import uuid
from datetime import datetime
from services.db import applications_col
import logging

logger = logging.getLogger(__name__)


def create_application(data):
    """
    Create a new application record in database
    """
    try:
        application = {
            "id": str(uuid.uuid4()),
            "job_id": data.get("job_id"),
            "user_id": data.get("user_id"),
            "candidate_name": data.get("candidate_name"),
            "candidate_email": data.get("candidate_email"),
            "cover_letter": data.get("cover_letter", ""),
            "resume_path": data.get("resume_path"),
            "cv_text": data.get("cv_text", ""),
            "cv_score": data.get("cv_score", 0),
            "cv_analysis": data.get("cv_analysis"),  # full CV↔JD breakdown for recruiters
            "status": data.get("status", "pending"),
            "applied_at": data.get("applied_at", datetime.now().isoformat()),
            "updated_at": datetime.now().isoformat()
        }
        
        applications_col.insert_one(application)
        application.pop("_id", None)
        logger.info(f"✅ Application created: {application['id']} for user {application['user_id']}")
        return application
        
    except Exception as e:
        logger.error(f"Error creating application: {e}")
        raise e


def get_applications_by_job(job_id):
    """
    Get all applications for a specific job
    """
    try:
        apps = list(applications_col.find({"job_id": job_id}))
        for app in apps:
            app.pop("_id", None)
        logger.info(f"Found {len(apps)} applications for job {job_id}")
        return apps
    except Exception as e:
        logger.error(f"Error getting applications by job: {e}")
        return []


def get_applications_by_user(user_id):
    """
    Get all applications by a specific user (candidate)
    """
    try:
        apps = list(applications_col.find({"user_id": user_id}))
        for app in apps:
            app.pop("_id", None)
        logger.info(f"Found {len(apps)} applications for user {user_id}")
        return apps
    except Exception as e:
        logger.error(f"Error getting applications by user: {e}")
        return []


def get_application_by_id(application_id):
    """
    Get a single application by ID
    """
    try:
        app = applications_col.find_one({"id": application_id})
        if app:
            app.pop("_id", None)
        return app
    except Exception as e:
        logger.error(f"Error getting application: {e}")
        return None


def update_status(application_id, new_status):
    """
    Update the status of an application
    """
    try:
        applications_col.update_one(
            {"id": application_id}, 
            {"$set": {
                "status": new_status, 
                "updated_at": datetime.now().isoformat()
            }}
        )
        
        app = get_application_by_id(application_id)
        logger.info(f"✅ Application {application_id} status updated to {new_status}")
        return app
        
    except Exception as e:
        logger.error(f"Error updating application status: {e}")
        raise e


def update_cv_score(application_id, cv_score):
    """
    Update the CV score for an application
    """
    try:
        applications_col.update_one(
            {"id": application_id},
            {"$set": {
                "cv_score": cv_score,
                "updated_at": datetime.now().isoformat()
            }}
        )
        logger.info(f"✅ CV score updated for {application_id}: {cv_score}%")
        return get_application_by_id(application_id)
        
    except Exception as e:
        logger.error(f"Error updating CV score: {e}")
        raise e


def get_applications_by_company(company_id):
    """
    Get all applications for jobs posted by a company
    This requires joining with jobs collection
    """
    try:
        from services.job_manager import get_jobs_by_company
        company_jobs = get_jobs_by_company(company_id)
        job_ids = [job["id"] for job in company_jobs]
        
        apps = list(applications_col.find({"job_id": {"$in": job_ids}}))
        for app in apps:
            app.pop("_id", None)
        
        logger.info(f"Found {len(apps)} applications for company {company_id}")
        return apps
        
    except Exception as e:
        logger.error(f"Error getting applications by company: {e}")
        return []