"""
Facebook + Instagram Graph API Client
======================================

Uses OAuth 2.0 page tokens to access Facebook Page and Instagram Business data.

API docs: https://developers.facebook.com/docs/graph-api/
"""

import json
import logging
from datetime import datetime, timedelta
from typing import Dict, List, Optional

import requests

logger = logging.getLogger(__name__)


class FacebookGraphService:
    """Facebook + Instagram Graph API client."""

    BASE_URL = "https://graph.facebook.com/v21.0"

    def __init__(self, access_token: str):
        self.access_token = access_token
        self.session = requests.Session()
        self.session.timeout = 15

    def _get(self, endpoint: str, params: dict = None) -> Optional[Dict]:
        """Make authenticated GET request."""
        params = params or {}
        params['access_token'] = self.access_token
        try:
            resp = self.session.get(f"{self.BASE_URL}/{endpoint}", params=params)
            resp.raise_for_status()
            return resp.json()
        except Exception as e:
            logger.error(f"Facebook API {endpoint} failed: {e}")
            return None

    def get_managed_pages(self) -> List[Dict]:
        """Get Facebook pages managed by the authenticated user."""
        data = self._get('me/accounts', {'fields': 'id,name,category,access_token,fan_count'})
        return data.get('data', []) if data else []

    def get_page_info(self, page_id: str) -> Optional[Dict]:
        """Get detailed page information."""
        return self._get(page_id, {
            'fields': 'id,name,fan_count,category,link,about,website,phone,single_line_address,followers_count'
        })

    def get_page_insights(self, page_id: str, days: int = 28) -> Dict:
        """Get page insights (impressions, engaged users, reactions).

        Note: Requires page access token, not user access token.
        The page token should be stored during OAuth connection.
        """
        since = datetime.now() - timedelta(days=days)
        until = datetime.now()

        metrics = 'page_impressions,page_engaged_users,page_fans,page_views_total'
        data = self._get(f'{page_id}/insights', {
            'metric': metrics,
            'period': 'day',
            'since': int(since.timestamp()),
            'until': int(until.timestamp()),
        })

        if not data:
            return {}

        result = {}
        for metric in data.get('data', []):
            name = metric.get('name', '')
            values = metric.get('values', [])
            if values:
                total = sum(v.get('value', 0) for v in values if isinstance(v.get('value'), (int, float)))
                result[name] = total

        return result

    def get_instagram_account(self, page_id: str) -> Optional[str]:
        """Get linked Instagram Business account ID from a Facebook Page."""
        data = self._get(page_id, {'fields': 'instagram_business_account'})
        if data and 'instagram_business_account' in data:
            return data['instagram_business_account'].get('id')
        return None

    def get_ig_media_insights(self, ig_account_id: str, days: int = 28) -> Dict:
        """Get Instagram account insights.

        Returns follower_count, media_count, and recent media engagement.
        """
        result = {}

        # Basic account info
        account_data = self._get(ig_account_id, {
            'fields': 'followers_count,media_count,username,biography'
        })
        if account_data:
            result['followers_count'] = account_data.get('followers_count', 0)
            result['media_count'] = account_data.get('media_count', 0)
            result['username'] = account_data.get('username', '')

        # Account insights (reach, impressions)
        since = datetime.now() - timedelta(days=days)
        until = datetime.now()
        insights_data = self._get(f'{ig_account_id}/insights', {
            'metric': 'impressions,reach,follower_count',
            'period': 'day',
            'since': int(since.timestamp()),
            'until': int(until.timestamp()),
        })

        if insights_data:
            for metric in insights_data.get('data', []):
                name = metric.get('name', '')
                values = metric.get('values', [])
                if values:
                    total = sum(v.get('value', 0) for v in values if isinstance(v.get('value'), (int, float)))
                    result[f'ig_{name}_total'] = total

        return result

    # ============================================================
    # PUBLISHING METHODS (Social Publisher)
    # ============================================================

    def _post(self, endpoint: str, data: dict = None, files: dict = None) -> Optional[Dict]:
        """Make authenticated POST request."""
        data = data or {}
        params = {'access_token': self.access_token}
        try:
            if files:
                resp = self.session.post(f"{self.BASE_URL}/{endpoint}", params=params, data=data, files=files)
            else:
                resp = self.session.post(f"{self.BASE_URL}/{endpoint}", params=params, data=data)
            resp.raise_for_status()
            return resp.json()
        except requests.exceptions.HTTPError as e:
            error_data = None
            try:
                error_data = e.response.json()
            except Exception:
                pass
            logger.error(f"Facebook API POST {endpoint} failed: {e}, response: {error_data}")
            return None
        except Exception as e:
            logger.error(f"Facebook API POST {endpoint} failed: {e}")
            return None

    def _delete(self, endpoint: str) -> Optional[Dict]:
        """Make authenticated DELETE request."""
        params = {'access_token': self.access_token}
        try:
            resp = self.session.delete(f"{self.BASE_URL}/{endpoint}", params=params)
            resp.raise_for_status()
            return resp.json()
        except Exception as e:
            logger.error(f"Facebook API DELETE {endpoint} failed: {e}")
            return None

    def upload_photo_unpublished(self, page_id: str, image_path: str) -> Optional[str]:
        """Upload photo as unpublished to get photo_id for feed attachment.

        Two-step process:
        1. Upload photo with published=false -> get photo_id
        2. Use photo_id in create_post() attached_media

        Args:
            page_id: Facebook Page ID
            image_path: Local path to image file

        Returns:
            Photo ID (media_fbid) or None on failure
        """
        try:
            with open(image_path, 'rb') as f:
                files = {'source': (image_path.split('/')[-1], f, 'image/png')}
                result = self._post(f'{page_id}/photos', data={'published': 'false'}, files=files)
            if result and 'id' in result:
                logger.info(f"Uploaded unpublished photo: {result['id']}")
                return result['id']
            logger.error(f"Photo upload failed: {result}")
            return None
        except FileNotFoundError:
            logger.error(f"Image file not found: {image_path}")
            return None

    def create_post(self, page_id: str, message: str, image_path: str = None,
                    published: bool = True, scheduled_time: int = None) -> Optional[Dict]:
        """Create a post on Facebook Page feed.

        For posts with images, uses two-step process:
        1. Upload photo as unpublished -> photo_id
        2. Create feed post with attached_media[0]

        Args:
            page_id: Facebook Page ID
            message: Post text content
            image_path: Optional local path to image
            published: If False, creates draft (visible only to page admins)
            scheduled_time: Unix timestamp for scheduled publishing (min 10 min ahead)

        Returns:
            API response dict with 'id' key, or None on failure
        """
        data = {'message': message}

        # Handle image upload
        if image_path:
            photo_id = self.upload_photo_unpublished(page_id, image_path)
            if photo_id:
                data['attached_media[0]'] = json.dumps({'media_fbid': photo_id})
            else:
                logger.warning("Image upload failed, posting without image")

        # Handle scheduling
        if scheduled_time:
            data['published'] = 'false'
            data['scheduled_publish_time'] = str(scheduled_time)
        elif not published:
            data['published'] = 'false'

        result = self._post(f'{page_id}/feed', data=data)
        if result and 'id' in result:
            logger.info(f"Created post: {result['id']} (published={published})")
        return result

    def publish_draft(self, post_id: str) -> Optional[Dict]:
        """Publish an unpublished (draft) post.

        Args:
            post_id: Facebook post ID (format: PAGE_ID_POST_ID)

        Returns:
            API response or None on failure
        """
        return self._post(post_id, data={'is_published': 'true'})

    def unpublish_post(self, post_id: str) -> Optional[Dict]:
        """Unpublish a public post (make it draft/hidden).

        Args:
            post_id: Facebook post ID (format: PAGE_ID_POST_ID)

        Returns:
            API response or None on failure
        """
        return self._post(post_id, data={'is_published': 'false'})

    def get_post_engagement(self, post_id: str) -> Optional[Dict]:
        """Get engagement metrics for a published post.

        Args:
            post_id: Facebook post ID

        Returns:
            Dict with likes, comments, shares, reactions_total or None
        """
        fields = 'id,created_time,message,likes.summary(true),comments.summary(true),shares,reactions.summary(true).limit(0)'
        result = self._get(post_id, {'fields': fields})
        if not result:
            return None

        return {
            'post_id': result.get('id'),
            'created_time': result.get('created_time'),
            'likes': result.get('likes', {}).get('summary', {}).get('total_count', 0),
            'comments': result.get('comments', {}).get('summary', {}).get('total_count', 0),
            'shares': result.get('shares', {}).get('count', 0) if result.get('shares') else 0,
            'reactions_total': result.get('reactions', {}).get('summary', {}).get('total_count', 0),
        }

    def get_page_posts(self, page_id: str, limit: int = 10) -> Optional[List[Dict]]:
        """Get recent posts from a Facebook Page with engagement metrics.

        Args:
            page_id: Facebook Page ID
            limit: Number of posts to fetch (max 100)

        Returns:
            List of post dicts or None on failure
        """
        fields = (
            'id,message,created_time,full_picture,permalink_url,status_type,'
            'likes.summary(true).limit(0),comments.summary(true).limit(0),'
            'shares,reactions.summary(true).limit(0)'
        )
        result = self._get(f'{page_id}/posts', {'fields': fields, 'limit': limit})
        if not result:
            return None

        posts = []
        for item in result.get('data', []):
            posts.append({
                'id': item.get('id'),
                'message': item.get('message', ''),
                'created_time': item.get('created_time'),
                'full_picture': item.get('full_picture'),
                'permalink_url': item.get('permalink_url'),
                'status_type': item.get('status_type', ''),
                'likes': item.get('likes', {}).get('summary', {}).get('total_count', 0),
                'comments': item.get('comments', {}).get('summary', {}).get('total_count', 0),
                'shares': item.get('shares', {}).get('count', 0) if item.get('shares') else 0,
                'reactions_total': item.get('reactions', {}).get('summary', {}).get('total_count', 0),
            })
        return posts

    def get_post_insights_metrics(self, post_id: str) -> Optional[Dict]:
        """Get detailed insights metrics for a specific post.

        Note: Only available for posts on Pages with 100+ fans.

        Args:
            post_id: Facebook post ID

        Returns:
            Dict with impressions, reach, engaged_users, clicks or None
        """
        metrics = 'post_impressions,post_impressions_unique,post_engaged_users,post_clicks'
        result = self._get(f'{post_id}/insights', {'metric': metrics})
        if not result:
            return None

        insights = {}
        for metric in result.get('data', []):
            name = metric.get('name', '')
            values = metric.get('values', [])
            if values:
                # Lifetime metrics have a single value
                value = values[0].get('value', 0)
                if name == 'post_impressions':
                    insights['impressions'] = value
                elif name == 'post_impressions_unique':
                    insights['reach'] = value
                elif name == 'post_engaged_users':
                    insights['engaged_users'] = value
                elif name == 'post_clicks':
                    insights['clicks'] = value

        return insights if insights else None

    def delete_post(self, post_id: str) -> bool:
        """Delete a post (published or unpublished).

        Args:
            post_id: Facebook post ID

        Returns:
            True if deleted successfully
        """
        result = self._delete(post_id)
        return bool(result and result.get('success'))


# ============================================================
# SYNC: Facebook Page → CompanySocialMedia
# ============================================================

def sync_facebook_to_social_media(db, company_id: int) -> dict:
    """Fetch Facebook page stats via Graph API and upsert into CompanySocialMedia.

    Requires an active OAuth token and SocialMediaConfig for the company.
    Called automatically after page selection and manually via sync endpoint.

    Args:
        db: SQLAlchemy session
        company_id: Company ID to sync data for

    Returns:
        dict with 'success' bool and either 'data' or 'error'
    """
    from oauth_service import OAuthService
    from database import SocialMediaConfig, CompanySocialMedia

    # 1. Get valid page access token
    oauth = OAuthService()
    token = oauth.get_valid_token(db, company_id, 'meta', 'facebook')
    if not token:
        return {'success': False, 'error': 'no_token', 'message': 'Brak aktywnego tokenu Facebook'}

    # 2. Get page_id from SocialMediaConfig
    config = db.query(SocialMediaConfig).filter(
        SocialMediaConfig.platform == 'facebook',
        SocialMediaConfig.company_id == company_id,
        SocialMediaConfig.is_active == True,
    ).first()

    if not config or not config.page_id:
        return {'success': False, 'error': 'no_page', 'message': 'Brak skonfigurowanej strony Facebook'}

    page_id = config.page_id

    # 3. Fetch page info from Graph API
    fb = FacebookGraphService(token)
    page_info = fb.get_page_info(page_id)

    if not page_info:
        return {'success': False, 'error': 'api_failed', 'message': 'Nie udało się pobrać danych strony z Facebook API'}

    # 4. Fetch page insights (best-effort, may be empty)
    insights = fb.get_page_insights(page_id, 28)

    # 5. Calculate metrics
    followers = page_info.get('followers_count') or page_info.get('fan_count') or 0
    engaged_users = insights.get('page_engaged_users', 0)
    engagement_rate = None
    if followers > 0 and engaged_users > 0:
        engagement_rate = round((engaged_users / followers) * 100, 2)

    # Profile completeness: 25 points each for about, website, phone, address
    completeness = 0
    if page_info.get('about'):
        completeness += 25
    if page_info.get('website'):
        completeness += 25
    if page_info.get('phone'):
        completeness += 25
    if page_info.get('single_line_address'):
        completeness += 25

    # URL: prefer API vanity link, then existing URL, then numeric fallback
    # Don't replace a vanity URL with a numeric one (e.g. facebook.com/inpipl → facebook.com/123456)
    import re
    api_link = page_info.get('link')
    if api_link and re.search(r'facebook\.com/\d+$', api_link):
        api_link = None  # Numeric URL, not useful as replacement

    # 6. Upsert CompanySocialMedia record
    # Look for existing Facebook record for this company (any URL)
    existing = db.query(CompanySocialMedia).filter(
        CompanySocialMedia.company_id == company_id,
        CompanySocialMedia.platform == 'facebook',
    ).first()

    now = datetime.now()

    if existing:
        csm = existing
        # Only update URL if API returned a proper link (not numeric fallback)
        if api_link:
            csm.url = api_link
        # Keep existing URL if API didn't return link
    else:
        page_url = api_link or f"https://facebook.com/{page_id}"
        csm = CompanySocialMedia(
            company_id=company_id,
            platform='facebook',
            url=page_url,
        )
        db.add(csm)

    csm.source = 'facebook_api'
    csm.is_valid = True
    csm.check_status = 'ok'
    csm.page_name = page_info.get('name', '')
    csm.followers_count = followers if followers > 0 else csm.followers_count
    csm.has_bio = bool(page_info.get('about'))
    csm.profile_description = (page_info.get('about') or '')[:500]
    if engagement_rate is not None:
        csm.engagement_rate = engagement_rate
    csm.profile_completeness_score = completeness
    csm.verified_at = now
    csm.last_checked_at = now

    # Store extra API fields in content_types JSONB (no migration needed)
    extra = csm.content_types or {}
    if page_info.get('category'):
        extra['category'] = page_info['category']
    if page_info.get('website'):
        extra['website'] = page_info['website']
    if page_info.get('phone'):
        extra['phone'] = page_info['phone']
    if page_info.get('single_line_address'):
        extra['address'] = page_info['single_line_address']
    csm.content_types = extra

    # Append to followers_history
    history = csm.followers_history or []
    if followers > 0:
        today_str = now.strftime('%Y-%m-%d')
        # Don't duplicate entries for the same day
        if not history or history[-1].get('date') != today_str:
            history.append({'date': today_str, 'count': followers})
            csm.followers_history = history

    db.commit()

    logger.info(f"FB sync OK for company {company_id}: {followers} followers, engagement={engagement_rate}")

    return {
        'success': True,
        'data': {
            'page_name': csm.page_name,
            'followers_count': followers,
            'engagement_rate': engagement_rate,
            'profile_completeness_score': completeness,
            'source': 'facebook_api',
        }
    }