two_phase_search.py

from typing import List, Dict, Optional
from opensearch_client import OpenSearchClient
from chroma_storage import ChromaMatchingSystem
from embeddings import JobPosting

class TwoPhaseSearchSystem:
    def __init__(self, chroma_matcher: ChromaMatchingSystem, opensearch_client: OpenSearchClient):
        self.chroma_matcher = chroma_matcher
        self.opensearch_client = opensearch_client

    def search_candidates(self, 
                        job_posting: JobPosting,
                        search_params: Dict,
                        n_results: int = 10) -> List[Dict]:
        """
        Two-phase search:
        1. OpenSearch boolean filtering
        2. ChromaDB embedding matching
        """
        # Phase 1: OpenSearch Filtering
        opensearch_results = self.opensearch_client.search_jobseekers(search_params)

        if not opensearch_results:
            return []

        # Phase 2: ChromaDB Embedding Matching
        # Get matches only for jobseekers that passed OpenSearch filtering
        matches = self.chroma_matcher.get_matches(
            job_posting=job_posting,
            n_results=n_results,
            where_conditions={"jobseeker_id": {"$in": [r['jobseeker_id'] for r in opensearch_results]}}
        )

        # Combine OpenSearch scores with ChromaDB match results
        final_results = []
        for match in matches:
            # Find corresponding OpenSearch result
            opensearch_result = next(
                (r for r in opensearch_results if r['jobseeker_id'] == match.jobseeker_id), 
                None
            )
            if opensearch_result:
                final_results.append({
                    'jobseeker_id': match.jobseeker_id,
                    'similarity_score': match.similarity_score,
                    'field_scores': match.field_scores,
                    'explanation': match.explanation,
                    'opensearch_score': opensearch_result.get('_score', 0.0)
                })

        return final_results

    def build_search_params(self,
                       job_posting: JobPosting,
                       location: Optional[Dict] = None,
                       certifications: Optional[Dict] = None,
                       tags: Optional[List[Dict]] = None,
                       minimum_skills_match: int = 3,
                       minimum_results: int = 10) -> Dict:
        """
        Build OpenSearch query parameters with fallback logic
        """
        # Try increasingly relaxed queries until we get enough results
        params_list = self._generate_param_variations(
            job_posting=job_posting,
            location=location,
            certifications=certifications,
            tags=tags,
            minimum_skills_match=minimum_skills_match
        )
        
        # Try each parameter set until we get enough results
        for params in params_list:
            results = self.opensearch_client.search_jobseekers(params)
            if results and len(results) >= minimum_results:
                return params
                
        # If no parameter set gives enough results, return most basic query
        return {
            "skills": [skill.skill_name for skill in job_posting.primary_skills],
            "minimum_skills_should_match": 1,  # Most relaxed skills matching
            "size": 100,
            "sort_by": ["score"]
        }

    def _generate_param_variations(self,
                                job_posting: JobPosting,
                                location: Optional[Dict] = None,
                                certifications: Optional[Dict] = None,
                                tags: Optional[List[Dict]] = None,
                                minimum_skills_match: int = 3) -> List[Dict]:
        """Generate variations of search parameters from strict to relaxed"""
        primary_skills = [skill.skill_name for skill in job_posting.primary_skills]
        
        # Start with most restrictive parameters
        strict_params = {
            "boolean_search_query": job_posting.title,
            "skills": primary_skills,
            "minimum_skills_should_match": minimum_skills_match,
            "size": 100,
            "sort_by": ["score"]
        }
        
        # Add additional filters if provided
        if location:
            strict_params.update({
                "country_filter": location.get("country"),
                "state_filter": location.get("state")
            })
        
        if certifications:
            strict_params.update({
                "certifications_name": certifications.get("name"),
                "certifications_organization": certifications.get("organization")
            })
        
        if tags:
            strict_params["tags"] = tags
        
        # Create variations with progressively fewer restrictions
        variations = [
            strict_params,  # Try all filters first
            {**strict_params, "minimum_skills_should_match": 2},  # Relax skills matching
            {k: v for k, v in strict_params.items() 
            if k not in ["certifications_name", "certifications_organization"]},  # Remove cert filters
            {k: v for k, v in strict_params.items() 
            if k not in ["state_filter", "country_filter"]},  # Remove location filters
            {k: v for k, v in strict_params.items() 
            if k not in ["tags"]},  # Remove tag filters
            {  # Most basic query
                "skills": primary_skills,
                "minimum_skills_should_match": 1,
                "size": 100,
                "sort_by": ["score"]
            }
        ]
        
        return variations