"""Slack post Lambda: daily summary + batched 3rd-escalation alert.

Async-invoked by the classifier with ``{"dt": "YYYY-MM-DD"}`` once the day's
snapshot is written. Reads today's (and yesterday's, for deltas) ``summary.json``
from ``analytics/``, posts the daily summary to the WO channel via the reused bot
token (Secrets Manager), and — only when the 3rd-escalation count > 0 — posts the
standalone batched alert (reading ``details.json`` for the 3rd-escalation rows).

Runtime: Python 3.12, ARM64. No App Home — two push surfaces only (see CLAUDE.md).
"""

from __future__ import annotations

from datetime import datetime, timedelta, timezone

import blockkit
import slackio


def _yesterday(dt: str) -> str:
    return (datetime.strptime(dt, "%Y-%m-%d") - timedelta(days=1)).strftime("%Y-%m-%d")


def handler(event, context):
    """Post the daily summary and (conditionally) the 3rd-escalation alert."""
    dt = (event or {}).get("dt") or datetime.now(timezone.utc).strftime("%Y-%m-%d")

    today = slackio.read_analytics_json(dt, "summary.json")
    if today is None:
        print(f"No summary.json for dt={dt}; nothing to post.")
        return {"posted": False, "reason": "no summary", "dt": dt}
    yesterday = slackio.read_analytics_json(_yesterday(dt), "summary.json")

    client = slackio.web_client()
    channel = slackio.channel_id()
    dashboard_url = slackio.get_dashboard_url()

    summary_blocks = blockkit.build_daily_summary(today, yesterday, dashboard_url)
    client.chat_postMessage(
        channel=channel, blocks=summary_blocks, text=f"APM Work Orders — {dt}"
    )
    posted = {"summary": True, "alert": False}

    # Standalone batched alert — only when there are 3rd escalations. Pull the
    # rows from details.json so the alert can name the WOs.
    if today.get("third_escalation_count", 0) > 0:
        details = slackio.read_analytics_json(dt, "details.json") or []
        thirds = [d for d in details if d.get("category") == "3rd Escalation"]
        alert_blocks = blockkit.build_escalation_alert(thirds)
        if alert_blocks:
            client.chat_postMessage(
                channel=channel,
                blocks=alert_blocks,
                text=f"🚨 {len(thirds)} 3rd-escalation work orders",
            )
            posted["alert"] = True

    print(f"Posted dt={dt}: {posted}")
    return {"posted": True, "dt": dt, **posted}