feat: implement YAML-based configuration, .env support, and customizable prompt templates for AI analysis

internal/analyzer/deepseek.go

@@ -12,38 +12,48 @@ import (
 )
 
 type DeepSeekAnalyzer struct {
-	apiKey  string
-	baseURL string
-	client  *http.Client
+	apiKey             string
+	baseURL            string
+	systemPrompt       string
+	userPromptTemplate string
+	client             *http.Client
 }
 
-func NewDeepSeekAnalyzer(apiKey, baseURL string) *DeepSeekAnalyzer {
+func NewDeepSeekAnalyzer(apiKey, baseURL, systemPrompt, userPromptTemplate string) *DeepSeekAnalyzer {
 	if baseURL == "" {
 		baseURL = "https://api.deepseek.com"
 	}
 	return &DeepSeekAnalyzer{
-		apiKey:  apiKey,
-		baseURL: strings.TrimRight(baseURL, "/"),
-		client:  &http.Client{Timeout: 30 * time.Second},
+		apiKey:             apiKey,
+		baseURL:            strings.TrimRight(baseURL, "/"),
+		systemPrompt:       systemPrompt,
+		userPromptTemplate: userPromptTemplate,
+		client:             &http.Client{Timeout: 30 * time.Second},
 	}
 }
 
-func (d *DeepSeekAnalyzer) AnalyzeJD(ctx context.Context, jobTitle, rawContent string) (*AnalysisOutput, error) {
-	prompt := fmt.Sprintf(`You are an expert technical resume screener. Analyze the following job description for the title "%s".
-Provide a structured JSON output with 3 fields:
-- "matched_highlights": list of 3-5 core technical skills/requirements matched (e.g. ["Go (Golang)", "Microservices", "REST APIs"]).
-- "missing_highlights": list of 1-3 missing skills, experience gaps, or extra requirements (e.g. ["10+ yrs experience", "Kubernetes administration"]).
-- "tailoring_suggestions": list of 2-3 specific action points for tailoring a resume to this JD.
+func (d *DeepSeekAnalyzer) buildUserPrompt(jobTitle, rawContent string) string {
+	if d.userPromptTemplate == "" {
+		return fmt.Sprintf("Analyze the following job description for candidate Pengzhan Hao.\n\nJob Title: %s\n\nJob Description:\n%s\n\nProvide the structured evaluation adhering to the JSON schema.", jobTitle, rawContent)
+	}
+	res := strings.ReplaceAll(d.userPromptTemplate, "{{.JobTitle}}", jobTitle)
+	res = strings.ReplaceAll(res, "{{.JobContent}}", rawContent)
+	return res
+}
 
-Job Title: %s
-Job Content:
-%s`, jobTitle, jobTitle, rawContent)
+func (d *DeepSeekAnalyzer) AnalyzeJD(ctx context.Context, jobTitle, rawContent string) (*AnalysisOutput, error) {
+	sysPrompt := d.systemPrompt
+	if sysPrompt == "" {
+		sysPrompt = "You are an expert technical resume screener. You MUST respond with a valid JSON object matching {\"ai_score\": 80.0, \"is_qualified\": true, \"summary\": \"...\", \"matched_highlights\": [...], \"missing_highlights\": [...], \"tailoring_suggestions\": [...]}."
+	}
+
+	userPrompt := d.buildUserPrompt(jobTitle, rawContent)
 
 	reqBody := map[string]interface{}{
 		"model": "deepseek-chat",
 		"messages": []map[string]string{
-			{"role": "system", "content": "You are a professional hiring assistant. You MUST respond ONLY with valid JSON matching {\"matched_highlights\": [...], \"missing_highlights\": [...], \"tailoring_suggestions\": [...]}."},
-			{"role": "user", "content": prompt},
+			{"role": "system", "content": sysPrompt},
+			{"role": "user", "content": userPrompt},
 		},
 		"response_format": map[string]string{
 			"type": "json_object",
@@ -99,7 +109,28 @@ Job Content:
 
 	var output AnalysisOutput
 	if err := json.Unmarshal([]byte(rawJSON), &output); err != nil {
-		return nil, fmt.Errorf("failed to parse DeepSeek JSON output: %w", err)
+		return nil, fmt.Errorf("failed to parse DeepSeek JSON output: %w (content: %s)", err, rawJSON)
+	}
+
+	// Sanitize output bounds
+	if output.AIScore < 0 {
+		output.AIScore = 0
+	} else if output.AIScore > 100 {
+		output.AIScore = 100
+	}
+
+	if output.AIScore >= 60.0 {
+		output.IsQualified = true
+	}
+
+	if output.MatchedHighlights == nil {
+		output.MatchedHighlights = []string{}
+	}
+	if output.MissingHighlights == nil {
+		output.MissingHighlights = []string{}
+	}
+	if output.TailoringSuggestions == nil {
+		output.TailoringSuggestions = []string{}
 	}
 
 	return &output, nil