Add Completion api

Might add a builder or something to make setting specific parameters easier

example/src/main/java/example/OpenAiApiExample.java

@@ -1,6 +1,7 @@
 package example;
 
 import openai.OpenAiService;
+import openai.completion.CompletionRequest;
 import openai.engine.Engine;
 
 class OpenAiApiExample {
@@ -8,11 +9,18 @@ class OpenAiApiExample {
         String token = System.getenv("OPENAI_TOKEN");
         OpenAiService service = new OpenAiService(token);
 
-        System.out.println("Getting available engines");
+        System.out.println("Getting available engines...");
         service.getEngines().forEach(System.out::println);
 
-        System.out.println("Getting ada engine");
+        System.out.println("Getting ada engine...");
         Engine ada = service.getEngine("ada");
         System.out.println(ada);
+
+        System.out.println("Creating completion...");
+        CompletionRequest completionRequest = new CompletionRequest();
+        completionRequest.setPrompt("Somebody once told me the world is gonna roll me");
+        completionRequest.setEcho(true);
+        service.createCompletion("ada", completionRequest).getChoices().forEach(System.out::println);
+
     }
 }

openai/src/main/java/openai/OpenAiApi.java

@@ -1,8 +1,12 @@
 package openai;
 
 import io.reactivex.Single;
+import openai.completion.CompletionRequest;
+import openai.completion.CompletionResult;
 import openai.engine.Engine;
+import retrofit2.http.Body;
 import retrofit2.http.GET;
+import retrofit2.http.POST;
 import retrofit2.http.Path;
 
 public interface OpenAiApi {
@@ -12,4 +16,7 @@ public interface OpenAiApi {
 
     @GET("/v1/engines/{engine_id}")
     Single<Engine> getEngine(@Path("engine_id") String engineId);
+
+    @POST("/v1/engines/{engine_id}/completions")
+    Single<CompletionResult> createCompletion(@Path("engine_id") String engineId, @Body CompletionRequest request);
 }

openai/src/main/java/openai/OpenAiService.java

@@ -6,6 +6,8 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.PropertyNamingStrategy;
 import okhttp3.ConnectionPool;
 import okhttp3.OkHttpClient;
+import openai.completion.CompletionRequest;
+import openai.completion.CompletionResult;
 import openai.engine.Engine;
 import retrofit2.Retrofit;
 import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory;
@@ -46,4 +48,8 @@ public class OpenAiService {
     public Engine getEngine(String engineId) {
         return api.getEngine(engineId).blockingGet();
     }
+
+    public CompletionResult createCompletion(String engineId, CompletionRequest request) {
+        return api.createCompletion(engineId, request).blockingGet();
+    }
 }

openai/src/main/java/openai/completion/CompletionChoice.java

@@ -0,0 +1,11 @@
+package openai.completion;
+
+import lombok.Data;
+
+@Data
+public class CompletionChoice {
+    String text;
+    Integer index;
+    // todo add logprobs
+    String finish_reason;
+}

openai/src/main/java/openai/completion/CompletionRequest.java

@@ -0,0 +1,21 @@
+package openai.completion;
+
+import lombok.Data;
+
+import java.util.List;
+
+@Data
+public class CompletionRequest {
+    String prompt;
+    Integer maxTokens;
+    Double temperature;
+    Double topP;
+    Integer n;
+    Boolean stream;
+    Integer logprobs;
+    Boolean echo;
+    List<String> stop; //todo test this
+    Double presencePenalty;
+    Double frequencyPenalty;
+    Integer bestOf;
+}

openai/src/main/java/openai/completion/CompletionResult.java

@@ -0,0 +1,14 @@
+package openai.completion;
+
+import lombok.Data;
+
+import java.util.List;
+
+@Data
+public class CompletionResult {
+    String id;
+    String object;
+    long created;
+    String model;
+    List<CompletionChoice> choices;
+}