package friendli

import (

	"context"

	"encoding/json"

	"fmt"

	"io"

)

// ChatService handles chat completion operations

type ChatService struct {

	client *Client

}

// CreateCompletion creates a non-streaming chat completion

func (s *ChatService) CreateCompletion(ctx context.Context, req *ChatCompletionRequest) (*ChatCompletionResponse, error) {

	// Validate request

	if err := validateChatCompletionRequest(req); err != nil {

		return nil, err

	}

	// Ensure streaming is disabled

	stream := false

	req.Stream = &stream

	resp, err := s.client.doRequest(ctx, "POST", "/chat/completions", req)

	if err != nil {

		return nil, err

	}

	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)

	if err != nil {

		return nil, fmt.Errorf("failed to read response body: %w", err)

	}

	var completion ChatCompletionResponse

	if err := json.Unmarshal(body, &completion); err != nil {

		return nil, fmt.Errorf("failed to unmarshal response: %w", err)

	}

	return &completion, nil

}

// CreateCompletionStream creates a streaming chat completion

func (s *ChatService) CreateCompletionStream(ctx context.Context, req *ChatCompletionRequest) (*ChatCompletionStream, error) {

	// Validate request

	if err := validateChatCompletionRequest(req); err != nil {

		return nil, err

	}

	// Ensure streaming is enabled

	stream := true

	req.Stream = &stream

	resp, err := s.client.doStreamingRequest(ctx, "POST", "/chat/completions", req)

	if err != nil {

		return nil, err

	}

	return newChatCompletionStream(resp), nil

}

// validateChatCompletionRequest validates the chat completion request

func validateChatCompletionRequest(req *ChatCompletionRequest) error {

	if req.Model == "" {

		return ErrMissingModel

	}

	if len(req.Messages) == 0 {

		return ErrEmptyMessages

	}

	return nil

}