behavior_model.py

# behavior_model.py  -- REPLACED with "Neural Structure / MoE-style Dispatcher"
"""
Large, modular 'neural structure' dispatcher (software MoE) for intent/complexity routing.

How to use:
- Replace your existing behavior_model.py with this file.
- app.py expects analyze_flow(messages) -> dict with keys:
    { route: "direct"|"planning", is_complex: bool, flow_label: str, confidence: float, explanation: str, experts: [...] }

Design:
- Feature extractor -> gating network (scoring) -> top-K expert selection -> combine/explain decision
- Experts are modular callables; by default they are heuristic "experts".
- To scale: implement Expert.run(...) to call real submodels/endpoints (local small models, remote microservices).
"""

from typing import List, Dict, Any, Callable, Tuple
import re
import math
import json
import os
import statistics

# ---------- Configurable constants ----------
TOP_K = int(os.environ.get("NS_TOP_K", "2"))         # how many experts to activate per request
SOFTMAX_TEMPERATURE = float(os.environ.get("NS_TEMP", "1.0"))
MIN_COMPLEX_CONF_FOR_PLANNING = float(os.environ.get("NS_MIN_COMPLEX_CONF", "0.56"))
MAX_EXPERTS = int(os.environ.get("NS_MAX_EXPERTS", "12"))

# Weights (tunables)
WEIGHT_LENGTH = float(os.environ.get("NS_W_LENGTH", "1.0"))
WEIGHT_KEYWORD = float(os.environ.get("NS_W_KEYWORD", "1.9"))
WEIGHT_CODE = float(os.environ.get("NS_W_CODE", "2.4"))
WEIGHT_NUMERIC = float(os.environ.get("NS_W_NUMERIC", "1.2"))
WEIGHT_QUESTION = float(os.environ.get("NS_W_QUESTION", "0.6"))
WEIGHT_URGENT = float(os.environ.get("NS_W_URGENT", "2.2"))
WEIGHT_HISTORY = float(os.environ.get("NS_W_HISTORY", "0.8"))

# ---------- Regex / keyword lists ----------
_code_fence_re = re.compile(r"```.+?```", flags=re.DOTALL | re.IGNORECASE)
_inline_code_re = re.compile(r"`[^`]+`")
_number_re = re.compile(r"\b\d+(\.\d+)?\b")
_list_marker_re = re.compile(r"(^\s*[-*•]\s+)|(^\s*\d+\.\s+)", flags=re.MULTILINE)
_url_re = re.compile(r"https?://\S+")
_question_word_re = re.compile(r"^\s*(who|what|why|how|when|which|where)\b", flags=re.IGNORECASE)
_question_mark_re = re.compile(r"\?$")

_task_keywords = set(k.lower() for k in [
    "build", "create", "implement", "develop", "deploy", "install", "setup", "configure",
    "optimi", "debug", "fix", "error", "crash", "stacktrace", "exception", "traceback",
    "code", "script", "function", "api", "endpoint", "database", "sql", "mongodb", "mysql",
    "docker", "deno", "node", "express", "php", "python", "java", "rust", "golang", "compile",
    "performance", "latency", "bandwidth", "optimization", "optimize",
    "algorithm", "complexity", "big o", "time complexity", "space complexity",
    "report", "plan", "design", "architecture", "integration", "migrate", "refactor",
    "test case", "unit test", "e2e test",
    "prove", "derive", "integral", "differentiate", "matrix", "neural network", "train", "model",
])

_urgent_words = set(w.lower() for w in ["urgent", "asap", "immediately", "now", "critical", "important", "priority", "must"])
_short_chat_terms = set(w.lower() for w in ["hi", "hello", "thanks", "thank you", "bye", "ok", "okay", "nice", "cool", "🙂", "😊"])

# ---------- Utility functions ----------
def _word_count(text: str) -> int:
    return len(re.findall(r"\w+", text)) if text else 0

def _has_code(text: str) -> bool:
    if not text: return False
    return bool(_code_fence_re.search(text) or _inline_code_re.search(text) or re.search(r"\bdef\s+\w+\(|;\s*$", text, flags=re.IGNORECASE))

def _has_list(text: str) -> bool:
    return bool(_list_marker_re.search(text))

def _keyword_matches(text: str) -> int:
    if not text: return 0
    t = text.lower()
    cnt = 0
    for kw in _task_keywords:
        if kw in t:
            cnt += 1
    return cnt

def _numeric_count(text: str) -> int:
    return len(_number_re.findall(text or ""))

def _is_urgent(text: str) -> bool:
    t = (text or "").lower()
    return any(w in t for w in _urgent_words)

def _short_chat_score(text: str) -> bool:
    t = (text or "").strip().lower()
    if len(t.split()) <= 2 and any(tok in t for tok in _short_chat_terms):
        return True
    return False

def _question_score(text: str) -> float:
    s = 0.0
    if _question_mark_re.search(text or ""): s += 1.0
    if _question_word_re.match((text or "").strip()): s += 0.6
    return s

def _history_signal(messages: List[Dict[str,str]]) -> float:
    # simple heuristic: if previous user messages contained technical keywords recently, boost
    if not messages or len(messages) < 2: return 0.0
    prev = " ".join(m.get("content","") for m in messages[-4:-1] if isinstance(m, dict))
    return float(min(3, _keyword_matches(prev))) * 0.2

# ---------- Softmax helper ----------
def _softmax(scores: List[float], temp: float = 1.0) -> List[float]:
    if not scores:
        return []
    exps = [math.exp(s / temp) for s in scores]
    s = sum(exps)
    if s == 0: return [1.0/len(scores)]*len(scores)
    return [e/s for e in exps]

# ---------- Expert base classes ----------
class Expert:
    name: str
    description: str

    def __init__(self, name:str, description:str):
        self.name = name
        self.description = description

    def score(self, features: Dict[str,Any]) -> float:
        """Return a heuristic affinity score (higher = more relevant)."""
        # default neutral
        return 0.0

    def run(self, messages: List[Dict[str,str]], features: Dict[str,Any]) -> Dict[str,Any]:
        """
        Optionally run expert-specific logic (synchronously).
        For now return metadata only. In production this could call a model endpoint.
        """
        return {"expert": self.name, "action": "noop", "note": "heuristic-only"}

# ---------- Concrete experts ----------
class ShortChatExpert(Expert):
    def __init__(self):
        super().__init__("short_chat", "Handles greetings/short conversational turns")

    def score(self, f):
        if f.get("short_chat"): return 5.0
        return 0.1

    def run(self, messages, features):
        return {"expert": self.name, "action": "short_reply", "note": "Use concise response template."}

class CodeExpert(Expert):
    def __init__(self):
        super().__init__("code_expert", "Handles code, stacktraces, debugging tasks")

    def score(self, f):
        sc = 0.0
        if f.get("has_code"): sc += 4.0
        sc += 0.8 * f.get("kw_count",0)
        sc += 0.6 * f.get("numeric_count",0)
        return sc

    def run(self, messages, features):
        # Placeholder: in production call a code-specialized model or analyzer endpoint
        return {"expert": self.name, "action": "analyze_code", "note": "Run code LLM or static-checker (not implemented)."}

class NLUExpert(Expert):
    def __init__(self):
        super().__init__("nlu_expert", "Deep intent and slot extraction / classification")

    def score(self, f):
        sc = 1.0 * f.get("kw_count",0)
        sc += 0.8 * f.get("question_score",0)
        sc += 0.4 * (f.get("word_count",0) / 30.0)
        sc += 0.6 * f.get("history_signal",0)
        return sc

    def run(self, messages, features):
        # Example: return intent classification tags (heuristic)
        intent = "general"
        if features.get("kw_count",0) >= 2 or features.get("has_code"):
            intent = "technical_task"
        elif features.get("short_chat"):
            intent = "social"
        return {"expert": self.name, "action": "classify_intent", "intent": intent}

class RAGExpert(Expert):
    def __init__(self):
        super().__init__("rag_expert", "Handles retrieval-augmented requests (RAG/agent)")

    def score(self, f):
        sc = 0.0
        # if user mentions 'search', 'latest', has urls, or long context -> RAG useful
        if f.get("has_url"): sc += 2.0
        sc += 1.2 * f.get("kw_count",0)
        sc += 0.9 * f.get("numeric_count",0)
        if f.get("word_count",0) > 60: sc += 1.5
        return sc

    def run(self, messages, features):
        # Placeholder: should trigger a retrieval job or agent
        return {"expert": self.name, "action": "retrieve", "note": "Trigger RAG pipeline or agent (not implemented)."}

class SafetyExpert(Expert):
    def __init__(self):
        super().__init__("safety_expert", "Safety checks, identity questions, hallucination guards")

    def score(self, f):
        sc = 0.0
        txt = f.get("last_text","").lower() if f.get("last_text") else ""
        if any(w in txt for w in ["who created you","who made you","identity","where are you from"]):
            sc += 3.0
        # any suspicious tokens (email, ssn, credit card-like) -> safety
        if re.search(r"\b\d{4}[- ]?\d{4}[- ]?\d{4}[- ]?\d{4}\b", txt):
            sc += 4.0
        return sc

    def run(self, messages, features):
        return {"expert": self.name, "action": "safety_check", "note": "Run policy checks."}

# Add more experts as needed...
_DEFAULT_EXPERTS: List[Expert] = [
    ShortChatExpert(),
    NLUExpert(),
    CodeExpert(),
    RAGExpert(),
    SafetyExpert(),
]

# ---------- Core gating/routing function ----------
def _extract_features(messages: List[Dict[str,str]]) -> Dict[str,Any]:
    if not messages:
        return {"word_count": 0, "kw_count":0, "has_code": False, "numeric_count":0, "question_score":0.0, "short_chat": False, "has_url": False, "history_signal":0.0, "last_text":""}
    last = messages[-1].get("content","") if isinstance(messages[-1], dict) else str(messages[-1])
    prev = " ".join(m.get("content","") for m in messages[:-1] if isinstance(m, dict))
    full = (prev + "\n" + last).strip()

    features = {}
    features["last_text"] = last
    features["word_count"] = _word_count(last)
    features["total_word_count"] = _word_count(full)
    features["kw_count"] = _keyword_matches(full)
    features["has_code"] = _has_code(full)
    features["has_list"] = _has_list(full)
    features["numeric_count"] = _numeric_count(full)
    features["question_score"] = _question_score(last)
    features["short_chat"] = _short_chat_score(last)
    features["has_url"] = bool(_url_re.search(full))
    features["is_urgent"] = _is_urgent(full)
    features["history_signal"] = _history_signal(messages)
    return features

def _gate_select_experts(features: Dict[str,Any], experts: List[Expert]) -> Tuple[List[Tuple[Expert,float]], List[float]]:
    # compute raw scores per expert
    raw_scores = [max(0.0, e.score(features)) for e in experts]
    if not raw_scores:
        return [], []

    # normalize via softmax for relative weighting
    probs = _softmax(raw_scores, temp=SOFTMAX_TEMPERATURE)
    # select top-K experts by probability
    indexed = list(enumerate(probs))
    indexed.sort(key=lambda x: x[1], reverse=True)
    top = indexed[:TOP_K]
    chosen = [(experts[i], probs[i]) for i, _ in top]
    return chosen, probs

# ---------- Public API: analyze_flow ----------
def analyze_flow(messages: List[Dict[str,str]]) -> Dict[str,Any]:
    """
    Returns:
    {
      "route": "direct" / "planning",
      "is_complex": bool,
      "flow_label": str,
      "confidence": float,
      "explanation": str,
      "experts": [ {"name":.., "score":.., "note":..}, ... ]
    }
    """
    features = _extract_features(messages)
    experts = _DEFAULT_EXPERTS.copy()

    # gating
    chosen, probs = _gate_select_experts(features, experts)

    # Decide flow_label heuristics based on features
    flow_label = "general"
    if features.get("has_code") or features.get("kw_count",0) >= 2:
        flow_label = "coding_request"
    elif features.get("is_urgent"):
        flow_label = "escalation"
    elif features.get("kw_count",0) >= 1 and features.get("word_count",0) >= 25:
        flow_label = "task_request"
    elif features.get("short_chat"):
        flow_label = "short_chat"
    elif features.get("question_score",0) > 0.9 and features.get("word_count",0) < 25:
        flow_label = "short_question"

    # compute a complexity/confidence scalar from features + expert probs
    feature_score = (
        WEIGHT_LENGTH * (features.get("word_count",0) / 30.0) +
        WEIGHT_KEYWORD * features.get("kw_count",0) +
        WEIGHT_CODE * (4.0 if features.get("has_code") else 0.0) +
        WEIGHT_NUMERIC * features.get("numeric_count",0) +
        WEIGHT_QUESTION * features.get("question_score",0) +
        WEIGHT_URGENT * (1.0 if features.get("is_urgent") else 0.0) +
        WEIGHT_HISTORY * features.get("history_signal",0)
    )

    # Map to 0..1 via logistic
    conf = 1.0 / (1.0 + math.exp(-0.45 * (feature_score - 2.0)))
    conf = max(0.0, min(1.0, conf))

    # route decision
    is_complex = conf >= MIN_COMPLEX_CONF_FOR_PLANNING or features.get("has_code") or features.get("kw_count",0) >= 2
    # short-chat override: always direct
    if features.get("short_chat"):
        route = "direct"
        is_complex = False
    else:
        route = "planning" if is_complex else "direct"

    # Build explanation and expert list
    expert_list = []
    for e, p in chosen:
        # we can call run() here for metadata without actually executing heavy ops
        meta = e.run(messages, features)
        expert_list.append({"name": e.name, "prob": round(float(p),4), "meta": meta})

    explanation = ("features=" + json.dumps(features) + f" | feature_score={feature_score:.2f} | conf={conf:.3f} | chosen={[e.name for e,_ in chosen]}")
    return {
        "route": route,
        "is_complex": bool(is_complex),
        "flow_label": flow_label,
        "confidence": round(float(conf), 3),
        "explanation": explanation,
        "experts": expert_list
    }

# ---------- Debug helper ----------
def debug_flow(text: str, history: List[str] = None):
    hist_msgs = [{"role":"user","content":h} for h in (history or [])]
    hist_msgs.append({"role":"user","content": text})
    return analyze_flow(hist_msgs)

# Example self-test when run directly
if __name__ == "__main__":
    tests = [
        "Hi 🙂",
        "What is your name?",
        "What is neural network",
        "My app crashes with TypeError: undefined is not a function. Stacktrace: ```TypeError: ...``` How to fix?",
        "Deploy my node app to Docker with Nginx and SSL — step-by-step please.",
        "Quick: 2+2?"
    ]
    for t in tests:
        print("----")
        print("MSG:", t)
        out = debug_flow(t)
        print(json.dumps(out, indent=2))