package main

import (
	"encoding/json"
	"errors"
	"reflect"
	"strings"
	"testing"
	"time"

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

// overviewWorld is a page model over the sources played here: what each verb answers, and what fails.
type overviewWorld struct {
	o       *Overview
	now     time.Time
	answers map[string]string
	fail    map[string]bool
	entries []*Entry
}

func newOverviewWorld(t *testing.T) *overviewWorld {
	t.Helper()
	w := &overviewWorld{now: time.Date(2026, 11, 4, 12, 0, 0, 0, time.UTC), fail: map[string]bool{}, answers: map[string]string{
		TrackerMilestonesVerb: `{"milestones":[{"design":47,"id":"1","outcome":"A merge is never dropped","status":"open","issues":[973,525]},{"design":47,"id":"2","outcome":"Done thing","status":"done","issues":[1]}]}`,
		TrackerListVerb:       `[{"number":973,"title":"The window","status":"fixing"},{"number":525,"title":"The queue","status":"open"}]`,
		DeliveryGroupsVerb:    `[{"id":"fix/a","state":"held","why":"a member is held","members":["x@1"]}]`,
		AsksVerb:              `{"asks":[{"key":"mesh-knowledge.1","asker":"mesh-knowledge","headline":"Approve ADR 0301","state":"open","offered_on":["telegram"]},{"key":"ask-0","asker":"x","headline":"old","state":"answered"}]}`,
	}}
	w.o = NewOverview(func(key string, body any) (json.RawMessage, error) {
		if w.fail[key] {
			return nil, errors.New("no answer in time")
		}
		return json.RawMessage(w.answers[key]), nil
	}, func() ([]*Entry, error) { return w.entries, nil }, func() time.Time { return w.now })
	return w
}

func recordEntry(n int, status, date string, accepted time.Time, mut func(*Record)) *Entry {
	r := &Record{Kind: KindDecision, Number: n, Title: "Record " + itoa(n), Status: status, Date: date, AcceptedAt: accepted}
	if mut != nil {
		mut(r)
	}
	return &Entry{Current: r, CurrentVersion: 1, Versions: 1}
}

// The page's model (ADR 0616 §1-3, AC P1): three blocks built from the ledger, the tracker's milestones and issues, the delivery
// groups and the operator channel's asks; events change the blocks and ask no verb; a record accepted eight days before the
// answer is not in the seven-day block, with no event between.
func TestThePageModelHasThreeBlocksKeptByEventsAndAsksNoVerbAgain(t *testing.T) {
	w := newOverviewWorld(t)
	w.entries = []*Entry{
		recordEntry(301, StatusAccepted, "2026-11-02", w.now.Add(-2*24*time.Hour), nil),
		recordEntry(302, StatusAccepted, "2026-10-20", w.now.Add(-6*24*time.Hour-23*time.Hour), nil),
		recordEntry(303, StatusProposed, "2026-11-04", time.Time{}, func(r *Record) {
			r.NeedsOperator = true
			r.Ask = &OperatorAsk{ID: "a", Said: "waiting"}
		}),
		recordEntry(304, StatusProposed, "2026-11-04", time.Time{}, nil),
	}
	w.o.Start()
	m, err := w.o.Model()
	if err != nil {
		t.Fatal(err)
	}
	if len(m.Designs) != 1 || m.Designs[0].ID != "1" || len(m.Designs[0].Issues) != 2 || m.Designs[0].Issues[0].Title != "The window" {
		t.Fatalf("the design block: %+v", m.Designs)
	}
	if len(m.Accepted) != 2 || len(m.Waiting) != 2 || len(m.Operator.Records) != 1 || m.Operator.Records[0].Record != "ADR 0303" ||
		len(m.Operator.Asks) != 1 || m.Operator.Asks[0].Key != "mesh-knowledge.1" || len(m.Operator.Groups) != 1 {
		t.Fatalf("%+v", m)
	}
	asked := map[string]int{}
	for _, v := range []string{TrackerMilestonesVerb, TrackerListVerb, DeliveryGroupsVerb, AsksVerb} {
		asked[v] = w.o.Calls(v)
	}
	// Events change the blocks.
	w.o.Heard(SourceDelivery, "mesh-delivery-gate.group", json.RawMessage(`{"group":"fix/b","state":"checking","members":["y@2"]}`))
	w.o.Heard(SourceDelivery, "mesh-delivery-gate.transition", json.RawMessage(`{"group":"fix/a","to":"approved"}`))
	w.o.Heard(SourceAsks, "messenger.offered", json.RawMessage(`{"id":"2","asker":"mesh-delivery","headline":"Approve the group","channels":["telegram"]}`))
	w.o.Heard(SourceTracker, "mesh-issues.opened", json.RawMessage(`{"number":1999,"title":"New","status":"open"}`))
	w.o.Heard(SourceTracker, "mesh-issues.milestone-moved", json.RawMessage(`{"design":47,"id":"1","to":"done","issues":[973,525,1999]}`))
	m, _ = w.o.Model()
	if len(m.Operator.Groups) != 2 || m.Operator.Groups[0].State != "approved" || len(m.Operator.Asks) != 2 || len(m.Designs) != 0 {
		t.Fatalf("after the events: %+v", m)
	}
	w.o.Heard(SourceDelivery, "mesh-delivery-gate.merged", json.RawMessage(`{"group":"fix/a"}`))
	w.o.Heard(SourceAsks, "messenger.closed", json.RawMessage(`{"id":"1","asker":"mesh-knowledge","how":"answered"}`))
	m, _ = w.o.Model()
	if len(m.Operator.Groups) != 1 || m.Operator.Groups[0].ID != "fix/b" || len(m.Operator.Asks) != 1 || m.Operator.Asks[0].Key != "mesh-delivery.2" {
		t.Fatalf("after merged and closed: %+v", m.Operator)
	}
	for v, n := range asked {
		if w.o.Calls(v) != n {
			t.Errorf("%s was asked again by an event", v)
		}
	}
	// The seven days are counted when the answer is given: no event between, the record falls out of the block.
	w.now = w.now.Add(2 * 24 * time.Hour)
	m, _ = w.o.Model()
	if len(m.Accepted) != 1 || m.Accepted[0].Record != "ADR 0301" {
		t.Fatalf("the seven-day block: %+v", m.Accepted)
	}
}

// A source that does not answer says so, never as an empty list (ADR 0616 §5, §6; AC P3): from its verb, on a bounded backoff
// asked again alone, its first answer clearing the mark; from its subscription, asking nothing while it is silent and the verb once on its
// next event; the model as a tool equals the page's model; the re-read tool asks one source and records the hand act.
func TestASourceThatDoesNotAnswerIsSaidAndAskedAgainOnABackoff(t *testing.T) {
	w := newOverviewWorld(t)
	w.fail[DeliveryGroupsVerb] = true
	w.o.Start()
	m, _ := w.o.Model()
	var delivery SourceState
	for _, s := range m.Sources {
		if s.Name == SourceDelivery {
			delivery = s
		}
	}
	if delivery.Answered || delivery.Mark == nil || delivery.Mark.Cause != MarkVerb || len(m.Operator.Groups) != 0 || !strings.Contains(delivery.Mark.Why, "no answer in time") {
		t.Fatalf("%+v", delivery)
	}
	if len(m.Designs) != 1 {
		t.Fatalf("another source's block was lost: %+v", m.Designs)
	}
	// Asked again on the backoff alone: 10 s, then doubling, at most 5 minutes; no other source is asked.
	calls := w.o.Calls(DeliveryGroupsVerb)
	if got := w.o.Due(); len(got) != 0 {
		t.Fatalf("asked before the backoff ran out: %v", got)
	}
	var waits []time.Duration
	for i := 0; i < 8; i++ {
		before := w.now
		w.now = w.o.state[SourceDelivery].Mark.Next
		waits = append(waits, w.now.Sub(before))
		if got := w.o.Due(); len(got) != 1 || got[0] != SourceDelivery {
			t.Fatalf("%v", got)
		}
	}
	if waits[0] != BackoffFrom || waits[1] != 2*BackoffFrom || waits[7] != BackoffMost || w.o.Calls(DeliveryGroupsVerb) != calls+8 || w.o.Calls(AsksVerb) != 1 {
		t.Fatalf("waits %v, delivery asked %d, asks asked %d", waits, w.o.Calls(DeliveryGroupsVerb), w.o.Calls(AsksVerb))
	}
	// Its first answer rebuilds the block and clears the mark.
	w.fail[DeliveryGroupsVerb] = false
	w.now = w.o.state[SourceDelivery].Mark.Next
	w.o.Due()
	m, _ = w.o.Model()
	if len(w.o.Unanswered()) != 0 || len(m.Operator.Groups) != 1 {
		t.Fatalf("%+v", m)
	}
	// A subscription that goes silent marks the source from the subscription and asks nothing while it is silent.
	asked := w.o.Calls(AsksVerb)
	w.now = w.now.Add(HeartbeatWithin + time.Second)
	if got := w.o.Silent(); len(got) != 3 {
		t.Fatalf("%v", got)
	}
	if got := w.o.Due(); len(got) != 0 || w.o.Calls(AsksVerb) != asked {
		t.Fatalf("a silent subscription was asked: %v", got)
	}
	if u := w.o.Unanswered(); len(u) != 3 || u[0].Mark.Cause != MarkSubscription {
		t.Fatalf("%+v", u)
	}
	// Its next event (or heartbeat) makes the module ask the verb once, and that answer clears the mark.
	w.o.Heard(SourceAsks, "messenger.offered", json.RawMessage(`{"id":"9","asker":"x","headline":"x"}`))
	if w.o.Calls(AsksVerb) != asked+1 || w.o.state[SourceAsks].Mark != nil {
		t.Fatalf("asked %d, mark %+v", w.o.Calls(AsksVerb), w.o.state[SourceAsks].Mark)
	}
	// An unanswered verb then turns the mark into one from the verb.
	w.fail[DeliveryGroupsVerb] = true
	w.o.Heard(SourceDelivery, "", nil)
	if mk := w.o.state[SourceDelivery].Mark; mk == nil || mk.Cause != MarkVerb {
		t.Fatalf("%+v", mk)
	}
	// The runtime's word on the module's consumer (stdio.OnHeartbeat): a missed heartbeat marks every subscribed source
	// at once, before the bound passes, with the runtime's why; the next beat asks each verb once and clears the marks.
	w.fail[DeliveryGroupsVerb] = false
	w.now = w.o.state[SourceDelivery].Mark.Next
	w.o.Due()
	asked = w.o.Calls(AsksVerb)
	w.o.Beat(stdio.Heartbeat{At: w.now, Missed: true, Why: "the bus's heartbeat stopped arriving"})
	if u := w.o.Unanswered(); len(u) != 3 || u[0].Mark.Cause != MarkSubscription || !strings.Contains(u[0].Mark.Why, "stopped arriving") {
		t.Fatalf("a missed heartbeat marked %+v", u)
	}
	w.o.Beat(stdio.Heartbeat{At: w.now})
	if len(w.o.Unanswered()) != 0 || w.o.Calls(AsksVerb) != asked+1 {
		t.Fatalf("a beat left %+v, asks asked %d", w.o.Unanswered(), w.o.Calls(AsksVerb)-asked)
	}
	// A beat keeps a quiet source from being marked silent: it is heard, not silent.
	w.now = w.now.Add(HeartbeatWithin - time.Second)
	w.o.Beat(stdio.Heartbeat{At: w.now})
	w.now = w.now.Add(2 * time.Second)
	if got := w.o.Silent(); len(got) != 0 {
		t.Fatalf("a source heard by its beat was marked silent: %v", got)
	}
}

func TestThePagesModelIsAToolAndItsRereadIsAHandAct(t *testing.T) {
	w := newOverviewWorld(t)
	w.entries = []*Entry{recordEntry(301, StatusAccepted, "2026-11-02", w.now.Add(-24*time.Hour), nil)}
	w.o.Start()
	var acts []string
	k := &KB{Overview: w.o, Seats: func(key string, body any) (json.RawMessage, error) {
		acts = append(acts, key)
		return json.RawMessage(`{}`), nil
	}, Now: func() time.Time { return w.now }}
	var tools []toolRun
	for _, tool := range moduleTools(k, callerOf) {
		tools = append(tools, toolRun{tool.Name, tool.Run})
	}
	got, err := callTool(t, tools, OverviewTool, map[string]any{})
	want, _ := w.o.Model()
	raw, _ := json.Marshal(want)
	var wantMap map[string]any
	_ = json.Unmarshal(raw, &wantMap)
	if err != nil || !reflect.DeepEqual(got, wantMap) {
		t.Fatalf("the tool's answer is not the page's model: %v", err)
	}
	// The re-read asks the one source and no other, and records itself.
	before := map[string]int{}
	for _, v := range []string{TrackerListVerb, DeliveryGroupsVerb, AsksVerb} {
		before[v] = w.o.Calls(v)
	}
	w.fail[AsksVerb] = true
	res, err := callTool(t, tools, RereadTool, map[string]any{"source": SourceAsks, "why": "the page showed it stale"})
	if err != nil || res["answered"] != false || w.o.Calls(AsksVerb) != before[AsksVerb]+1 || w.o.Calls(DeliveryGroupsVerb) != before[DeliveryGroupsVerb] || w.o.Calls(TrackerListVerb) != before[TrackerListVerb] {
		t.Fatalf("%v %v", err, res)
	}
	if len(acts) != 1 || acts[0] != "seat:mesh-hand-acts.hand-act" {
		t.Fatalf("the hand act: %v", acts)
	}
	if _, err := callTool(t, tools, RereadTool, map[string]any{"source": "nobody"}); err == nil {
		t.Fatal("a source the page lacks was re-read")
	}
	// The health carries the page: degraded while a source is unanswered, healthy.
	h := k.pageHealth(HealthAnswer{State: "healthy", Healthy: true, Why: "ok"})
	if !h.Healthy || !strings.Contains(h.Why, "overview page is degraded") || !strings.Contains(h.Why, SourceAsks) {
		t.Fatalf("%+v", h)
	}
}