Add OpenProject Gitea integration plugin

Implements a Gitea integration for OpenProject following the same
patterns as the bundled GitHub and GitLab integrations.

- Webhook endpoint at /webhooks/gitea with HMAC-SHA256 verification
- Handles pull_request and issue_comment events
- Links Gitea PRs to work packages via OP# references or URLs
- Posts journal comments on WPs for PR lifecycle events
- Gitea tab on the work package split view
- V3 API endpoint: GET /api/v3/work_packages/:id/gitea_pull_requests
- Admin settings UI for bot user and webhook secret
- Nightly cron job to clean up unlinked PR records

lib/open_project/gitea_integration/engine.rb

@@ -0,0 +1,123 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+require "open_project/plugins"
+
+require_relative "patches/api/work_package_representer"
+require_relative "notification_handlers"
+require_relative "hook_handler"
+require_relative "services"
+
+module OpenProject::GiteaIntegration
+  class Engine < ::Rails::Engine
+    engine_name :openproject_gitea_integration
+
+    include OpenProject::Plugins::ActsAsOpEngine
+
+    def self.settings
+      {
+        default: {
+          "gitea_user_id" => nil,
+          "webhook_secret" => nil
+        }
+      }
+    end
+
+    register "openproject-gitea_integration",
+             author_url: "https://www.openproject.org",
+             bundled: false,
+             settings: do
+      ::Redmine::MenuManager.map(:admin_menu) do |menu|
+        menu.push :admin_gitea_integration,
+                  { controller: "/gitea_integration/admin/settings", action: "show" },
+                  parent: :admin_integrations,
+                  if: ->(_) { User.current.admin? },
+                  caption: "Gitea",
+                  icon: :"op-logo-gitea"
+      end
+
+      project_module(:gitea, dependencies: :work_package_tracking) do
+        permission(:show_gitea_content,
+                   {},
+                   permissible_on: %i[work_package project])
+      end
+
+      menu :work_package_split_view,
+           :gitea,
+           { tab: :gitea },
+           if: ->(project) {
+             User.current.allowed_in_project?(:show_gitea_content, project)
+           },
+           skip_permissions_check: true,
+           badge: ->(work_package:, **) {
+             work_package.gitea_pull_requests.count
+           },
+           before: :watchers,
+           caption: :project_module_gitea
+    end
+
+    patches %w[WorkPackage]
+
+    initializer "gitea.register_hook" do
+      ::OpenProject::Webhooks.register_hook "gitea" do |hook, environment, params, user|
+        HookHandler.new.process(hook, environment, params, user)
+      end
+    end
+
+    initializer "gitea.subscribe_to_notifications" do
+      ::OpenProject::Notifications.subscribe("gitea.pull_request",
+                                             &NotificationHandlers.method(:pull_request))
+      ::OpenProject::Notifications.subscribe("gitea.issue_comment",
+                                             &NotificationHandlers.method(:issue_comment))
+    end
+
+    extend_api_response(:v3, :work_packages, :work_package,
+                        &::OpenProject::GiteaIntegration::Patches::API::WorkPackageRepresenter.extension)
+
+    add_api_path :gitea_pull_requests_by_work_package do |id|
+      "#{work_package(id)}/gitea_pull_requests"
+    end
+
+    add_api_path :gitea_user do |id|
+      "gitea_users/#{id}"
+    end
+
+    add_api_endpoint "API::V3::WorkPackages::WorkPackagesAPI", :id do
+      mount ::API::V3::GiteaPullRequests::GiteaPullRequestsByWorkPackageAPI
+    end
+
+    add_cron_jobs do
+      {
+        "Cron::ClearOldGiteaPullRequestsJob": {
+          cron: "25 1 * * *",
+          class: ::Cron::ClearOldGiteaPullRequestsJob.name
+        }
+      }
+    end
+  end
+end

lib/open_project/gitea_integration/hook_handler.rb

@@ -0,0 +1,87 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject::GiteaIntegration
+  class HookHandler
+    # Gitea webhook events we handle.
+    KNOWN_EVENTS = %w[
+      pull_request
+      issue_comment
+    ].freeze
+
+    def process(_hook, request, params, user)
+      event_type = request.env["HTTP_X_GITEA_EVENT"].to_s.downcase.tr(" ", "_")
+
+      Rails.logger.debug { "Received Gitea webhook #{event_type}" }
+
+      return 404 unless KNOWN_EVENTS.include?(event_type)
+      return 403 unless authorized?(request, user)
+
+      notify(params, user, event_type)
+      200
+    end
+
+    private
+
+    def authorized?(request, user)
+      valid_signature?(request) &&
+        user.present? &&
+        (configured_user_id.blank? || user.id == configured_user_id)
+    end
+
+    def notify(params, user, event_type)
+      payload = params[:payload]
+                .permit!
+                .to_h
+                .merge("open_project_user_id" => user.id,
+                       "gitea_event" => event_type)
+
+      OpenProject::Notifications.send(:"gitea.#{event_type}", payload)
+    end
+
+    # Gitea uses HMAC-SHA256, same as GitHub (X-Gitea-Signature header).
+    def valid_signature?(request)
+      secret = plugin_settings[:webhook_secret].presence
+      return true if secret.blank?
+
+      signature_header = request.env["HTTP_X_GITEA_SIGNATURE"]
+      return false if signature_header.blank?
+
+      expected = "sha256=#{OpenSSL::HMAC.hexdigest("SHA256", secret, request.raw_post)}"
+      ActiveSupport::SecurityUtils.secure_compare(expected, signature_header)
+    end
+
+    def configured_user_id
+      plugin_settings[:gitea_user_id].presence&.to_i
+    end
+
+    def plugin_settings
+      Hash(Setting.plugin_openproject_gitea_integration).with_indifferent_access
+    end
+  end
+end

lib/open_project/gitea_integration/notification_handler/helper.rb

@@ -0,0 +1,104 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject::GiteaIntegration
+  module NotificationHandler
+    module Helper
+      def extract_work_package_ids(text)
+        host_name = Regexp.escape(Setting.host_name)
+        wp_id     = WorkPackage::SemanticIdentifier::ID_ROUTE_CONSTRAINT
+        url_part  = /http(?:s?):\/\/#{host_name}\/(?:\S+?\/)*(?:work_packages|wp)\/(#{wp_id})/
+
+        wp_regex = /OP#(#{wp_id})|#{url_part}/
+
+        String(text)
+          .scan(wp_regex)
+          .filter_map { |groups| groups.compact.first }
+          .uniq
+      end
+
+      def find_visible_work_packages(ids, user)
+        WorkPackage
+          .includes(:project)
+          .where_display_id_in(ids)
+          .select { |wp| user.allowed_in_work_package?(:add_work_package_comments, wp) }
+      end
+
+      def find_mentioned_work_packages(text, user)
+        find_visible_work_packages(extract_work_package_ids(text), user)
+      end
+
+      def comment_on_referenced_work_packages(work_packages, user, notes)
+        return if notes.nil?
+
+        work_packages.each do |work_package|
+          ::WorkPackages::UpdateService
+            .new(user:, model: work_package)
+            .call(journal_notes: notes, send_notifications: false)
+        end
+      end
+
+      ##
+      # A wrapper around a ruby Hash to access webhook payloads.
+      # All methods called on it are converted to `.fetch` hash-access, raising an error if the key does not exist.
+      # If the method ends with a question mark, no error is raised if the key does not exist.
+      # If the fetched value is again a hash, the value is wrapped into a new Payload object.
+      class Payload
+        def initialize(payload)
+          @payload = payload
+        end
+
+        def to_h
+          @payload.dup
+        end
+
+        def method_missing(name, *args, &block)
+          super unless args.empty? && block.nil?
+
+          value = if name.end_with?("?")
+                    @payload.fetch(name.to_s[..-2], nil)
+                  else
+                    @payload.fetch(name.to_s)
+                  end
+
+          return Payload.new(value) if value.is_a?(Hash)
+
+          value
+        end
+
+        def respond_to_missing?(_method_name, _include_private = false)
+          true
+        end
+      end
+
+      def wrap_payload(payload)
+        Payload.new(payload)
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/notification_handler/issue_comment.rb

@@ -0,0 +1,69 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject::GiteaIntegration
+  module NotificationHandler
+    ##
+    # Handles Gitea issue/PR comment notifications.
+    # Gitea sends issue_comment events for comments on both issues and pull requests.
+    class IssueComment
+      include OpenProject::GiteaIntegration::NotificationHandler::Helper
+
+      def process(payload_params)
+        @payload = wrap_payload(payload_params)
+
+        return unless payload.action == "created"
+
+        user = User.find_by(id: payload.open_project_user_id)
+        text = payload.comment.body
+        work_packages = find_mentioned_work_packages(text, user)
+
+        return if work_packages.empty?
+
+        notes = generate_notes(payload)
+        comment_on_referenced_work_packages(work_packages, user, notes)
+      end
+
+      private
+
+      attr_reader :payload
+
+      def generate_notes(payload)
+        I18n.t("gitea_integration.issue_comment_referenced_comment",
+               comment_url: payload.comment.html_url,
+               comment_body: payload.comment.body,
+               issue_number: payload.issue.number,
+               issue_title: payload.issue.title,
+               repository: payload.repository.full_name,
+               repository_url: payload.repository.html_url,
+               gitea_user: payload.sender.login,
+               gitea_user_url: payload.sender.avatar_url)
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/notification_handler/pull_request.rb

@@ -0,0 +1,94 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject::GiteaIntegration
+  module NotificationHandler
+    ##
+    # Handles Gitea pull request notifications.
+    class PullRequest
+      include OpenProject::GiteaIntegration::NotificationHandler::Helper
+
+      COMMENT_ACTIONS = %w[opened closed reopened].freeze
+      TRACKED_ACTIONS = %w[opened closed reopened edited synchronized].freeze
+
+      def process(payload_params)
+        @payload = wrap_payload(payload_params)
+
+        return unless TRACKED_ACTIONS.include?(payload.action)
+
+        user = User.find_by(id: payload.open_project_user_id)
+        text = [payload.pull_request.title, payload.pull_request.body]
+          .compact_blank
+          .join(" - ")
+        work_packages = find_mentioned_work_packages(text, user)
+        notes = generate_notes(payload)
+
+        if COMMENT_ACTIONS.include?(payload.action)
+          comment_on_referenced_work_packages(work_packages, user, notes)
+        end
+
+        upsert_pull_request(work_packages)
+      end
+
+      private
+
+      attr_reader :payload
+
+      def generate_notes(payload)
+        key = {
+          "opened" => "opened",
+          "closed" => (payload.pull_request.merged? ? "merged" : "closed"),
+          "reopened" => "reopened"
+        }[payload.action]
+
+        return nil unless key
+
+        I18n.t("gitea_integration.pull_request_#{key}_comment",
+               pr_number: payload.pull_request.number,
+               pr_title: payload.pull_request.title,
+               pr_url: payload.pull_request.html_url,
+               repository: payload.repository.full_name,
+               repository_url: payload.repository.html_url,
+               gitea_user: payload.sender.login,
+               gitea_user_url: payload.sender.avatar_url)
+      end
+
+      def pull_request_record
+        return @pull_request_record if defined?(@pull_request_record)
+
+        @pull_request_record = GiteaPullRequest.find_by(gitea_html_url: payload.pull_request.html_url)
+      end
+
+      def upsert_pull_request(work_packages)
+        return if work_packages.empty? && pull_request_record.nil?
+
+        OpenProject::GiteaIntegration::Services::UpsertPullRequest.new.call(payload, work_packages:)
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/notification_handlers.rb

@@ -0,0 +1,58 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+require_relative "notification_handler/helper"
+require_relative "notification_handler/pull_request"
+require_relative "notification_handler/issue_comment"
+
+module OpenProject::GiteaIntegration
+  module NotificationHandlers
+    class << self
+      def pull_request(payload)
+        with_logging("pull_request") do
+          OpenProject::GiteaIntegration::NotificationHandler::PullRequest.new.process(payload)
+        end
+      end
+
+      def issue_comment(payload)
+        with_logging("issue_comment") do
+          OpenProject::GiteaIntegration::NotificationHandler::IssueComment.new.process(payload)
+        end
+      end
+
+      private
+
+      def with_logging(event_hook)
+        yield if block_given?
+      rescue StandardError => e
+        Rails.logger.error "Failed to handle #{event_hook} from Gitea: #{e} #{e.message}"
+        raise e
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/patches/api/work_package_representer.rb

@@ -0,0 +1,60 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject::GiteaIntegration
+  module Patches
+    module API
+      module WorkPackageRepresenter
+        module_function
+
+        def extension
+          ->(*) do
+            link :gitea,
+                 cache_if: -> { current_user.allowed_in_work_package?(:show_gitea_content, represented) } do
+              next if represented.new_record?
+
+              {
+                href: "#{work_package_path(id: represented.id)}/tabs/gitea",
+                title: "gitea"
+              }
+            end
+
+            link :gitea_pull_requests do
+              next if represented.new_record?
+
+              {
+                href: api_v3_paths.gitea_pull_requests_by_work_package(represented.id),
+                title: "Gitea pull requests"
+              }
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/patches/work_package_patch.rb

@@ -0,0 +1,13 @@
+module OpenProject::GiteaIntegration
+  module Patches
+    module WorkPackagePatch
+      extend ActiveSupport::Concern
+
+      included do
+        has_and_belongs_to_many :gitea_pull_requests
+      end
+    end
+  end
+end
+
+WorkPackage.include OpenProject::GiteaIntegration::Patches::WorkPackagePatch

lib/open_project/gitea_integration/services.rb

@@ -0,0 +1,31 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+require_relative "services/params_helper"
+require_relative "services/upsert_gitea_user"
+require_relative "services/upsert_pull_request"

lib/open_project/gitea_integration/services/params_helper.rb

@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject
+  module GiteaIntegration
+    module Services
+      module ParamsHelper
+        private
+
+        EMPTY_AVATAR_URL = "https://www.gravatar.com/avatar/?d=mp"
+        EMPTY_DESCRIPTION = "No description provided"
+
+        def avatar_url(raw_url)
+          raw_url.presence || EMPTY_AVATAR_URL
+        end
+
+        def description(raw_description)
+          raw_description.presence || EMPTY_DESCRIPTION
+        end
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/services/upsert_gitea_user.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject
+  module GiteaIntegration
+    module Services
+      ##
+      # Takes user data from a Gitea webhook payload and stores it as a GiteaUser.
+      # If the GiteaUser already exists, it is updated.
+      class UpsertGiteaUser
+        include ParamsHelper
+
+        def call(payload)
+          GiteaUser.find_or_initialize_by(gitea_id: payload.id)
+                   .tap do |gitea_user|
+                     gitea_user.update!(extract_params(payload))
+                   end
+        end
+
+        private
+
+        def extract_params(payload)
+          {
+            gitea_id: payload.id,
+            gitea_name: payload.full_name.presence || payload.login,
+            gitea_login: payload.login,
+            gitea_avatar_url: avatar_url(payload.avatar_url)
+          }
+        end
+      end
+    end
+  end
+end

lib/open_project/gitea_integration/services/upsert_pull_request.rb

@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# 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) 2006-2013 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 COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject
+  module GiteaIntegration
+    module Services
+      class UpsertPullRequest
+        include ParamsHelper
+
+        def call(payload, work_packages: [])
+          find_or_initialize(payload).tap do |pr|
+            pr.update!(work_packages: pr.work_packages | work_packages, **extract_params(payload))
+          end
+        end
+
+        private
+
+        def find_or_initialize(payload)
+          GiteaPullRequest.find_by_gitea_identifiers(
+            id: payload.pull_request.number,
+            url: payload.pull_request.html_url,
+            initialize: true
+          )
+        end
+
+        # rubocop:disable Metrics/AbcSize
+        def extract_params(payload)
+          merged = payload.pull_request.merged?
+          {
+            gitea_id: payload.pull_request.number,
+            gitea_user: gitea_user_record(payload.pull_request.user),
+            number: payload.pull_request.number,
+            gitea_html_url: payload.pull_request.html_url,
+            gitea_updated_at: payload.pull_request.updated_at,
+            state: pr_state(payload),
+            title: payload.pull_request.title,
+            body: description(payload.pull_request.body),
+            repository: payload.repository.full_name,
+            draft: payload.pull_request.draft?,
+            merged:,
+            merged_by: merged ? gitea_user_record(payload.pull_request.merged_by?) : nil,
+            merged_at: merged ? payload.pull_request.merged_at? : nil,
+            labels: Array(payload.pull_request.labels?).map { |l| extract_label(l) }
+          }
+        end
+        # rubocop:enable Metrics/AbcSize
+
+        def pr_state(payload)
+          return "merged" if payload.pull_request.merged?
+
+          payload.pull_request.state
+        end
+
+        def extract_label(label)
+          { "name" => label["name"], "color" => "##{label["color"]}" }
+        end
+
+        def gitea_user_record(payload)
+          return if payload.blank?
+
+          ::OpenProject::GiteaIntegration::Services::UpsertGiteaUser.new.call(payload)
+        end
+      end
+    end
+  end
+end