"""CloudKit Web Services client for sportstime-parser.

This module provides a client for uploading data to CloudKit using the
CloudKit Web Services API. It handles JWT authentication, request signing,
and batch operations.

Reference: https://developer.apple.com/documentation/cloudkitwebservices
"""

import base64
import hashlib
import json
import os
import time
from dataclasses import dataclass, field
from datetime import datetime
from pathlib import Path
from typing import Any, Optional
from enum import Enum

import jwt
import requests
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.backends import default_backend

from ..config import (
    CLOUDKIT_CONTAINER_ID,
    CLOUDKIT_ENVIRONMENT,
    CLOUDKIT_BATCH_SIZE,
    CLOUDKIT_KEY_ID,
    CLOUDKIT_PRIVATE_KEY_PATH,
)
from ..utils.logging import get_logger


class RecordType(str, Enum):
    """CloudKit record types for SportsTime.

    Must match CKRecordType constants in CKModels.swift.
    """
    GAME = "Game"
    TEAM = "Team"
    STADIUM = "Stadium"
    TEAM_ALIAS = "TeamAlias"
    STADIUM_ALIAS = "StadiumAlias"
    SPORT = "Sport"
    LEAGUE_STRUCTURE = "LeagueStructure"
    TRIP_POLL = "TripPoll"
    POLL_VOTE = "PollVote"
    ITINERARY_ITEM = "ItineraryItem"


@dataclass
class CloudKitRecord:
    """Represents a CloudKit record for upload.

    Attributes:
        record_name: Unique record identifier (canonical ID)
        record_type: CloudKit record type
        fields: Dictionary of field name -> field value
        record_change_tag: Version tag for conflict detection (None for new records)
    """
    record_name: str
    record_type: RecordType
    fields: dict[str, Any]
    record_change_tag: Optional[str] = None

    def to_cloudkit_dict(self) -> dict:
        """Convert to CloudKit API format."""
        record = {
            "recordName": self.record_name,
            "recordType": self.record_type.value,
            "fields": self._format_fields(),
        }
        if self.record_change_tag:
            record["recordChangeTag"] = self.record_change_tag
        return record

    def _format_fields(self) -> dict:
        """Format fields for CloudKit API."""
        formatted = {}
        for key, value in self.fields.items():
            if value is None:
                continue
            formatted[key] = self._format_field_value(value)
        return formatted

    def _format_field_value(self, value: Any) -> dict:
        """Format a single field value for CloudKit API."""
        # Check bool BEFORE int (bool is a subclass of int in Python)
        if isinstance(value, bool):
            return {"value": 1 if value else 0, "type": "INT64"}
        elif isinstance(value, str):
            return {"value": value, "type": "STRING"}
        elif isinstance(value, int):
            return {"value": value, "type": "INT64"}
        elif isinstance(value, float):
            return {"value": value, "type": "DOUBLE"}
        elif isinstance(value, datetime):
            # CloudKit expects milliseconds since epoch
            timestamp_ms = int(value.timestamp() * 1000)
            return {"value": timestamp_ms, "type": "TIMESTAMP"}
        elif isinstance(value, list):
            return {"value": value, "type": "STRING_LIST"}
        elif isinstance(value, dict) and "latitude" in value and "longitude" in value:
            return {
                "value": {
                    "latitude": value["latitude"],
                    "longitude": value["longitude"],
                },
                "type": "LOCATION",
            }
        else:
            # Default to string
            return {"value": str(value), "type": "STRING"}


@dataclass
class OperationResult:
    """Result of a CloudKit operation."""
    record_name: str
    success: bool
    record_change_tag: Optional[str] = None
    error_code: Optional[str] = None
    error_message: Optional[str] = None


@dataclass
class BatchResult:
    """Result of a batch CloudKit operation."""
    successful: list[OperationResult] = field(default_factory=list)
    failed: list[OperationResult] = field(default_factory=list)

    @property
    def all_succeeded(self) -> bool:
        return len(self.failed) == 0

    @property
    def success_count(self) -> int:
        return len(self.successful)

    @property
    def failure_count(self) -> int:
        return len(self.failed)


class CloudKitClient:
    """Client for CloudKit Web Services API.

    Handles authentication via server-to-server JWT tokens and provides
    methods for CRUD operations on CloudKit records.

    Authentication requires:
    - Key ID: CloudKit key identifier from Apple Developer Portal
    - Private Key: EC private key in PEM format

    Environment variables:
    - CLOUDKIT_KEY_ID: The key identifier
    - CLOUDKIT_PRIVATE_KEY_PATH: Path to the private key file
    - CLOUDKIT_PRIVATE_KEY: The private key contents (alternative to path)
    """

    BASE_URL = "https://api.apple-cloudkit.com"
    TOKEN_EXPIRY_SECONDS = 3600  # 1 hour

    def __init__(
        self,
        container_id: str = CLOUDKIT_CONTAINER_ID,
        environment: str = CLOUDKIT_ENVIRONMENT,
        key_id: Optional[str] = None,
        private_key: Optional[str] = None,
        private_key_path: Optional[str] = None,
    ):
        """Initialize the CloudKit client.

        Args:
            container_id: CloudKit container identifier
            environment: 'development' or 'production'
            key_id: CloudKit server-to-server key ID
            private_key: PEM-encoded EC private key contents
            private_key_path: Path to PEM-encoded EC private key file
        """
        self.container_id = container_id
        self.environment = environment
        self.logger = get_logger()

        # Load authentication credentials (config defaults > env vars > None)
        self.key_id = key_id or os.environ.get("CLOUDKIT_KEY_ID") or CLOUDKIT_KEY_ID

        if private_key:
            self._private_key_pem = private_key
        elif private_key_path:
            self._private_key_pem = Path(private_key_path).read_text()
        elif os.environ.get("CLOUDKIT_PRIVATE_KEY"):
            self._private_key_pem = os.environ["CLOUDKIT_PRIVATE_KEY"]
        elif os.environ.get("CLOUDKIT_PRIVATE_KEY_PATH"):
            self._private_key_pem = Path(os.environ["CLOUDKIT_PRIVATE_KEY_PATH"]).read_text()
        elif CLOUDKIT_PRIVATE_KEY_PATH.exists():
            self._private_key_pem = CLOUDKIT_PRIVATE_KEY_PATH.read_text()
        else:
            self._private_key_pem = None

        # Parse the private key if available
        self._private_key = None
        if self._private_key_pem:
            self._private_key = serialization.load_pem_private_key(
                self._private_key_pem.encode(),
                password=None,
                backend=default_backend(),
            )

        # Token cache
        self._token: Optional[str] = None
        self._token_expiry: float = 0

        # Session for connection pooling
        self._session = requests.Session()

    @property
    def is_configured(self) -> bool:
        """Check if the client has valid authentication credentials."""
        return bool(self.key_id and self._private_key)

    def _get_api_path(self, operation: str) -> str:
        """Build the full API path for an operation."""
        return f"/database/1/{self.container_id}/{self.environment}/public/{operation}"

    def _get_token(self) -> str:
        """Get a valid JWT token, generating a new one if needed."""
        if not self.is_configured:
            raise ValueError(
                "CloudKit client not configured. Set CLOUDKIT_KEY_ID and "
                "CLOUDKIT_PRIVATE_KEY_PATH environment variables."
            )

        now = time.time()

        # Return cached token if still valid (with 5 min buffer)
        if self._token and (self._token_expiry - now) > 300:
            return self._token

        # Generate new token
        expiry = now + self.TOKEN_EXPIRY_SECONDS

        payload = {
            "iss": self.key_id,
            "iat": int(now),
            "exp": int(expiry),
            "sub": self.container_id,
        }

        self._token = jwt.encode(
            payload,
            self._private_key,
            algorithm="ES256",
        )
        self._token_expiry = expiry

        return self._token

    def _sign_request(self, method: str, path: str, body: Optional[bytes] = None) -> dict:
        """Generate request headers with authentication.

        Args:
            method: HTTP method
            path: API path
            body: Request body bytes

        Returns:
            Dictionary of headers to include in the request
        """
        token = self._get_token()

        # CloudKit uses date in ISO format
        date_str = datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%SZ")

        # Calculate body hash
        if body:
            body_hash = base64.b64encode(
                hashlib.sha256(body).digest()
            ).decode()
        else:
            body_hash = base64.b64encode(
                hashlib.sha256(b"").digest()
            ).decode()

        # Build the message to sign
        # Format: date:body_hash:path
        message = f"{date_str}:{body_hash}:{path}"

        # Sign the message
        signature = self._private_key.sign(
            message.encode(),
            ec.ECDSA(hashes.SHA256()),
        )
        signature_b64 = base64.b64encode(signature).decode()

        return {
            "Authorization": f"Bearer {token}",
            "X-Apple-CloudKit-Request-KeyID": self.key_id,
            "X-Apple-CloudKit-Request-ISO8601Date": date_str,
            "X-Apple-CloudKit-Request-SignatureV1": signature_b64,
            "Content-Type": "application/json",
        }

    def _request(
        self,
        method: str,
        operation: str,
        body: Optional[dict] = None,
    ) -> dict:
        """Make a request to the CloudKit API.

        Args:
            method: HTTP method
            operation: API operation path
            body: Request body as dictionary

        Returns:
            Response data as dictionary

        Raises:
            CloudKitError: If the request fails
        """
        path = self._get_api_path(operation)
        url = f"{self.BASE_URL}{path}"

        body_bytes = json.dumps(body).encode() if body else None
        headers = self._sign_request(method, path, body_bytes)

        response = self._session.request(
            method=method,
            url=url,
            headers=headers,
            data=body_bytes,
        )

        if response.status_code == 200:
            return response.json()
        elif response.status_code == 421:
            # Authentication required - token may be expired
            self._token = None
            raise CloudKitAuthError("Authentication failed - check credentials")
        elif response.status_code == 429:
            raise CloudKitRateLimitError("Rate limit exceeded")
        elif response.status_code >= 500:
            raise CloudKitServerError(f"Server error: {response.status_code}")
        else:
            try:
                error_data = response.json()
                error_msg = error_data.get("serverErrorCode", str(response.status_code))
            except (json.JSONDecodeError, KeyError):
                error_msg = response.text
            raise CloudKitError(f"Request failed: {error_msg}")

    def fetch_records(
        self,
        record_type: RecordType,
        record_names: Optional[list[str]] = None,
        limit: int = 200,
    ) -> list[dict]:
        """Fetch records from CloudKit.

        Args:
            record_type: Type of records to fetch
            record_names: Specific record names to fetch (optional)
            limit: Maximum records to return (default 200)

        Returns:
            List of record dictionaries
        """
        if record_names:
            # Fetch specific records by name
            body = {
                "records": [{"recordName": name} for name in record_names],
            }
            response = self._request("POST", "records/lookup", body)
        else:
            # Query all records of type
            body = {
                "query": {
                    "recordType": record_type.value,
                },
                "resultsLimit": limit,
            }
            response = self._request("POST", "records/query", body)

        records = response.get("records", [])
        return [r for r in records if "recordName" in r]

    def fetch_all_records(self, record_type: RecordType) -> list[dict]:
        """Fetch all records of a type using pagination.

        Args:
            record_type: Type of records to fetch

        Returns:
            List of all record dictionaries
        """
        all_records = []
        continuation_marker = None

        while True:
            body = {
                "query": {
                    "recordType": record_type.value,
                },
                "resultsLimit": 200,
            }

            if continuation_marker:
                body["continuationMarker"] = continuation_marker

            response = self._request("POST", "records/query", body)

            records = response.get("records", [])
            all_records.extend([r for r in records if "recordName" in r])

            continuation_marker = response.get("continuationMarker")
            if not continuation_marker:
                break

        return all_records

    def save_records(self, records: list[CloudKitRecord]) -> BatchResult:
        """Save records to CloudKit (create or update).

        Args:
            records: List of records to save

        Returns:
            BatchResult with success/failure details
        """
        result = BatchResult()

        # Process in batches
        for i in range(0, len(records), CLOUDKIT_BATCH_SIZE):
            batch = records[i:i + CLOUDKIT_BATCH_SIZE]
            batch_result = self._save_batch(batch)
            result.successful.extend(batch_result.successful)
            result.failed.extend(batch_result.failed)

        return result

    def _save_batch(self, records: list[CloudKitRecord]) -> BatchResult:
        """Save a single batch of records.

        Args:
            records: List of records (max CLOUDKIT_BATCH_SIZE)

        Returns:
            BatchResult with success/failure details
        """
        result = BatchResult()

        operations = []
        for record in records:
            op = {
                "operationType": "forceReplace",
                "record": record.to_cloudkit_dict(),
            }
            operations.append(op)

        body = {"operations": operations}

        try:
            response = self._request("POST", "records/modify", body)
        except CloudKitError as e:
            # Entire batch failed
            for record in records:
                result.failed.append(OperationResult(
                    record_name=record.record_name,
                    success=False,
                    error_message=str(e),
                ))
            return result

        # Process individual results
        for record_data in response.get("records", []):
            record_name = record_data.get("recordName", "unknown")

            if "serverErrorCode" in record_data:
                result.failed.append(OperationResult(
                    record_name=record_name,
                    success=False,
                    error_code=record_data.get("serverErrorCode"),
                    error_message=record_data.get("reason"),
                ))
            else:
                result.successful.append(OperationResult(
                    record_name=record_name,
                    success=True,
                    record_change_tag=record_data.get("recordChangeTag"),
                ))

        return result

    def delete_records(
        self,
        record_type: RecordType,
        records: list[dict],
    ) -> BatchResult:
        """Delete records from CloudKit.

        Args:
            record_type: Type of records to delete
            records: List of record dicts (must have recordName and recordChangeTag)

        Returns:
            BatchResult with success/failure details
        """
        result = BatchResult()

        # Process in batches
        for i in range(0, len(records), CLOUDKIT_BATCH_SIZE):
            batch = records[i:i + CLOUDKIT_BATCH_SIZE]

            operations = []
            for record in batch:
                operations.append({
                    "operationType": "delete",
                    "record": {
                        "recordName": record["recordName"],
                        "recordChangeTag": record.get("recordChangeTag"),
                    },
                })

            body = {"operations": operations}

            try:
                response = self._request("POST", "records/modify", body)
            except CloudKitError as e:
                for record in batch:
                    result.failed.append(OperationResult(
                        record_name=record["recordName"],
                        success=False,
                        error_message=str(e),
                    ))
                continue

            for record_data in response.get("records", []):
                record_name = record_data.get("recordName", "unknown")

                if "serverErrorCode" in record_data:
                    result.failed.append(OperationResult(
                        record_name=record_name,
                        success=False,
                        error_code=record_data.get("serverErrorCode"),
                        error_message=record_data.get("reason"),
                    ))
                else:
                    result.successful.append(OperationResult(
                        record_name=record_name,
                        success=True,
                    ))

        return result


class CloudKitError(Exception):
    """Base exception for CloudKit errors."""
    pass


class CloudKitAuthError(CloudKitError):
    """Authentication error."""
    pass


class CloudKitRateLimitError(CloudKitError):
    """Rate limit exceeded."""
    pass


class CloudKitServerError(CloudKitError):
    """Server-side error."""
    pass