import os
import json
import logging
import requests
from PyPDF2 import PdfReader
from recruitment.models import Candidate

logger = logging.getLogger(__name__)

OPENROUTER_API_KEY ='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'
OPENROUTER_MODEL = 'qwen/qwen-2.5-72b-instruct:free'

if not OPENROUTER_API_KEY:
    logger.warning("OPENROUTER_API_KEY not set. Resume scoring will be skipped.")

def extract_text_from_pdf(file_path):
    print("text extraction")
    text = ""
    try:
        with open(file_path, "rb") as f:
            reader = PdfReader(f)
            for page in reader.pages:
                text += (page.extract_text() or "")
    except Exception as e:
        logger.error(f"PDF extraction failed: {e}")
        raise
    return text.strip()

def ai_handler(prompt):
    print("model call")
    response = requests.post(
        url="https://openrouter.ai/api/v1/chat/completions",
        headers={
            "Authorization": f"Bearer {OPENROUTER_API_KEY}",
            "Content-Type": "application/json",
        },
        data=json.dumps({
            "model": OPENROUTER_MODEL,
            "messages": [{"role": "user", "content": prompt}],
        },
        )
    )
    res = {}
    print(response.status_code)
    if response.status_code == 200:
        res = response.json()
        content = res["choices"][0]['message']['content']
        try:

            content = content.replace("```json","").replace("```","")

            res = json.loads(content)

        except Exception as e:
            print(e)

        # res = raw_output["choices"][0]["message"]["content"]
    else:
        print("error response")
    return res

def handle_reume_parsing_and_scoring(pk):
    logger.info(f"Scoring resume for candidate {pk}")
    try:
        instance = Candidate.objects.get(pk=pk)
        file_path = instance.resume.path
        if not os.path.exists(file_path):
            logger.warning(f"Resume file not found: {file_path}")
            return

        resume_text = extract_text_from_pdf(file_path)
        job_detail= f"{instance.job.description} {instance.job.qualifications}"
        resume_parser_prompt = f"""
                You are an expert resume parser and summarizer. Given a resume in plain text format, extract and organize the following key-value information into a clean, valid JSON object:

                full_name: Full name of the candidate
                current_title: Most recent or current job title
                location: City and state (or country if outside the U.S.)
                contact: Phone number and email (as a single string or separate fields)
                linkedin: LinkedIn profile URL (if present)
                github: GitHub or portfolio URL (if present)
                summary: Brief professional profile or summary (1–2 sentences)
                education: List of degrees, each with:
                institution
                degree
                year
                gpa (if provided)
                relevant_courses (as a list, if mentioned)
                skills: Grouped by category if possible (e.g., programming, big data, visualization), otherwise as a flat list of technologies/tools
                experience: List of roles, each with:
                company
                job_title
                location
                start_date and end_date (or "Present" if applicable)
                key_achievements (as a list of concise bullet points)
                projects: List of notable projects (if clearly labeled), each with:
                name
                year
                technologies_used
                brief_description
                Instructions:

                Be concise but preserve key details.
                Normalize formatting (e.g., “Jun. 2014” → “2014-06”).
                Omit redundant or promotional language.
                If a section is missing, omit the key or set it to null/empty list as appropriate.
                Output only valid JSON—no markdown, no extra text.
                Now, process the following resume text:
                    {resume_text}
        """
        resume_parser_result = ai_handler(resume_parser_prompt)
        resume_scoring_prompt = f"""
            You are an expert technical recruiter. Your task is to score the following candidate for the role of a Senior Data Analyst based on the provided job criteria.

            **Job Criteria:**
            {job_detail}

            **Candidate's Extracted Resume Json:**
            \"\"\"
            {resume_parser_result}
            \"\"\"

            **Your Task:**
            Provide a response in strict JSON format with the following keys:
            1. 'match_score': A score from 0 to 100 representing how well the candidate fits the role.
            2. 'strengths': A brief summary of why the candidate is a strong fit, referencing specific criteria.
            3. 'weaknesses': A brief summary of where the candidate falls short or what criteria are missing.
            4. 'criteria_checklist': An object where you rate the candidate's match for each specific criterion (e.g., {{'Python': 'Met', 'AWS': 'Not Mentioned'}}).


            Only output valid JSON. Do not include any other text.
            """

        resume_scoring_result = ai_handler(resume_scoring_prompt)

        instance.parsed_summary = str(resume_parser_result)

        # Update candidate with scoring results
        instance.match_score = resume_scoring_result.get('match_score')
        instance.strengths = resume_scoring_result.get('strengths', '')
        instance.weaknesses = resume_scoring_result.get('weaknesses', '')
        instance.criteria_checklist = resume_scoring_result.get('criteria_checklist', {})

        instance.is_resume_parsed = True

        # Save only scoring-related fields to avoid recursion
        instance.save(update_fields=[
            'match_score', 'strengths', 'weaknesses',
            'criteria_checklist','parsed_summary', 'is_resume_parsed'
        ])

        logger.info(f"Successfully scored resume for candidate {instance.id}")

    except Exception as e:
        logger.error(f"Failed to score resume for candidate {instance.id}: {e}")