# frozen_string_literal: true

# Base class for Chat notifications services
# This class is not meant to be used directly, but only to inherit from.

module Integrations
  class BaseChatNotification < Integration
    include ChatMessage
    include NotificationBranchSelection

    SUPPORTED_EVENTS = %w[
      push issue confidential_issue merge_request note confidential_note
      tag_push pipeline wiki_page deployment
    ].freeze

    SUPPORTED_EVENTS_FOR_LABEL_FILTER = %w[issue confidential_issue merge_request note confidential_note].freeze

    EVENT_CHANNEL = proc { |event| "#{event}_channel" }

    LABEL_NOTIFICATION_BEHAVIOURS = [
      MATCH_ANY_LABEL = 'match_any',
      MATCH_ALL_LABELS = 'match_all'
    ].freeze

    default_value_for :category, 'chat'

    prop_accessor :webhook, :username, :channel, :branches_to_be_notified, :labels_to_be_notified, :labels_to_be_notified_behavior

    # Custom serialized properties initialization
    prop_accessor(*SUPPORTED_EVENTS.map { |event| EVENT_CHANNEL[event] })

    boolean_accessor :notify_only_broken_pipelines, :notify_only_default_branch

    validates :webhook, presence: true, public_url: true, if: :activated?
    validates :labels_to_be_notified_behavior, inclusion: { in: LABEL_NOTIFICATION_BEHAVIOURS }, allow_blank: true

    def initialize_properties
      if properties.nil?
        self.properties = {}
        self.notify_only_broken_pipelines = true
        self.branches_to_be_notified = "default"
        self.labels_to_be_notified_behavior = MATCH_ANY_LABEL
      elsif !self.notify_only_default_branch.nil?
        # In older versions, there was only a boolean property named
        # `notify_only_default_branch`. Now we have a string property named
        # `branches_to_be_notified`. Instead of doing a background migration, we
        # opted to set a value for the new property based on the old one, if
        # users haven't specified one already. When users edit the service and
        # select a value for this new property, it will override everything.

        self.branches_to_be_notified ||= notify_only_default_branch? ? "default" : "all"
      end
    end

    def confidential_issue_channel
      properties['confidential_issue_channel'].presence || properties['issue_channel']
    end

    def confidential_note_channel
      properties['confidential_note_channel'].presence || properties['note_channel']
    end

    def self.supported_events
      SUPPORTED_EVENTS
    end

    def fields
      default_fields + build_event_channels
    end

    def default_fields
      [
        { type: 'text', name: 'webhook', placeholder: "#{webhook_placeholder}", required: true }.freeze,
        { type: 'text', name: 'username', placeholder: 'GitLab-integration' }.freeze,
        { type: 'checkbox', name: 'notify_only_broken_pipelines', help: 'Do not send notifications for successful pipelines.' }.freeze,
        { type: 'select', name: 'branches_to_be_notified', choices: branch_choices }.freeze,
        {
          type: 'text',
          name: 'labels_to_be_notified',
          placeholder: '~backend,~frontend',
          help: 'Send notifications for issue, merge request, and comment events with the listed labels only. Leave blank to receive notifications for all events.'
        }.freeze,
        {
          type: 'select',
          name: 'labels_to_be_notified_behavior',
          choices: [
            ['Match any of the labels', MATCH_ANY_LABEL],
            ['Match all of the labels', MATCH_ALL_LABELS]
          ]
        }.freeze
      ].freeze
    end

    def execute(data)
      return unless supported_events.include?(data[:object_kind])

      return unless webhook.present?

      object_kind = data[:object_kind]

      data = custom_data(data)

      return unless notify_label?(data)

      # WebHook events often have an 'update' event that follows a 'open' or
      # 'close' action. Ignore update events for now to prevent duplicate
      # messages from arriving.

      message = get_message(object_kind, data)

      return false unless message

      event_type = data[:event_type] || object_kind

      channel_names = get_channel_field(event_type).presence || channel.presence
      channels = channel_names&.split(',')&.map(&:strip)

      opts = {}
      opts[:channel] = channels if channels.present?
      opts[:username] = username if username

      if notify(message, opts)
        log_usage(event_type, user_id_from_hook_data(data))
        return true
      end

      false
    end

    def event_channel_names
      supported_events.map { |event| event_channel_name(event) }
    end

    def event_field(event)
      fields.find { |field| field[:name] == event_channel_name(event) }
    end

    def global_fields
      fields.reject { |field| field[:name].end_with?('channel') }
    end

    def default_channel_placeholder
      raise NotImplementedError
    end

    private

    def log_usage(_, _)
      # Implement in child class
    end

    def labels_to_be_notified_list
      return [] if labels_to_be_notified.nil?

      labels_to_be_notified.delete('~').split(',').map(&:strip)
    end

    def notify_label?(data)
      return true unless SUPPORTED_EVENTS_FOR_LABEL_FILTER.include?(data[:object_kind]) && labels_to_be_notified.present?

      labels = data[:labels] || data.dig(:issue, :labels) || data.dig(:merge_request, :labels) || data.dig(:object_attributes, :labels)

      return false if labels.blank?

      matching_labels = labels_to_be_notified_list & labels.pluck(:title)

      if labels_to_be_notified_behavior == MATCH_ALL_LABELS
        labels_to_be_notified_list.difference(matching_labels).empty?
      else
        matching_labels.any?
      end
    end

    def user_id_from_hook_data(data)
      data.dig(:user, :id) || data[:user_id]
    end

    # every notifier must implement this independently
    def notify(message, opts)
      raise NotImplementedError
    end

    def custom_data(data)
      data.merge(project_url: project_url, project_name: project_name).with_indifferent_access
    end

    def get_message(object_kind, data)
      case object_kind
      when "push", "tag_push"
        Integrations::ChatMessage::PushMessage.new(data) if notify_for_ref?(data)
      when "issue"
        Integrations::ChatMessage::IssueMessage.new(data) unless update?(data)
      when "merge_request"
        Integrations::ChatMessage::MergeMessage.new(data) unless update?(data)
      when "note"
        Integrations::ChatMessage::NoteMessage.new(data)
      when "pipeline"
        Integrations::ChatMessage::PipelineMessage.new(data) if should_pipeline_be_notified?(data)
      when "wiki_page"
        Integrations::ChatMessage::WikiPageMessage.new(data)
      when "deployment"
        Integrations::ChatMessage::DeploymentMessage.new(data)
      end
    end

    def get_channel_field(event)
      field_name = event_channel_name(event)
      self.public_send(field_name) # rubocop:disable GitlabSecurity/PublicSend
    end

    def build_event_channels
      supported_events.reduce([]) do |channels, event|
        channels << { type: 'text', name: event_channel_name(event), placeholder: default_channel_placeholder }
      end
    end

    def event_channel_name(event)
      EVENT_CHANNEL[event]
    end

    def project_name
      project.full_name
    end

    def project_url
      project.web_url
    end

    def update?(data)
      data[:object_attributes][:action] == 'update'
    end

    def should_pipeline_be_notified?(data)
      notify_for_ref?(data) && notify_for_pipeline?(data)
    end

    def notify_for_ref?(data)
      return true if data[:object_kind] == 'tag_push'
      return true if data.dig(:object_attributes, :tag)

      notify_for_branch?(data)
    end

    def notify_for_pipeline?(data)
      case data[:object_attributes][:status]
      when 'success'
        !notify_only_broken_pipelines?
      when 'failed'
        true
      else
        false
      end
    end
  end
end

Integrations::BaseChatNotification.prepend_mod_with('Integrations::BaseChatNotification')
