package openai_test

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

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

func TestChatCompletionsWrongModel(t *testing.T) {
	config := DefaultConfig("whatever")
	config.BaseURL = "http://localhost/v1"
	client := NewClientWithConfig(config)
	ctx := context.Background()

	req := ChatCompletionRequest{
		MaxTokens: 5,
		Model:     "ada",
		Messages: []ChatCompletionMessage{
			{
				Role:    ChatMessageRoleUser,
				Content: "Hello!",
			},
		},
	}
	_, err := client.CreateChatCompletion(ctx, req)
	if !errors.Is(err, ErrChatCompletionInvalidModel) {
		t.Fatalf("CreateChatCompletion should return ErrChatCompletionInvalidModel, but returned: %v", err)
	}
}

func TestChatCompletionsWithStream(t *testing.T) {
	config := DefaultConfig("whatever")
	config.BaseURL = "http://localhost/v1"
	client := NewClientWithConfig(config)
	ctx := context.Background()

	req := ChatCompletionRequest{
		Stream: true,
	}
	_, err := client.CreateChatCompletion(ctx, req)
	if !errors.Is(err, ErrChatCompletionStreamNotSupported) {
		t.Fatalf("CreateChatCompletion didn't return ErrChatCompletionStreamNotSupported error")
	}
}

// TestCompletions Tests the completions endpoint of the API using the mocked server.
func TestChatCompletions(t *testing.T) {
	server := test.NewTestServer()
	server.RegisterHandler("/v1/chat/completions", handleChatCompletionEndpoint)
	// 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 := ChatCompletionRequest{
		MaxTokens: 5,
		Model:     GPT3Dot5Turbo,
		Messages: []ChatCompletionMessage{
			{
				Role:    ChatMessageRoleUser,
				Content: "Hello!",
			},
		},
	}
	_, err = client.CreateChatCompletion(ctx, req)
	if err != nil {
		t.Fatalf("CreateChatCompletion error: %v", err)
	}
}

// handleChatCompletionEndpoint Handles the ChatGPT completion endpoint by the test server.
func handleChatCompletionEndpoint(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 ChatCompletionRequest
	if completionReq, err = getChatCompletionBody(r); err != nil {
		http.Error(w, "could not read request", http.StatusInternalServerError)
		return
	}
	res := ChatCompletionResponse{
		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)

		res.Choices = append(res.Choices, ChatCompletionChoice{
			Message: ChatCompletionMessage{
				Role:    ChatMessageRoleAssistant,
				Content: completionStr,
			},
			Index: i,
		})
	}
	inputTokens := numTokens(completionReq.Messages[0].Content) * 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))
}

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