"""
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 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