package asks

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"reflect"
	"strings"
	"testing"
	"time"
)

var now = time.Date(2026, 10, 8, 14, 0, 0, 0, time.UTC)

func held() Ask {
	return Ask{ID: "d-1", Headline: "openrazer delivery held", Explanation: "Needs you: release it, or stop it.",
		Who: Operator, Expires: now.Add(time.Hour), OnExpiry: "the delivery stays held", About: "delivery.openrazer",
		Options: []Option{
			{ID: "release", Label: "Release", Does: "the delivery goes on", Level: Approve, Binds: bind("release", "openrazer")},
			{ID: "stop", Label: "Stop", Does: "the delivery ends", Level: Approve, Binds: bind("stop", "openrazer")},
			{ID: "silence", Label: "Silence for a week", Does: "nothing more is said for a week", Level: Acknowledge},
		}}
}

func bind(verb, what string) string {
	d, err := ActDigest(Act{"verb": verb, "delivery": what})
	if err != nil {
		panic(err)
	}
	return d
}

func TestASoundAskPasses(t *testing.T) {
	if err := held().Check(now); err != nil {
		t.Fatal(err)
	}
}

func TestAnAskIsRefusedInWordsForEachFault(t *testing.T) {
	for want, change := range map[string]func(*Ask){
		"is not letters":             func(a *Ask) { a.ID = "a.b" },
		"headline is empty":          func(a *Ask) { a.Headline = "" },
		"explains nothing":           func(a *Ask) { a.Explanation = " " },
		"only the operator answers":  func(a *Ask) { a.Who = "agent" },
		"offers 0 options":           func(a *Ask) { a.Options = nil },
		"offers 5 options":           func(a *Ask) { a.Options = append(a.Options, a.Options[0], a.Options[1]) },
		"is offered twice":           func(a *Ask) { a.Options[1].ID = "release" },
		"does not say what it does":  func(a *Ask) { a.Options[0].Does = "" },
		"none of acknowledge":        func(a *Ask) { a.Options[0].Level = "admin" },
		"expires before it is asked": func(a *Ask) { a.Expires = now },
		"approves lasts at most":     func(a *Ask) { a.Expires = now.Add(25 * time.Hour) },
		"destroys lasts at most":     func(a *Ask) { a.Options[0].Level = Destroy },
		"never defaults":             func(a *Ask) { a.OnExpiry = "" },
		"is a key, without spaces":   func(a *Ask) { a.About = "a b" },
		"does not bind what it":      func(a *Ask) { a.Options[0].Binds = "" },
	} {
		a := held()
		change(&a)
		if err := a.Check(now); err == nil || !strings.Contains(err.Error(), want) {
			t.Errorf("want a refusal saying %q, got %v", want, err)
		}
	}
	ack := held()
	ack.Options = ack.Options[2:]
	ack.OnExpiry = ""
	ack.Expires = now.Add(7 * 24 * time.Hour)
	if err := ack.Check(now); err != nil {
		t.Errorf("an ask that only acknowledges needs no expiry words and may last a week: %v", err)
	}
}

func TestAnAskerActsOnlyOnAWarrantForItsOwnAskAndOption(t *testing.T) {
	w := Warrant{Ask: "d-1", Asker: "mesh-delivery", Outcome: OutcomeChosen, Option: "release", Label: "Release",
		Level: Approve, By: &Person{Who: Operator, Kind: "telegram", Identity: "42", Verified: "user id verified"},
		AskDigest: held().Digest(), At: now.Add(time.Minute)}
	if o, err := w.For("mesh-delivery", held()); err != nil || o.ID != "release" {
		t.Fatalf("a sound warrant was refused: %v", err)
	}
	if got := w.Says(); got != "the operator, via telegram (user id verified), chose Release" {
		t.Errorf("the warrant says %q", got)
	}
	for why, change := range map[string]func(*Warrant){
		"another asker": func(w *Warrant) { w.Asker = "mesh-controller" },
		"another ask":   func(w *Warrant) { w.Ask = "d-2" },
		"no choice":     func(w *Warrant) { w.Outcome = OutcomeExpired },
		"nobody":        func(w *Warrant) { w.By = nil },
		"not offered":   func(w *Warrant) { w.Option = "delete" },
		"a lower level": func(w *Warrant) { w.Level = Acknowledge },
		"another role":  func(w *Warrant) { w.By = &Person{Who: "agent"} },
		"no digest":     func(w *Warrant) { w.AskDigest = "" },
		"no time given": func(w *Warrant) { w.At = time.Time{} },
		"after expiry":  func(w *Warrant) { w.At = now.Add(2 * time.Hour) },
		"another ask's digest": func(w *Warrant) {
			other := held()
			other.Options[0].Binds = bind("release", "another")
			w.AskDigest = other.Digest()
		},
	} {
		c := w
		by := *w.By
		c.By = &by
		change(&c)
		if _, err := c.For("mesh-delivery", held()); err == nil {
			t.Errorf("a warrant with %s was acted on", why)
		}
	}
}

func TestTheSubjectsNameTheirPublisher(t *testing.T) {
	for got, want := range map[string]string{
		AskSubject("mesh-delivery"):         "mesh.seat.operator-channel.accept.ask.mesh-delivery",
		DecidedSubject("mesh-delivery"):     "mesh.seat.operator-channel.event.decided.mesh-delivery",
		ChannelSubject(Show, "telegram"):    "mesh.seat.channel.accept.show.telegram",
		IntakeSubject(Chosen, "desktop"):    "mesh.seat.intake.event.choice.desktop",
		ProofSubject(CodeProof, "telegram"): "mesh.seat.intake.proof.code.telegram",
	} {
		if got != want {
			t.Errorf("%s, want %s", got, want)
		}
	}
}

// A warrant answers one ask as it was shown, and authorises the act its option bound and no other
// (novox/hq ADR 0259 §6: the warrant is bound to the exact ask and its arguments).
func TestAWarrantAuthorisesOnlyTheActItsOptionBound(t *testing.T) {
	a := held()
	// The digest survives the trip through the bus: what the router decodes and digests is what was sent.
	raw, err := json.Marshal(a)
	if err != nil {
		t.Fatal(err)
	}
	var decoded Ask
	if err := json.Unmarshal(raw, &decoded); err != nil {
		t.Fatal(err)
	}
	if decoded.Digest() != a.Digest() {
		t.Fatalf("the ask's digest changed on the way: %s, %s", decoded.Digest(), a.Digest())
	}
	local := a
	local.Expires = a.Expires.In(time.FixedZone("CEST", 2*3600))
	if local.Digest() != a.Digest() {
		t.Error("the same instant in another zone digests differently")
	}
	// Changing anything the person was shown, or what an option binds, changes the digest.
	for what, change := range map[string]func(*Ask){
		"the headline":     func(a *Ask) { a.Headline += "!" },
		"the explanation":  func(a *Ask) { a.Explanation += " " },
		"a label":          func(a *Ask) { a.Options[0].Label = "Go" },
		"what it binds":    func(a *Ask) { a.Options[0].Binds = bind("release", "another") },
		"the expiry":       func(a *Ask) { a.Expires = a.Expires.Add(time.Second) },
		"what it is about": func(a *Ask) { a.About = "delivery.other" },
	} {
		c := held()
		change(&c)
		if c.Digest() == a.Digest() {
			t.Errorf("changing %s leaves the digest", what)
		}
	}
	o, _ := a.Option("release")
	if err := o.Performs(Act{"verb": "release", "delivery": "openrazer"}); err != nil {
		t.Errorf("the bound act was refused: %v", err)
	}
	if err := o.Performs(Act{"verb": "release", "delivery": "another"}); err == nil {
		t.Error("an act the option did not bind was let through")
	}
	ack, _ := a.Option("silence")
	if err := ack.Performs(Act{"anything": "x"}); err != nil {
		t.Errorf("an acknowledgement that bound nothing: %v", err)
	}
}

// The digests are over named fields in a canonical encoding (the review of 2026-10-09): not over Go's
// encoding of a struct, so a field added to Ask or Option, a JSON tag renamed, or a map built in another
// order changes nothing it should not — and every field that is shown or bound is in it.
func TestDigestsAreCanonicalOverNamedFields(t *testing.T) {
	a1, _ := ActDigest(Act{"verb": "release", "arg.delivery": "hq"})
	b := Act{}
	b["arg.delivery"] = "hq"
	b["verb"] = "release"
	a2, _ := ActDigest(b)
	if a1 != a2 {
		t.Error("the order an act was built in changed its digest")
	}
	// A value cannot be read as two: "a"+"b=c" is not "a=b"+"c".
	x, _ := ActDigest(Act{"a": "b\n1:c"})
	y, _ := ActDigest(Act{"a": "b", "c": ""})
	if x == y {
		t.Error("two different acts encode the same")
	}
	if _, err := ActDigest(Act{}); err == nil {
		t.Error("an empty act was digested")
	}
	// The encoding, by hand: any language reproduces it.
	sum := sha256.Sum256([]byte("novox.act.v1\n4:verb\n7:release\n"))
	if got, _ := ActDigest(Act{"verb": "release"}); got != "sha256:"+hex.EncodeToString(sum[:]) {
		t.Errorf("the act's encoding is not the one written down: %s", got)
	}

	// Every exported field of Ask and Option is in the digest: changing any one changes it.
	base := held()
	mutations := map[string]func(*Ask){
		"ID":          func(a *Ask) { a.ID = "other" },
		"Headline":    func(a *Ask) { a.Headline += "!" },
		"Explanation": func(a *Ask) { a.Explanation += "!" },
		"Who":         func(a *Ask) { a.Who = "someone" },
		"Expires":     func(a *Ask) { a.Expires = a.Expires.Add(time.Nanosecond) },
		"OnExpiry":    func(a *Ask) { a.OnExpiry += "!" },
		"About":       func(a *Ask) { a.About += "!" },
		"Urgent":      func(a *Ask) { a.Urgent = !a.Urgent },
		"Options":     func(a *Ask) { a.Options = a.Options[:1] },
		"Option.ID":   func(a *Ask) { a.Options = append([]Option(nil), a.Options...); a.Options[0].ID = "x" },
		"Option.Label": func(a *Ask) {
			a.Options = append([]Option(nil), a.Options...)
			a.Options[0].Label += "!"
		},
		"Option.Does": func(a *Ask) { a.Options = append([]Option(nil), a.Options...); a.Options[0].Does += "!" },
		"Option.Level": func(a *Ask) {
			a.Options = append([]Option(nil), a.Options...)
			a.Options[0].Level = Destroy
		},
		"Option.Binds": func(a *Ask) {
			a.Options = append([]Option(nil), a.Options...)
			a.Options[0].Binds = "sha256:00"
		},
	}
	for name, mutate := range mutations {
		c := base
		mutate(&c)
		if c.Digest() == base.Digest() {
			t.Errorf("changing %s left the digest the same", name)
		}
	}
	// Whole and Details (issue 383) are in the digest once given, and change it; an ask without either digests
	// exactly as before they existed — the encoding by hand, so no build can drift from it unseen.
	plain := Ask{ID: "p", Headline: "h", Explanation: "e", Who: Operator, Expires: now, OnExpiry: "o", About: "a",
		Options: []Option{{ID: "ok", Label: "OK", Does: "d", Level: Acknowledge}}}
	byHand := sha256.Sum256([]byte("novox.ask.v1\n1:p\n1:h\n1:e\n8:operator\n20:2026-10-08T14:00:00Z\n1:o\n1:a\n5:false\n1:1\n" +
		"2:ok\n2:OK\n1:d\n11:acknowledge\n0:\n"))
	if plain.Digest() != "sha256:"+hex.EncodeToString(byHand[:]) {
		t.Errorf("an ask without Whole and Details does not digest as it did before them: %s", plain.Digest())
	}
	withWhole, withDetails := plain, plain
	withWhole.Whole = "e, whole"
	withDetails.Details = "fingerprint 1234"
	if withWhole.Digest() == plain.Digest() || withDetails.Digest() == plain.Digest() || withWhole.Digest() == withDetails.Digest() {
		t.Error("Whole or Details left the digest the same")
	}
	both := withWhole
	both.Details = "fingerprint 1234"
	changed := both
	changed.Whole += "!"
	if changed.Digest() == both.Digest() {
		t.Error("changing Whole beside Details left the digest the same")
	}
	// A field added to Ask or Option without being added to Digest fails here.
	if n := reflect.TypeOf(Ask{}).NumField(); n != 11 {
		t.Errorf("Ask has %d fields, and Digest covers 11: add the new one to Digest and to this test", n)
	}
	if n := reflect.TypeOf(Option{}).NumField(); n != 5 {
		t.Errorf("Option has %d fields, and Digest covers 5: add the new one to Digest and to this test", n)
	}
	// The same instant in another zone is the same ask.
	z := base
	z.Expires = z.Expires.In(time.FixedZone("x", 3600))
	if z.Digest() != base.Digest() {
		t.Error("the expiry's zone changed the digest")
	}
}

// An ask that says no expiry is answered by no warrant (the confirmation review of 2026-10-09): nothing could
// show the answer was in time.
func TestAWarrantForAnAskWithNoExpiryIsRefused(t *testing.T) {
	a := held()
	a.Expires = time.Time{}
	w := Warrant{Ask: "d-1", Asker: "mesh-delivery", Outcome: OutcomeChosen, Option: "release", Label: "Release",
		Level: Approve, By: &Person{Who: Operator, Kind: "telegram", Identity: "42"}, AskDigest: a.Digest(),
		At: now.Add(time.Minute)}
	if _, err := w.For("mesh-delivery", a); err == nil {
		t.Error("a warrant for an ask with no expiry was taken")
	}
}