from typing import Dict, Any, Optional
import time


class CachePolicy:
    """
    Determines caching behavior for Solana RPC methods based on their characteristics.
    """

    # Methods that return immutable data - cache indefinitely
    CACHEABLE_IMMUTABLE = {
        'getGenesisHash'         # Network genesis hash never changes
    }

    # Methods with time-based TTL caching based on data change frequency
    CACHEABLE_WITH_TTL = {
        # Network/validator information - changes periodically
        'getVoteAccounts': 120,         # Validator vote accounts change every few minutes
        'getSupply': 300,               # Total SOL supply changes slowly

        # Epoch and network info - changes with epoch boundaries (~2-3 days)
        'getEpochInfo': 3600,           # Current epoch info changes slowly
        'getInflationRate': 1800,       # Inflation rate changes infrequently
        'getInflationGovernor': 3600,   # Inflation governor params rarely change

        # Network constants - change very rarely or never
        'getEpochSchedule': 86400,      # Epoch schedule rarely changes
        'getVersion': 3600,             # RPC version changes occasionally
        'getIdentity': 3600,            # Node identity changes rarely

        # Never change for the given parameters but will add new entry in the DB if the input parameters change
        'getBlock': 86400,
        'getTransaction':86400
    }

    def should_cache(self, method: str, params: Dict[str, Any]) -> bool:
        """
        Determine if a method should be cached based on the method name and parameters.

        Args:
            method: The RPC method name
            params: The method parameters

        Returns:
            True if the method should be cached, False otherwise
        """

        if method in self.CACHEABLE_WITH_TTL:
            # For getBlock, only cache finalized blocks
            if method == 'getBlock':
                commitment = self._get_commitment(params)
                return commitment == 'finalized'
            return True

        if method in self.CACHEABLE_IMMUTABLE:
            return True

        # Default to not caching unknown methods
        return False

    def get_cache_ttl(self, method: str, params: Dict[str, Any]) -> Optional[int]:
        """
        Get the Time To Live (TTL) for a cached method in seconds.

        Args:
            method: The RPC method name
            params: The method parameters

        Returns:
            TTL in seconds, or None for indefinite caching
        """
        if method in self.CACHEABLE_IMMUTABLE:
            return None  # Cache indefinitely

        if method in self.CACHEABLE_WITH_TTL:
            return self.CACHEABLE_WITH_TTL[method]

        return None

    def _get_commitment(self, params: Dict[str, Any]) -> str:
        """
        Extract the commitment level from RPC parameters.

        Args:
            params: The method parameters

        Returns:
            The commitment level, defaults to 'processed'
        """
        if isinstance(params, list) and len(params) > 1:
            if isinstance(params[1], dict) and 'commitment' in params[1]:
                return params[1]['commitment']
        elif isinstance(params, dict) and 'commitment' in params:
            return params['commitment']

        return 'processed'  # Default commitment level