package hostclaim

import (
	"context"
	"github.com/carlosframework/platform/internal/release"
)

// PendingMoveFenceLoss selects the frozen target writer until its first recovery admission.
func PendingMoveFenceLoss(c *Claim) (LossRecord, bool) {
	ref, ok := ConsumedMoveTargetFence(c)
	if !ok {
		return LossRecord{}, false
	}
	for _, l := range c.EvidenceRefs {
		if l.Op != c.Op.ID || l.Box != c.Op.Intent["target"] || l.Fence != ref || l.Session == 0 || c.Op.Journal["fence_admitted."+l.ID] != "" {
			continue
		}
		region := c.Op.Intent["to"]
		return LossRecord{ID: l.ID, Host: c.Host, OpID: l.Op, OpKind: l.Kind, OpPhase: l.Phase, HolderIncarnation: l.Incarnation, HolderStamp: l.Stamp, HolderSession: l.Session, Box: l.Box, Enrollment: l.Enrollment, Automatic: &l, WriteSources: []WriteSource{{Reason: "target", Box: l.Box, Session: l.Session, Generation: l.Generation, Region: region, Baseline: "replica:" + region + "/" + l.Generation}}}, true
	}
	return LossRecord{}, false
}

// AdmitWriterWithFencedTargetLoss binds the frozen target maximum independently of restore.
func AdmitWriterWithFencedTargetLoss(ctx context.Context, s release.Store, o Observed, in Admission, sources []ValidatedWriteSource) (Observed, error) {
	record, ok := PendingMoveFenceLoss(o.Claim)
	if !ok || o.Claim.Op.Phase != PhaseProbing || len(sources) != 1 || in.Coverage != "" || in.Mode != "cold" || in.KeepStamp || in.PredecessorCertified || in.LossID != "" || len(in.AdditionalWritesLost) != 0 {
		return Observed{}, ErrFence
	}
	want, got := record.WriteSources[0], sources[0]
	if got.Reason != want.Reason || got.Box != want.Box || got.Session != want.Session || got.Generation != want.Generation || got.Region != want.Region || got.Baseline != want.Baseline || in.RemoteMaxTXID != got.RemoteMaxTXID {
		return Observed{}, ErrFence
	}
	h := o.Claim.Holder
	p := AdmissionRecord{Box: h.WriterBox, Session: h.Session, Generation: h.Generation}
	if len(h.Admissions) > 0 {
		p = h.Admissions[len(h.Admissions)-1]
	}
	if p.Box != want.Box || p.Session != want.Session || p.Generation != want.Generation {
		return Observed{}, ErrFence
	}
	in.fenceVerified = true
	return Update(ctx, s, o, func(c *Claim) error {
		if err := AdmitWriter(in)(c); err != nil {
			return err
		}
		setJournal(c, "fence_admitted."+record.ID, "true")
		return nil
	})
}