import re
import json
import requests
import urllib.parse
from urllib.parse import urlparse
from django.utils import timezone
from celery import shared_task
from crawler.models import CrawlRun, CrawlTask
from ads.models import Ad, AdEvaluation

def parse_divar_url(divar_url):
    """
    Parses a public Divar search link to extract city, category path,
    and query parameters.
    """
    parsed = urlparse(divar_url)
    path_parts = [p for p in parsed.path.split('/') if p]
    
    city = 'tehran'
    category = ''
    
    if len(path_parts) >= 2 and path_parts[0] == 's':
        city = path_parts[1]
        if len(path_parts) > 2:
            category = '/'.join(path_parts[2:])
    elif len(path_parts) >= 1:
        city = path_parts[0]
        if len(path_parts) > 1:
            category = '/'.join(path_parts[1:])
            
    query_params = dict(urllib.parse.parse_qsl(parsed.query))
    return city, category, query_params

def extract_widgets_from_dict(d, found_ads):
    """
    Recursively searches a JSON structure for dictionaries matching
    the properties of an ad widget, extracting token, title, description,
    price, and image details.
    """
    if isinstance(d, dict):
        # Retrieve token
        token = d.get('token')
        if not token:
            token = d.get('action', {}).get('payload', {}).get('token')
            if not token:
                token = d.get('data', {}).get('token')
                
        # Retrieve title
        title = d.get('title') or d.get('data', {}).get('title')
        
        # Verify it represents an ad widget (token length >= 6 and has a title)
        if token and title and isinstance(token, str) and len(token) >= 6:
            desc = (
                d.get('description') or 
                d.get('data', {}).get('description') or 
                d.get('data', {}).get('top_description_text') or 
                d.get('data', {}).get('middle_description_text') or 
                d.get('data', {}).get('bottom_description_text') or 
                ''
            )
            
            price = (
                d.get('price') or 
                d.get('data', {}).get('price_text') or 
                d.get('data', {}).get('price') or 
                ''
            )
            
            image_url = ''
            image_data = d.get('image') or d.get('data', {}).get('image') or d.get('data', {}).get('image_url')
            if isinstance(image_data, str):
                image_url = image_data
            elif isinstance(image_data, dict):
                image_url = image_data.get('url') or image_data.get('src') or ''
                
            ad_info = {
                'token': token,
                'title': title,
                'description': desc,
                'price': price,
                'image_url': image_url,
                'category': d.get('category') or d.get('data', {}).get('category') or ''
            }
            found_ads[token] = ad_info
            
        for v in d.values():
            extract_widgets_from_dict(v, found_ads)
            
    elif isinstance(d, list):
        for item in d:
            extract_widgets_from_dict(item, found_ads)

@shared_task
def run_crawl_pipeline(run_id, force=False):
    """
    Background Celery task that executes a crawling run.
    Parses Divar listing data, registers new Ads, and queues AI evaluations.
    """
    try:
        run = CrawlRun.objects.get(pk=run_id)
    except CrawlRun.DoesNotExist:
        return
        
    task = run.crawl_task
    
    # 1. Verification checks
    if not task.is_active:
        run.status = 'FAILED'
        run.finished_at = timezone.now()
        run.error_log = "CrawlTask is inactive."
        run.save()
        return
        
    if not force:
        now = timezone.localtime(timezone.now()).time()
        if not (task.start_hour <= now <= task.end_hour):
            run.status = 'SUCCESS'
            run.finished_at = timezone.now()
            run.error_log = f"Skipped: current time {now.strftime('%H:%M')} is outside allowed window {task.start_hour.strftime('%H:%M')} to {task.end_hour.strftime('%H:%M')}"
            run.save()
            return

    # Update run status to RUNNING
    run.status = 'RUNNING'
    run.save()

    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36'
    }
    
    city, category, query_params = parse_divar_url(task.divar_url)
    found_ads = {}
    
    # 2. Try fetching from Divar public web search API
    api_url = f"https://api.divar.ir/v8/web-search/{city}/{category}"
    try:
        res = requests.get(api_url, params=query_params, headers=headers, timeout=15)
        if res.status_code == 200:
            extract_widgets_from_dict(res.json(), found_ads)
    except Exception as api_err:
        # Log error but proceed to HTML scraper fallback
        pass

    # 3. Fallback: Parse HTML state if API failed/returned nothing
    if not found_ads:
        try:
            res = requests.get(task.divar_url, headers=headers, timeout=15)
            if res.status_code == 200:
                match = re.search(r'window\.__PRELOADED_STATE__\s*=\s*(\{[\s\S]*?\});', res.text)
                if not match:
                    match = re.search(r'window\.__INITIAL_STATE__\s*=\s*(\{[\s\S]*?\});', res.text)
                if match:
                    state_data = json.loads(match.group(1))
                    extract_widgets_from_dict(state_data, found_ads)
        except Exception as html_err:
            run.status = 'FAILED'
            run.finished_at = timezone.now()
            run.error_log = f"Scraping failed. API and HTML fallbacks both failed.\nAPI Error: {str(api_err) if 'api_err' in locals() else 'None'}\nHTML Error: {str(html_err)}"
            run.save()
            return

    # 4. Save listings & trigger AI evaluations
    ads_fetched = len(found_ads)
    new_eval_ids = []
    
    for token, ad_info in found_ads.items():
        # Check if run was cancelled/stopped by user during loop
        run.refresh_from_db()
        if run.status != 'RUNNING':
            return

        try:
            # Create or get Ad metadata
            ad, created = Ad.objects.get_or_create(
                divar_token=token,
                defaults={
                    'title': ad_info['title'],
                    'description': ad_info['description'],
                    'price': ad_info['price'],
                    'category': ad_info['category'],
                    'images': [ad_info['image_url']] if ad_info['image_url'] else [],
                    'url': f"https://divar.ir/v/{token}"
                }
            )
            
            # Check if an evaluation already exists for this crawler on this ad
            eval_exists = AdEvaluation.objects.filter(ad=ad, crawl_task=task).exists()
            if not eval_exists:
                eval_obj = AdEvaluation.objects.create(ad=ad, crawl_task=task)
                new_eval_ids.append(str(eval_obj.id))
        except Exception:
            # If a single ad save fails, continue processing other ads
            pass

    # Batch process AI evaluations (5 ads per API request)
    if new_eval_ids:
        from ads.tasks import evaluate_ad_batch_with_ai
        batch_size = 5
        for i in range(0, len(new_eval_ids), batch_size):
            batch = new_eval_ids[i:i + batch_size]
            evaluate_ad_batch_with_ai.delay(batch)

    # Update runs counters and status
    run.refresh_from_db()
    if run.status == 'RUNNING':
        run.status = 'SUCCESS'
        run.finished_at = timezone.now()
        run.ads_fetched_count = ads_fetched
        run.ads_evaluated_count = len(new_eval_ids)
        run.save()