web-hosts/domains/coppertone.tech/backend/functions/llm-service/providers.go

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"

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

// callOpenAI sends a message to OpenAI's API
func callOpenAI(apiKey, model, message string, history []ChatMessage, temperature float64, maxTokens int) (string, int, error) {
	if model == "" {
		model = "gpt-4o"
	}

	client := openai.NewClient(apiKey)

	// Build messages array
	messages := []openai.ChatCompletionMessage{}

	// Add history
	for _, msg := range history {
		role := msg.Role
		if role == "assistant" {
			role = openai.ChatMessageRoleAssistant
		} else {
			role = openai.ChatMessageRoleUser
		}
		messages = append(messages, openai.ChatCompletionMessage{
			Role:    role,
			Content: msg.Content,
		})
	}

	// Add current message
	messages = append(messages, openai.ChatCompletionMessage{
		Role:    openai.ChatMessageRoleUser,
		Content: message,
	})

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := client.CreateChatCompletion(ctx, openai.ChatCompletionRequest{
		Model:       model,
		Messages:    messages,
		Temperature: float32(temperature),
		MaxTokens:   maxTokens,
	})

	if err != nil {
		return "", 0, fmt.Errorf("openai api error: %w", err)
	}

	if len(resp.Choices) == 0 {
		return "", 0, fmt.Errorf("no response from openai")
	}

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

// callGemini sends a message to Google Gemini's API
func callGemini(apiKey, model, message string, history []ChatMessage, temperature float64, maxTokens int) (string, int, error) {
	if model == "" {
		model = "gemini-2.0-flash-exp"
	}

	url := fmt.Sprintf("https://generativelanguage.googleapis.com/v1beta/models/%s:generateContent?key=%s", model, apiKey)

	// Build request
	type Part struct {
		Text string `json:"text"`
	}
	type Content struct {
		Role  string `json:"role,omitempty"`
		Parts []Part `json:"parts"`
	}
	type GenerationConfig struct {
		Temperature     float64 `json:"temperature"`
		MaxOutputTokens int     `json:"maxOutputTokens"`
	}
	type Request struct {
		Contents         []Content        `json:"contents"`
		GenerationConfig GenerationConfig `json:"generationConfig"`
	}

	contents := []Content{}

	// Add history
	for _, msg := range history {
		role := "user"
		if msg.Role == "assistant" {
			role = "model"
		}
		contents = append(contents, Content{
			Role:  role,
			Parts: []Part{{Text: msg.Content}},
		})
	}

	// Add current message
	contents = append(contents, Content{
		Role:  "user",
		Parts: []Part{{Text: message}},
	})

	reqBody := Request{
		Contents: contents,
		GenerationConfig: GenerationConfig{
			Temperature:     temperature,
			MaxOutputTokens: maxTokens,
		},
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return "", 0, err
	}

	resp, err := http.Post(url, "application/json", bytes.NewBuffer(jsonData))
	if err != nil {
		return "", 0, fmt.Errorf("gemini api error: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", 0, fmt.Errorf("gemini api error: %s - %s", resp.Status, string(body))
	}

	type Candidate struct {
		Content struct {
			Parts []Part `json:"parts"`
		} `json:"content"`
	}
	type UsageMetadata struct {
		TotalTokenCount int `json:"totalTokenCount"`
	}
	type Response struct {
		Candidates    []Candidate   `json:"candidates"`
		UsageMetadata UsageMetadata `json:"usageMetadata"`
	}

	var geminiResp Response
	if err := json.NewDecoder(resp.Body).Decode(&geminiResp); err != nil {
		return "", 0, err
	}

	if len(geminiResp.Candidates) == 0 || len(geminiResp.Candidates[0].Content.Parts) == 0 {
		return "", 0, fmt.Errorf("no response from gemini")
	}

	return geminiResp.Candidates[0].Content.Parts[0].Text, geminiResp.UsageMetadata.TotalTokenCount, nil
}

// callClaude sends a message to Anthropic Claude's API
func callClaude(apiKey, model, message string, history []ChatMessage, temperature float64, maxTokens int) (string, int, error) {
	if model == "" {
		model = "claude-sonnet-4-5-20250929"
	}

	url := "https://api.anthropic.com/v1/messages"

	// Build request
	type Message struct {
		Role    string `json:"role"`
		Content string `json:"content"`
	}
	type Request struct {
		Model       string    `json:"model"`
		Messages    []Message `json:"messages"`
		MaxTokens   int       `json:"max_tokens"`
		Temperature float64   `json:"temperature"`
	}

	messages := []Message{}

	// Add history
	for _, msg := range history {
		messages = append(messages, Message{
			Role:    msg.Role,
			Content: msg.Content,
		})
	}

	// Add current message
	messages = append(messages, Message{
		Role:    "user",
		Content: message,
	})

	reqBody := Request{
		Model:       model,
		Messages:    messages,
		MaxTokens:   maxTokens,
		Temperature: temperature,
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return "", 0, err
	}

	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return "", 0, err
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-api-key", apiKey)
	req.Header.Set("anthropic-version", "2023-06-01")

	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return "", 0, fmt.Errorf("claude api error: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", 0, fmt.Errorf("claude api error: %s - %s", resp.Status, string(body))
	}

	type ContentBlock struct {
		Type string `json:"type"`
		Text string `json:"text"`
	}
	type Usage struct {
		InputTokens  int `json:"input_tokens"`
		OutputTokens int `json:"output_tokens"`
	}
	type Response struct {
		Content []ContentBlock `json:"content"`
		Usage   Usage          `json:"usage"`
	}

	var claudeResp Response
	if err := json.NewDecoder(resp.Body).Decode(&claudeResp); err != nil {
		return "", 0, err
	}

	if len(claudeResp.Content) == 0 {
		return "", 0, fmt.Errorf("no response from claude")
	}

	totalTokens := claudeResp.Usage.InputTokens + claudeResp.Usage.OutputTokens
	return claudeResp.Content[0].Text, totalTokens, nil
}

// callQwen sends a message to Qwen AI's API
func callQwen(apiKey, model, message string, history []ChatMessage, temperature float64, maxTokens int) (string, int, error) {
	if model == "" {
		model = "qwen-max"
	}

	url := "https://dashscope.aliyuncs.com/api/v1/services/aigc/text-generation/generation"

	// Build request
	type Message struct {
		Role    string `json:"role"`
		Content string `json:"content"`
	}
	type Input struct {
		Messages []Message `json:"messages"`
	}
	type Parameters struct {
		ResultFormat string  `json:"result_format"`
		Temperature  float64 `json:"temperature,omitempty"`
		MaxTokens    int     `json:"max_tokens,omitempty"`
	}
	type Request struct {
		Model      string     `json:"model"`
		Input      Input      `json:"input"`
		Parameters Parameters `json:"parameters"`
	}

	messages := []Message{}

	// Add history
	for _, msg := range history {
		messages = append(messages, Message{
			Role:    msg.Role,
			Content: msg.Content,
		})
	}

	// Add current message
	messages = append(messages, Message{
		Role:    "user",
		Content: message,
	})

	reqBody := Request{
		Model: model,
		Input: Input{Messages: messages},
		Parameters: Parameters{
			ResultFormat: "message",
			Temperature:  temperature,
			MaxTokens:    maxTokens,
		},
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return "", 0, err
	}

	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return "", 0, err
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+apiKey)

	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return "", 0, fmt.Errorf("qwen api error: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", 0, fmt.Errorf("qwen api error: %s - %s", resp.Status, string(body))
	}

	type Output struct {
		Choices []struct {
			Message Message `json:"message"`
		} `json:"choices"`
	}
	type Usage struct {
		TotalTokens int `json:"total_tokens"`
	}
	type Response struct {
		Output Output `json:"output"`
		Usage  Usage  `json:"usage"`
	}

	var qwenResp Response
	if err := json.NewDecoder(resp.Body).Decode(&qwenResp); err != nil {
		return "", 0, err
	}

	if len(qwenResp.Output.Choices) == 0 {
		return "", 0, fmt.Errorf("no response from qwen")
	}

	return qwenResp.Output.Choices[0].Message.Content, qwenResp.Usage.TotalTokens, nil
}

// callHuggingFace sends a message to HuggingFace's Inference API
func callHuggingFace(apiKey, model, message string, history []ChatMessage, temperature float64, maxTokens int) (string, int, error) {
	if model == "" {
		model = "meta-llama/Llama-3.3-70B-Instruct"
	}

	url := fmt.Sprintf("https://api-inference.huggingface.co/models/%s", model)

	// Build conversation prompt
	prompt := ""
	for _, msg := range history {
		if msg.Role == "user" {
			prompt += fmt.Sprintf("User: %s\n", msg.Content)
		} else {
			prompt += fmt.Sprintf("Assistant: %s\n", msg.Content)
		}
	}
	prompt += fmt.Sprintf("User: %s\nAssistant:", message)

	// Build request
	type Parameters struct {
		Temperature float64 `json:"temperature"`
		MaxNewTokens int    `json:"max_new_tokens"`
		ReturnFullText bool `json:"return_full_text"`
	}
	type Request struct {
		Inputs     string     `json:"inputs"`
		Parameters Parameters `json:"parameters"`
	}

	reqBody := Request{
		Inputs: prompt,
		Parameters: Parameters{
			Temperature:    temperature,
			MaxNewTokens:   maxTokens,
			ReturnFullText: false,
		},
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return "", 0, err
	}

	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return "", 0, err
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+apiKey)

	client := &http.Client{Timeout: 60 * time.Second} // HF can be slower
	resp, err := client.Do(req)
	if err != nil {
		return "", 0, fmt.Errorf("huggingface api error: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", 0, fmt.Errorf("huggingface api error: %s - %s", resp.Status, string(body))
	}

	type Response struct {
		GeneratedText string `json:"generated_text"`
	}

	var hfResp []Response
	if err := json.NewDecoder(resp.Body).Decode(&hfResp); err != nil {
		return "", 0, err
	}

	if len(hfResp) == 0 {
		return "", 0, fmt.Errorf("no response from huggingface")
	}

	// Estimate tokens (rough approximation: ~4 chars per token)
	estimatedTokens := len(hfResp[0].GeneratedText) / 4

	return hfResp[0].GeneratedText, estimatedTokens, nil
}