package cli

import (
	"context"
	"errors"
	"io"
	"strings"

	openai "github.com/sashabaranov/go-openai"
)

func CreateChatCompletionRequest(model string, messages []Message, maxTokens int) openai.ChatCompletionRequest {
	chatCompletionMessages := []openai.ChatCompletionMessage{}
	for _, m := range messages {
		chatCompletionMessages = append(chatCompletionMessages, openai.ChatCompletionMessage{
			Role:    m.Role,
			Content: m.OriginalContent,
		})
	}

	return openai.ChatCompletionRequest{
		Model:     model,
		Messages:  chatCompletionMessages,
		MaxTokens: maxTokens,
	}
}

// CreateChatCompletion submits a Chat Completion API request and returns the
// response.
func CreateChatCompletion(model string, messages []Message, maxTokens int) (string, error) {
	client := openai.NewClient(*config.OpenAI.APIKey)
	req := CreateChatCompletionRequest(model, messages, maxTokens)
	resp, err := client.CreateChatCompletion(context.Background(), req)
	if err != nil {
		return "", err
	}

	return resp.Choices[0].Message.Content, nil
}

// CreateChatCompletionStream submits a streaming Chat Completion API request
// and both returns and streams the response to the provided output channel.
// May return a partial response if an error occurs mid-stream.
func CreateChatCompletionStream(model string, messages []Message, maxTokens int, output chan<- string) (string, error) {
	client := openai.NewClient(*config.OpenAI.APIKey)
	req := CreateChatCompletionRequest(model, messages, maxTokens)

	defer close(output)

	stream, err := client.CreateChatCompletionStream(context.Background(), req)
	if err != nil {
		return "", err
	}
	defer stream.Close()

	sb := strings.Builder{}
	for {
		response, e := stream.Recv()
		if errors.Is(e, io.EOF) {
			break
		}

		if e != nil {
			err = e
			break
		}
		chunk := response.Choices[0].Delta.Content
		output <- chunk
		sb.WriteString(chunk)
	}
	return sb.String(), err
}