1 files changed, 94 insertions, 0 deletions
diff --git a/app/models/ci/catalog/components_project.rb b/app/models/ci/catalog/components_project.rb
new file mode 100644
index 00000000000..2bc33a6f050
--- /dev/null
+++ b/app/models/ci/catalog/components_project.rb
@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+module Ci
+  module Catalog
+    class ComponentsProject
+      # ComponentsProject is a type of Catalog Resource which contains one or more
+      # CI/CD components.
+      # It is responsible for retrieving the data of a component file, including the content, name, and file path.
+
+      TEMPLATE_FILE = 'template.yml'
+      TEMPLATES_DIR = 'templates'
+      TEMPLATE_PATH_REGEX = '^templates\/\w+\-?\w+(?:\/template)?\.yml$'
+
+      ComponentData = Struct.new(:content, :path, keyword_init: true)
+
+      def initialize(project, sha = project&.default_branch)
+        @project = project
+        @sha = sha
+      end
+
+      def fetch_component_paths(sha)
+        project.repository.search_files_by_regexp(TEMPLATE_PATH_REGEX, sha)
+      end
+
+      def extract_component_name(path)
+        return unless path.match?(TEMPLATE_PATH_REGEX)
+
+        dirname = File.dirname(path)
+        filename = File.basename(path, '.*')
+
+        if dirname == TEMPLATES_DIR
+          filename
+        else
+          File.basename(dirname)
+        end
+      end
+
+      def extract_inputs(blob)
+        result = Gitlab::Ci::Config::Yaml::Loader.new(blob).load_uninterpolated_yaml
+
+        raise result.error_class, result.error unless result.valid?
+
+        result.inputs
+      end
+
+      def fetch_component(component_name)
+        path = simple_template_path(component_name)
+        content = fetch_content(path)
+
+        if content.nil?
+          path = complex_template_path(component_name)
+          content = fetch_content(path)
+        end
+
+        if content.nil?
+          path = legacy_template_path(component_name)
+          content = fetch_content(path)
+        end
+
+        ComponentData.new(content: content, path: path)
+      end
+
+      private
+
+      attr_reader :project, :sha
+
+      def fetch_content(component_path)
+        project.repository.blob_data_at(sha, component_path)
+      end
+
+      # A simple template consists of a single file
+      def simple_template_path(component_name)
+        # TODO: Extract this line and move to fetch_content once we remove legacy fetching
+        return unless component_name.index('/').nil?
+
+        File.join(TEMPLATES_DIR, "#{component_name}.yml")
+      end
+
+      # A complex template is directory-based and may consist of multiple files.
+      # Given a path like "my-org/sub-group/the-project/templates/component"
+      # returns the entry point path: "templates/component/template.yml".
+      def complex_template_path(component_name)
+        # TODO: Extract this line and move to fetch_content once we remove legacy fetching
+        return unless component_name.index('/').nil?
+
+        File.join(TEMPLATES_DIR, component_name, TEMPLATE_FILE)
+      end
+
+      def legacy_template_path(component_name)
+        File.join(component_name, TEMPLATE_FILE).delete_prefix('/')
+      end
+    end
+  end
+end