import imaplib
import email
import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from typing import Dict, List, Any, Optional, Tuple
from datetime import datetime
import re

from utils.logging import setup_logger
from utils.error_handling import handle_exceptions, IntegrationError
from utils.storage import load_data, save_data

# Initialize logger
logger = setup_logger(__name__)

class EmailIntegration:
    """Email integration for converting emails to tasks and sending notifications"""
    
    def __init__(self, email_address: Optional[str] = None, password: Optional[str] = None,
                 imap_server: str = "imap.gmail.com", imap_port: int = 993,
                 smtp_server: str = "smtp.gmail.com", smtp_port: int = 587):
        """Initialize Email integration
        
        Args:
            email_address: Email address (optional)
            password: Email password or app password (optional)
            imap_server: IMAP server address (default: imap.gmail.com)
            imap_port: IMAP server port (default: 993)
            smtp_server: SMTP server address (default: smtp.gmail.com)
            smtp_port: SMTP server port (default: 587)
        """
        self.email_address = email_address
        self.password = password
        self.imap_server = imap_server
        self.imap_port = imap_port
        self.smtp_server = smtp_server
        self.smtp_port = smtp_port
    
    @handle_exceptions
    def set_credentials(self, email_address: str, password: str) -> None:
        """Set email credentials
        
        Args:
            email_address: Email address
            password: Email password or app password
        """
        self.email_address = email_address
        self.password = password
    
    @handle_exceptions
    def set_imap_server(self, server: str, port: int = 993) -> None:
        """Set IMAP server settings
        
        Args:
            server: IMAP server address
            port: IMAP server port (default: 993)
        """
        self.imap_server = server
        self.imap_port = port
    
    @handle_exceptions
    def set_smtp_server(self, server: str, port: int = 587) -> None:
        """Set SMTP server settings
        
        Args:
            server: SMTP server address
            port: SMTP server port (default: 587)
        """
        self.smtp_server = server
        self.smtp_port = port
    
    @handle_exceptions
    def test_connection(self) -> bool:
        """Test email connection
        
        Returns:
            True if connection is successful, False otherwise
        """
        if not self.email_address or not self.password:
            logger.error("Email credentials not set")
            return False
        
        try:
            # Test IMAP connection
            imap = imaplib.IMAP4_SSL(self.imap_server, self.imap_port)
            imap.login(self.email_address, self.password)
            imap.logout()
            
            # Test SMTP connection
            smtp = smtplib.SMTP(self.smtp_server, self.smtp_port)
            smtp.ehlo()
            smtp.starttls()
            smtp.login(self.email_address, self.password)
            smtp.quit()
            
            return True
        except Exception as e:
            logger.error(f"Email connection test failed: {str(e)}")
            return False
    
    @handle_exceptions
    def fetch_emails(self, folder: str = "INBOX", limit: int = 10, 
                    unread_only: bool = True, search_criteria: str = "ALL") -> List[Dict[str, Any]]:
        """Fetch emails from the specified folder
        
        Args:
            folder: Email folder to fetch from (default: INBOX)
            limit: Maximum number of emails to fetch (default: 10)
            unread_only: Only fetch unread emails (default: True)
            search_criteria: IMAP search criteria (default: ALL)
            
        Returns:
            List of email data dictionaries
        """
        if not self.email_address or not self.password:
            raise IntegrationError("Email credentials not set")
        
        try:
            # Connect to IMAP server
            imap = imaplib.IMAP4_SSL(self.imap_server, self.imap_port)
            imap.login(self.email_address, self.password)
            
            # Select folder
            imap.select(folder)
            
            # Search for emails
            if unread_only:
                search_criteria = "(UNSEEN)"
            
            status, data = imap.search(None, search_criteria)
            if status != "OK":
                raise IntegrationError(f"Failed to search emails: {status}")
            
            # Get email IDs
            email_ids = data[0].split()
            if not email_ids:
                return []
            
            # Limit the number of emails
            if limit > 0:
                email_ids = email_ids[-limit:]
            
            emails = []
            for email_id in reversed(email_ids):  # Process newest first
                status, data = imap.fetch(email_id, "(RFC822)")
                if status != "OK":
                    logger.error(f"Failed to fetch email {email_id}: {status}")
                    continue
                
                raw_email = data[0][1]
                email_message = email.message_from_bytes(raw_email)
                
                # Extract email data
                email_data = self._parse_email(email_message, email_id)
                emails.append(email_data)
            
            imap.logout()
            return emails
        
        except Exception as e:
            logger.error(f"Failed to fetch emails: {str(e)}")
            raise IntegrationError(f"Failed to fetch emails: {str(e)}")
    
    def _parse_email(self, email_message: email.message.Message, email_id: bytes) -> Dict[str, Any]:
        """Parse email message into a dictionary
        
        Args:
            email_message: Email message object
            email_id: Email ID
            
        Returns:
            Email data dictionary
        """
        # Extract headers
        subject = self._decode_header(email_message.get("Subject", ""))
        from_addr = self._decode_header(email_message.get("From", ""))
        to_addr = self._decode_header(email_message.get("To", ""))
        date_str = email_message.get("Date", "")
        
        # Parse date
        date = None
        if date_str:
            try:
                date = email.utils.parsedate_to_datetime(date_str)
            except:
                pass
        
        # Extract body
        body = ""
        if email_message.is_multipart():
            for part in email_message.walk():
                content_type = part.get_content_type()
                content_disposition = str(part.get("Content-Disposition", ""))
                
                # Skip attachments
                if "attachment" in content_disposition:
                    continue
                
                # Get text content
                if content_type == "text/plain":
                    try:
                        body_part = part.get_payload(decode=True).decode()
                        body += body_part
                    except:
                        pass
        else:
            # Not multipart - get payload directly
            try:
                body = email_message.get_payload(decode=True).decode()
            except:
                pass
        
        # Create email data dictionary
        email_data = {
            "id": email_id.decode(),
            "subject": subject,
            "from": from_addr,
            "to": to_addr,
            "date": date.isoformat() if date else None,
            "body": body,
            "is_read": "\\Seen" in email_message.get_flags() if hasattr(email_message, "get_flags") else False
        }
        
        return email_data
    
    def _decode_header(self, header: str) -> str:
        """Decode email header
        
        Args:
            header: Email header
            
        Returns:
            Decoded header
        """
        if not header:
            return ""
        
        try:
            decoded_header = email.header.decode_header(header)
            decoded_parts = []
            
            for part, encoding in decoded_header:
                if isinstance(part, bytes):
                    if encoding:
                        try:
                            decoded_parts.append(part.decode(encoding))
                        except:
                            decoded_parts.append(part.decode("utf-8", errors="replace"))
                    else:
                        decoded_parts.append(part.decode("utf-8", errors="replace"))
                else:
                    decoded_parts.append(str(part))
            
            return "".join(decoded_parts)
        except:
            return header
    
    @handle_exceptions
    def mark_as_read(self, email_id: str, folder: str = "INBOX") -> bool:
        """Mark an email as read
        
        Args:
            email_id: Email ID
            folder: Email folder (default: INBOX)
            
        Returns:
            True if successful, False otherwise
        """
        if not self.email_address or not self.password:
            raise IntegrationError("Email credentials not set")
        
        try:
            # Connect to IMAP server
            imap = imaplib.IMAP4_SSL(self.imap_server, self.imap_port)
            imap.login(self.email_address, self.password)
            
            # Select folder
            imap.select(folder)
            
            # Mark as read
            imap.store(email_id.encode(), "+FLAGS", "\\Seen")
            
            imap.logout()
            return True
        except Exception as e:
            logger.error(f"Failed to mark email as read: {str(e)}")
            return False
    
    @handle_exceptions
    def send_email(self, to_addr: str, subject: str, body: str, 
                  html_body: Optional[str] = None) -> bool:
        """Send an email
        
        Args:
            to_addr: Recipient email address
            subject: Email subject
            body: Email body (plain text)
            html_body: Email body (HTML, optional)
            
        Returns:
            True if successful, False otherwise
        """
        if not self.email_address or not self.password:
            raise IntegrationError("Email credentials not set")
        
        try:
            # Create message
            msg = MIMEMultipart("alternative")
            msg["Subject"] = subject
            msg["From"] = self.email_address
            msg["To"] = to_addr
            
            # Attach plain text body
            msg.attach(MIMEText(body, "plain"))
            
            # Attach HTML body if provided
            if html_body:
                msg.attach(MIMEText(html_body, "html"))
            
            # Connect to SMTP server and send email
            smtp = smtplib.SMTP(self.smtp_server, self.smtp_port)
            smtp.ehlo()
            smtp.starttls()
            smtp.login(self.email_address, self.password)
            smtp.send_message(msg)
            smtp.quit()
            
            return True
        except Exception as e:
            logger.error(f"Failed to send email: {str(e)}")
            return False
    
    @handle_exceptions
    def convert_email_to_task(self, email_data: Dict[str, Any]) -> Dict[str, Any]:
        """Convert an email to a task
        
        Args:
            email_data: Email data dictionary
            
        Returns:
            Task data dictionary
        """
        # Extract task information from email
        subject = email_data.get("subject", "")
        body = email_data.get("body", "")
        sender = email_data.get("from", "")
        date = email_data.get("date")
        
        # Extract task title from subject
        title = subject
        
        # Extract priority from subject if present
        priority = "medium"
        priority_patterns = {
            "low": r"\[low\]|\(low\)|low priority",
            "high": r"\[high\]|\(high\)|high priority|urgent|important"
        }
        
        for p, pattern in priority_patterns.items():
            if re.search(pattern, subject, re.IGNORECASE):
                priority = p
                # Remove priority tag from title
                title = re.sub(pattern, "", title, flags=re.IGNORECASE).strip()
        
        # Extract due date from body if present
        due_date = None
        due_date_patterns = [
            r"due\s*(?:date|by)?\s*:?\s*(\d{1,2}[/-]\d{1,2}[/-]\d{2,4})",
            r"deadline\s*:?\s*(\d{1,2}[/-]\d{1,2}[/-]\d{2,4})"
        ]
        
        for pattern in due_date_patterns:
            match = re.search(pattern, body, re.IGNORECASE)
            if match:
                due_date_str = match.group(1)
                try:
                    # Try to parse the date
                    # This is a simplified version and might need more robust parsing
                    due_date = datetime.strptime(due_date_str, "%d/%m/%Y").isoformat()
                except:
                    try:
                        due_date = datetime.strptime(due_date_str, "%m/%d/%Y").isoformat()
                    except:
                        pass
        
        # Create task data
        task = {
            "title": title,
            "description": f"From: {sender}\n\n{body[:500]}{'...' if len(body) > 500 else ''}",
            "status": "todo",
            "priority": priority,
            "due_date": due_date,
            "created_at": datetime.now().isoformat(),
            "source": "email",
            "source_id": email_data.get("id"),
            "metadata": {
                "email_from": sender,
                "email_date": date,
                "email_subject": subject
            }
        }
        
        return task
    
    @handle_exceptions
    def process_emails_to_tasks(self, folder: str = "INBOX", limit: int = 10, 
                              unread_only: bool = True, mark_as_read: bool = True) -> List[Dict[str, Any]]:
        """Process emails and convert them to tasks
        
        Args:
            folder: Email folder to fetch from (default: INBOX)
            limit: Maximum number of emails to fetch (default: 10)
            unread_only: Only fetch unread emails (default: True)
            mark_as_read: Mark processed emails as read (default: True)
            
        Returns:
            List of task data dictionaries
        """
        # Fetch emails
        emails = self.fetch_emails(folder, limit, unread_only)
        
        tasks = []
        for email_data in emails:
            # Convert email to task
            task = self.convert_email_to_task(email_data)
            tasks.append(task)
            
            # Mark email as read if requested
            if mark_as_read:
                self.mark_as_read(email_data["id"], folder)
        
        return tasks