import re
import redis.asyncio as redis
from config import settings

_redis: redis.Redis | None = None

INJECTION_PATTERNS = [
    re.compile(r"ignore\s+(all\s+)?(previous|prior|above)\s+(instructions|prompts|rules)", re.I),
    re.compile(r"(system\s*prompt|system\s*message|initial\s*prompt)", re.I),
    re.compile(r"you\s+are\s+now\s+", re.I),
    re.compile(r"(pretend|act)\s+(to\s+be|as\s+if|like|you.re)\s+", re.I),
    re.compile(r"(reveal|show|print|output|repeat)\s+(your|the)\s+(system|instructions|prompt|rules)", re.I),
    re.compile(r"do\s+not\s+follow\s+(your|the)\s+(rules|instructions)", re.I),
    re.compile(r"disregard\s+(all|your|the)\s+(previous|prior|rules|instructions)", re.I),
    re.compile(r"jailbreak", re.I),
    re.compile(r"\bDAN\b"),
    re.compile(r"override\s+(your|safety|the)\s+", re.I),
]

BUSINESS_KEYWORDS = [
    "ai", "automation", "chatbot", "bot", "service", "price", "pricing", "cost",
    "plan", "retainer", "consult", "book", "meeting", "call", "demo",
    "workflow", "process", "solution", "business", "company", "help",
    "website", "analytics", "data", "custom", "integrate", "integration",
    "email", "contact", "phone", "name", "hi", "hello", "hey", "thanks",
    "thank", "yes", "no", "ok", "okay", "sure", "please", "what", "how",
    "when", "where", "who", "why", "can", "do", "does", "is", "are",
    "tell", "more", "about", "your", "offer", "work", "project",
    "startup", "charity", "discount", "free", "trial", "poc", "mvp",
    "assessment", "briefing", "challenge", "case", "study", "result",
    "aimpress", "impress", "uk", "client", "customer", "need", "want",
    "looking", "interested", "budget", "timeline", "estimate", "quote",
]


async def get_redis() -> redis.Redis:
    global _redis
    if _redis is None:
        _redis = redis.from_url(settings.redis_url, decode_responses=True)
    return _redis


def detect_injection(message: str) -> bool:
    for pattern in INJECTION_PATTERNS:
        if pattern.search(message):
            return True
    return False


def is_off_topic(message: str) -> bool:
    """Returns True only if we're fairly confident the message is off-topic.
    When uncertain, returns False and lets Claude handle it via system prompt."""
    words = set(re.findall(r"[a-zA-Z]+", message.lower()))
    if len(words) <= 3:
        return False
    matches = words & set(BUSINESS_KEYWORDS)
    return len(matches) == 0 and len(words) > 5


async def check_rate_limit(session_id: str) -> tuple[bool, int]:
    r = await get_redis()
    key = f"chat:rate:{session_id}"
    count = await r.get(key)
    current = int(count) if count else 0
    if current >= settings.max_messages_per_session:
        return True, current
    pipe = r.pipeline()
    pipe.incr(key)
    pipe.expire(key, settings.conversation_ttl)
    results = await pipe.execute()
    return False, results[0]


async def store_messages(session_id: str, role: str, content: str) -> list[dict]:
    r = await get_redis()
    key = f"chat:history:{session_id}"
    import json
    msg = json.dumps({"role": role, "content": content})
    await r.rpush(key, msg)
    await r.expire(key, settings.conversation_ttl)
    raw = await r.lrange(key, -settings.conversation_window, -1)
    return [json.loads(m) for m in raw]


async def get_session_mode(session_id: str) -> str:
    r = await get_redis()
    mode = await r.get(f"chat:mode:{session_id}")
    return mode or "ai"


async def set_session_mode(session_id: str, mode: str) -> None:
    r = await get_redis()
    await r.set(f"chat:mode:{session_id}", mode, ex=settings.conversation_ttl)