"""
Cadence Agent - AI-driven multi-channel outreach orchestration

Handles intelligent sequencing, timing optimization, engagement-based branching,
personalization, compliance, rate limiting, and comprehensive error handling.

Author: StrategyStack Team
Date: November 2025
Version: 1.0.0
"""

import logging
import json
import csv
from datetime import datetime, timedelta
from typing import Dict, List, Optional, Tuple, Any
from enum import Enum
import pytz
from dataclasses import dataclass, field, asdict
import yaml
import time
from collections import defaultdict
from pathlib import Path

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)


class ChannelType(Enum):
    """Enumeration of supported outreach channels"""
    EMAIL = "email"
    LINKEDIN = "linkedin"
    SMS = "sms"
    PHONE = "phone"
    DIRECT_MAIL = "direct_mail"


class TouchpointStatus(Enum):
    """Enumeration of touchpoint execution statuses"""
    PENDING = "pending"
    SCHEDULED = "scheduled"
    SENT = "sent"
    DELIVERED = "delivered"
    OPENED = "opened"
    CLICKED = "clicked"
    REPLIED = "replied"
    FAILED = "failed"
    SKIPPED = "skipped"
    CANCELLED = "cancelled"


class EngagementLevel(Enum):
    """Enumeration of engagement levels for branching logic"""
    HIGH = "high"
    MEDIUM = "medium"
    LOW = "low"
    NEGATIVE = "negative"
    UNKNOWN = "unknown"


class CadenceError(Exception):
    """Base exception class for cadence-related errors"""
    pass


class RateLimitError(CadenceError):
    """Exception raised when rate limits are exceeded"""
    pass


class ComplianceError(CadenceError):
    """Exception raised for compliance violations"""
    pass


class DataValidationError(CadenceError):
    """Exception raised for data validation failures"""
    pass


@dataclass
class Touchpoint:
    """Represents a single touchpoint in a cadence sequence"""
    step: int
    day: int
    channel: ChannelType
    template: str
    priority: str
    conditions: Dict[str, Any] = field(default_factory=dict)
    status: TouchpointStatus = TouchpointStatus.PENDING
    scheduled_time: Optional[datetime] = None
    sent_time: Optional[datetime] = None
    engagement_data: Dict[str, Any] = field(default_factory=dict)
    error_log: List[Dict[str, Any]] = field(default_factory=list)
    retry_count: int = 0
    max_retries: int = 3


@dataclass
class CadenceState:
    """Represents the current state of a lead's cadence journey"""
    lead_id: str
    cadence_template: str
    start_date: datetime
    current_step: int = 0
    touchpoints_completed: List[int] = field(default_factory=list)
    touchpoints_pending: List[int] = field(default_factory=list)
    engagement_level: EngagementLevel = EngagementLevel.UNKNOWN
    engagement_score: float = 0.0
    total_opens: int = 0
    total_clicks: int = 0
    total_replies: int = 0
    opted_out: bool = False
    suppressed: bool = False
    paused: bool = False
    completed: bool = False
    last_touchpoint_date: Optional[datetime] = None
    next_touchpoint_date: Optional[datetime] = None
    metadata: Dict[str, Any] = field(default_factory=dict)
    error_history: List[Dict[str, Any]] = field(default_factory=list)


@dataclass
class RateLimitTracker:
    """Tracks rate limits per channel"""
    channel: ChannelType
    hourly_count: int = 0
    daily_count: int = 0
    hourly_reset_time: datetime = field(default_factory=datetime.now)
    daily_reset_time: datetime = field(default_factory=datetime.now)
    domain_counts: Dict[str, int] = field(default_factory=dict)
    contact_counts: Dict[str, int] = field(default_factory=dict)


class CadenceAgent:
    """
    Main Cadence Agent class for orchestrating multi-channel outreach sequences.
    
    Handles:
    - Intelligent sequencing and timing optimization
    - Engagement-based branching logic
    - Personalization and context-aware messaging
    - Compliance and consent management
    - Rate limiting and throttling
    - Comprehensive error handling and recovery
    """
    
    def __init__(self, config_path: str = "docs/configs/cadence_config.yaml"):
        """
        Initialize the Cadence Agent.
        
        Args:
            config_path: Path to cadence configuration YAML file
        
        Raises:
            FileNotFoundError: If config file not found
            DataValidationError: If config validation fails
        """
        try:
            self.config = self._load_config(config_path)
            self.cadence_states: Dict[str, CadenceState] = {}
            self.rate_limiters: Dict[ChannelType, RateLimitTracker] = {
                channel: RateLimitTracker(channel=channel) 
                for channel in ChannelType
            }
            self.suppression_lists: Dict[str, set] = self._load_suppression_lists()
            
            # State persistence files
            self.state_file = Path("cadence_states.json")
            self.activity_log = Path("cadence_activity_log.csv")
            self.error_log = Path("cadence_error_log.csv")
            
            # Load existing states if available
            self._load_cadence_states()
            
            # Initialize activity logging
            self._initialize_activity_log()
            
            logger.info("CadenceAgent initialized successfully")
            
        except Exception as e:
            logger.error(f"Failed to initialize CadenceAgent: {str(e)}")
            raise DataValidationError(f"Initialization failed: {str(e)}")
    
    def _load_config(self, config_path: str) -> Dict[str, Any]:
        """
        Load and validate cadence configuration.
        
        Args:
            config_path: Path to configuration file
        
        Returns:
            Validated configuration dictionary
        
        Raises:
            FileNotFoundError: If config file not found
            DataValidationError: If config validation fails
        """
        try:
            with open(config_path, 'r') as f:
                config = yaml.safe_load(f)
            
            # Validate required config sections
            required_sections = [
                'cadence_templates',
                'touchpoint_sequence',
                'timing_optimization',
                'engagement_branching',
                'rate_limits',
                'compliance'
            ]
            
            for section in required_sections:
                if section not in config:
                    raise DataValidationError(
                        f"Missing required config section: {section}"
                    )
            
            logger.info(f"Configuration loaded from {config_path}")
            return config
            
        except FileNotFoundError:
            logger.error(f"Configuration file not found: {config_path}")
            raise
        except yaml.YAMLError as e:
            logger.error(f"YAML parsing error: {str(e)}")
            raise DataValidationError(f"Invalid YAML configuration: {str(e)}")
        except Exception as e:
            logger.error(f"Unexpected error loading config: {str(e)}")
            raise DataValidationError(f"Config load failed: {str(e)}")
    
    def _load_suppression_lists(self) -> Dict[str, set]:
        """
        Load suppression lists from configuration.
        
        Returns:
            Dictionary of suppression lists
        
        Note:
            In production, these would be loaded from database or files.
            This implementation uses placeholder data.
        """
        suppression_lists = {
            'global_unsubscribe': set(),
            'domain_blocklist': set(),
            'competitor_list': set(),
            'do_not_contact': set()
        }
        
        # TODO: Load from actual data sources
        logger.info("Suppression lists loaded")
        return suppression_lists
    
    def _load_cadence_states(self) -> None:
        """
        Load persisted cadence states from disk.
        
        Error handling:
        - FileNotFoundError: Log and continue (first run)
        - JSONDecodeError: Log error, backup corrupt file, continue
        - Exception: Log error and continue with empty state
        """
        try:
            if self.state_file.exists():
                with open(self.state_file, 'r') as f:
                    states_data = json.load(f)
                    # Reconstruct CadenceState objects
                    for lead_id, state_dict in states_data.items():
                        # Convert string dates back to datetime objects
                        state_dict['start_date'] = datetime.fromisoformat(
                            state_dict['start_date']
                        )
                        if state_dict.get('last_touchpoint_date'):
                            state_dict['last_touchpoint_date'] = datetime.fromisoformat(
                                state_dict['last_touchpoint_date']
                            )
                        if state_dict.get('next_touchpoint_date'):
                            state_dict['next_touchpoint_date'] = datetime.fromisoformat(
                                state_dict['next_touchpoint_date']
                            )
                        # Reconstruct EngagementLevel enum
                        state_dict['engagement_level'] = EngagementLevel(
                            state_dict['engagement_level']
                        )
                        self.cadence_states[lead_id] = CadenceState(**state_dict)
                logger.info(f"Loaded {len(self.cadence_states)} cadence states")
        except FileNotFoundError:
            logger.info("No existing cadence states found (first run)")
        except json.JSONDecodeError as e:
            logger.error(f"Corrupt state file detected: {str(e)}")
            # Backup corrupt file
            backup_file = self.state_file.with_suffix('.json.corrupt')
            self.state_file.rename(backup_file)
            logger.info(f"Backed up corrupt state file to {backup_file}")
        except Exception as e:
            logger.error(f"Unexpected error loading states: {str(e)}")
    
    def _initialize_activity_log(self) -> None:
        """
        Initialize activity log CSV file.
        
        Error handling:
        - PermissionError: Log error and raise (critical)
        - OSError: Log error and raise (critical)
        """
        try:
            if not self.activity_log.exists():
                with open(self.activity_log, 'w', newline='') as f:
                    writer = csv.writer(f)
                    writer.writerow([
                        'timestamp', 'lead_id', 'step', 'channel', 'template',
                        'status', 'engagement_level', 'error_message'
                    ])
                logger.info(f"Activity log initialized at {self.activity_log}")
        except (PermissionError, OSError) as e:
            logger.error(f"Failed to initialize activity log: {str(e)}")
            raise
        except Exception as e:
            logger.error(f"Unexpected error initializing activity log: {str(e)}")
            raise