#!/usr/bin/env python3
"""Agent for detecting insider data exfiltration via DLP analysis."""

import json
import argparse
from datetime import datetime

import pandas as pd


def load_activity_logs(log_path):
    """Load file/cloud activity logs."""
    if log_path.endswith(".csv"):
        return pd.read_csv(log_path, parse_dates=["timestamp"])
    return pd.read_json(log_path, lines=True)


def detect_volume_anomalies(df, multiplier=3.0):
    """Detect users with data transfer volume exceeding baseline."""
    df["date"] = df["timestamp"].dt.date
    daily_volume = df.groupby(["user", "date"])["bytes_transferred"].sum().reset_index()
    user_baseline = daily_volume.groupby("user")["bytes_transferred"].agg(
        ["mean", "std"]).reset_index()
    user_baseline.columns = ["user", "avg_bytes", "std_bytes"]
    latest_date = df["date"].max()
    latest_day = daily_volume[daily_volume["date"] == latest_date]
    merged = latest_day.merge(user_baseline, on="user")
    threshold = merged["avg_bytes"] + (multiplier * merged["std_bytes"].fillna(0))
    anomalies = merged[merged["bytes_transferred"] > threshold]
    findings = []
    for _, row in anomalies.iterrows():
        findings.append({
            "user": row["user"],
            "today_bytes": int(row["bytes_transferred"]),
            "avg_bytes": int(row["avg_bytes"]),
            "multiplier": round(row["bytes_transferred"] / max(row["avg_bytes"], 1), 1),
            "severity": "CRITICAL" if row["bytes_transferred"] > row["avg_bytes"] * 5 else "HIGH",
        })
    return sorted(findings, key=lambda x: x["multiplier"], reverse=True)


def detect_off_hours_activity(df, start_hour=6, end_hour=22):
    """Detect file access during off-hours."""
    df["hour"] = df["timestamp"].dt.hour
    off_hours = df[(df["hour"] < start_hour) | (df["hour"] >= end_hour)]
    if off_hours.empty:
        return []
    user_counts = off_hours.groupby("user").agg(
        events=("timestamp", "count"),
        bytes_total=("bytes_transferred", "sum"),
        unique_files=("file_path", "nunique") if "file_path" in df.columns
        else ("filename", "nunique"),
    ).reset_index()
    findings = []
    for _, row in user_counts.iterrows():
        if row["events"] > 10:
            findings.append({
                "user": row["user"],
                "off_hours_events": int(row["events"]),
                "bytes_transferred": int(row["bytes_total"]),
                "unique_files": int(row["unique_files"]),
                "severity": "HIGH",
            })
    return sorted(findings, key=lambda x: x["off_hours_events"], reverse=True)


def detect_bulk_downloads(df, file_threshold=50, time_window="1h"):
    """Detect bulk file downloads in short time windows."""
    findings = []
    df_sorted = df.sort_values("timestamp")
    download_actions = ["download", "copy", "export"]
    action_col = "action" if "action" in df.columns else "event_type"
    downloads = df_sorted[df_sorted[action_col].str.lower().isin(download_actions)]
    if downloads.empty:
        return findings
    downloads = downloads.set_index("timestamp")
    for user, group in downloads.groupby("user"):
        rolling = group.resample(time_window).size()
        bursts = rolling[rolling >= file_threshold]
        if len(bursts) > 0:
            findings.append({
                "user": user,
                "max_downloads_per_hour": int(rolling.max()),
                "burst_periods": len(bursts),
                "total_downloads": len(group),
                "severity": "CRITICAL",
            })
    return findings


def detect_sensitive_file_access(df, sensitive_patterns=None):
    """Detect access to sensitive file types or directories."""
    if sensitive_patterns is None:
        sensitive_patterns = [
            r"\.pem$", r"\.key$", r"\.env$", r"credentials",
            r"password", r"\.kdbx$", r"\.pfx$", r"secret",
            r"financial", r"payroll", r"customer.*data",
        ]
    file_col = "file_path" if "file_path" in df.columns else "filename"
    findings = []
    import re
    for _, row in df.iterrows():
        filepath = str(row.get(file_col, ""))
        for pattern in sensitive_patterns:
            if re.search(pattern, filepath, re.IGNORECASE):
                findings.append({
                    "user": row.get("user", ""),
                    "file": filepath,
                    "pattern_matched": pattern,
                    "action": row.get("action", row.get("event_type", "")),
                    "timestamp": str(row.get("timestamp", "")),
                    "severity": "HIGH",
                })
                break
    return findings[:500]


def detect_usb_activity(df):
    """Detect USB device usage for data transfer."""
    usb_indicators = ["removable", "usb", "external"]
    dest_col = "destination" if "destination" in df.columns else "target"
    usb_events = df[df[dest_col].str.lower().str.contains(
        "|".join(usb_indicators), na=False)]
    if usb_events.empty:
        return []
    user_usb = usb_events.groupby("user").agg(
        events=("timestamp", "count"),
        bytes_total=("bytes_transferred", "sum"),
    ).reset_index()
    findings = []
    for _, row in user_usb.iterrows():
        findings.append({
            "user": row["user"],
            "usb_events": int(row["events"]),
            "bytes_to_usb": int(row["bytes_total"]),
            "severity": "HIGH",
        })
    return findings


def main():
    parser = argparse.ArgumentParser(description="Insider Data Exfiltration Detection Agent")
    parser.add_argument("--log-file", required=True, help="Activity log file")
    parser.add_argument("--output", default="dlp_exfiltration_report.json")
    parser.add_argument("--action", choices=[
        "volume", "off_hours", "bulk", "sensitive", "full_analysis"
    ], default="full_analysis")
    args = parser.parse_args()

    df = load_activity_logs(args.log_file)
    report = {"generated_at": datetime.utcnow().isoformat(), "total_events": len(df),
              "findings": {}}
    print(f"[+] Loaded {len(df)} activity events")

    if args.action in ("volume", "full_analysis"):
        findings = detect_volume_anomalies(df)
        report["findings"]["volume_anomalies"] = findings
        print(f"[+] Volume anomalies: {len(findings)}")

    if args.action in ("off_hours", "full_analysis"):
        findings = detect_off_hours_activity(df)
        report["findings"]["off_hours_activity"] = findings
        print(f"[+] Off-hours activity users: {len(findings)}")

    if args.action in ("bulk", "full_analysis"):
        findings = detect_bulk_downloads(df)
        report["findings"]["bulk_downloads"] = findings
        print(f"[+] Bulk download users: {len(findings)}")

    if args.action in ("sensitive", "full_analysis"):
        findings = detect_sensitive_file_access(df)
        report["findings"]["sensitive_access"] = findings
        print(f"[+] Sensitive file accesses: {len(findings)}")

    with open(args.output, "w") as f:
        json.dump(report, f, indent=2, default=str)
    print(f"[+] Report saved to {args.output}")


if __name__ == "__main__":
    main()