#!/usr/bin/env python3
"""
IMAP Email CLI - Python version
Supports: check, fetch, search, mark-read, mark-unread, list-mailboxes
"""
import imaplib
import email
import os
import sys
import argparse
import json
from pathlib import Path
from email.header import decode_header
from datetime import datetime, timedelta
import re

# Load .env
env_file = Path(__file__).parent.parent / '.env'
if env_file.exists():
    for line in env_file.read_text().splitlines():
        if line.strip() and not line.startswith('#') and '=' in line:
            key, _, value = line.partition('=')
            os.environ[key.strip()] = value.strip()

def connect_imap():
    """Connect and login to IMAP server"""
    host = os.environ.get('IMAP_HOST', 'imap.gmail.com')
    port = int(os.environ.get('IMAP_PORT', '993'))
    user = os.environ.get('IMAP_USER')
    password = os.environ.get('IMAP_PASS')
    
    if not user or not password:
        print("Error: IMAP_USER and IMAP_PASS must be set", file=sys.stderr)
        sys.exit(1)
    
    mail = imaplib.IMAP4_SSL(host, port)
    mail.login(user, password)
    return mail

def decode_header_value(value):
    """Decode email header value"""
    if not value:
        return ""
    decoded_parts = decode_header(value)
    result = []
    for part, encoding in decoded_parts:
        if isinstance(part, bytes):
            result.append(part.decode(encoding or 'utf-8', errors='ignore'))
        else:
            result.append(part)
    return ' '.join(result)

def parse_time_filter(time_str):
    """Parse time filter like '30m', '2h', '7d' into datetime"""
    match = re.match(r'(\d+)([mhd])', time_str)
    if not match:
        return None
    
    value, unit = int(match.group(1)), match.group(2)
    if unit == 'm':
        delta = timedelta(minutes=value)
    elif unit == 'h':
        delta = timedelta(hours=value)
    elif unit == 'd':
        delta = timedelta(days=value)
    else:
        return None
    
    return datetime.now() - delta

def cmd_check(args):
    """Check for recent emails"""
    mail = connect_imap()
    mailbox = args.mailbox or 'INBOX'
    mail.select(mailbox)
    
    # Search criteria
    criteria = ['ALL']
    if args.recent:
        since_date = parse_time_filter(args.recent)
        if since_date:
            date_str = since_date.strftime('%d-%b-%Y')
            criteria = [f'SINCE {date_str}']
    
    # Search
    status, messages = mail.search(None, *criteria)
    if status != 'OK':
        print("Error searching mailbox", file=sys.stderr)
        sys.exit(1)
    
    msg_nums = messages[0].split()
    if not msg_nums:
        print("No messages found")
        mail.close()
        mail.logout()
        return
    
    # Get last N messages
    limit = int(args.limit) if args.limit else 10
    msg_nums = msg_nums[-limit:]
    
    print(f"Showing {len(msg_nums)} most recent messages:\n")
    
    for num in reversed(msg_nums):
        typ, data = mail.fetch(num, '(FLAGS BODY[HEADER.FIELDS (FROM SUBJECT DATE)])')
        if data[0]:
            msg_data = data[0][1].decode('utf-8', errors='ignore')
            msg = email.message_from_string(msg_data)
            
            from_addr = decode_header_value(msg.get('From', ''))
            subject = decode_header_value(msg.get('Subject', ''))
            date = msg.get('Date', '')
            
            # Check if unread
            flags = data[1].decode('utf-8', errors='ignore') if len(data) > 1 else ''
            unread = '●' if '\\Seen' not in flags else ' '
            
            print(f"{unread} UID: {num.decode()}")
            print(f"  From: {from_addr}")
            print(f"  Subject: {subject}")
            print(f"  Date: {date}")
            print()
    
    mail.close()
    mail.logout()

def cmd_fetch(args):
    """Fetch full email content"""
    if not args.uid:
        print("Error: UID required", file=sys.stderr)
        sys.exit(1)
    
    mail = connect_imap()
    mailbox = args.mailbox or 'INBOX'
    mail.select(mailbox)
    
    uid = args.uid
    typ, data = mail.fetch(uid, '(RFC822)')
    
    if data[0] is None:
        print(f"Error: Message {uid} not found", file=sys.stderr)
        sys.exit(1)
    
    msg = email.message_from_bytes(data[0][1])
    
    print(f"From: {decode_header_value(msg.get('From', ''))}")
    print(f"To: {decode_header_value(msg.get('To', ''))}")
    print(f"Subject: {decode_header_value(msg.get('Subject', ''))}")
    print(f"Date: {msg.get('Date', '')}")
    print("-" * 80)
    
    # Get body
    if msg.is_multipart():
        for part in msg.walk():
            content_type = part.get_content_type()
            if content_type == 'text/plain':
                body = part.get_payload(decode=True)
                if body:
                    print(body.decode('utf-8', errors='ignore'))
                    break
            elif content_type == 'text/html' and args.html:
                body = part.get_payload(decode=True)
                if body:
                    print(body.decode('utf-8', errors='ignore'))
                    break
    else:
        body = msg.get_payload(decode=True)
        if body:
            print(body.decode('utf-8', errors='ignore'))
    
    mail.close()
    mail.logout()

def cmd_search(args):
    """Search emails with filters"""
    mail = connect_imap()
    mailbox = args.mailbox or 'INBOX'
    mail.select(mailbox)
    
    # Build search criteria
    criteria = []
    
    if args.unseen:
        criteria.append('UNSEEN')
    if args.seen:
        criteria.append('SEEN')
    if args.from_:
        criteria.extend(['FROM', f'"{args.from_}"'])
    if args.subject:
        criteria.extend(['SUBJECT', f'"{args.subject}"'])
    if args.since:
        criteria.extend(['SINCE', args.since])
    if args.before:
        criteria.extend(['BEFORE', args.before])
    if args.recent:
        since_date = parse_time_filter(args.recent)
        if since_date:
            date_str = since_date.strftime('%d-%b-%Y')
            criteria.extend(['SINCE', date_str])
    
    if not criteria:
        criteria = ['ALL']
    
    # Search
    status, messages = mail.search(None, *criteria)
    if status != 'OK':
        print("Error searching mailbox", file=sys.stderr)
        sys.exit(1)
    
    msg_nums = messages[0].split()
    if not msg_nums:
        print("No messages found")
        mail.close()
        mail.logout()
        return
    
    # Get last N messages
    limit = int(args.limit) if args.limit else 20
    msg_nums = msg_nums[-limit:]
    
    print(f"Found {len(msg_nums)} messages:\n")
    
    for num in reversed(msg_nums):
        typ, data = mail.fetch(num, '(FLAGS BODY[HEADER.FIELDS (FROM SUBJECT DATE)])')
        if data[0]:
            msg_data = data[0][1].decode('utf-8', errors='ignore')
            msg = email.message_from_string(msg_data)
            
            from_addr = decode_header_value(msg.get('From', ''))
            subject = decode_header_value(msg.get('Subject', ''))
            date = msg.get('Date', '')
            
            flags = data[1].decode('utf-8', errors='ignore') if len(data) > 1 else ''
            unread = '●' if '\\Seen' not in flags else ' '
            
            print(f"{unread} UID: {num.decode()}")
            print(f"  From: {from_addr}")
            print(f"  Subject: {subject}")
            print(f"  Date: {date}")
            print()
    
    mail.close()
    mail.logout()

def cmd_mark_read(args):
    """Mark message(s) as read"""
    if not args.uids:
        print("Error: At least one UID required", file=sys.stderr)
        sys.exit(1)
    
    mail = connect_imap()
    mailbox = args.mailbox or 'INBOX'
    mail.select(mailbox)
    
    for uid in args.uids:
        mail.store(uid, '+FLAGS', '\\Seen')
        print(f"Marked {uid} as read")
    
    mail.close()
    mail.logout()

def cmd_mark_unread(args):
    """Mark message(s) as unread"""
    if not args.uids:
        print("Error: At least one UID required", file=sys.stderr)
        sys.exit(1)
    
    mail = connect_imap()
    mailbox = args.mailbox or 'INBOX'
    mail.select(mailbox)
    
    for uid in args.uids:
        mail.store(uid, '-FLAGS', '\\Seen')
        print(f"Marked {uid} as unread")
    
    mail.close()
    mail.logout()

def cmd_list_mailboxes(args):
    """List all mailboxes"""
    mail = connect_imap()
    
    status, mailboxes = mail.list()
    if status == 'OK':
        print("Available mailboxes:")
        for mb in mailboxes:
            parts = mb.decode().split(' "/" ')
            if len(parts) >= 2:
                name = parts[1].strip('"')
                print(f"  {name}")
    
    mail.logout()

def main():
    parser = argparse.ArgumentParser(description='IMAP Email CLI')
    subparsers = parser.add_subparsers(dest='command', help='Command to execute')
    
    # check
    check_parser = subparsers.add_parser('check', help='Check for new/unread emails')
    check_parser.add_argument('--limit', help='Max results', default='10')
    check_parser.add_argument('--mailbox', help='Mailbox name', default='INBOX')
    check_parser.add_argument('--recent', help='Only show emails from last X time (e.g., 30m, 2h, 7d)')
    
    # fetch
    fetch_parser = subparsers.add_parser('fetch', help='Fetch full email content')
    fetch_parser.add_argument('uid', help='Email UID')
    fetch_parser.add_argument('--mailbox', help='Mailbox name', default='INBOX')
    fetch_parser.add_argument('--html', action='store_true', help='Show HTML content')
    
    # search
    search_parser = subparsers.add_parser('search', help='Search emails')
    search_parser.add_argument('--unseen', action='store_true', help='Only unread messages')
    search_parser.add_argument('--seen', action='store_true', help='Only read messages')
    search_parser.add_argument('--from', dest='from_', help='From address contains')
    search_parser.add_argument('--subject', help='Subject contains')
    search_parser.add_argument('--recent', help='From last X time (e.g., 30m, 2h, 7d)')
    search_parser.add_argument('--since', help='After date (DD-Mon-YYYY)')
    search_parser.add_argument('--before', help='Before date (DD-Mon-YYYY)')
    search_parser.add_argument('--limit', help='Max results', default='20')
    search_parser.add_argument('--mailbox', help='Mailbox name', default='INBOX')
    
    # mark-read
    read_parser = subparsers.add_parser('mark-read', help='Mark message(s) as read')
    read_parser.add_argument('uids', nargs='+', help='Email UIDs')
    read_parser.add_argument('--mailbox', help='Mailbox name', default='INBOX')
    
    # mark-unread
    unread_parser = subparsers.add_parser('mark-unread', help='Mark message(s) as unread')
    unread_parser.add_argument('uids', nargs='+', help='Email UIDs')
    unread_parser.add_argument('--mailbox', help='Mailbox name', default='INBOX')
    
    # list-mailboxes
    subparsers.add_parser('list-mailboxes', help='List all mailboxes')
    
    args = parser.parse_args()
    
    if not args.command:
        parser.print_help()
        sys.exit(1)
    
    # Execute command
    if args.command == 'check':
        cmd_check(args)
    elif args.command == 'fetch':
        cmd_fetch(args)
    elif args.command == 'search':
        cmd_search(args)
    elif args.command == 'mark-read':
        cmd_mark_read(args)
    elif args.command == 'mark-unread':
        cmd_mark_unread(args)
    elif args.command == 'list-mailboxes':
        cmd_list_mailboxes(args)

if __name__ == '__main__':
    main()