#!/usr/bin/env -S uv run --script
# /// script
# requires-python = ">=3.10"
# dependencies = ["boto3>=1.34"]
# ///
"""List AWS Cost Anomaly Detection anomalies as compact JSON.

Usage:
    uv run scripts/list_anomalies.py [--days 60] [--profile NAME] [--max-results 25]
"""
import argparse
import json
from datetime import date, timedelta

import boto3


def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--days", type=int, default=60, help="lookback window in days (default: 60)")
    parser.add_argument("--profile", help="AWS profile name")
    parser.add_argument("--max-results", type=int, default=25, help="cap on anomalies returned (default: 25)")
    args = parser.parse_args()

    session = boto3.Session(profile_name=args.profile)
    # Cost Explorer is only served out of us-east-1
    ce = session.client("ce", region_name="us-east-1")

    end = date.today()
    start = end - timedelta(days=args.days)

    anomalies = []
    token = None
    while True:
        kwargs = {
            "DateInterval": {"StartDate": start.isoformat(), "EndDate": end.isoformat()},
            "MaxResults": 100,
        }
        if token:
            kwargs["NextPageToken"] = token
        resp = ce.get_anomalies(**kwargs)
        anomalies.extend(resp.get("Anomalies", []))
        token = resp.get("NextPageToken")
        if not token:
            break

    out = []
    for a in anomalies:
        impact = a.get("Impact", {})
        out.append(
            {
                "anomaly_id": a.get("AnomalyId"),
                "start": a.get("AnomalyStartDate"),
                "end": a.get("AnomalyEndDate"),
                "total_impact_usd": impact.get("TotalImpact"),
                "max_daily_impact_usd": impact.get("MaxImpact"),
                "total_actual_spend_usd": impact.get("TotalActualSpend"),
                "total_expected_spend_usd": impact.get("TotalExpectedSpend"),
                "anomaly_score": (a.get("AnomalyScore") or {}).get("MaxScore"),
                "feedback": a.get("Feedback"),
                "monitor_arn": a.get("MonitorArn"),
                # AWS's own root-cause hints (service/region/usage type/account)
                "root_cause_hints": [
                    {k: v for k, v in rc.items() if v} for rc in a.get("RootCauses", [])
                ],
            }
        )

    out.sort(key=lambda x: x["start"] or "", reverse=True)
    out = out[: args.max_results]
    print(json.dumps({"lookback_days": args.days, "count": len(out), "anomalies": out},
                     indent=1, default=str))


if __name__ == "__main__":
    main()