"""Tibber API Client."""

from __future__ import annotations

import asyncio
import base64
import logging
import re
import socket
from datetime import timedelta
from typing import TYPE_CHECKING, Any
from zoneinfo import ZoneInfo

import aiohttp

from homeassistant.util import dt as dt_utils

from .exceptions import (
    TibberPricesApiClientAuthenticationError,
    TibberPricesApiClientCommunicationError,
    TibberPricesApiClientError,
    TibberPricesApiClientPermissionError,
)
from .helpers import (
    flatten_price_info,
    prepare_headers,
    verify_graphql_response,
    verify_response_or_raise,
)
from .queries import TibberPricesQueryType

if TYPE_CHECKING:
    from custom_components.tibber_prices.coordinator.time_service import TibberPricesTimeService

_LOGGER = logging.getLogger(__name__)


class TibberPricesApiClient:
    """Tibber API Client."""

    def __init__(
        self,
        access_token: str,
        session: aiohttp.ClientSession,
        version: str,
    ) -> None:
        """Tibber API Client."""
        self._access_token = access_token
        self._session = session
        self._version = version
        self._request_semaphore = asyncio.Semaphore(2)  # Max 2 concurrent requests
        self.time: TibberPricesTimeService | None = None  # Set externally by coordinator (optional during config flow)
        self._last_request_time = None  # Set on first request
        self._min_request_interval = timedelta(seconds=1)  # Min 1 second between requests
        self._max_retries = 5
        self._retry_delay = 2  # Base retry delay in seconds

        # Timeout configuration - more granular control
        self._connect_timeout = 10  # Connection timeout in seconds
        self._request_timeout = 25  # Total request timeout in seconds
        self._socket_connect_timeout = 5  # Socket connection timeout

    async def async_get_viewer_details(self) -> Any:
        """Get comprehensive viewer and home details from Tibber API."""
        return await self._api_wrapper(
            data={
                "query": """
                    {
                        viewer {
                            userId
                            name
                            login
                            accountType
                            homes {
                                id
                                type
                                appNickname
                                appAvatar
                                size
                                timeZone
                                mainFuseSize
                                numberOfResidents
                                primaryHeatingSource
                                hasVentilationSystem
                                address {
                                    address1
                                    address2
                                    address3
                                    postalCode
                                    city
                                    country
                                    latitude
                                    longitude
                                }
                                owner {
                                    id
                                    firstName
                                    lastName
                                    isCompany
                                    name
                                    contactInfo {
                                        email
                                        mobile
                                    }
                                    language
                                }
                                meteringPointData {
                                    consumptionEan
                                    gridCompany
                                    gridAreaCode
                                    priceAreaCode
                                    productionEan
                                    energyTaxType
                                    vatType
                                    estimatedAnnualConsumption
                                }
                                currentSubscription {
                                    id
                                    status
                                    validFrom
                                    validTo
                                    priceInfo {
                                        current {
                                            currency
                                        }
                                    }
                                }
                                features {
                                    realTimeConsumptionEnabled
                                }
                            }
                        }
                    }
                """
            },
            query_type=TibberPricesQueryType.USER,
        )

    async def async_get_price_info(self, home_ids: set[str], user_data: dict[str, Any]) -> dict:
        """
        Get price info for specific homes using GraphQL aliases.

        Uses timezone-aware cursor calculation per home based on the home's actual timezone
        from Tibber API (not HA system timezone). This ensures correct "day before yesterday
        midnight" calculation for homes in different timezones.

        Args:
            home_ids: Set of home IDs to fetch price data for.
            user_data: User data dict containing home metadata (including timezone).
                      REQUIRED - must be fetched before calling this method.

        Returns:
            Dict with "homes" key containing home_id -> price_data mapping.

        Raises:
            TibberPricesApiClientError: If TimeService not initialized or user_data missing.

        """
        if not self.time:
            msg = "TimeService not initialized - required for price info processing"
            raise TibberPricesApiClientError(msg)

        if not user_data:
            msg = "User data required for timezone-aware price fetching - fetch user data first"
            raise TibberPricesApiClientError(msg)

        if not home_ids:
            return {"homes": {}}

        # Build home_id -> timezone mapping from user_data
        home_timezones = self._extract_home_timezones(user_data)

        # Build query with aliases for each home
        # Each home gets its own cursor based on its timezone
        home_queries = []
        for idx, home_id in enumerate(sorted(home_ids)):
            alias = f"home{idx}"

            # Get timezone for this home (fallback to HA system timezone)
            home_tz = home_timezones.get(home_id)

            # Calculate cursor: day before yesterday midnight in home's timezone
            cursor = self._calculate_cursor_for_home(home_tz)

            home_query = f"""
                {alias}: home(id: "{home_id}") {{
                    id
                    currentSubscription {{
                        priceInfoRange(resolution:QUARTER_HOURLY, first:192, after: "{cursor}") {{
                            pageInfo{{ count }}
                            edges{{node{{
                                startsAt total level
                            }}}}
                        }}
                        priceInfo(resolution:QUARTER_HOURLY) {{
                            today{{startsAt total level}}
                            tomorrow{{startsAt total level}}
                        }}
                    }}
                }}
            """
            home_queries.append(home_query)

        query = "{viewer{" + "".join(home_queries) + "}}"

        _LOGGER.debug("Fetching price info for %d specific home(s)", len(home_ids))

        data = await self._api_wrapper(
            data={"query": query},
            query_type=TibberPricesQueryType.PRICE_INFO,
        )

        # Parse aliased response
        viewer = data.get("viewer", {})
        homes_data = {}

        for idx, home_id in enumerate(sorted(home_ids)):
            alias = f"home{idx}"
            home = viewer.get(alias)

            if not home:
                _LOGGER.debug("Home %s not found in API response", home_id)
                homes_data[home_id] = {}
                continue

            if "currentSubscription" in home and home["currentSubscription"] is not None:
                homes_data[home_id] = flatten_price_info(home["currentSubscription"])
            else:
                _LOGGER.debug(
                    "Home %s has no active subscription - price data will be unavailable",
                    home_id,
                )
                homes_data[home_id] = {}

        data["homes"] = homes_data
        return data

    def _extract_home_timezones(self, user_data: dict[str, Any]) -> dict[str, str]:
        """
        Extract home_id -> timezone mapping from user_data.

        Args:
            user_data: User data dict from async_get_viewer_details() (required).

        Returns:
            Dict mapping home_id to timezone string (e.g., "Europe/Oslo").

        """
        home_timezones = {}
        viewer = user_data.get("viewer", {})
        homes = viewer.get("homes", [])

        for home in homes:
            home_id = home.get("id")
            timezone = home.get("timeZone")

            if home_id and timezone:
                home_timezones[home_id] = timezone
                _LOGGER.debug("Extracted timezone %s for home %s", timezone, home_id)
            elif home_id:
                _LOGGER.warning("Home %s has no timezone in user data, will use fallback", home_id)

        return home_timezones

    def _calculate_cursor_for_home(self, home_timezone: str | None) -> str:
        """
        Calculate cursor (day before yesterday midnight) for a home's timezone.

        Args:
            home_timezone: Timezone string (e.g., "Europe/Oslo", "America/New_York").
                          If None, falls back to HA system timezone.

        Returns:
            Base64-encoded ISO timestamp string for use as GraphQL cursor.

        """
        if not self.time:
            msg = "TimeService not initialized"
            raise TibberPricesApiClientError(msg)

        # Get current time
        now = self.time.now()

        # Convert to home's timezone or fallback to HA system timezone
        if home_timezone:
            try:
                tz = ZoneInfo(home_timezone)
                now_in_home_tz = now.astimezone(tz)
            except (KeyError, ValueError, OSError) as error:
                _LOGGER.warning(
                    "Invalid timezone %s (%s), falling back to HA system timezone",
                    home_timezone,
                    error,
                )
                now_in_home_tz = dt_utils.as_local(now)
        else:
            # Fallback to HA system timezone
            now_in_home_tz = dt_utils.as_local(now)

        # Calculate day before yesterday midnight in home's timezone
        day_before_yesterday_midnight = (now_in_home_tz - timedelta(days=2)).replace(
            hour=0, minute=0, second=0, microsecond=0
        )

        # Convert to ISO format and base64 encode
        iso_string = day_before_yesterday_midnight.isoformat()
        return base64.b64encode(iso_string.encode()).decode()

    async def _make_request(
        self,
        headers: dict[str, str],
        data: dict,
        query_type: TibberPricesQueryType,
    ) -> dict[str, Any]:
        """Make an API request with comprehensive error handling for network issues."""
        _LOGGER.debug("Making API request with data: %s", data)

        try:
            # More granular timeout configuration for better network failure handling
            timeout = aiohttp.ClientTimeout(
                total=self._request_timeout,  # Total request timeout: 25s
                connect=self._connect_timeout,  # Connection timeout: 10s
                sock_connect=self._socket_connect_timeout,  # Socket connection: 5s
            )

            response = await self._session.request(
                method="POST",
                url="https://api.tibber.com/v1-beta/gql",
                headers=headers,
                json=data,
                timeout=timeout,
            )

            verify_response_or_raise(response)
            response_json = await response.json()
            _LOGGER.debug("Received API response: %s", response_json)

            await verify_graphql_response(response_json, query_type)

            return response_json["data"]

        except aiohttp.ClientResponseError as error:
            _LOGGER.exception("HTTP error during API request")
            raise TibberPricesApiClientCommunicationError(
                TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=str(error))
            ) from error

        except aiohttp.ClientConnectorError as error:
            _LOGGER.exception("Connection error - server unreachable or network down")
            raise TibberPricesApiClientCommunicationError(
                TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=str(error))
            ) from error

        except aiohttp.ServerDisconnectedError as error:
            _LOGGER.exception("Server disconnected during request")
            raise TibberPricesApiClientCommunicationError(
                TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=str(error))
            ) from error

        except TimeoutError as error:
            _LOGGER.exception(
                "Request timeout after %d seconds - slow network or server overload",
                self._request_timeout,
            )
            raise TibberPricesApiClientCommunicationError(
                TibberPricesApiClientCommunicationError.TIMEOUT_ERROR.format(exception=str(error))
            ) from error

        except socket.gaierror as error:
            self._handle_dns_error(error)
            raise  # Ensure type checker knows this path always raises

        except OSError as error:
            self._handle_network_error(error)
            raise  # Ensure type checker knows this path always raises

    def _handle_dns_error(self, error: socket.gaierror) -> None:
        """Handle DNS resolution errors with IPv4/IPv6 dual stack considerations."""
        error_msg = str(error)

        if "Name or service not known" in error_msg:
            _LOGGER.exception("DNS resolution failed - domain name not found")
        elif "Temporary failure in name resolution" in error_msg:
            _LOGGER.exception("DNS resolution temporarily failed - network or DNS server issue")
        elif "Address family for hostname not supported" in error_msg:
            _LOGGER.exception("DNS resolution failed - IPv4/IPv6 address family not supported")
        elif "No address associated with hostname" in error_msg:
            _LOGGER.exception("DNS resolution failed - no IPv4/IPv6 addresses found")
        else:
            _LOGGER.exception("DNS resolution failed - check internet connection: %s", error_msg)

        raise TibberPricesApiClientCommunicationError(
            TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=str(error))
        ) from error

    def _handle_network_error(self, error: OSError) -> None:
        """Handle network-level errors with IPv4/IPv6 dual stack considerations."""
        error_msg = str(error)
        errno = getattr(error, "errno", None)

        # Common IPv4/IPv6 dual stack network error codes
        errno_network_unreachable = 101  # ENETUNREACH
        errno_host_unreachable = 113  # EHOSTUNREACH
        errno_connection_refused = 111  # ECONNREFUSED
        errno_connection_timeout = 110  # ETIMEDOUT

        if errno == errno_network_unreachable:
            _LOGGER.exception("Network unreachable - check internet connection or IPv4/IPv6 routing")
        elif errno == errno_host_unreachable:
            _LOGGER.exception("Host unreachable - routing issue or IPv4/IPv6 connectivity problem")
        elif errno == errno_connection_refused:
            _LOGGER.exception("Connection refused - server not accepting connections")
        elif errno == errno_connection_timeout:
            _LOGGER.exception("Connection timed out - network latency or server overload")
        elif "Address family not supported" in error_msg:
            _LOGGER.exception("Address family not supported - IPv4/IPv6 configuration issue")
        elif "Protocol not available" in error_msg:
            _LOGGER.exception("Protocol not available - IPv4/IPv6 stack configuration issue")
        elif "Network is down" in error_msg:
            _LOGGER.exception("Network interface is down - check network adapter")
        elif "Permission denied" in error_msg:
            _LOGGER.exception("Network permission denied - firewall or security restriction")
        else:
            _LOGGER.exception("Network error - internet may be down: %s", error_msg)

        raise TibberPricesApiClientCommunicationError(
            TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=str(error))
        ) from error

    async def _handle_request(
        self,
        headers: dict[str, str],
        data: dict,
        query_type: TibberPricesQueryType,
    ) -> Any:
        """Handle a single API request with rate limiting."""
        async with self._request_semaphore:
            # Rate limiting: ensure minimum interval between requests
            if self.time and self._last_request_time:
                now = self.time.now()
                time_since_last_request = now - self._last_request_time
                if time_since_last_request < self._min_request_interval:
                    sleep_time = (self._min_request_interval - time_since_last_request).total_seconds()
                    _LOGGER.debug(
                        "Rate limiting: waiting %s seconds before next request",
                        sleep_time,
                    )
                    await asyncio.sleep(sleep_time)

            if self.time:
                self._last_request_time = self.time.now()
            return await self._make_request(
                headers,
                data or {},
                query_type,
            )

    def _should_retry_error(self, error: Exception, retry: int) -> tuple[bool, int]:
        """Determine if an error should be retried and calculate delay."""
        # Check if we've exceeded max retries first
        if retry >= self._max_retries:
            return False, 0

        # Non-retryable errors - authentication and permission issues
        if isinstance(
            error,
            (
                TibberPricesApiClientAuthenticationError,
                TibberPricesApiClientPermissionError,
            ),
        ):
            return False, 0

        # Handle API-specific errors
        if isinstance(error, TibberPricesApiClientError):
            return self._handle_api_error_retry(error, retry)

        # Network and timeout errors - retryable with exponential backoff
        if isinstance(error, (aiohttp.ClientError, socket.gaierror, TimeoutError)):
            delay = min(self._retry_delay * (2**retry), 30)  # Cap at 30 seconds
            return True, delay

        # Unknown errors - not retryable
        return False, 0

    def _handle_api_error_retry(self, error: TibberPricesApiClientError, retry: int) -> tuple[bool, int]:
        """Handle retry logic for API-specific errors."""
        error_msg = str(error)

        # Non-retryable: Invalid queries
        if "Invalid GraphQL query" in error_msg or "Bad request" in error_msg:
            return False, 0

        # Rate limits - special handling with extracted delay
        if "Rate limit exceeded" in error_msg or "rate limited" in error_msg.lower():
            delay = self._extract_retry_delay(error, retry)
            return True, delay

        # Empty data - retryable with capped exponential backoff
        if "Empty data received" in error_msg:
            delay = min(self._retry_delay * (2**retry), 60)  # Cap at 60 seconds
            return True, delay

        # Other API errors - retryable with capped exponential backoff
        delay = min(self._retry_delay * (2**retry), 30)  # Cap at 30 seconds
        return True, delay

    def _extract_retry_delay(self, error: Exception, retry: int) -> int:
        """Extract retry delay from rate limit error or use exponential backoff."""
        error_msg = str(error)

        # Try to extract Retry-After value from error message
        retry_after_match = re.search(r"retry after (\d+) seconds", error_msg.lower())
        if retry_after_match:
            try:
                retry_after = int(retry_after_match.group(1))
                return min(retry_after + 1, 300)  # Add buffer, max 5 minutes
            except ValueError:
                pass

        # Try to extract generic seconds value
        seconds_match = re.search(r"(\d+) seconds", error_msg)
        if seconds_match:
            try:
                seconds = int(seconds_match.group(1))
                return min(seconds + 1, 300)  # Add buffer, max 5 minutes
            except ValueError:
                pass

        # Fall back to exponential backoff with cap
        base_delay = self._retry_delay * (2**retry)
        return min(base_delay, 120)  # Cap at 2 minutes for rate limits

    async def _api_wrapper(
        self,
        data: dict | None = None,
        headers: dict | None = None,
        query_type: TibberPricesQueryType = TibberPricesQueryType.USER,
    ) -> Any:
        """Get information from the API with rate limiting and retry logic."""
        headers = headers or prepare_headers(self._access_token, self._version)
        last_error: Exception | None = None

        for retry in range(self._max_retries + 1):
            try:
                return await self._handle_request(headers, data or {}, query_type)

            except (
                TibberPricesApiClientAuthenticationError,
                TibberPricesApiClientPermissionError,
            ):
                _LOGGER.exception("Non-retryable error occurred")
                raise
            except (
                TibberPricesApiClientError,
                aiohttp.ClientError,
                socket.gaierror,
                TimeoutError,
            ) as error:
                last_error = (
                    error
                    if isinstance(error, TibberPricesApiClientError)
                    else TibberPricesApiClientCommunicationError(
                        TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=str(error))
                    )
                )

                should_retry, delay = self._should_retry_error(error, retry)
                if should_retry:
                    error_type = self._get_error_type(error)
                    _LOGGER.warning(
                        "Tibber %s error, attempt %d/%d. Retrying in %d seconds: %s",
                        error_type,
                        retry + 1,
                        self._max_retries,
                        delay,
                        str(error),
                    )
                    await asyncio.sleep(delay)
                    continue

                if "Invalid GraphQL query" in str(error):
                    _LOGGER.exception("Invalid query - not retrying")
                raise

        # Handle final error state
        if isinstance(last_error, TimeoutError):
            raise TibberPricesApiClientCommunicationError(
                TibberPricesApiClientCommunicationError.TIMEOUT_ERROR.format(exception=last_error)
            ) from last_error
        if isinstance(last_error, (aiohttp.ClientError, socket.gaierror)):
            raise TibberPricesApiClientCommunicationError(
                TibberPricesApiClientCommunicationError.CONNECTION_ERROR.format(exception=last_error)
            ) from last_error

        raise last_error or TibberPricesApiClientError(TibberPricesApiClientError.UNKNOWN_ERROR)

    def _get_error_type(self, error: Exception) -> str:
        """Get a descriptive error type for logging."""
        if "Rate limit" in str(error):
            return "rate limit"
        if isinstance(error, (aiohttp.ClientError, socket.gaierror, TimeoutError)):
            return "network"
        return "API"