"""
Logo Fetch Service - Downloads multiple logo candidates from company websites.

Strategies (in priority order):
1. <img> elements with "logo" in class/id/alt/src
2. apple-touch-icon / link rel="icon" (largest size)
3. og:image / twitter:image meta tags
4. Google Favicon API fallback

Flow:
1. Fetch website, find all candidates
2. Download up to MAX_CANDIDATES, save as {slug}_cand_{i}.webp
3. Frontend shows gallery — user picks one
4. confirm_candidate() renames chosen file to {slug}.webp
5. cleanup_candidates() removes temp files
"""

import glob
import logging
import os
import re
from io import BytesIO
from urllib.parse import urljoin, urlparse

import requests
from bs4 import BeautifulSoup

logger = logging.getLogger(__name__)

USER_AGENT = 'Mozilla/5.0 (compatible; NordaBizBot/1.0)'
TIMEOUT = 10
MAX_DOWNLOAD_SIZE = 5 * 1024 * 1024  # 5MB
MIN_LOGO_SIZE = 32  # px (lowered to catch more candidates)
MAX_LOGO_SIZE = 800  # px
WEBP_QUALITY = 85
MAX_CANDIDATES = 6

LOGO_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'static', 'img', 'companies')


SOURCE_LABELS = {
    'img_scan': 'Element HTML',
    'css_bg': 'Tło CSS',
    'apple-touch-icon': 'Apple Touch Icon',
    'og:image': 'Open Graph',
    'twitter:image': 'Twitter Card',
    'favicon': 'Favicon',
    'google_favicon': 'Google Favicon',
}


class LogoFetchService:

    def fetch_candidates(self, website_url: str, slug: str) -> dict:
        """
        Fetch multiple logo candidates from company website.

        Returns: {
            'success': bool,
            'message': str,
            'candidates': [{'index': 0, 'source': str, 'label': str, 'ext': str, 'width': int, 'height': int}, ...],
            'steps': [...]
        }
        """
        steps = []
        candidates = []

        if not website_url.startswith('http'):
            website_url = 'https://' + website_url

        # Step 1: Fetch website
        html, base_url = self._step_fetch_website(website_url, steps)
        if html is None:
            return {'success': False, 'message': steps[-1]['message'], 'candidates': [], 'steps': steps}

        soup = BeautifulSoup(html, 'html.parser')

        # Step 2: Meta tags
        self._step_meta_tags(soup, base_url, candidates, steps)

        # Step 3: Scan images
        self._step_scan_images(soup, base_url, candidates, steps)

        # Add Google Favicon as last-resort fallback
        domain = urlparse(base_url).netloc
        if domain:
            candidates.append({
                'url': f'https://www.google.com/s2/favicons?domain={domain}&sz=128',
                'source': 'google_favicon',
                'priority': 100
            })

        if not candidates:
            steps.append({'step': 'download', 'status': 'error', 'message': 'Nie znaleziono kandydatów na logo'})
            return {'success': False, 'message': 'Nie znaleziono logo na stronie firmy', 'candidates': [], 'steps': steps}

        # Deduplicate by URL
        seen_urls = set()
        unique = []
        for c in candidates:
            if c['url'] not in seen_urls:
                seen_urls.add(c['url'])
                unique.append(c)
        candidates = unique

        # Sort by priority
        candidates.sort(key=lambda c: c['priority'])

        # Step 4+5+6: Download, convert, save each candidate
        saved = self._download_and_save_candidates(candidates, slug, steps)

        if not saved:
            return {'success': False, 'message': 'Nie udało się pobrać żadnego kandydata', 'candidates': [], 'steps': steps}

        steps.append({
            'step': 'save',
            'status': 'complete',
            'message': f'Zapisano {len(saved)} kandydatów do wyboru'
        })

        return {
            'success': True,
            'message': f'Znaleziono {len(saved)} kandydatów na logo',
            'candidates': saved,
            'steps': steps
        }

    def _download_and_save_candidates(self, candidates, slug, steps):
        """Download up to MAX_CANDIDATES, convert and save each."""
        saved = []
        idx = 0

        # Clean up old candidates first
        self.cleanup_candidates(slug)

        for candidate in candidates:
            if idx >= MAX_CANDIDATES:
                break

            url = candidate['url']
            try:
                response = requests.get(url, timeout=TIMEOUT, headers={
                    'User-Agent': USER_AGENT
                })

                content_length = int(response.headers.get('content-length', 0))
                if content_length > MAX_DOWNLOAD_SIZE:
                    continue

                content_type = response.headers.get('content-type', '')

                if not any(t in content_type for t in ['image', 'svg', 'octet-stream']):
                    if 'html' in content_type:
                        continue

                data = response.content
                if len(data) > MAX_DOWNLOAD_SIZE or len(data) < 100:
                    continue

                is_svg = 'svg' in content_type
                width, height = 0, 0

                if not is_svg:
                    try:
                        from PIL import Image
                        img = Image.open(BytesIO(data))
                        width, height = img.size
                        if width < MIN_LOGO_SIZE or height < MIN_LOGO_SIZE:
                            continue
                    except Exception:
                        continue

                # Convert
                output_data, file_ext = self._convert(data, is_svg)
                if output_data is None:
                    continue

                # Get dimensions after conversion
                if not is_svg and width == 0:
                    try:
                        from PIL import Image
                        img = Image.open(BytesIO(output_data))
                        width, height = img.size
                    except Exception:
                        pass

                # Save as candidate file
                os.makedirs(LOGO_DIR, exist_ok=True)
                filename = f'{slug}_cand_{idx}.{file_ext}'
                filepath = os.path.join(LOGO_DIR, filename)
                with open(filepath, 'wb') as f:
                    f.write(output_data)

                saved.append({
                    'index': idx,
                    'source': candidate['source'],
                    'label': SOURCE_LABELS.get(candidate['source'], candidate['source']),
                    'ext': file_ext,
                    'width': width,
                    'height': height,
                    'size': len(output_data),
                    'filename': filename
                })
                idx += 1

            except Exception as e:
                logger.debug(f"Failed to download candidate {url}: {e}")
                continue

        count = len(saved)
        if count > 0:
            steps.append({
                'step': 'download',
                'status': 'complete',
                'message': f'Pobrano {count} obrazów'
            })
        else:
            steps.append({
                'step': 'download',
                'status': 'error',
                'message': 'Żaden kandydat nie spełnił wymagań'
            })

        return saved

    def _convert(self, image_data, is_svg):
        """Convert image to WebP (or keep SVG). Returns (data, ext) or (None, None)."""
        if is_svg:
            return image_data, 'svg'

        try:
            from PIL import Image

            img = Image.open(BytesIO(image_data))

            if img.mode in ('RGBA', 'LA', 'P'):
                if img.mode == 'P':
                    img = img.convert('RGBA')
                background = Image.new('RGBA', img.size, (255, 255, 255, 255))
                background.paste(img, mask=img.split()[-1] if 'A' in img.mode else None)
                img = background.convert('RGB')
            elif img.mode != 'RGB':
                img = img.convert('RGB')

            w, h = img.size
            if w > MAX_LOGO_SIZE or h > MAX_LOGO_SIZE:
                img.thumbnail((MAX_LOGO_SIZE, MAX_LOGO_SIZE), Image.LANCZOS)

            output = BytesIO()
            img.save(output, format='WEBP', quality=WEBP_QUALITY)
            return output.getvalue(), 'webp'

        except Exception as e:
            logger.debug(f"Conversion error: {e}")
            return None, None

    @staticmethod
    def confirm_candidate(slug: str, index: int) -> bool:
        """Rename chosen candidate to final logo file."""
        # Find candidate file
        for ext in ('webp', 'svg'):
            cand = os.path.join(LOGO_DIR, f'{slug}_cand_{index}.{ext}')
            if os.path.exists(cand):
                final = os.path.join(LOGO_DIR, f'{slug}.{ext}')
                # Remove old logo in other format
                for old_ext in ('webp', 'svg'):
                    old = os.path.join(LOGO_DIR, f'{slug}.{old_ext}')
                    if old != final and os.path.exists(old):
                        os.remove(old)
                os.rename(cand, final)
                # Cleanup remaining candidates
                LogoFetchService.cleanup_candidates(slug)
                return True
        return False

    @staticmethod
    def cleanup_candidates(slug: str):
        """Delete all candidate files for a slug."""
        pattern = os.path.join(LOGO_DIR, f'{slug}_cand_*')
        for f in glob.glob(pattern):
            try:
                os.remove(f)
            except OSError:
                pass

    @staticmethod
    def has_existing_logo(slug: str) -> str | None:
        """Check if company already has a logo. Returns extension or None."""
        for ext in ('webp', 'svg'):
            if os.path.exists(os.path.join(LOGO_DIR, f'{slug}.{ext}')):
                return ext
        return None

    def _step_fetch_website(self, url, steps):
        """Step 1: Fetch the website HTML."""
        try:
            response = requests.get(url, timeout=TIMEOUT, headers={
                'User-Agent': USER_AGENT,
                'Accept': 'text/html,application/xhtml+xml'
            }, allow_redirects=True)
            response.raise_for_status()
            steps.append({
                'step': 'fetch_website',
                'status': 'complete',
                'message': f'Strona pobrana ({len(response.text)} znaków)'
            })
            return response.text, response.url
        except requests.exceptions.SSLError:
            try:
                http_url = url.replace('https://', 'http://')
                response = requests.get(http_url, timeout=TIMEOUT, headers={
                    'User-Agent': USER_AGENT
                }, allow_redirects=True)
                response.raise_for_status()
                steps.append({
                    'step': 'fetch_website',
                    'status': 'complete',
                    'message': f'Strona pobrana przez HTTP (błąd SSL)'
                })
                return response.text, response.url
            except Exception as e:
                steps.append({
                    'step': 'fetch_website',
                    'status': 'error',
                    'message': f'Błąd SSL i HTTP: {str(e)[:100]}'
                })
                return None, None
        except Exception as e:
            steps.append({
                'step': 'fetch_website',
                'status': 'error',
                'message': f'Nie udało się pobrać strony: {str(e)[:100]}'
            })
            return None, None

    def _step_meta_tags(self, soup, base_url, candidates, steps):
        """Step 2: Search meta tags for logo candidates."""
        found = []

        og_img = soup.find('meta', property='og:image')
        if og_img and og_img.get('content'):
            url = urljoin(base_url, og_img['content'])
            candidates.append({'url': url, 'source': 'og:image', 'priority': 10})
            found.append('og:image')

        tw_img = soup.find('meta', attrs={'name': 'twitter:image'})
        if tw_img and tw_img.get('content'):
            url = urljoin(base_url, tw_img['content'])
            candidates.append({'url': url, 'source': 'twitter:image', 'priority': 11})
            found.append('twitter:image')

        touch_icons = soup.find_all('link', rel=lambda r: r and 'apple-touch-icon' in r)
        if touch_icons:
            best = max(touch_icons, key=lambda t: self._parse_size(t.get('sizes', '0x0')))
            url = urljoin(base_url, best.get('href', ''))
            if url:
                candidates.append({'url': url, 'source': 'apple-touch-icon', 'priority': 5})
                found.append('apple-touch-icon')

        icons = soup.find_all('link', rel=lambda r: r and 'icon' in r and 'apple' not in str(r))
        for icon in icons:
            size = self._parse_size(icon.get('sizes', '0x0'))
            href = icon.get('href', '')
            if href and size >= 32:
                url = urljoin(base_url, href)
                candidates.append({'url': url, 'source': 'favicon', 'priority': 15})
                found.append(f'favicon ({icon.get("sizes", "?")})')

        if found:
            steps.append({'step': 'meta_tags', 'status': 'complete', 'message': f'Znaleziono: {", ".join(found)}'})
        else:
            steps.append({'step': 'meta_tags', 'status': 'missing', 'message': 'Brak meta tagów z logo'})

    def _step_scan_images(self, soup, base_url, candidates, steps):
        """Step 3: Scan img elements for logo candidates."""
        found_count = 0

        for img in soup.find_all('img'):
            attrs_text = ' '.join([
                img.get('class', [''])[0] if isinstance(img.get('class'), list) else str(img.get('class', '')),
                img.get('id', ''),
                img.get('alt', ''),
                img.get('src', '')
            ]).lower()

            if 'logo' in attrs_text:
                src = img.get('src') or img.get('data-src') or img.get('data-lazy-src')
                if src:
                    url = urljoin(base_url, src)
                    priority = 20
                    if 'logo' in (img.get('id', '') + ' '.join(img.get('class', []))).lower():
                        priority = 3
                    elif 'logo' in img.get('alt', '').lower():
                        priority = 8
                    candidates.append({'url': url, 'source': 'img_scan', 'priority': priority})
                    found_count += 1

        for el in soup.select('header a[class*="logo"], nav a[class*="logo"], .logo, #logo, [class*="brand"]'):
            style = el.get('style', '')
            bg_match = re.search(r'url\(["\']?([^"\')\s]+)["\']?\)', style)
            if bg_match:
                url = urljoin(base_url, bg_match.group(1))
                candidates.append({'url': url, 'source': 'css_bg', 'priority': 7})
                found_count += 1

        if found_count > 0:
            steps.append({'step': 'scan_images', 'status': 'complete', 'message': f'Znaleziono {found_count} kandydatów z elementów img/CSS'})
        else:
            steps.append({'step': 'scan_images', 'status': 'missing', 'message': 'Brak elementów img z "logo" w atrybutach'})

    @staticmethod
    def _parse_size(sizes_str):
        """Parse '180x180' to max dimension int."""
        match = re.search(r'(\d+)', str(sizes_str))
        return int(match.group(1)) if match else 0