"""
Local FAQ Library for instant responses
Common questions can be answered immediately without API calls
"""
import re
from typing import Optional, Dict
from .logger import get_logger

logger = get_logger(__name__)


class FAQLibrary:
    """Local FAQ library for instant common question responses"""

    def __init__(self):
        """Initialize FAQ library with ONLY common greetings and social responses

        Note: Business-related FAQs (register, order, payment, shipment, return, etc.)
        should be handled by Strapi MCP to ensure accuracy and consistency.
        This library only contains instant social responses for better UX.
        """
        self.faqs = {
            # ========== 问候类 Greetings ==========
            "你好": "你好！我是您的B2B客户服务助手，很高兴为您服务。我可以帮您处理订单查询、产品咨询、售后问题等。请问有什么可以帮到您的吗？",
            "您好": "您好！我是您的B2B客户服务助手，很高兴为您服务。我可以帮您处理订单查询、产品咨询、售后问题等。请问有什么可以帮到您的吗？",
            "hi": "Hello! I'm your B2B customer service assistant. How can I help you today?",
            "hello": "Hello! I'm here to assist you. How can I help you today?",
            "hey": "Hey there! How can I help you today?",

            # ========== 感谢类 Gratitude ==========
            "谢谢": "不客气！如果还有其他问题，随时可以问我。祝您购物愉快！",
            "感谢": "感谢您的支持！如有任何问题，随时联系我们。",
            "thank you": "You're welcome! If you have any other questions, feel free to ask. Have a great day!",
            "thanks": "You're welcome! Let me know if you need anything else.",

            # ========== 再见类 Farewell ==========
            "再见": "再见！如有需要，随时联系。祝您生活愉快！",
            "bye": "Goodbye! Feel free to reach out anytime. Have a great day!",
            "goodbye": "Goodbye! Have a wonderful day!",

            # ========== 社交礼貌类 Social Politeness ==========
            "早上好": "早上好！很高兴为您服务。请问有什么可以帮到您的吗？",
            "下午好": "下午好！很高兴为您服务。请问有什么可以帮到您的吗？",
            "晚上好": "晚上好！很高兴为您服务。请问有什么可以帮到您的吗？",
            "good morning": "Good morning! How can I assist you today?",
            "good afternoon": "Good afternoon! How can I assist you today?",
            "good evening": "Good evening! How can I assist you today?",
        }

        # Compile regex patterns for fuzzy matching
        self._compile_patterns()

    def _compile_patterns(self):
        """Compile regex patterns for fuzzy FAQ matching"""
        self.patterns = []
        for keyword, response in self.faqs.items():
            # Case-insensitive pattern with word boundaries
            pattern = re.compile(re.escape(keyword), re.IGNORECASE)
            self.patterns.append((pattern, response))

    def find_match(self, query: str) -> Optional[str]:
        """Find matching FAQ response

        Args:
            query: User query text

        Returns:
            Matching FAQ response or None if no match found
        """
        # Remove HTML tags and extra whitespace
        clean_query = re.sub(r'<[^>]+>', '', query)
        clean_query = ' '.join(clean_query.split())

        # Try exact match first
        if clean_query.lower() in (k.lower() for k in self.faqs.keys()):
            for key, response in self.faqs.items():
                if key.lower() == clean_query.lower():
                    logger.info("FAQ exact match", key=key, query=clean_query[:50])
                    return response

        # Try fuzzy match (contains keyword)
        for pattern, response in self.patterns:
            if pattern.search(clean_query):
                logger.info("FAQ fuzzy match", pattern=pattern.pattern, query=clean_query[:50])
                return response

        # No match found
        logger.debug("No FAQ match found", query=clean_query[:50])
        return None

    def add_faq(self, keyword: str, response: str) -> None:
        """Add or update FAQ entry

        Args:
            keyword: Question keyword
            response: Answer text
        """
        self.faqs[keyword] = response
        pattern = re.compile(re.escape(keyword), re.IGNORECASE)
        self.patterns.append((pattern, response))
        logger.info("FAQ added", keyword=keyword)

    def get_all_keywords(self) -> list[str]:
        """Get all FAQ keywords

        Returns:
            List of FAQ keywords
        """
        return list(self.faqs.keys())


# Global FAQ library instance
faq_library: Optional[FAQLibrary] = None


def get_faq_library() -> FAQLibrary:
    """Get or create global FAQ library instance"""
    global faq_library
    if faq_library is None:
        faq_library = FAQLibrary()
    return faq_library