"""
Abstract and generic rule system for triggering bot commands.

This module provides a flexible rule system that allows defining conditions
under which commands should be triggered. Rules can be combined using
logical AND/OR operations.
"""

from abc import ABC, abstractmethod
from datetime import datetime, time, timedelta
from typing import Optional, Dict, Any, List, Iterable


class CommandContext:
    """Context object containing information about the current command execution."""
    
    def __init__(
        self,
        command: str,
        user_id: str,
        reaction_count: int = 0,
        current_time: Optional[datetime] = None,
        message_data: Optional[Dict[str, Any]] = None
    ):
        self.command = command
        self.user_id = user_id
        self.reaction_count = reaction_count
        self.current_time = current_time or datetime.now()
        self.message_data = message_data or {}


class CommandState:
    """Tracks state for command usage (usage count, last user, last time)."""
    
    def __init__(self):
        # Per-command state: command -> {usage_count, last_user, last_time}
        self._command_states: Dict[str, Dict[str, Any]] = {}
    
    def get_state(self, command: str) -> Dict[str, Any]:
        """Get state for a specific command."""
        if command not in self._command_states:
            self._command_states[command] = {
                'usage_count': 0,
                'last_user': None,
                'last_time': None
            }
        return self._command_states[command]
    
    def record_usage(self, command: str, user_id: str, timestamp: Optional[datetime] = None):
        """Record that a command was used."""
        state = self.get_state(command)
        state['usage_count'] += 1
        state['last_user'] = user_id
        state['last_time'] = timestamp or datetime.now()
    
    def get_usage_count(self, command: str) -> int:
        """Get total usage count for a command."""
        return self.get_state(command)['usage_count']
    
    def get_last_user(self, command: str) -> Optional[str]:
        """Get the last user who used a command."""
        return self.get_state(command)['last_user']
    
    def get_last_time(self, command: str) -> Optional[datetime]:
        """Get the last time a command was used."""
        return self.get_state(command)['last_time']
    
    def reset_command(self, command: str):
        """Reset state for a specific command."""
        if command in self._command_states:
            del self._command_states[command]
    
    def reset_all(self):
        """Reset all command states."""
        self._command_states.clear()


class Rule(ABC):
    """Abstract base class for command trigger rules."""
    
    @abstractmethod
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        """
        Evaluate whether the rule passes.
        
        Args:
            context: The current command context
            state: The command state tracker
            
        Returns:
            True if the rule passes (command should be allowed), False otherwise
        """
        pass
    
    @abstractmethod
    def get_failure_message(self) -> Optional[str]:
        """
        Get a message explaining why the rule failed.
        
        Returns:
            A human-readable message or None if no message should be sent
        """
        pass


class MinReactionsRule(Rule):
    """Rule that passes if the message has at least n reactions."""
    
    def __init__(self, min_reactions: int, failure_message: Optional[str] = None):
        self.min_reactions = min_reactions
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        return context.reaction_count >= self.min_reactions
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class MaxUsageRule(Rule):
    """Rule that passes if total command usage has not exceeded n."""
    
    def __init__(self, max_usage: int, failure_message: Optional[str] = None):
        self.max_usage = max_usage
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        current_usage = state.get_usage_count(context.command)
        return current_usage < self.max_usage
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class CooldownRule(Rule):
    """Rule that passes if sufficient time has passed since last command use."""
    
    def __init__(self, cooldown: timedelta, failure_message: Optional[str] = None):
        self.cooldown = cooldown
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        last_time = state.get_last_time(context.command)
        if last_time is None:
            return True
        return context.current_time - last_time >= self.cooldown
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class NotUserRule(Rule):
    """Rule that passes if the command was not last used by a specific user."""
    
    def __init__(self, excluded_user: str, failure_message: Optional[str] = None):
        self.excluded_user = excluded_user
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        last_user = state.get_last_user(context.command)
        if last_user is None:
            return True
        return last_user != self.excluded_user
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class NotSameUserRule(Rule):
    """Rule that passes if the current user is not the same as the last user."""
    
    def __init__(self, failure_message: Optional[str] = None):
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        last_user = state.get_last_user(context.command)
        if last_user is None:
            return True
        return last_user != context.user_id
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class TimeWindowRule(Rule):
    """Rule that passes if current time is within the specified window."""
    
    def __init__(
        self,
        start_time: time,
        end_time: time,
        failure_message: Optional[str] = None
    ):
        self.start_time = start_time
        self.end_time = end_time
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        current_time = context.current_time.time()
        
        # Handle window that spans midnight (e.g., 22:00 to 06:00)
        if self.start_time <= self.end_time:
            return self.start_time <= current_time <= self.end_time
        else:
            return current_time >= self.start_time or current_time <= self.end_time
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class AlwaysPassRule(Rule):
    """Rule that always passes. Useful as a default or placeholder."""
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        return True
    
    def get_failure_message(self) -> Optional[str]:
        return None


class AlwaysFailRule(Rule):
    """Rule that always fails. Useful for disabling commands."""
    
    def __init__(self, failure_message: Optional[str] = None):
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        return False
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class AndRule(Rule):
    """Composite rule that passes only if ALL child rules pass."""
    
    def __init__(self, rules: List[Rule]):
        self.rules = rules
        self._failed_rule: Optional[Rule] = None
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        self._failed_rule = None
        for rule in self.rules:
            if not rule.evaluate(context, state):
                self._failed_rule = rule
                return False
        return True
    
    def get_failure_message(self) -> Optional[str]:
        if self._failed_rule is not None:
            return self._failed_rule.get_failure_message()
        return None


class OrRule(Rule):
    """Composite rule that passes if ANY child rule passes."""
    
    def __init__(self, rules: List[Rule], failure_message: Optional[str] = None):
        self.rules = rules
        self.failure_message = failure_message
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        for rule in self.rules:
            if rule.evaluate(context, state):
                return True
        return False
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class GlobalCooldownRule(Rule):
    """Rule that enforces a cooldown across all commands (not per-command)."""
    
    def __init__(self, cooldown: timedelta, failure_message: Optional[str] = None):
        self.cooldown = cooldown
        self.failure_message = failure_message
        self._last_global_time: Optional[datetime] = None
    
    def evaluate(self, context: CommandContext, state: CommandState) -> bool:
        if self._last_global_time is None:
            return True
        return context.current_time - self._last_global_time >= self.cooldown
    
    def record_usage(self, timestamp: Optional[datetime] = None):
        """Record that a command was used globally."""
        self._last_global_time = timestamp or datetime.now()
    
    def get_failure_message(self) -> Optional[str]:
        return self.failure_message


class RuleEngine:
    """
    Engine for evaluating rules and managing command state.
    
    This provides a higher-level interface for working with rules.
    """
    
    def __init__(self):
        self.state = CommandState()
        self._command_rules: Dict[str, Rule] = {}
        self._default_rule: Rule = AlwaysPassRule()
        self._global_rules: List[Rule] = []
    
    def set_command_rule(self, command: str, rule: Rule):
        """Set the rule for a specific command."""
        self._command_rules[command] = rule
    
    def set_command_rules(self, commands: Iterable[str], rule: Rule):
        """Set the same rule for multiple commands."""
        for command in commands:
            self._command_rules[command] = rule
    
    def set_default_rule(self, rule: Rule):
        """Set the default rule for commands without specific rules."""
        self._default_rule = rule
    
    def add_global_rule(self, rule: Rule):
        """Add a rule that applies to all commands."""
        self._global_rules.append(rule)
    
    def clear_global_rules(self):
        """Clear all global rules."""
        self._global_rules.clear()
    
    def get_rule(self, command: str) -> Rule:
        """Get the rule for a specific command."""
        return self._command_rules.get(command, self._default_rule)
    
    def evaluate(self, context: CommandContext) -> tuple:
        """
        Evaluate whether a command should be triggered.
        
        Args:
            context: The command context
            
        Returns:
            Tuple of (should_trigger: bool, failure_message: Optional[str])
        """
        # First check global rules
        for global_rule in self._global_rules:
            if not global_rule.evaluate(context, self.state):
                return False, global_rule.get_failure_message()
        
        # Then check command-specific rule
        rule = self.get_rule(context.command)
        if not rule.evaluate(context, self.state):
            return False, rule.get_failure_message()
        
        return True, None
    
    def record_usage(self, command: str, user_id: str, timestamp: Optional[datetime] = None):
        """Record that a command was used."""
        self.state.record_usage(command, user_id, timestamp)
        
        # Also record for global rules that need it
        for global_rule in self._global_rules:
            if isinstance(global_rule, GlobalCooldownRule):
                global_rule.record_usage(timestamp)