package openai_test

import (
	. "github.com/sashabaranov/go-openai"
	"github.com/sashabaranov/go-openai/internal/test"

	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
	"testing"
	"time"
)

// TestCompletions Tests the completions endpoint of the API using the mocked server.
func TestCompletions(t *testing.T) {
	server := test.NewTestServer()
	server.RegisterHandler("/v1/completions", handleCompletionEndpoint)
	// create the test server
	var err error
	ts := server.OpenAITestServer()
	ts.Start()
	defer ts.Close()

	config := DefaultConfig(test.GetTestToken())
	config.BaseURL = ts.URL + "/v1"
	client := NewClientWithConfig(config)
	ctx := context.Background()

	req := CompletionRequest{
		MaxTokens: 5,
		Model:     "ada",
	}
	req.Prompt = "Lorem ipsum"
	_, err = client.CreateCompletion(ctx, req)
	if err != nil {
		t.Fatalf("CreateCompletion error: %v", err)
	}
}

// handleCompletionEndpoint Handles the completion endpoint by the test server.
func handleCompletionEndpoint(w http.ResponseWriter, r *http.Request) {
	var err error
	var resBytes []byte

	// completions only accepts POST requests
	if r.Method != "POST" {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
	}
	var completionReq CompletionRequest
	if completionReq, err = getCompletionBody(r); err != nil {
		http.Error(w, "could not read request", http.StatusInternalServerError)
		return
	}
	res := CompletionResponse{
		ID:      strconv.Itoa(int(time.Now().Unix())),
		Object:  "test-object",
		Created: time.Now().Unix(),
		// would be nice to validate Model during testing, but
		// this may not be possible with how much upkeep
		// would be required / wouldn't make much sense
		Model: completionReq.Model,
	}
	// create completions
	for i := 0; i < completionReq.N; i++ {
		// generate a random string of length completionReq.Length
		completionStr := strings.Repeat("a", completionReq.MaxTokens)
		if completionReq.Echo {
			completionStr = completionReq.Prompt + completionStr
		}
		res.Choices = append(res.Choices, CompletionChoice{
			Text:  completionStr,
			Index: i,
		})
	}
	inputTokens := numTokens(completionReq.Prompt) * completionReq.N
	completionTokens := completionReq.MaxTokens * completionReq.N
	res.Usage = Usage{
		PromptTokens:     inputTokens,
		CompletionTokens: completionTokens,
		TotalTokens:      inputTokens + completionTokens,
	}
	resBytes, _ = json.Marshal(res)
	fmt.Fprintln(w, string(resBytes))
}

// getCompletionBody Returns the body of the request to create a completion.
func getCompletionBody(r *http.Request) (CompletionRequest, error) {
	completion := CompletionRequest{}
	// read the request body
	reqBody, err := io.ReadAll(r.Body)
	if err != nil {
		return CompletionRequest{}, err
	}
	err = json.Unmarshal(reqBody, &completion)
	if err != nil {
		return CompletionRequest{}, err
	}
	return completion, nil
}