import os
import re
import html
import asyncio
import logging
import hashlib
import xml.etree.ElementTree as ET
from datetime import datetime, timezone, timedelta
from typing import Optional, List, Dict, Any, Callable, Awaitable
import httpx
from db.models import SourceWebsite
from db.repository import Repository
from services.website_analyzer import WebsiteAnalyzer, USER_AGENT
from core.error_logger import log_exception

logger = logging.getLogger(__name__)

def _clean_html(raw_html: str) -> str:
    if not raw_html:
        return ""
    text = re.sub(r'<[^>]+>', ' ', raw_html)
    text = html.unescape(text)
    return re.sub(r'\s+', ' ', text).strip()

def _extract_nested(data: Any, path: str) -> Any:
    if not path or not data:
        return data
    parts = path.split(".")
    curr = data
    for p in parts:
        if isinstance(curr, dict):
            curr = curr.get(p)
        elif isinstance(curr, list) and p.isdigit():
            idx = int(p)
            curr = curr[idx] if idx < len(curr) else None
        else:
            return None
    return curr

class WebsiteCollectorService:
    def __init__(
        self,
        repo: Repository,
        analyzer: WebsiteAnalyzer,
        ai_processor = None,
        on_post_received: Optional[Callable[[int], Awaitable[None]]] = None,
        on_error_alert: Optional[Callable[[str, List[Any]], Awaitable[None]]] = None,
    ):
        self.repo = repo
        self.analyzer = analyzer
        self.ai_processor = ai_processor
        self.on_post_received = on_post_received
        self.on_error_alert = on_error_alert
        self._running = False
        self._task: Optional[asyncio.Task] = None

    async def start(self):
        logger.info("Starting Website Collector Service...")
        self._running = True
        self._task = asyncio.create_task(self._collector_loop())

    async def stop(self):
        self._running = False
        if self._task:
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass
        logger.info("Website Collector Service stopped.")

    async def _collector_loop(self):
        while self._running:
            try:
                if not await self.repo.is_system_paused():
                    await self._process_websites()
            except Exception as e:
                await log_exception("website_collector.loop", e)
            await asyncio.sleep(60)

    async def _process_websites(self):
        websites = await self.repo.get_active_source_websites()
        now = datetime.now(timezone.utc)

        for site in websites:
            try:
                # 1. Check Periodic Auto Re-analysis
                if site.auto_reanalyze_hours > 0 and site.last_reanalyzed_at:
                    last_re = site.last_reanalyzed_at
                    if last_re.tzinfo is None:
                        last_re = last_re.replace(tzinfo=timezone.utc)
                    if (now - last_re).total_seconds() / 3600.0 >= site.auto_reanalyze_hours:
                        logger.info(f"Auto re-analyzing website #{site.id} ({site.name})...")
                        await self.reanalyze_website(site.id)

                # 2. Check Fetch Interval
                if site.last_fetched_at:
                    last_fe = site.last_fetched_at
                    if last_fe.tzinfo is None:
                        last_fe = last_fe.replace(tzinfo=timezone.utc)
                    if (now - last_fe).total_seconds() / 60.0 < site.check_interval_min:
                        continue

                await self.fetch_website_posts(site.id)
            except Exception as e:
                logger.error(f"Error processing website {site.name}: {e}", exc_info=True)

    async def reanalyze_website(self, site_id: int) -> Tuple[bool, str]:
        site = await self.repo.get_source_website_by_id(site_id)
        if not site:
            return False, "وبسایت یافت نشد."

        ok, api_cfg, summary = await self.analyzer.analyze_website(site.url)
        if ok and api_cfg:
            await self.repo.update_source_website_api_config(site_id, api_cfg)
            return True, f"✅ وبسایت «{site.name}» با موفقیت تحلیل شد:\n{summary}"
        else:
            err_msg = summary or "خطا در تحلیل وبسایت"
            await self.repo.update_source_website_fetch_status(site_id, error=err_msg)
            if self.on_error_alert:
                await self.on_error_alert(
                    f"⚠️ <b>خطا در تحلیل مجدد هوشمند وبسایت «{site.name}»:</b>\n<code>{err_msg}</code>",
                    site_id
                )
            return False, err_msg

    async def fetch_website_posts(self, site_id: int) -> int:
        site = await self.repo.get_source_website_by_id(site_id)
        if not site or not site.is_active:
            return 0

        api_cfg = site.api_config or {}
        endpoint_url = api_cfg.get("endpoint_url")
        if not endpoint_url:
            # Trigger initial analysis
            ok, new_cfg, _ = await self.analyzer.analyze_website(site.url)
            if ok and new_cfg:
                await self.repo.update_source_website_api_config(site_id, new_cfg)
                api_cfg = new_cfg
                endpoint_url = api_cfg.get("endpoint_url")
            else:
                await self.repo.update_source_website_fetch_status(site_id, error="بدون اندپوینت معتبر")
                return 0

        headers = api_cfg.get("headers") or {"User-Agent": USER_AGENT, "Accept": "*/*"}
        parser_type = api_cfg.get("parser_type", "rss")
        mappings = api_cfg.get("field_mappings", {})

        articles = []
        try:
            async with httpx.AsyncClient(timeout=20.0, follow_redirects=True) as client:
                resp = await client.get(endpoint_url, headers=headers)
                resp.raise_for_status()

                if parser_type == "wordpress_json" or "json" in resp.headers.get("content-type", "") or parser_type == "rest_json":
                    raw_data = resp.json()
                    items = _extract_nested(raw_data, api_cfg.get("items_path", ""))
                    if isinstance(items, list):
                        for item in items[:15]:
                            title = _clean_html(str(_extract_nested(item, mappings.get("title", "title.rendered")) or ""))
                            content = _clean_html(str(_extract_nested(item, mappings.get("content", "content.rendered")) or ""))
                            link = str(_extract_nested(item, mappings.get("link", "link")) or "")
                            img_url = str(_extract_nested(item, mappings.get("image_url", "yoast_head_json.og_image.0.url")) or "")
                            pub_at = _extract_nested(item, mappings.get("published_at", "date_gmt"))
                            if title and link:
                                articles.append({
                                    "title": title,
                                    "content": content,
                                    "link": link,
                                    "image_url": img_url if img_url.startswith("http") else None,
                                    "published_at": pub_at
                                })

                elif parser_type == "rss" or "xml" in resp.headers.get("content-type", ""):
                    root = ET.fromstring(resp.content)
                    channel = root.find("channel") or root
                    items = channel.findall("item") or root.findall(".//item")
                    for item in items[:15]:
                        t_node = item.find("title")
                        l_node = item.find("link")
                        d_node = item.find("description")
                        p_node = item.find("pubDate")
                        enc_node = item.find("enclosure")

                        title = _clean_html(t_node.text if t_node is not None else "")
                        link = (l_node.text or "").strip() if l_node is not None else ""
                        desc = _clean_html(d_node.text if d_node is not None else "")
                        img_url = enc_node.attrib.get("url") if enc_node is not None else None

                        if title and link:
                            articles.append({
                                "title": title,
                                "content": desc,
                                "link": link,
                                "image_url": img_url,
                                "published_at": p_node.text if p_node is not None else None
                            })

            await self.repo.update_source_website_fetch_status(site_id, error=None)

        except Exception as e:
            err_msg = str(e)
            logger.warning(f"Error fetching website #{site.id} ({site.name}): {err_msg}")
            await self.repo.update_source_website_fetch_status(site_id, error=err_msg)
            if self.on_error_alert:
                await self.on_error_alert(
                    f"⚠️ <b>خطا در دریافت اطلاعات از وبسایت «{site.name}»:</b>\n"
                    f"🌐 URL: <code>{endpoint_url}</code>\n"
                    f"❌ خطا: <code>{err_msg}</code>",
                    site_id
                )
            return 0

        # Ingest new articles into database
        new_count = 0
        pseudo_channel_id = -900000000 - site.id

        for art in reversed(articles):
            link = art["link"]
            text_body = f"📌 <b>{art['title']}</b>\n\n{art['content']}\n\n🔗 منبع: {link}"
            msg_id = int(hashlib.md5(link.encode("utf-8")).hexdigest()[:8], 16) % 1000000000

            # Tags & Semantic deduplication
            tags, subject = [], art["title"]
            if self.ai_processor:
                try:
                    tags, subject = await self.ai_processor.extract_tags_and_subject(art['title'] + "\n" + art['content'])
                except Exception:
                    pass

            is_duplicate = False
            duplicate_of_id = None
            similarity_reason = None
            if tags and self.ai_processor:
                try:
                    candidates = await self.repo.find_candidate_posts_by_tags(tags, limit=10)
                    if candidates:
                        is_dup, dup_id, reason = await self.ai_processor.check_semantic_duplicate(text_body, candidates)
                        if is_dup:
                            is_duplicate = True
                            duplicate_of_id = dup_id
                            similarity_reason = reason
                except Exception:
                    pass

            post_id = await self.repo.create_raw_post(
                source_channel_id=pseudo_channel_id,
                source_message_id=msg_id,
                raw_text=text_body,
                tags=tags,
                subject=subject,
                is_duplicate=is_duplicate,
                duplicate_of_id=duplicate_of_id,
                similarity_reason=similarity_reason,
            )

            if post_id:
                new_count += 1
                logger.info(f"Ingested post ID {post_id} from source website '{site.name}'")
                if self.on_post_received:
                    await self.on_post_received(post_id)

        return new_count