"""Safe aggregate health semantics: required failures are unhealthy, optional
connector and Redis failures are isolated and reported as degraded."""

from __future__ import annotations

from collections.abc import Iterable, Mapping
from dataclasses import dataclass
from typing import Any


@dataclass(frozen=True)
class DependencyHealth:
    name: str
    status: str
    required: bool = True
    authoritative: bool = True
    detail: str = ""

    def payload(self) -> dict[str, Any]:
        return {
            "status": self.status
            if self.status in {"healthy", "ready", "degraded", "unhealthy", "unknown"}
            else "unknown",
            "required": self.required,
            "authoritative": self.authoritative,
            "detail": self.detail[:160],
        }


@dataclass(frozen=True)
class AggregateHealth:
    status: str
    dependencies: Mapping[str, Mapping[str, Any]]

    def payload(self, *, service: str, trace_id: str) -> dict[str, Any]:
        return {
            "status": self.status,
            "service": service,
            "traceId": trace_id,
            "dependencies": self.dependencies,
        }


def aggregate_health(dependencies: Iterable[DependencyHealth]) -> AggregateHealth:
    values = list(dependencies)
    if not values:
        return AggregateHealth("unhealthy", {})
    payload = {item.name: item.payload() for item in values}
    required_failure = any(
        item.required and item.status not in {"healthy", "ready"} for item in values
    )
    degraded = any(not item.required and item.status not in {"healthy", "ready"} for item in values)
    status = "unhealthy" if required_failure else "degraded" if degraded else "healthy"
    return AggregateHealth(status, payload)