package kvm2

import (
	"context"
	"fmt"

	"github.com/digitalocean/go-libvirt"

	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/provider"
)

// ListByTag is spec entry 12: every domain on every configured host, in
// config order, filtered client-side on the kvm2 mark. GC uses only ID, UID
// and CreatedAt (contract §2.4), all of which the name and the metadata
// element give, so no state or address RPC is made and State and IP stay
// empty. A host that cannot be reached or listed fails the whole call
// (fail-whole); a single domain whose metadata cannot be read is skipped,
// unless ctx ended, which fails the call rather than pass off an empty view
// as the truth.
func (p *Provider) ListByTag(ctx context.Context) ([]provider.Instance, error) {
	log := p.logger(ctx)
	var out []provider.Instance
	for _, host := range p.cfg.Hosts {
		hlog := log.WithValues("host", host.Name)
		be, err := p.hosts.get(ctx, host)
		if err != nil {
			logAPIError(hlog, "list", err)
			return nil, p.wrapErr("list", "", err)
		}
		doms, _, err := be.ConnectListAllDomains(ctx, 1, libvirt.ConnectListDomainsActive|libvirt.ConnectListDomainsInactive)
		if err != nil {
			err = fmt.Errorf("listing domains on host %s: %w", host.Name, err)
			logAPIError(hlog, "list", err)
			return nil, p.wrapErr("list", "", err)
		}
		for _, dom := range doms {
			dlog := hlog.WithValues("name", dom.Name)
			meta, err := readMetadata(ctx, be, dom)
			if err != nil {
				if ctx.Err() != nil {
					return nil, p.wrapErr("list", "", err)
				}
				dlog.V(1).Info("skipping domain with unreadable metadata", "error", err.Error())
				continue
			}
			if !meta.managed() {
				continue
			}
			inst := provider.Instance{ID: formatProviderID(host.Name, dom.Name), UID: meta.UID, CreatedAt: meta.createdAt()}
			dlog.V(2).Info("kvm2 listed instance", "id", inst.ID, "uid", inst.UID, "createdAt", inst.CreatedAt)
			out = append(out, inst)
		}
	}
	log.V(1).Info("kvm2 domains listed", "hosts", len(p.cfg.Hosts), "managed", len(out))
	return out, nil
}