status.default_done_ratio
    else
      read_attribute(:done_ratio)
    end
  end

  def estimated_hours=(h)
    converted_hours = (h.is_a?(String) ? h.to_hours : h)
    write_attribute :estimated_hours, !!converted_hours ? converted_hours : h
  end

  # Overrides Redmine::Acts::Customizable::InstanceMethods#available_custom_fields
  def available_custom_fields
    WorkPackage::AvailableCustomFields.for(project, type)
  end

  # aliasing subject to name
  # using :alias is not possible as AR will add the subject method later
  def name
    subject
  end

  def status_id=(sid)
    self.status = nil
    write_attribute(:status_id, sid)
  end

  def priority_id=(pid)
    self.priority = nil
    write_attribute(:priority_id, pid)
  end

  def type_id=(tid)
    self.type = nil
    result = write_attribute(:type_id, tid)
    @custom_field_values = nil
    result
  end

  # Overrides attributes= so that type_id gets assigned first
  def attributes=(new_attributes)
    return if new_attributes.nil?
    new_type_id = new_attributes['type_id'] || new_attributes[:type_id]
    if new_type_id
      self.type_id = new_type_id
    end

    super
  end

  # Set the done_ratio using the status if that setting is set.  This will keep the done_ratios
  # even if the user turns off the setting later
  def update_done_ratio_from_status
    if WorkPackage.use_status_for_done_ratio? && status && status.default_done_ratio
      self.done_ratio = status.default_done_ratio
    end
  end

  # Is the amount of work done less than it should for the finish date
  def behind_schedule?
    return false if start_date.nil? || due_date.nil?
    done_date = start_date + (duration * done_ratio / 100).floor
    done_date <= Date.today
  end

  # check if user is allowed to edit WorkPackage Journals.
  # see Redmine::Acts::Journalized::Permissions#journal_editable_by
  def editable_by?(user)
    project = self.project
    user.allowed_to?(:edit_work_package_notes, project, global: project.present?) ||
      user.allowed_to?(:edit_own_work_package_notes, project, global: project.present?)
  end

  # Adds the 'virtual' attribute 'hours' to the result set.  Using the
  # patch in config/initializers/eager_load_with_hours, the value is
  # returned as the #hours attribute on each work package.
  def self.include_spent_hours(user)
    WorkPackage::SpentTime
      .new(user)
      .scope
      .select('SUM(time_entries.hours) AS hours')
  end

  # Returns the total number of hours spent on this work package and its descendants.
  # The result can be a subset of the actual spent time in cases where the user's permissions
  # are limited, i.e. he lacks the view_time_entries and/or view_work_packages permission.
  #
  # Example:
  #   spent_hours => 0.0
  #   spent_hours => 50.2
  #
  #   The value can stem from either eager loading the value via
  #   WorkPackage.include_spent_hours in which case the work package has an
  #   #hours attribute or it is loaded on calling the method.
  def spent_hours(user = User.current)
    if respond_to?(:hours)
      hours.to_f
    else
      compute_spent_hours(user)
    end || 0.0
  end

  # Returns a scope for the projects
  # the user is allowed to move a work package to
  def self.allowed_target_projects_on_move(user)
    Project.allowed_to(user, :move_work_packages)
  end

  # Returns a scope for the projects
  # the user is create a work package in
  def self.allowed_target_projects_on_create(user)
    Project.allowed_to(user, :add_work_packages)
  end

  # Unassigns issues from +version+ if it's no longer shared with issue's project
  def self.update_versions_from_sharing_change(version)
    # Update issues assigned to the version
    update_versions(["#{WorkPackage.table_name}.fixed_version_id = ?", version.id])
  end

  # Unassigns issues from versions that are no longer shared
  # after +project+ was moved
  def self.update_versions_from_hierarchy_change(project)
    moved_project_ids = project.self_and_descendants.reload.map(&:id)
    # Update issues of the moved projects and issues assigned to a version of a moved project
    update_versions(
      ["#{Version.table_name}.project_id IN (?) OR #{WorkPackage.table_name}.project_id IN (?)",
       moved_project_ids,
       moved_project_ids]
    )
  end

  # Extracted from the ReportsController.
  def self.by_type(project)
    count_and_group_by project: project,
                       field: 'type_id',
                       joins: ::Type.table_name
  end

  def self.by_version(project)
    count_and_group_by project: project,
                       field: 'fixed_version_id',
                       joins: Version.table_name
  end

  def self.by_priority(project)
    count_and_group_by project: project,
                       field: 'priority_id',
                       joins: IssuePriority.table_name
  end

  def self.by_category(project)
    count_and_group_by project: project,
                       field: 'category_id',
                       joins: Category.table_name
  end

  def self.by_assigned_to(project)
    count_and_group_by project: project,
                       field: 'assigned_to_id',
                       joins: User.table_name
  end

  def self.by_responsible(project)
    count_and_group_by project: project,
                       field: 'responsible_id',
                       joins: User.table_name
  end

  def self.by_author(project)
    count_and_group_by project: project,
                       field: 'author_id',
                       joins: User.table_name
  end

  def self.by_subproject(project)
    return unless project.descendants.active.any?

    ActiveRecord::Base.connection.select_all(
      "select    s.id as status_id,
        s.is_closed as closed,
        i.project_id as project_id,
        count(i.id) as total
      from
        #{WorkPackage.table_name} i, #{Status.table_name} s
      where
        i.status_id=s.id
        and i.project_id IN (#{project.descendants.active.map(&:id).join(',')})
      group by s.id, s.is_closed, i.project_id"
    ).to_a
  end

  def self.relateable_to(wp)
    # can't relate to itself and not to a descendant (see relations)
    relateable_shared(wp)
      .not_having_relations_from(wp) # can't relate to wp that relates to us (direct or transitively)
      .not_having_direct_relation_to(wp) # can't relate to wp we relate to directly
  end

  def self.relateable_from(wp)
    # can't relate to itself and not to a descendant (see relations)
    relateable_shared(wp)
      .not_having_relations_to(wp) # can't relate to wp that relates to us (direct or transitively)
      .not_having_direct_relation_from(wp) # can't relate to wp we relate to directly
  end

  def self.relateable_shared(wp)
    visible
      .not_self(wp) # can't relate to itself
      .not_being_descendant_of(wp) # can't relate to a descendant (see relations)
      .satisfying_cross_project_setting(wp)
  end
  private_class_method :relateable_shared

  def self.satisfying_cross_project_setting(wp)
    if Setting.cross_project_work_package_relations?
      all
    else
      where(project_id: wp.project_id)
    end
  end

  def self.not_self(wp)
    where.not(id: wp.id)
  end

  def self.not_having_direct_relation_to(wp)
    where.not(id: wp.relations_to.direct.select(:to_id))
  end

  def self.not_having_direct_relation_from(wp)
    where.not(id: wp.relations_from.direct.select(:from_id))
  end

  def self.not_having_relations_from(wp)
    where.not(id: wp.relations_from.select(:from_id))
  end

  def self.not_having_relations_to(wp)
    where.not(id: wp.relations_to.select(:to_id))
  end

  def self.not_being_descendant_of(wp)
    where.not(id: wp.descendants.select(:to_id))
  end

  def self.order_by_ancestors(direction)
    max_relation_depth = Relation
                         .hierarchy
                         .group(:to_id)
                         .select(:to_id,
                                 "MAX(hierarchy) AS depth")

    joins("LEFT OUTER JOIN (#{max_relation_depth.to_sql}) AS max_depth ON max_depth.to_id = work_packages.id")
      .reorder(Arel.sql("COALESCE(max_depth.depth, 0) #{direction}"))
      .select("#{table_name}.*, COALESCE(max_depth.depth, 0)")
  end

  def self.self_and_descendants_of_condition(work_package)
    relation_subquery = Relation
                        .with_type_columns_not(hierarchy: 0)
                        .select(:to_id)
                        .where(from_id: work_package.id)
    "#{table_name}.id IN (#{relation_subquery.to_sql}) OR #{table_name}.id = #{work_package.id}"
  end

  def self.hierarchy_tree_following(work_packages)
    following = Relation
                .where(to: work_packages)
                .hierarchy_or_follows

    following_from_hierarchy = Relation
                               .hierarchy
                               .where(from_id: following.select(:from_id))
                               .select("to_id common_id")

    following_from_self = following.select("from_id common_id")

    # Using a union here for performance.
    # Using or would yield the same results and be less complicated
    # but it will require two orders of magnitude more time.
    sub_query = [following_from_hierarchy, following_from_self].map(&:to_sql).join(" UNION ")

    where("id IN (SELECT common_id FROM (#{sub_query}) following_relations)")
  end

  protected

  def <=>(other)
    other.id <=> id
  end

  private

  def add_time_entry_for(user, attributes)
    return if time_entry_blank?(attributes)

    attributes.reverse_merge!(user: user,
                              spent_on: Date.today)

    time_entries.build(attributes)
  end

  def new_statuses_allowed_by_workflow_to(user)
    status.new_statuses_allowed_to(
      user.roles_for_project(project),
      type,
      author == user,
      assigned_to_id_changed? ? assigned_to_id_was == user.id : assigned_to_id == user.id
    )
  end

  ##
  # Checks if the time entry defined by the given attributes is blank.
  # A time entry counts as blank despite a selected activity if that activity
  # is simply the default activity and all other attributes are blank.
  def time_entry_blank?(attributes)
    return true if attributes.nil?
    key = 'activity_id'
    id = attributes[key]
    default_id = if id && !id.blank?
                   Enumeration.exists? id: id, is_default: true, type: 'TimeEntryActivity'
                 else
                   true
                 end

    default_id && attributes.except(key).values.all?(&:blank?)
  end

  def self.having_fixed_version_from_other_project
    where(
      "#{WorkPackage.table_name}.fixed_version_id IS NOT NULL" +
      " AND #{WorkPackage.table_name}.project_id <> #{Version.table_name}.project_id" +
      " AND #{Version.table_name}.sharing <> 'system'"
    )
  end
  private_class_method :having_fixed_version_from_other_project

  # Update issues so their versions are not pointing to a
  # fixed_version that is not shared with the issue's project
  def self.update_versions(conditions = nil)
    # Only need to update issues with a fixed_version from
    # a different project and that is not systemwide shared
    having_fixed_version_from_other_project
      .where(conditions)
      .includes(:project, :fixed_version)
      .references(:versions).each do |issue|
      next if issue.project.nil? || issue.fixed_version.nil?
      unless issue.project.shared_versions.include?(issue.fixed_version)
        issue.fixed_version = nil
        issue.save
      end
    end
  end
  private_class_method :update_versions

  # Default assignment based on category
  def default_assign
    if assigned_to.nil? && category && category.assigned_to
      self.assigned_to = category.assigned_to
    end
  end

  # Closes duplicates if the issue is being closed
  def close_duplicates
    return unless closing?

    duplicates.each do |duplicate|
      # Reload is needed in case the duplicate was updated by a previous duplicate
      duplicate.reload
      # Don't re-close it if it's already closed
      next if duplicate.closed?
      # Implicitly creates a new journal
      duplicate.update_attribute :status, status

      override_last_journal_notes_and_user_of!(duplicate)
    end
  end

  def override_last_journal_notes_and_user_of!(other_work_package)
    journal = other_work_package.journals.last
    # Same user and notes
    journal.user = current_journal.user
    journal.notes = current_journal.notes

    journal.save
  end

  # Query generator for selecting groups of issue counts for a project
  # based on specific criteria.
  # DANGER: :field and :joins MUST never come from user input, because
  # they are not SQL-escaped.
  #
  # Options
  # * project - Project to search in.
  # * field - String. Issue field to key off of in the grouping.
  # * joins - String. The table name to join against.
  def self.count_and_group_by(options)
    project = options.delete(:project)
    select_field = options.delete(:field)
    joins = options.delete(:joins)

    where = "i.#{select_field}=j.id"

    ActiveRecord::Base.connection.select_all(
      "select    s.id as status_id,
        s.is_closed as closed,
        j.id as #{select_field},
        count(i.id) as total
      from
          #{WorkPackage.table_name} i, #{Status.table_name} s, #{joins} j
      where
        i.status_id=s.id
        and #{where}
        and i.project_id=#{project.id}
      group by s.id, s.is_closed, j.id"
    ).to_a
  end
  private_class_method :count_and_group_by

  def set_attachments_error_details
    if invalid_attachment = attachments.detect { |a| !a.valid? }
      errors.messages[:attachments].first << " - #{invalid_attachment.errors.full_messages.first}"
    end
  end

  def compute_spent_hours(user)
    WorkPackage::SpentTime
      .new(user, self)
      .scope
      .where(id: id)
      .pluck(Arel.sql('SUM(hours)'))
      .first
  end

  def attribute_users
    related = [author]

    [responsible, assigned_to].each do |user|
      if user.is_a?(Group)
        related += user.users
      else
        related << user
      end
    end

    related.select(&:present?)
  end
end