package health

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

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

// ADR 0564 clause 3 (issue 1952 S2): the bodies of condition-raised, condition-changed and condition-cleared read the
// events the live controller said unchanged. testdata/condition-events.json holds five transitions of the controller's
// condition history (mesh-controller_condition-history, whose entries are the events' bodies, events.go Event), captured
// on 2026-10-29 with `mesh-controller.conditions history=true days=1`: a raising, a reopening with gaps, a resolver and a
// severity change with tried and was, and a clearing with why. Never written by hand.
func TestTheControllersConditionEventsReadUnchanged(t *testing.T) {
	raw, err := os.ReadFile("testdata/condition-events.json")
	if err != nil {
		t.Fatal(err)
	}
	var captured []json.RawMessage
	if err := json.Unmarshal(raw, &captured); err != nil {
		t.Fatal(err)
	}
	changes := map[string]bool{}
	for _, body := range captured {
		var e Event
		if err := json.Unmarshal(body, &e); err != nil {
			t.Fatalf("%s: %v", body, err)
		}
		changes[e.Change] = true
		again, err := json.Marshal(e)
		if err != nil {
			t.Fatal(err)
		}
		var want, got map[string]any
		_ = json.Unmarshal(body, &want)
		_ = json.Unmarshal(again, &got)
		if !reflect.DeepEqual(want, got) {
			t.Errorf("the controller's %s of %s reads back as\n%s\nnot\n%s", e.Change, e.Key, again, body)
		}
		if EventFor(e.Change) != e.Event || e.Key != Key(e.Subject.Scope, e.Subject.ID, e.Key[strings.LastIndex(e.Key, ".")+1:]) {
			t.Errorf("%s: said as %s for a %s, or its key is not its subject's", e.Key, e.Event, e.Change)
		}
	}
	for _, c := range []string{ChangeRaised, ChangeReopened, ChangeResolver, ChangeSeverity, ChangeCleared} {
		if !changes[c] {
			t.Errorf("no captured %s", c)
		}
	}
	// The keeper's own body (Limits 9, 10): epoch 0, said and not left out, silenced null, and its show and silence
	// naming the new seat.
	c := Condition{Key: "machine.g14.silent", Actions: []Action{SilenceAction("machine.g14.silent")}}
	b, _ := json.Marshal(Event{Condition: c, Event: EventRaised, Change: ChangeRaised, Show: ShowKeeper(c.Key)})
	for _, says := range []string{`"epoch":0`, `"silenced":null`, `"show":"mesh-conditions.conditions key=machine.g14.silent"`,
		`"verb":"mesh-conditions.silence"`} {
		if !strings.Contains(string(b), says) {
			t.Errorf("the keeper's body %s does not say %s", b, says)
		}
	}
}

// ADR 0564 clauses 2, 7, 8, 9 (issue 1952 S3, S4): the layouts between the observers, the healers and the keeper, and the
// take-over key the readers follow.
func TestTheHealthLayoutsHoldTheKeepersRules(t *testing.T) {
	at := time.Date(2026, 10, 29, 12, 0, 0, 0, time.UTC)
	// ADR 0571 clause 3: a reading keeps its seven-day peak and is written only when it changes; a partial size is no peak.
	var prev *Reading
	for i, step := range []struct {
		day, size      int64
		partial, wrote bool
		peak           int64
	}{{20, 100, false, true, 100}, {20, 100, false, false, 100}, {21, 300, false, true, 300}, {22, 50, false, true, 300},
		{23, 9000, true, true, 300}, {29, 10, false, true, 50}, {30, 10, false, true, 10}} {
		now := time.Date(2026, 10, int(step.day), 1, 0, 0, 0, time.UTC)
		size := step.size
		m := Measured{SizeBytes: &size, MeasuredAt: &now, Precision: "exact"}
		if step.partial {
			m.Precision = "partial: stopped"
		}
		r, wrote := NextReading(prev, "ace", catalogue.PlacedDataItem{Module: "pg", ID: "data", Path: "/srv/pg"}, m, now)
		raw, _ := json.Marshal(r)
		back, err := DecodeReading(raw)
		if wrote != step.wrote || r.Peak == nil || *r.Peak != step.peak || err != nil || back.ID != "data" {
			t.Fatalf("reading %d: wrote %v, peak %v, read back %v", i, wrote, r.Peak, err)
		}
		prev = &r
	}
	// The first reading sets FirstSeen and every one after keeps it, as it keeps a retirement; an older reading reads as before.
	if first := time.Date(2026, 10, 20, 1, 0, 0, 0, time.UTC); !prev.FirstSeen.Equal(first) {
		t.Fatalf("first seen %s, not %s", prev.FirstSeen, first)
	}
	retired := *prev
	retired.RetiredAt, retired.RetiredWhy = at, "its module left ace"
	if r, _ := NextReading(&retired, "ace", retired.PlacedDataItem, retired.Measured, at.Add(time.Hour)); !r.RetiredAt.Equal(at) ||
		r.RetiredWhy != "its module left ace" || !r.FirstSeen.Equal(prev.FirstSeen) {
		t.Fatalf("a retired reading moved on as %+v", r)
	}
	if old, err := DecodeReading([]byte(`{"v":1,"node":"ace","module":"pg","item":"data"}`)); err != nil || !old.FirstSeen.IsZero() {
		t.Fatalf("a reading of before read as %+v: %v", old, err)
	}
	if raw, _ := json.Marshal(Reading{V: ReadingVersion}); strings.Contains(string(raw), "first_seen") || strings.Contains(string(raw), "retired") {
		t.Fatalf("zero fields were written: %s", raw)
	}
	if ReadingKey("ace", "pg", "data") != "ace.pg.data" || ReadingsBucket != "disk-load_readings" {
		t.Fatal("the readings' key or bucket moved")
	}
	// And restic's last good night per item, keyed as a reading.
	goodRow, _ := json.Marshal(GoodRow{V: GoodVersion, Node: "ace", Module: "pg", Item: "data", CoveredBy: "/srv/pg", LastGood: at})
	if g, err := DecodeGoodRow(goodRow); err != nil || !g.LastGood.Equal(at) || GoodKey("ace", "pg", "data") != "ace.pg.data" ||
		GoodBucket != "restic_good" || GoodRead != "restic.good" {
		t.Fatalf("a last good night read back as %+v: %v", g, err)
	}
	if _, err := DecodeGoodRow([]byte(`{"v":2}`)); err == nil {
		t.Fatal("a last good night of another version was read")
	}
	good := Finding{Key: "provider.keycloak.ace.mesh-mail.failing", Kind: "provider-failing", Token: "failing",
		Subject:  Subject{Scope: ScopeProvider, ID: "keycloak.ace.mesh-mail", Machine: "ace"},
		Severity: Warning, Summary: "keycloak on ace fails mesh-mail", Source: "S8", Observer: WatchmanModule, At: at}
	for _, c := range []struct {
		name  string
		edit  func(*Finding)
		fails string
	}{
		{name: "a finding keyed by the controller's key rule"},
		// The key rule is the controller's (condition.go Key): a character the bus refuses becomes `_`, so the finding
		// and the condition it raises share one key.
		{name: "an unsafe id", edit: func(f *Finding) {
			f.Subject.ID, f.Key = "keycloak.ace.mesh mail*", "provider.keycloak.ace.mesh_mail_.failing"
		}},
		{name: "a key not its parts'", edit: func(f *Finding) { f.Key = "provider.keycloak.failing" }, fails: "not"},
		{name: "an unknown scope", edit: func(f *Finding) { f.Subject.Scope = "thing" }, fails: "scope"},
		{name: "no severity", edit: func(f *Finding) { f.Severity = "" }, fails: "urgent or a warning"},
		{name: "no observer", edit: func(f *Finding) { f.Observer = "" }, fails: "observer"},
		{name: "eleven observations", edit: func(f *Finding) { f.Evidence = make([]Evidence, KeptEvidence+1) }, fails: "at most"},
	} {
		f := good
		if c.edit != nil {
			c.edit(&f)
		}
		b, err := EncodeFinding(f)
		if c.fails != "" {
			if err == nil || !strings.Contains(err.Error(), c.fails) {
				t.Errorf("%s: encoded (%v), want refused saying %q", c.name, err, c.fails)
			}
			continue
		}
		back, err := DecodeFinding(b)
		if err != nil || back.Key != f.Key || back.V != FindingVersion || back.Evidence == nil {
			t.Errorf("%s: read back as %+v, %v", c.name, back, err)
		}
	}
	if FindingsBucket(SelfCheckModule) != "mesh-self-check_findings" || Bucket(HealersModule, AttemptsState) != "mesh-healers_attempts" ||
		Bucket(KeeperModule, TakeoverState) != "mesh-conditions_takeover" {
		t.Errorf("the buckets are named %s, %s", FindingsBucket(SelfCheckModule), Bucket(HealersModule, AttemptsState))
	}

	// An attempt reaches the condition's tried as the controller wrote it: by the healer, its outcome and what it said.
	if tr := (Attempt{Healer: "H3", Act: "asserted the grants", Outcome: OutcomeEscalated, Said: "budget spent", Begun: at}).Tried(); tr !=
		(Tried{At: at, What: "asserted the grants", Outcome: "escalated: budget spent", By: "healer H3"}) {
		t.Errorf("an attempt is tried as %+v", tr)
	}

	// The take-over key (clause 9): absent follows the controller; the keeper's names who chose; anything else refused.
	for _, c := range []struct {
		raw          string
		found        bool
		seat, events string
		fails        bool
	}{
		{found: false, seat: "mesh-controller", events: "mesh-controller.doctor-heartbeat"},
		{raw: `{"v":1,"follow":"controller","by":"the operator"}`, found: true, seat: "mesh-controller", events: "mesh-controller.doctor-heartbeat"},
		{raw: `{"v":1,"follow":"keeper","by":"the operator","ask":"ask-1"}`, found: true, seat: "mesh-conditions", events: "mesh-self-check.checked"},
		{raw: `{"v":1,"follow":"keeper"}`, found: true, fails: true},
		{raw: `{"v":1,"follow":"both","by":"x"}`, found: true, fails: true},
		{raw: `{"v":2,"follow":"keeper","by":"x"}`, found: true, fails: true},
	} {
		got, err := DecodeTakeover([]byte(c.raw), c.found)
		if c.fails != (err != nil) {
			t.Errorf("%q: read as %+v, %v", c.raw, got, err)
			continue
		}
		if c.fails {
			continue
		}
		seat, event := got.SelfCheckEvent()
		if got.Seat() != c.seat || seat+"."+event != c.events {
			t.Errorf("%q follows %s and %s.%s", c.raw, got.Seat(), seat, event)
		}
		if b, err := EncodeTakeover(got); err != nil || !strings.Contains(string(b), `"v":1`) {
			t.Errorf("%q encodes as %s, %v", c.raw, b, err)
		}
	}
}