package hostops

import (
	"context"
	"log"

	"github.com/carlosframework/platform/internal/boxchoice"
	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/release"
)

// ClaimLoads counts, from one listing of control/hosts/ (ListClaims), the
// hosts whose claim names each box as op.exec, in total and per
// "acct/app": choose()'s second rule until spec 2 (region HA §5.2, claim
// P5-D2). The count only balances, so a claim that cannot be read is
// logged and left out; a listing that fails is an error, because a count
// of nothing would send every create to one box.
func ClaimLoads(ctx context.Context, s release.Store) (map[string]boxchoice.Load, error) {
	hosts, err := ListClaims(ctx, s)
	if err != nil {
		return nil, err
	}
	out := map[string]boxchoice.Load{}
	for _, host := range hosts {
		obs, err := hostclaim.Read(ctx, s, host)
		if err != nil {
			log.Printf("hostops: claim loads: %s: %v", host, err)
			continue
		}
		if obs.Absent || obs.Claim.Holder == nil || obs.Claim.Op.Exec == "" || obs.Claim.Op.Exec == "none" {
			continue
		}
		box, h := obs.Claim.Op.Exec, obs.Claim.Holder
		l := out[box]
		if l.Apps == nil {
			l.Apps = map[string]int{}
		}
		l.Hosts++
		l.Apps[h.Account+"/"+h.App]++
		out[box] = l
	}
	return out, nil
}