feat: add linked issue api

app/controllers/api/v1/accounts/integrations/linear_controller.rb

@@ -49,6 +49,19 @@ class Api::V1::Accounts::Integrations::LinearController < Api::V1::Accounts::Bas
     end
   end
 
+  def linked_issue
+    render json: { error: 'Specify link with parameter link' }, status: :unprocessable_entity if params[:link].blank? && return
+
+    url = params[:link]
+    issues = linear_processor_service.linked_issue(url)
+
+    if issues.is_a?(Hash) && issues[:error]
+      render json: { error: issues[:error] }, status: :unprocessable_entity
+    else
+      render json: issues, status: :ok
+    end
+  end
+
   def search_issue
     render json: { error: 'Specify search string with parameter q' }, status: :unprocessable_entity if params[:q].blank? && return
 

config/routes.rb

@@ -235,6 +235,7 @@ Rails.application.routes.draw do
                 post :link_issue
                 post :unlink_issue
                 get :search_issue
+                get :linked_issue
               end
             end
           end

lib/integrations/linear/processor_service.rb

@@ -58,6 +58,13 @@ class Integrations::Linear::ProcessorService
     response['searchIssues']['nodes'].map(&:as_json)
   end
 
+  def linked_issue(url)
+    response = linear_client.linked_issue(url)
+    return response if response[:error]
+
+    response['attachmentsForURL']['nodes'].map(&:as_json)
+  end
+
   private
 
   def linear_hook

lib/linear.rb

@@ -35,6 +35,12 @@ class Linear
     execute_query(LinearQueries.search_issue(term))
   end
 
+  def linked_issue(url)
+    raise ArgumentError, 'Missing link' if url.blank?
+
+    execute_query(LinearQueries.linked_issue(url))
+  end
+
   def create_issue(params)
     validate_team_and_title(params)
     validate_priority(params[:priority])

lib/linear_queries.rb

@@ -58,4 +58,22 @@ module LinearQueries
       }
     GRAPHQL
   end
+
+  def self.linked_issue(url)
+    <<~GRAPHQL
+      query {
+        attachmentsForURL(url: "#{url}") {
+          nodes {
+            id
+            title
+            issue {
+              id
+              title
+              description
+            }
+          }
+        }
+      }
+    GRAPHQL
+  end
 end

spec/controllers/api/v1/accounts/integrations/linear_controller_spec.rb

@@ -219,4 +219,36 @@ RSpec.describe 'Linear Integration API', type: :request do
       end
     end
   end
+
+  describe 'GET /api/v1/accounts/:account_id/integrations/linear/linked_issue' do
+    let(:link) { 'https://linear.app/issue1' }
+
+    context 'when it is an authenticated user' do
+      context 'when linked issue is found' do
+        let(:linked_issue) { [{ 'id' => 'issue1', 'title' => 'Sample Issue' }] }
+
+        it 'returns linked issue' do
+          allow(processor_service).to receive(:linked_issue).with(link).and_return(linked_issue)
+          get "/api/v1/accounts/#{account.id}/integrations/linear/linked_issue",
+              params: { link: link },
+              headers: agent.create_new_auth_token,
+              as: :json
+          expect(response).to have_http_status(:ok)
+          expect(response.body).to include('Sample Issue')
+        end
+      end
+
+      context 'when linked issue is not found' do
+        it 'returns error message' do
+          allow(processor_service).to receive(:linked_issue).with(link).and_return(error: 'error message')
+          get "/api/v1/accounts/#{account.id}/integrations/linear/linked_issue",
+              params: { link: link },
+              headers: agent.create_new_auth_token,
+              as: :json
+          expect(response).to have_http_status(:unprocessable_entity)
+          expect(response.body).to include('error message')
+        end
+      end
+    end
+  end
 end

spec/lib/integrations/linear/processor_service_spec.rb

@@ -178,4 +178,31 @@ describe Integrations::Linear::ProcessorService do
       end
     end
   end
+
+  describe '#linked_issue' do
+    let(:url) { 'https://example.com' }
+    let(:linked_response) do
+      {
+        'attachmentsForURL' => { 'nodes' => [{ 'id' => 'attachment1', :issue => { 'id' => 'issue1' } }] }
+      }
+    end
+
+    context 'when Linear client returns valid data' do
+      it 'returns parsed linked data' do
+        allow(linear_client).to receive(:linked_issue).with(url).and_return(linked_response)
+        result = service.linked_issue(url)
+        expect(result).to contain_exactly({ 'id' => 'attachment1', 'issue' => { 'id' => 'issue1' } })
+      end
+    end
+
+    context 'when Linear client returns an error' do
+      let(:error_response) { { error: 'Some error message' } }
+
+      it 'returns the error' do
+        allow(linear_client).to receive(:linked_issue).with(url).and_return(error_response)
+        result = service.linked_issue(url)
+        expect(result).to eq(error_response)
+      end
+    end
+  end
 end

spec/lib/linear_spec.rb

@@ -279,4 +279,34 @@ describe Linear do
       end
     end
   end
+
+  context 'when querying linked issues' do
+    let(:url) { 'https://example.com' }
+
+    context 'when the API response is success' do
+      before do
+        linear_client.instance_variable_set(:@client, client)
+        stub_request(:post, url)
+          .to_return(status: 200, body: { data: { linkedIssue: { id: 'issue1', title: 'Title' } } }.to_json)
+      end
+
+      it 'returns linked issues' do
+        response = linear_client.linked_issue(url)
+        expect(response).to eq({ 'linkedIssue' => { 'id' => 'issue1', 'title' => 'Title' } })
+      end
+    end
+
+    context 'when the API response is an error' do
+      before do
+        linear_client.instance_variable_set(:@client, client)
+        stub_request(:post, url)
+          .to_return(status: 422, body: { errors: [{ message: 'Error retrieving data' }] }.to_json)
+      end
+
+      it 'raises an exception' do
+        response = linear_client.linked_issue(url)
+        expect(response).to eq({ :error => 'Error: the server responded with status 422' })
+      end
+    end
+  end
 end