package main

// The knowledge base's writes (novox/hq ADR 0290 rules 4 and 5, to-be 55 §4, §5 and §6): a number reserved from
// the issue tracker, a record proposed and judged by the 29 rules, reviewed by the knowledge base's own judgement
// (review.go), and accepted — at once, or on the operator's proven warrant when it needs the operator — with every
// clause it changes or supersedes moved accordingly and the whole record set judged after.

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"sync"
	"time"

	stdio "git.novox.be/novox/mesh-sdk/go"
)

// Unproven is who acted, as recorded, where the runtime proves no caller (hq issue 365): the SDK's word. The caller
// is never taken from an argument.
const Unproven = stdio.Unproven

// proven says whether a caller is one the runtime proved.
func proven(caller string) bool { return caller != "" && caller != Unproven }

// The events this module says (ADR 0290 rule 7): every change, with what changed and who changed it.
const (
	EventReserved  = "reserved"
	EventProposed  = "proposed"
	EventReviewed  = "reviewed"
	EventAccepted  = "accepted"
	EventChanged   = "changed"
	EventImported  = "imported"
	EventDrafted   = "drafted"
	EventConfirmed = "confirmed"
	EventReturned  = "returned"
)

// Events are the events, in the order the manifest declares them.
var Events = []string{EventReserved, EventProposed, EventReviewed, EventAccepted, EventChanged, EventImported,
	EventDrafted, EventConfirmed, EventReturned}

// Settings are the operator's values for this module, merged by the mesh into one JSON file.
type Settings struct {
	// JudgeModel is the model the drafting and confirming judgements ask; sonnet when empty.
	JudgeModel string `json:"judge-model,omitempty"`
	// Drafting is "off" to stop drafting and confirming clauses; anything else is on.
	Drafting string `json:"drafting,omitempty"`
	// ReservedFor is how long a reserved number waits for its proposal before it is withdrawn, as a duration
	// such as 168h; DefaultReservedFor when empty.
	ReservedFor string `json:"reserved-for,omitempty"`
}

// DefaultReservedFor is how long a reservation waits for its proposal unless the settings say otherwise.
const DefaultReservedFor = 7 * 24 * time.Hour

// Reserver asks the issue tracker for the next number of a kind (issue-tracker.reserve).
type Reserver func(kind, title string) (int, error)

// Judgement asks the agent on the node one question with no tools (claude-code.claude_code_judge), and answers
// the structured answer and who judged.
type Judgement func(question string, schema map[string]any, model string) (json.RawMessage, string, error)

// Notifier tells the operator's channel something (operator-channel.notify). Resolved is the line its message says
// once it is cleared: the channel keeps the one given when it is raised (novox/hq issue 497); "" for none.
type Notifier func(key, summary, headline, explanation, resolved string) error

// Clearer tells the operator's channel that what it was told under key is over, in one resolved line.
type Clearer func(key, resolved string) error

// KB is the knowledge base.
type KB struct {
	Store    Store
	Records  Records
	Reserve  Reserver
	Judge    Judgement
	Asks     AskBus
	Notify   Notifier
	Clear    Clearer
	Emit     func(event string, body any) error
	Settings func() (Settings, error)
	Now      func() time.Time
	Logf     func(format string, a ...any)

	// mu serialises the writes: one instance holds the seat, and a write reads, judges and writes as one.
	mu sync.Mutex

	stuckMu sync.Mutex
	stuck   map[Key]*stuckReview

	// kick wakes the background work when a proposal waits for its review; nil where nothing runs in the
	// background (the tests take each step themselves).
	kick chan struct{}

	refMu sync.Mutex
	ref   *Reference
	refAt time.Time
}

func (k *KB) now() time.Time {
	if k.Now != nil {
		return k.Now().UTC()
	}
	return time.Now().UTC()
}

func (k *KB) logf(format string, a ...any) {
	if k.Logf != nil {
		k.Logf(format, a...)
	}
}

func (k *KB) settings() Settings {
	if k.Settings == nil {
		return Settings{}
	}
	s, err := k.Settings()
	if err != nil {
		k.logf("[mesh-knowledge] the settings cannot be read (%v): the defaults hold", err)
	}
	return s
}

// emit says a change. A change that could not be said is logged and kept: the store holds it whole, and its
// versions are the record of who changed what.
func (k *KB) emit(event string, r *Record, by, what string, version int) {
	if k.Emit == nil {
		return
	}
	body := map[string]any{"kind": r.Kind, "number": r.Number, "record": r.Key().String(), "by": by, "at": k.now(),
		"what": what, "version": version, "status": r.Status}
	if err := k.Emit(event, body); err != nil {
		k.logf("[mesh-knowledge] the event %s for %s could not be said: %v", event, r.Key(), err)
	}
}

// reference is the reading order and the glossary, read again after ten minutes.
func (k *KB) reference() (*Reference, error) {
	k.refMu.Lock()
	defer k.refMu.Unlock()
	if k.ref != nil && k.now().Sub(k.refAt) < 10*time.Minute {
		return k.ref, nil
	}
	if k.Records == nil {
		return nil, errors.New("hq cannot be read: the module has no way to the records module")
	}
	ref, err := LoadReference(k.Records)
	if err != nil {
		if k.ref != nil {
			return k.ref, nil
		}
		return nil, err
	}
	k.ref, k.refAt = ref, k.now()
	return ref, nil
}

func (k *KB) lookup(ctx context.Context) Lookup {
	return func(key Key) *Record {
		e, err := k.Store.Get(ctx, key)
		if err != nil || e == nil {
			return nil
		}
		return e.Current
	}
}

var kindNumber = regexp.MustCompile(`^\d{1,4}$`)

// ---- reserve -----------------------------------------------------------------------------------------------

// Reserved is the answer to reserve.
type Reserved struct {
	Kind   string `json:"kind"`
	Number int    `json:"number"`
	Record string `json:"record"`
	Says   string `json:"says"`
}

// ReserveNumber asks the issue tracker for the next number of a kind and holds it as reserved, with who reserved
// it and when (to-be 55 §6). The knowledge base keeps no counter.
func (k *KB) ReserveNumber(caller, kind, title string) (*Reserved, error) {
	if !contains(Kinds, kind) {
		return nil, fmt.Errorf("kind is decision or research, not %q; nothing was reserved", kind)
	}
	title = strings.TrimSpace(title)
	if title == "" || strings.Contains(title, "\n") || len([]rune(title)) > 200 {
		return nil, errors.New("for is the record's title, one line of at most 200 characters; nothing was reserved")
	}
	if k.Reserve == nil {
		return nil, errors.New("the issue tracker cannot be asked for a number here; nothing was reserved")
	}
	n, err := k.Reserve(kind, title)
	if err != nil {
		return nil, fmt.Errorf("the issue tracker did not hand out a %s number (%v); nothing was reserved", kind, err)
	}
	k.mu.Lock()
	defer k.mu.Unlock()
	ctx := context.Background()
	at := k.now()
	r := &Record{Kind: kind, Number: n, Title: title, Status: StatusReserved, ReservedBy: caller, ReservedAt: at, ReservedFor: title}
	err = k.Store.Create(ctx, Version{By: caller, At: at, Why: "number reserved from the issue tracker", Record: r})
	if errors.Is(err, ErrExists) {
		return nil, fmt.Errorf("the issue tracker handed out %s, which the knowledge base already holds: the number is spent, "+
			"and its counter stands below what the knowledge base holds. Reserve again, and tell the operator", r.Key())
	}
	if err != nil {
		return nil, fmt.Errorf("%s was handed out and could not be kept (%v): the number is spent; reserve again", r.Key(), err)
	}
	k.emit(EventReserved, r, caller, "reserved for "+title, 1)
	return &Reserved{Kind: kind, Number: n, Record: r.Key().String(),
		Says: fmt.Sprintf("%s is reserved for %q. Propose the record under this number; a number never proposed is withdrawn, and never handed out again.", r.Key(), title)}, nil
}

// ---- propose -----------------------------------------------------------------------------------------------

// LinkAsk is a link as a proposal gives it: its kind, its target as written ("0276 §4"), the clause it goes out
// from.
type LinkAsk struct {
	Kind string `json:"kind"`
	To   string `json:"to"`
	From int    `json:"from,omitempty"`
}

// ProposeAsk is a record proposed whole.
type ProposeAsk struct {
	Kind          string
	Number        int
	Title         string
	Topic         string
	Date          string
	Deciders      []string
	Clauses       []string
	Sections      []Section
	Links         []LinkAsk
	Homes         []string
	NeedsOperator bool
	// Status is a research effort's: active, graduated or abandoned.
	Status string
	// Insight, for an accepted record, is what stood before: the proposal is a progressive insight.
	Insight string
	Why     string
}

// Proposed is the answer to propose.
type Proposed struct {
	Record  string `json:"record"`
	Version int    `json:"version"`
	Status  string `json:"status"`
	Says    string `json:"says"`
}

var numberedClause = regexp.MustCompile(`^(\d+)\.\s+`)

// MostRecordBytes is the most one record may hold.
const MostRecordBytes = 512 << 10

// Propose writes a record whole as proposed, or refuses it naming every rule it breaks. Every version proposed
// waits for the knowledge base's own review (review.go), which the background work takes at once. A proposal is
// revised as new versions by its author until it is accepted; an accepted record is changed only by a progressive
// insight (Insight), which is reviewed like a proposal while the accepted version stays the one served.
func (k *KB) Propose(caller string, a ProposeAsk) (*Proposed, error) {
	ctx := context.Background()
	k.mu.Lock()
	defer k.mu.Unlock()
	if !contains(Kinds, a.Kind) {
		return nil, fmt.Errorf("kind is decision or research, not %q; nothing was proposed", a.Kind)
	}
	key := Key{a.Kind, a.Number}
	held, err := k.Store.Get(ctx, key)
	if err != nil {
		return nil, fmt.Errorf("the knowledge base cannot be read (%v); nothing was proposed", err)
	}
	ref, err := k.reference()
	if err != nil {
		return nil, fmt.Errorf("the rules cannot be judged: %v. Nothing was proposed", err)
	}
	r := &Record{Kind: a.Kind, Number: a.Number, Title: strings.TrimSpace(a.Title), Topic: strings.TrimSpace(a.Topic),
		Status: StatusProposed, Date: strings.TrimSpace(a.Date), Deciders: a.Deciders, Effort: a.Status,
		NeedsOperator: a.NeedsOperator, Sections: a.Sections, Homes: a.Homes, Author: caller}
	if r.Date == "" {
		r.Date = k.now().Format("2006-01-02")
	}
	var refusals []Refusal
	for i, text := range a.Clauses {
		n := i + 1
		text = strings.TrimSpace(text)
		if m := numberedClause.FindStringSubmatch(text); m != nil {
			n, _ = strconv.Atoi(m[1])
			text = strings.TrimSpace(text[len(m[0]):])
		}
		r.Clauses = append(r.Clauses, Clause{N: n, Text: text, Status: ClauseProposed, Source: SourceWritten})
	}
	for _, l := range a.Links {
		to, err := ParseRef(l.To)
		if err != nil {
			refusals = append(refusals, Refusal{Rule: "link-target", Says: err.Error()})
			continue
		}
		r.Links = append(r.Links, Link{Kind: l.Kind, From: l.From, To: to, Source: SourceWritten})
	}
	current := true
	why := strings.TrimSpace(a.Why)
	if held != nil {
		switch w := held.Working(); {
		case held.Current.Status == StatusReserved:
			r.ReservedBy, r.ReservedAt, r.ReservedFor = held.Current.ReservedBy, held.Current.ReservedAt, held.Current.ReservedFor
			if proven(r.ReservedBy) && caller != r.ReservedBy {
				return nil, fmt.Errorf("%s was reserved by %s: only who reserved a number proposes under it. Nothing was proposed", key, r.ReservedBy)
			}
			if why == "" {
				why = "proposed"
			}
		case w.Status == StatusProposed && held.Pending == nil:
			// A revision of a proposal: a new version, its earlier reviews kept with the versions they reviewed.
			if !proven(caller) || caller != w.Author {
				return nil, fmt.Errorf("%s is proposed by %s: only its author, proven by the runtime, revises it (this call is by %s). "+
					"Nothing was proposed", key, w.Author, caller)
			}
			r.Author, r.Reviews, r.ReservedBy, r.ReservedAt, r.ReservedFor = w.Author, w.Reviews, w.ReservedBy, w.ReservedAt, w.ReservedFor
			r.Writers = w.Writers
			if a.Insight != "" {
				refusals = append(refusals, Refusal{Rule: "reserved", Says: "a proposal not yet accepted is revised, not corrected by an insight"})
			}
			if why == "" {
				why = "revised"
			}
		case held.Current.Accepted():
			if held.Pending != nil && (!proven(caller) || caller != held.Pending.Author) {
				return nil, fmt.Errorf("%s has a progressive insight by %s waiting for its review: only its author, proven by the "+
					"runtime, revises it (this call is by %s). Nothing was proposed", key, held.Pending.Author, caller)
			}
			if strings.TrimSpace(a.Insight) == "" {
				return nil, fmt.Errorf("%s is %s: it changes only by a new record, or by a progressive insight, a correction of fact "+
					"that leaves the decision standing (give insight: what stood before). Nothing was proposed", key, held.Current.Status)
			}
			current = false
			r.Author = caller
			r.Writers = append([]string{}, held.Current.Writers...)
			if held.Current.Author != "" && !contains(r.Writers, held.Current.Author) {
				r.Writers = append(r.Writers, held.Current.Author)
			}
			r.AcceptedAt = held.Current.AcceptedAt
			r.Pending = &PendingState{Insight: Insight{Date: k.now().Format("2006-01-02"), Before: strings.TrimSpace(a.Insight), By: caller}}
			r.Date = held.Current.Date
			r.Effort = a.Status
			if why == "" {
				why = "a progressive insight proposed"
			}
		default:
			return nil, fmt.Errorf("%s is %s and takes no proposal; nothing was proposed", key, held.Working().Status)
		}
	}
	if current && held != nil && !held.Current.ReservedAt.IsZero() && r.Date < held.Current.ReservedAt.Format("2006-01-02") {
		// A new record is of its own day: a date before its reservation would put it under rules older records keep.
		refusals = append(refusals, Refusal{Rule: "date", Says: fmt.Sprintf("a new record is dated from the day its number was reserved, %s, not %s",
			held.Current.ReservedAt.Format("2006-01-02"), r.Date)})
	}
	if !contains(r.Writers, caller) {
		r.Writers = append(r.Writers, caller)
	}
	// Every version proposed is reviewed by the knowledge base itself, once; its earlier reviews stay with the
	// versions they reviewed.
	r.Judging = judgingOf(r)
	if !current && a.Kind == KindResearch && r.Effort == "" {
		r.Effort = held.Current.Status
	}
	refusals = append(refusals, JudgeRecord(r, held, k.lookup(ctx), ref)...)
	if raw, _ := json.Marshal(r); len(raw) > MostRecordBytes {
		refusals = append(refusals, Refusal{Rule: "size", Says: fmt.Sprintf("the record is %d bytes; a record holds at most %d", len(raw), MostRecordBytes)})
	}
	if len(refusals) > 0 {
		lines := make([]string, len(refusals))
		for i, x := range refusals {
			lines[i] = x.String()
		}
		return nil, fmt.Errorf("%s is refused by %d rule(s), and nothing was written:\n- %s", key, len(refusals), strings.Join(lines, "\n- "))
	}
	v := Version{By: caller, At: k.now(), Why: why, Record: r, Insight: !current}
	if err := k.Store.Save(ctx, v, current, false, held.Revision); err != nil {
		return nil, fmt.Errorf("%s could not be written (%v); nothing was proposed", key, err)
	}
	n := held.Versions + 1
	k.emit(EventProposed, r, caller, why, n)
	k.wake()
	if r.Judging.State == JudgingUnproven {
		return &Proposed{Record: key.String(), Version: n, Status: StatusProposed,
			Says: fmt.Sprintf("%s is proposed as version %d, and %s. Nothing of it is in force.", key, n, r.Judging.Reason)}, nil
	}
	says := fmt.Sprintf("%s is proposed as version %d. The knowledge base reviews it now, in a judgement of its own; nothing of it "+
		"is in force until that judgement approves it", key, n)
	if r.NeedsOperator {
		says += ", and then the operator's Approve"
	}
	if !current {
		says = fmt.Sprintf("A progressive insight to %s is proposed as version %d. The knowledge base reviews it now; the accepted "+
			"version is served until that review approves it", key, n)
	}
	says += ". get shows the review's verdict and findings once it is made; on changes, you revise it by proposing it again"
	return &Proposed{Record: key.String(), Version: n, Status: StatusProposed, Says: says + "."}, nil
}

// ---- acceptance ------------------------------------------------------------------------------------------

// accept makes a reviewed version the one served: accepted, its clauses in force, every clause and record it
// changes or supersedes moved; then the whole record set is judged. by is who acted; warrant, the operator's word
// it rests on.
func (k *KB) accept(ctx context.Context, held *Entry, w *Record, by, why, warrant string) (*Record, error) {
	r := w.Clone()
	insight := r.Pending != nil
	at := k.now()
	if insight {
		in := r.Pending.Insight
		r.Pending = nil
		r.Insights = append(r.Insights, in)
		r.Status = held.Current.Status
		if r.Kind == KindResearch && contains(ResearchStatuses, r.Effort) && held.Current.Status != StatusSuperseded {
			r.Status = r.Effort
		}
		for i, c := range r.Clauses {
			r.Clauses[i].Status = ClauseInForce
			if old := held.Current.Clause(c.N); old != nil && (old.Status == ClauseChanged || old.Status == ClauseSuperseded) {
				r.Clauses[i].Status, r.Clauses[i].ChangedBy = old.Status, old.ChangedBy
			}
		}
	} else {
		r.Status = StatusAccepted
		if r.Kind == KindResearch {
			r.Status = r.Effort
		}
		r.AcceptedAt = at
		for i := range r.Clauses {
			r.Clauses[i].Status = ClauseInForce
		}
	}
	r.Effort = ""
	if warrant != "" {
		why += "; " + warrant
	}
	if err := k.Store.Save(ctx, Version{By: by, At: at, Why: why, Record: r, Insight: insight}, true, true, held.Revision); err != nil {
		return nil, fmt.Errorf("%s could not be accepted (%v); it stays proposed", r.Key(), err)
	}
	k.emit(EventAccepted, r, by, why, held.Versions+1)
	// What it changes and supersedes, each a new version of that record.
	for _, l := range r.Links {
		to, ok := l.To.Record()
		if !ok || (l.Kind != LinkSupersedes && l.Kind != LinkChanges) || (insight && hasLink(held.Current, l)) {
			continue
		}
		t, err := k.Store.Get(ctx, to)
		if err != nil || t == nil {
			k.logf("[mesh-knowledge] %s %s %s, which cannot be read now (%v): the whole-set rules will say so", r.Key(), l.Kind, to, err)
			continue
		}
		c := t.Current.Clone()
		var what string
		switch l.Kind {
		case LinkSupersedes:
			c.Status = StatusSuperseded
			c.Extra = addExtra(c.Extra, "superseded-by", r.Key().String())
			for i := range c.Clauses {
				c.Clauses[i].Status = ClauseSuperseded
				c.Clauses[i].ChangedBy = append(c.Clauses[i].ChangedBy, r.Key().String())
			}
			what = "superseded by " + r.Key().String()
		case LinkChanges:
			cl := c.Clause(l.To.Clause)
			if cl == nil || cl.Status == ClauseSuperseded {
				continue
			}
			cl.Status = ClauseChanged
			from := r.Key().String()
			if l.From > 0 {
				from += " §" + strconv.Itoa(l.From)
			}
			cl.ChangedBy = append(cl.ChangedBy, from)
			what = fmt.Sprintf("§%d changed by %s", l.To.Clause, from)
		}
		if err := k.Store.Save(ctx, Version{By: by, At: at, Why: what, Record: c}, true, false, t.Revision); err != nil {
			k.logf("[mesh-knowledge] %s could not be marked %s (%v): the whole-set rules will say so", to, what, err)
			continue
		}
		k.emit(EventChanged, c, by, what, t.Versions+1)
	}
	k.judgeSet(ctx)
	return r, nil
}

// judgeSet holds the whole record set to its 4 rules and keeps what fails, which the module's health answers.
func (k *KB) judgeSet(ctx context.Context) []Finding {
	all, err := k.Store.All(ctx)
	if err != nil {
		k.logf("[mesh-knowledge] the whole record set cannot be read to judge it: %v", err)
		return nil
	}
	records := make([]*Record, len(all))
	for i, e := range all {
		records[i] = e.Current
	}
	findings := JudgeSet(records)
	at := k.now()
	for i := range findings {
		findings[i].At = at
	}
	if err := k.Store.SetFindings(ctx, findings); err != nil {
		k.logf("[mesh-knowledge] the whole-set findings could not be kept: %v", err)
	}
	for _, f := range findings {
		k.logf("[mesh-knowledge] the whole-set rule %s fails: %s", f.Rule, f.Says)
	}
	return findings
}

// findingPrefix keys the notice of one whole-set finding: the prefix, the rule, and the records it names.
const findingPrefix = "knowledge.finding."

func findingKey(f Finding) string {
	names := make([]string, len(f.Records))
	for i, r := range f.Records {
		names[i] = strings.ReplaceAll(strings.ToLower(r), " ", "-")
	}
	return findingPrefix + f.Rule + "." + strings.Join(names, ".")
}

// TellFindings, called by the background work and never under the write lock, tells the operator, once, each finding of the rules that judge the whole record set, as a warning
// naming the rule and the records, and clears the notice once the rule holds for them again. A finding is a fault
// of the records, which their authors repair; it is not the module failing, so it leaves the module's health as it
// is and never holds the module's own rollouts (the operator's decision of 2026-10-12 on novox/hq issue 504, as
// issue 508 decided for a proposal never reviewed). A notice that cannot be sent is not kept as told, and is sent
// again at the next step.
func (k *KB) TellFindings() {
	if k.Notify == nil || k.Clear == nil {
		return
	}
	ctx := context.Background()
	findings, err := k.Store.Findings(ctx)
	if err != nil {
		k.logf("[mesh-knowledge] the whole-set findings cannot be read to tell them: %v", err)
		return
	}
	now := map[string]bool{}
	for _, f := range findings {
		key := findingKey(f)
		now[key] = true
		first, err := k.Store.Told(ctx, key)
		if err != nil || !first {
			continue
		}
		records := strings.Join(f.Records, ", ")
		summary := fmt.Sprintf("The rule %s, which judges the whole record set, fails: %s.", f.Rule, f.Says)
		explanation := "The knowledge base works; its records break a rule. The acceptance stands. The author of " + records +
			" repairs it: a decision cited by nothing names its home in a progressive insight (propose with homes and insight), " +
			"or a record that cites it is accepted. get and links show the record."
		resolved := fmt.Sprintf("The rule %s holds again for %s", f.Rule, records)
		if err := k.Notify(key, summary, "A rule of the record set fails: "+records, explanation, resolved); err != nil {
			k.logf("[mesh-knowledge] the operator could not be told that %s fails for %s: %v; told again at the next step", f.Rule, records, err)
			if uerr := k.Store.Untold(ctx, key); uerr != nil {
				k.logf("[mesh-knowledge] and that it was not told could not be kept: %v", uerr)
			}
		}
	}
	told, err := k.Store.ToldOf(ctx, findingPrefix)
	if err != nil {
		k.logf("[mesh-knowledge] the notices of whole-set findings cannot be read: %v", err)
		return
	}
	for _, key := range told {
		if now[key] {
			continue
		}
		if err := k.Clear(key, ""); err != nil {
			k.logf("[mesh-knowledge] the notice %s could not be cleared: %v; it is cleared again at the next step", key, err)
			continue
		}
		if err := k.Store.Untold(ctx, key); err != nil {
			k.logf("[mesh-knowledge] the notice %s was cleared, and that could not be kept: %v", key, err)
		}
	}
}

// ---- reservations that were never proposed -------------------------------------------------------------------

// Withdraw withdraws every number reserved longer ago than the settings allow and never proposed: it stays spent,
// with who reserved it and when.
func (k *KB) Withdraw() (int, error) {
	ctx := context.Background()
	k.mu.Lock()
	defer k.mu.Unlock()
	bound := DefaultReservedFor
	if s := strings.TrimSpace(k.settings().ReservedFor); s != "" {
		if d, err := time.ParseDuration(s); err == nil && d > 0 {
			bound = d
		}
	}
	all, err := k.Store.All(ctx)
	if err != nil {
		return 0, err
	}
	n := 0
	for _, e := range all {
		if e.Current.Status != StatusReserved || k.now().Sub(e.Current.ReservedAt) < bound {
			continue
		}
		r := e.Current.Clone()
		r.Status = StatusWithdrawn
		why := fmt.Sprintf("withdrawn: reserved by %s at %s and never proposed", r.ReservedBy, r.ReservedAt.Format(time.RFC3339))
		if err := k.Store.Save(ctx, Version{By: "the knowledge base", At: k.now(), Why: why, Record: r}, true, false, e.Revision); err != nil {
			return n, err
		}
		k.emit(EventChanged, r, "the knowledge base", why, e.Versions+1)
		n++
	}
	return n, nil
}