import requests
import re
from bs4 import BeautifulSoup
from typing import List, Dict
import hashlib
import json
import os

class HTMLScraper:
    def __init__(self):
        self.session = requests.Session()
        self.session.headers.update({
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36'
        })
        
        self.program_urls = {
            'ai': 'https://abit.itmo.ru/program/master/ai',
            'ai_product': 'https://abit.itmo.ru/program/master/ai_product'
        }

    
    def scrape_programs(self) -> Dict:
        programs = {}
        
        for program_id, url in self.program_urls.items():
            try:
                print(f'Скрапинг программы {program_id}...')
                program_data = self._scrape_program_page(url, program_id)
                programs[program_id] = program_data
            except Exception as e:
                print(f'Ошибка при скрапинге {program_id}: {e}')
        
        return programs
    
    def _scrape_program_page(self, url: str, program_id: str) -> Dict:
        response = self.session.get(url, timeout=30)
        response.raise_for_status()
        
        soup = BeautifulSoup(response.content, 'html.parser')
        
        title = self._extract_title(soup)
        description = self._extract_description(soup)
        pdf_links = self._extract_pdf_links(soup, url)
        
        program_data = {
            'id': program_id,
            'title': title,
            'description': description,
            'url': url,
            'pdf_links': pdf_links,
            'hash': self._calculate_hash(response.content)
        }
        
        return program_data
    
    def _extract_title(self, soup: BeautifulSoup) -> str:
        title_elem = soup.find('h1') or soup.find('title')
        if title_elem:
            return title_elem.get_text().strip()
        return ''
    
    def _extract_description(self, soup: BeautifulSoup) -> str:
        desc_selectors = [
            '.program-description',
            '.description',
            '.program-info',
            'p',
            '.content'
        ]
        
        for selector in desc_selectors:
            elem = soup.select_one(selector)
            if elem:
                text = elem.get_text().strip()
                if len(text) > 50:
                    return text[:500]
        
        return ''
    
    def _extract_pdf_links(self, soup: BeautifulSoup, base_url: str) -> List[Dict]:
        pdf_links = []
        
        for link in soup.find_all('a', href=True):
            href = link.get('href', '')
            text = link.get_text().strip().lower()
            
            if self._is_pdf_link(href, text):
                full_url = self._make_absolute_url(href, base_url)
                pdf_links.append({
                    'url': full_url,
                    'text': text,
                    'filename': self._extract_filename(href)
                })
        
        return pdf_links
    
    def _is_pdf_link(self, href: str, text: str) -> bool:
        pdf_indicators = [
            'учебный план', 'учебный план', 'curriculum', 'plan',
            'pdf', '.pdf', 'программа', 'program'
        ]
        
        href_lower = href.lower()
        return any(indicator in href_lower or indicator in text for indicator in pdf_indicators)
    
    def _make_absolute_url(self, href: str, base_url: str) -> str:
        if href.startswith('http'):
            return href
        elif href.startswith('/'):
            base = '/'.join(base_url.split('/')[:3])
            return base + href
        else:
            return base_url.rstrip('/') + '/' + href.lstrip('/')
    
    def _extract_filename(self, href: str) -> str:
        filename = href.split('/')[-1]
        if not filename.endswith('.pdf'):
            filename += '.pdf'
        return filename
    
    def _calculate_hash(self, content: bytes) -> str:
        return hashlib.sha256(content).hexdigest()
    
    def save_programs(self, programs: Dict, output_path: str = 'data/processed/programs.json'):
        os.makedirs(os.path.dirname(output_path), exist_ok=True)
        
        with open(output_path, 'w', encoding='utf-8') as f:
            json.dump(programs, f, ensure_ascii=False, indent=2)
        
        print(f'Программы сохранены в {output_path}')

def main():
    scraper = HTMLScraper()
    programs = scraper.scrape_programs()
    scraper.save_programs(programs)
    
    for program_id, program in programs.items():
        print(f'\n{program["title"]}:')
        print(f'PDF ссылок найдено: {len(program["pdf_links"])}')
        for link in program['pdf_links']:
            print(f'  - {link["filename"]}: {link["url"]}')

if __name__ == '__main__':
    main()