"""DNS gate logic — Spec 019."""

from __future__ import annotations

import os
from typing import Any

from app.migration import store

GATE_MIN_RATIO = float(os.getenv("MIGRATION_GATE_MIN_RATIO", "0.99"))


def evaluate_job(conn, job_id: int) -> dict[str, Any]:
    job = store.get_job(conn, job_id)
    if not job:
        return {"gate": "blocked", "reason": "job_not_found"}

    mailboxes = job.get("mailboxes") or []
    checks: list[tuple[str, str, str]] = []

    if not mailboxes:
        checks.append(("mailboxes_present", "fail", "Nenhuma mailbox no job"))
        gate = "blocked"
    else:
        ratios = []
        for mb in mailboxes:
            src = max(mb.get("messages_source") or 0, 1)
            dst = mb.get("messages_dest") or 0
            ratio = dst / src if src else 0.0
            ratios.append(ratio)
            if ratio < GATE_MIN_RATIO:
                checks.append(
                    (
                        f"sync_{mb['email']}",
                        "warn" if ratio >= 0.9 else "fail",
                        f"{mb['email']}: {ratio * 100:.1f}% sincronizado",
                    )
                )
        avg = sum(ratios) / len(ratios) if ratios else 0.0
        checks.append(("count_ratio", "pass" if avg >= GATE_MIN_RATIO else "warn", f"Média {avg * 100:.1f}%"))

        if job.get("approved_by"):
            checks.append(("manual_approval", "pass", f"Aprovado por {job['approved_by']}"))
            gate = "ready_for_dns" if avg >= GATE_MIN_RATIO else "warning"
        elif avg >= GATE_MIN_RATIO:
            checks.append(("manual_approval", "fail", "Aguarda aprovação ops_lead"))
            gate = "warning"
        elif avg >= 0.9:
            gate = "warning"
        else:
            gate = "blocked"

    for check_id, status, message in checks:
        store.add_gate_check(conn, job_id, check_id, status, message)

    store.update_job(conn, job_id, migration_gate=gate, phase=job.get("phase") or "cutover_ready")
    return {"gate": gate, "checks": [{"check_id": c[0], "status": c[1], "message": c[2]} for c in checks]}


def approve_gate(conn, job_id: int, approved_by: str) -> dict[str, Any]:
    from datetime import datetime, timezone

    now = datetime.now(timezone.utc).isoformat()
    store.update_job(conn, job_id, approved_by=approved_by, approved_at=now, phase="cutover_ready")
    result = evaluate_job(conn, job_id)
    if result["gate"] in ("warning", "ready_for_dns"):
        store.update_job(conn, job_id, migration_gate="ready_for_dns")
        result["gate"] = "ready_for_dns"
    return result