#!/usr/bin/env python3
"""Anomaly Detector — Real-time pattern detection and alerting.

Detects error spikes, tool failures, repeated questions, security patterns.

Usage:
    cortex anomaly [--hours N] [--json] [--alert]
"""

import argparse
import base64
import json
import re
import subprocess
import sys
from datetime import datetime
from pathlib import Path

from cortex.config import cortex_home, memory_dir

THRESHOLDS = {
    "errorRate": 0.1,
    "toolFailureRate": 0.2,
    "repeatedQuestions": 3,
    "securityKeywords": ["password", "credential", "token", "api key", "secret"],
}


def state_file():
    return memory_dir() / "anomaly-state.json"


def _load_state():
    sf = state_file()
    if sf.exists():
        try:
            return json.loads(sf.read_text())
        except Exception:
            pass
    return {"lastCheck": 0, "alertedAnomalies": []}


def _save_state(state):
    sf = state_file()
    sf.parent.mkdir(parents=True, exist_ok=True)
    sf.write_text(json.dumps(state, indent=2))


def fetch_events(hours: int = 1) -> list:
    nats = str(Path.home() / "bin" / "nats")
    cutoff_ms = int((datetime.now().timestamp() - hours * 3600) * 1000)
    events = []

    try:
        r = subprocess.run([nats, "stream", "info", "openclaw-events", "--json"],
                           capture_output=True, text=True, timeout=10)
        if r.returncode != 0:
            return events
        info = json.loads(r.stdout)
        end_seq = info["state"]["last_seq"]
        start_seq = max(info["state"]["first_seq"], end_seq - 200)

        for seq in range(start_seq, end_seq + 1):
            try:
                r = subprocess.run(
                    [nats, "stream", "get", "openclaw-events", str(seq), "--json"],
                    capture_output=True, text=True, timeout=2,
                )
                if r.returncode != 0:
                    continue
                msg = json.loads(r.stdout)
                data = json.loads(base64.b64decode(msg["data"]).decode("utf-8"))
                ts = data.get("timestamp") or data.get("timestampMs", 0)
                if isinstance(ts, (int, float)) and ts > 1e12:
                    pass  # already ms
                elif isinstance(ts, (int, float)):
                    ts = int(ts * 1000)

                if ts > cutoff_ms:
                    events.append({
                        "time": ts,
                        "type": data.get("type", "unknown"),
                        "text": (data.get("payload", {}).get("data", {}).get("text", "") or ""),
                        "tool": data.get("payload", {}).get("data", {}).get("name", ""),
                        "isError": data.get("payload", {}).get("data", {}).get("isError", False),
                        "agent": data.get("agent", "unknown"),
                    })
            except Exception:
                continue
    except Exception:
        pass

    return events


def detect_anomalies(events: list) -> list:
    anomalies = []
    if len(events) < 10:
        return anomalies

    # Error rate
    error_count = sum(1 for e in events if "error" in e["type"] or e["isError"] or "error" in e["text"].lower())
    error_rate = error_count / len(events)
    if error_rate > THRESHOLDS["errorRate"]:
        anomalies.append({
            "type": "error_spike",
            "severity": "critical" if error_rate > 0.3 else "warning",
            "message": f"High error rate: {error_rate:.1%} ({error_count}/{len(events)} events)",
        })

    # Tool failures
    tool_events = [e for e in events if e["tool"]]
    tool_errors = [e for e in tool_events if e["isError"] or "error" in e["text"].lower()]
    if len(tool_events) > 5:
        fail_rate = len(tool_errors) / len(tool_events)
        if fail_rate > THRESHOLDS["toolFailureRate"]:
            anomalies.append({
                "type": "tool_failures",
                "severity": "warning",
                "message": f"High tool failure rate: {fail_rate:.1%}",
            })

    # Repeated questions
    user_msgs = [e["text"].lower().strip() for e in events if "message" in e["type"] and "in" in e["type"]]
    counts = {}
    for msg in user_msgs:
        if len(msg) > 10:
            key = re.sub(r"[?!.,]", "", msg)[:50]
            counts[key] = counts.get(key, 0) + 1
    repeated = [(k, c) for k, c in counts.items() if c >= THRESHOLDS["repeatedQuestions"]]
    if repeated:
        anomalies.append({
            "type": "repeated_questions",
            "severity": "warning",
            "message": f"User repeated questions {len(repeated)} times — possible frustration",
        })

    # Security exposure
    for e in events:
        text = e["text"]
        if re.search(r"(?:password|token|key|secret)[=:]\s*[^\s]{8,}", text, re.IGNORECASE):
            anomalies.append({
                "type": "security_exposure",
                "severity": "critical",
                "message": "Potential credential exposure detected",
            })
            break

    return anomalies


def format_report(anomalies: list) -> str:
    if not anomalies:
        return "✅ No anomalies detected — all patterns normal"

    lines = [f"⚠️  Found {len(anomalies)} anomalies:\n"]
    for a in anomalies:
        icon = {"critical": "🔴", "warning": "🟡"}.get(a["severity"], "🔵")
        lines.append(f"{icon} [{a['severity'].upper()}] {a['type']}")
        lines.append(f"   {a['message']}\n")
    return "\n".join(lines)


def main():
    parser = argparse.ArgumentParser(description="Anomaly Detector")
    parser.add_argument("--hours", type=int, default=1)
    parser.add_argument("--json", action="store_true")
    parser.add_argument("--alert", action="store_true")
    args = parser.parse_args()

    print("🚨 Anomaly Detector\n")

    state = _load_state()
    print(f"📥 Analyzing last {args.hours}h of events...")
    events = fetch_events(args.hours)
    print(f"   Found {len(events)} events\n")

    if len(events) < 10:
        print("✅ Not enough events to analyze")
        return

    anomalies = detect_anomalies(events)

    if args.json:
        print(json.dumps(anomalies, indent=2))
    else:
        print(format_report(anomalies))

    state["lastCheck"] = int(datetime.now().timestamp() * 1000)
    state["lastAnomalies"] = anomalies
    _save_state(state)


if __name__ == "__main__":
    main()