jobs-monorepo/internal/services/openrouter.go

package services

import (
	"encoding/json"
	"fmt"
	"log"
	"strings"

	"github.com/eduardolat/openroutergo"
	"github.com/jobs-scraper/internal/domain"
)

// JobAnalysisResult represents the structured response from job analysis
type JobAnalysisResult struct {
	Recommendation         string   `json:"recommendation"`
	ConfidenceScore        int      `json:"confidence_score"`
	MatchingSkills         []string `json:"matching_skills"`
	MissingSkills          []string `json:"missing_skills"`
	ExperienceMatch        string   `json:"experience_match"`
	Summary                string   `json:"summary"`
	ImprovementSuggestions []string `json:"improvement_suggestions"`
}

// ShouldApply returns true if the recommendation is to apply for the job
func (r *JobAnalysisResult) ShouldApply() bool {
	return r.Recommendation == "apply"
}

// IsHighConfidence returns true if the confidence score is 70 or above
func (r *JobAnalysisResult) IsHighConfidence() bool {
	return r.ConfidenceScore >= 70
}

type OpenRouterService struct {
	model  string
	apiKey string
}

func NewOpenRouterService(model string, apiKey string) OpenRouterService {
	return OpenRouterService{
		model:  model,
		apiKey: apiKey,
	}
}

func (s *OpenRouterService) AnalyzeJobDescription(cv string, jobDesc domain.JobDescription) (*JobAnalysisResult, error) {
	client, err := openroutergo.
		NewClient().
		WithAPIKey(s.apiKey).
		Create()
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}

	// Build the user message with all the provided data
	userMessage := fmt.Sprintf(`Analyze the following CV against the job description and criteria, then provide a recommendation following the schema below.
		1) If there are missing skills, try to guess if they still match based on similar skills or experience in the cv.
		for example: Javascript is mentioned in the cv, but the job requires Vanilla js, since they are the same thing, it should be included in the matching skills.

		2) The job shouldn't require any language skills, preferbly only english.

		3) The job should be remote, or provide relocation to the country.
	CV:
	%s
	
	Job Description:
	%s
	
	Job Criteria (key-value):
	%v
	
	CRITICAL OUTPUT REQUIREMENTS:
	- Return ONLY raw JSON - NO markdown formatting whatsoever
	- NO backticks, NO code blocks, NO json prefix
	- NO additional text before or after the JSON
	- Start your response directly with { and end with }
	- Use this exact schema and key names:
	{
	  "recommendation": "apply" | "do_not_apply",
	  "confidence_score": number,  // integer 0-100
	  "matching_skills": [string],
	  "missing_skills": [string],
	  "experience_match": "excellent" | "good" | "fair" | "poor",
	  "summary": string,
	  "improvement_suggestions": [string]
	}`, cv, jobDesc.Description, jobDesc.Criteria)

	// Build and execute your request with a fluent API
	_, resp, err := client.
		NewChatCompletion().
		WithModel(s.model).
		WithSystemMessage("You are an expert HR assistant specializing in job application analysis. You help candidates determine if they should apply for specific positions based on their CV and the job requirements. CRITICAL: You must respond with ONLY raw JSON - no markdown, no code blocks, no backticks, no additional text. Start directly with { and end with }.").
		WithUserMessage(userMessage).
		Execute()
	if err != nil {
		return nil, fmt.Errorf("failed to execute completion: %v", err)
	}

	if len(resp.Choices) == 0 {
		return nil, fmt.Errorf("no response choices received from API")
	}

	// Extract JSON from the response (handle markdown code blocks)
	jsonContent := resp.Choices[0].Message.Content

	// Log the raw response for debugging
	log.Printf("Raw API response: %s", jsonContent)

	// Check if response looks like HTML/XML (common error response format)
	if len(jsonContent) > 0 && jsonContent[0] == '<' {
		return nil, fmt.Errorf("API returned HTML/XML instead of JSON. This usually indicates an API error, authentication issue, or rate limiting. Response: %s", jsonContent[:min(200, len(jsonContent))])
	}

	// Clean up markdown code blocks if present
	jsonContent = cleanMarkdownCodeBlocks(jsonContent)

	// Parse the JSON response into our struct
	var result JobAnalysisResult
	if err := json.Unmarshal([]byte(jsonContent), &result); err != nil {
		return nil, fmt.Errorf("failed to parse JSON response: %v. Raw response: %s", err, jsonContent[:min(200, len(jsonContent))])
	}

	return &result, nil
}

// min returns the smaller of two integers
func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

// cleanMarkdownCodeBlocks removes markdown code block formatting from JSON response
func cleanMarkdownCodeBlocks(content string) string {
	// Remove ```json prefix and ``` suffix if present
	content = strings.TrimSpace(content)

	// Remove opening code block markers
	if strings.HasPrefix(content, "```json") {
		content = strings.TrimPrefix(content, "```json")
	} else if strings.HasPrefix(content, "```") {
		content = strings.TrimPrefix(content, "```")
	}

	// Remove closing code block markers
	content = strings.TrimSuffix(content, "```")

	return strings.TrimSpace(content)
}

// func (s *OpenRouterService) CreateCV(cv string, jobDesc domain.JobDescription) (*JobAnalysisResult, error) {
// }