first commit

internal/deepseek/deepseek.go

@@ -0,0 +1,99 @@
+// Package deepseek provides a minimal client for the DeepSeek API,
+// which is compatible with the OpenAI chat completions format.
+package deepseek
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+const (
+	apiURL = "https://api.deepseek.com/chat/completions"
+	model  = "deepseek-coder"
+
+	systemPrompt = `You are an expert code reviewer. When given a pull request diff, you:
+- Identify bugs, logic errors, and edge cases
+- Flag security vulnerabilities (injections, auth issues, data exposure, etc.)
+- Note performance concerns
+- Point out style or maintainability issues
+- Highlight anything that looks unfinished or unclear
+
+Be specific: reference file names and line numbers where relevant.
+Be concise: skip praise for obvious or trivial things.
+Format your response in Markdown with clear sections.
+If the diff is clean, say so briefly.`
+)
+
+// Client is a DeepSeek API client.
+type Client struct {
+	APIKey string
+	http   *http.Client
+}
+
+// New creates a new DeepSeek client.
+func New(apiKey string) *Client {
+	return &Client{
+		APIKey: apiKey,
+		http:   &http.Client{Timeout: 120 * time.Second},
+	}
+}
+
+type chatMessage struct {
+	Role    string `json:"role"`
+	Content string `json:"content"`
+}
+
+type chatRequest struct {
+	Model    string        `json:"model"`
+	Messages []chatMessage `json:"messages"`
+}
+
+type chatResponse struct {
+	Choices []struct {
+		Message chatMessage `json:"message"`
+	} `json:"choices"`
+	Error *struct {
+		Message string `json:"message"`
+	} `json:"error,omitempty"`
+}
+
+// Review sends a PR diff to deepseek-coder and returns the review text.
+func (c *Client) Review(title, diff string) (string, error) {
+	userContent := fmt.Sprintf("Please review this pull request.\n\n**Title:** %s\n\n```diff\n%s\n```", title, diff)
+
+	body, _ := json.Marshal(chatRequest{
+		Model: model,
+		Messages: []chatMessage{
+			{Role: "system", Content: systemPrompt},
+			{Role: "user", Content: userContent},
+		},
+	})
+
+	req, err := http.NewRequest("POST", apiURL, bytes.NewReader(body))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Authorization", "Bearer "+c.APIKey)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	var r chatResponse
+	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
+		return "", fmt.Errorf("deepseek: decode response: %w", err)
+	}
+	if r.Error != nil {
+		return "", fmt.Errorf("deepseek: %s", r.Error.Message)
+	}
+	if len(r.Choices) == 0 {
+		return "", fmt.Errorf("deepseek: empty response")
+	}
+	return r.Choices[0].Message.Content, nil
+}