// Resolves the customer admin's active workspace (tenant) + its subscription
// from the cached /api/me payload, and derives the license/billing figures the
// /admin surface needs. One round-trip (shared with useMe's cache) backs the
// whole admin shell.
//
// Scope note: this resolves the signed-in user's OWN tenant (tenants[0]). The
// partner "acting-as a customer" path uses the partner-scoped endpoints +
// usePartnerMode().activeCustomer instead, so it isn't handled here.

import type { SubscriptionDoc, TenantDoc } from '~/types/workspace'

const PLAN_LABEL: Record<string, string> = {
  mvp: 'Starter',
  pro: 'Business',
  enterprise: 'Enterprise',
}

// Subscription amounts are stored in MINOR units (øre/cents) and per BILLING
// CYCLE, not per month. This mirrors platform-api's normalizeToMonthly (used by
// the MRR/partner-billing aggregations) so the portal shows the same figures.
function cycleToMonthlyMinor(perCycleMinor: number, cycle: string): number {
  if (cycle === 'quarterly') return Math.round(perCycleMinor / 3)
  if (cycle === 'yearly') return Math.round(perCycleMinor / 12)
  return perCycleMinor
}

export function useTenant() {
  const { state, fetchMe } = useMe()

  // A user can technically belong to several tenants; the admin surface acts on
  // the first. Refine to an explicit picker if multi-tenant admins land later.
  const tenant = computed<TenantDoc | null>(() => state.value?.tenants?.[0] ?? null)

  const subscription = computed<SubscriptionDoc | null>(() => {
    const t = tenant.value
    const subs = state.value?.subscriptions ?? []
    if (!t) return subs[0] ?? null
    return subs.find((s) => s.tenantId === t._id) ?? subs[0] ?? null
  })

  const planKey = computed(() => subscription.value?.plan ?? tenant.value?.plan ?? 'mvp')
  const planLabel = computed(() => PLAN_LABEL[planKey.value] ?? planKey.value)
  const currency = computed(() => subscription.value?.currency ?? 'DKK')

  // Billed seat limit (license cap). Falls back to the tenant's seat count.
  const seatLimit = computed(() => subscription.value?.seats ?? tenant.value?.seats ?? 0)

  // Per-seat cost normalized to monthly, in MAJOR units (e.g. DKK). Drives the
  // add-seats modal math.
  const perSeatMonthly = computed(() => {
    const sub = subscription.value
    if (!sub?.perSeatAmount) return 0
    return cycleToMonthlyMinor(sub.perSeatAmount, sub.cycle) / 100
  })

  // Monthly recurring spend = per-seat × billed seats, cycle-normalized to
  // monthly, converted minor → major. In `currency`.
  const monthlySpend = computed(() => {
    const sub = subscription.value
    if (!sub?.perSeatAmount || !sub.seats) return 0
    return cycleToMonthlyMinor(sub.perSeatAmount * sub.seats, sub.cycle) / 100
  })

  const primaryDomain = computed(() => tenant.value?.domains?.[0] ?? null)
  const renewsAt = computed(() =>
    subscription.value?.currentPeriodEnd
      ? new Date(subscription.value.currentPeriodEnd)
      : null,
  )

  return {
    tenant,
    subscription,
    fetchMe,
    planKey,
    planLabel,
    currency,
    seatLimit,
    perSeatMonthly,
    monthlySpend,
    primaryDomain,
    renewsAt,
  }
}