package resolution

import (
	mcat "git.novox.be/novox/mesh-sdk/go/catalogue"
)

func providesAt(m mcat.Manifest, provision, scope string) bool {
	for _, o := range m.Provides {
		if o.Name == provision && o.At() == scope {
			return true
		}
	}
	return false
}

// HolderAmong is which of several providers of a provision holds the seat that delivers it.
//
// Found by the (node, module) pair, because a provider is identified by both (novox/hq to-be 23):
// two modules on one node could both provide a provision, and only the one holding the seat
// answers for it. Nothing when no seat delivers the provision, when nobody holds
// it, or when the holder is not among the providers offered.
//
// **The first holder in the providers' own order** (novox/hq ADR 0223). A replicated seat has
// several, and the answer must not depend on the order the mesh happened to resolve its machines
// in: the providers come sorted by machine, so every consumer is bound to the same one. A seat with
// one holder gets the same answer as before.
func HolderAmong(provision string, providers []mcat.Provider, held []mcat.Held) (mcat.Provider, bool) {
	seat, delivered := mcat.SeatDelivering(provision)
	if !delivered {
		return mcat.Provider{}, false
	}
	for _, p := range providers {
		for _, h := range held {
			// Resolve the held claim to a seat rather than comparing names, so a record naming a
			// seat's former name still matches it after a rename (novox/hq ADR 0122).
			hs, ok := mcat.SeatNamed(h.Claim)
			if !ok || hs.Name != seat.Name || h.Scope != seat.Scope {
				continue
			}
			if p.Node == h.Node && p.Module == h.Module {
				return p, true
			}
		}
	}
	return mcat.Provider{}, false
}