#!/usr/bin/env python3
"""Drop and recreate idx_detect_job_items_release_node_job on mainland."""

from __future__ import annotations

import os
import time
from pathlib import Path

import psycopg2
from psycopg2 import sql


ENV_FILE = Path("/etc/default/domaincheck-worker")
INDEX_NAME = "idx_detect_job_items_release_node_job"


def load_env(path: Path) -> None:
    if not path.exists():
        return
    for raw in path.read_text(encoding="utf-8").splitlines():
        line = raw.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue
        key, value = line.split("=", 1)
        os.environ[key] = value


def log(message: str) -> None:
    stamp = time.strftime("%Y-%m-%d %H:%M:%S")
    print(f"[{stamp}] {message}", flush=True)


def fetch_index_state(cur: psycopg2.extensions.cursor, index_name: str) -> tuple[bool, bool, bool] | None:
    cur.execute(
        """
        SELECT i.indisvalid, i.indisready, i.indislive
        FROM pg_index i
        JOIN pg_class c ON c.oid = i.indexrelid
        WHERE c.relname = %s
        """,
        (index_name,),
    )
    row = cur.fetchone()
    if not row:
        return None
    return bool(row[0]), bool(row[1]), bool(row[2])


def fetch_conflicting_backends(cur: psycopg2.extensions.cursor) -> list[tuple[int, str, str]]:
    cur.execute(
        """
        SELECT pid, query, coalesce(wait_event_type, '')
        FROM pg_stat_activity
        WHERE state <> 'idle'
          AND (
            query ILIKE %s OR
            query ILIKE %s
          )
        ORDER BY backend_start
        """,
        (
            "%idx_detect_job_items_release_node_job%",
            "%idx_detect_job_items_stalled_job_activity%",
        ),
    )
    rows = []
    for pid, query, wait_event_type in cur.fetchall():
        snippet = " ".join((query or "").split())[:160]
        rows.append((pid, wait_event_type, snippet))
    return rows


def main() -> int:
    load_env(ENV_FILE)
    conn = psycopg2.connect(
        host="127.0.0.1",
        port=5432,
        user=os.getenv("DB_USER", "postgres"),
        password=os.getenv("DB_PASSWORD"),
        dbname="domain",
    )
    conn.autocommit = True
    cur = conn.cursor()
    try:
        conflicts = fetch_conflicting_backends(cur)
        if conflicts:
            log(f"preflight conflicting_backends={conflicts}")

        log("drop start")
        cur.execute(sql.SQL("DROP INDEX CONCURRENTLY IF EXISTS {}").format(sql.Identifier(INDEX_NAME)))
        log("drop done")

        residual_state = fetch_index_state(cur, INDEX_NAME)
        if residual_state is not None:
            raise RuntimeError(
                f"index shell still present after drop: name={INDEX_NAME} "
                f"state={residual_state}"
            )

        log("create start")
        cur.execute(
            sql.SQL(
                """
                CREATE INDEX CONCURRENTLY {} 
                ON public.detect_job_items (claimed_by, job_id, status, id)
                WHERE claimed_by <> ''
                  AND status IN ('claimed', 'running')
                """
            ).format(sql.Identifier(INDEX_NAME))
        )
        log("create done")
        log(f"final state={fetch_index_state(cur, INDEX_NAME)}")
    finally:
        cur.close()
        conn.close()
    return 0


if __name__ == "__main__":
    raise SystemExit(main())