// Arcadia health probes.
//
// Backed by /api/v1/health* (public — no auth). Each subsystem is probed
// independently; the overall endpoint aggregates and returns 503 if any
// subsystem is not "ok". See arcadia-app commit f427892.

import type { ArcadiaClient } from "@crema/arcadia-client"

export type HealthSubsystem = "api" | "db" | "workers" | "storage"

export type HealthStatus = "ok" | "degraded" | "error" | "unconfigured"

export interface SubsystemHealth {
  status: HealthStatus
  /** Optional human-readable detail. */
  message?: string
  /** Free-form metrics — shape is subsystem-specific. */
  details?: Record<string, unknown>
}

export interface OverallHealth {
  status: HealthStatus
  checked_at: string
  subsystems: Record<HealthSubsystem, SubsystemHealth>
}

export interface DetailedHealth extends OverallHealth {
  /** BEAM info — present on /health/detailed only. */
  system?: {
    otp_release?: string
    elixir_version?: string
    process_count?: number
    memory_total_bytes?: number
    [k: string]: unknown
  }
}

export interface HostStats {
  cpu: {
    util_pct: number | null
    per_cpu_pct: number[]
    load_avg_1: number | null
    load_avg_5: number | null
    load_avg_15: number | null
    schedulers_online: number
    num_cpus: number | null
  }
  memory: {
    total_bytes: number | null
    free_bytes: number | null
    available_bytes: number | null
    buffered_bytes: number | null
    cached_bytes: number | null
    swap_total_bytes: number | null
    swap_free_bytes: number | null
  }
  disks: Array<{ mount: string; total_kb: number; used_pct: number }>
  checked_at: string
}

const BASE = "/api/v1/health"

export async function getHealth(arcadia: ArcadiaClient): Promise<OverallHealth> {
  const res = await arcadia.GET<{ data: OverallHealth } | OverallHealth>(BASE)
  return unwrap(res)
}

export async function getServiceHealth(
  arcadia: ArcadiaClient,
  service: HealthSubsystem,
): Promise<SubsystemHealth> {
  const res = await arcadia.GET<{ data: SubsystemHealth } | SubsystemHealth>(
    `${BASE}/${service}`,
  )
  return unwrap(res)
}

export async function getHealthDetailed(arcadia: ArcadiaClient): Promise<DetailedHealth> {
  const res = await arcadia.GET<{ data: DetailedHealth } | DetailedHealth>(`${BASE}/detailed`)
  return unwrap(res)
}

export async function getHostStats(arcadia: ArcadiaClient): Promise<HostStats> {
  const res = await arcadia.GET<{ data: HostStats } | HostStats>(`${BASE}/host`)
  return unwrap(res)
}

export const SUBSYSTEMS: HealthSubsystem[] = ["api", "db", "workers", "storage"]

function unwrap<T>(res: { data: T } | T): T {
  return res && typeof res === "object" && "data" in (res as object)
    ? (res as { data: T }).data
    : (res as T)
}