package hostops

import (
	"context"

	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/park"
)

type ParkScopeProvider func(context.Context, hostclaim.Observed, hostclaim.Obligation) (hostclaim.ParkScope, error)

// RunOwnedRemote is called only by the appointed regional worker. It never
// takes another region's chore or acknowledges local work on another box.
func RunOwnedRemote(ctx context.Context, e *park.Engine, w park.Work, scope ParkScopeProvider) error {
	if e == nil || e.Claims == nil || e.Region == "" || scope == nil || e.Authorize == nil || e.View == nil || e.Leases == nil {
		return ErrContract
	}
	obs, err := hostclaim.Read(ctx, e.Claims, w.Host)
	if err != nil {
		return err
	}
	if obs.Absent {
		return ErrPending
	}
	for _, ob := range obs.Claim.Obligations {
		if ob.ID != w.ID || ob.Op != w.Op {
			continue
		}
		if !e.OwnsRegion(ob.Region) || ob.Owner != "region:"+ob.Region || (ob.Kind != "park-replica" && ob.Kind != "park-generation") {
			return ErrIdentity
		}
		if ob.Park == nil {
			p, err := scope(ctx, obs, ob)
			if err != nil {
				return err
			}
			if err := e.Bind(ctx, w, p); err != nil {
				return err
			}
		}
		return e.Run(ctx, w)
	}
	return ErrPending
}