package catalogue

import (
	"encoding/json"
	"strings"
	"testing"
)

// Each test names the decision it defends: novox/hq ADR 0225, which refines ADR 0049 after issue 263.

// The provision a module requires sets the bound on its identity, not the tightest backend anywhere.
func TestABoundIsTheProvisionsOwn(t *testing.T) {
	store := Manifest{Module: "objects", Provides: []Offer{{Name: "s3-bucket", Scope: ScopeMesh,
		Identity: &OfferIdentity{Max: 20, In: "an S3 access key"}}},
		Receives: map[string]string{"s3-bucket": "/var/lib/mesh/objects/mesh.json"}}
	database := Manifest{Module: "db", Provides: []Offer{{Name: "postgres-database", Scope: ScopeMesh,
		Identity: &OfferIdentity{Max: 63, In: "a PostgreSQL role"}}},
		Receives: map[string]string{"postgres-database": "/var/lib/mesh/db/mesh.json"}}
	if b := store.IdentityBoundOf("s3-bucket"); b.Max != 20 || b.In != "an S3 access key" {
		t.Errorf("an object store's stated bound was not taken: %+v", b)
	}
	if b := database.IdentityBoundOf("postgres-database"); b.Max != 63 {
		t.Errorf("a database's stated bound was not taken: %+v", b)
	}
	// mesh_workstation_keycloak is 25: refused by the object store, accepted by the database.
	if CheckIdentityWithin("workstation", "keycloak", store.IdentityBoundOf("s3-bucket")) == nil {
		t.Error("a 25-character identity fit a 20-character access key")
	}
	if err := CheckIdentityWithin("workstation", "keycloak", database.IdentityBoundOf("postgres-database")); err != nil {
		t.Errorf("a database consumer paid the object store's limit: %v", err)
	}
}

// What an offer leaves unsaid follows from whether its provider can keep a name at all.
func TestAnUnstatedBoundFollowsWhatTheProviderIsTold(t *testing.T) {
	// Told nothing about its consumers — no receives, nothing served from their identity: no bound.
	// The resolver provision is exactly this, and its consumers paid an object store's limit (263).
	resolver := Manifest{Module: "resolver", Provides: []Offer{{Name: "wildcard-resolution", Scope: ScopeMesh}}}
	if b := resolver.IdentityBoundOf("wildcard-resolution"); b.Bounded() {
		t.Errorf("a provision that is told nothing of its consumers bounds them: %+v", b)
	}
	// Told each consumer and silent about its backend: the old global bound, not none.
	told := Manifest{Module: "told", Provides: []Offer{{Name: "thing", Scope: ScopeMesh}},
		Receives: map[string]string{"thing": "/var/lib/mesh/told/mesh.json"}}
	if b := told.IdentityBoundOf("thing"); b.Max != DefaultIdentityLimit {
		t.Errorf("a provider told its consumers and silent about its backend is not held to %d: %+v",
			DefaultIdentityLimit, b)
	}
	// Serving a value built from the identity is being told it, too.
	serving := Manifest{Module: "serving", Provides: []Offer{{Name: "bucket", Scope: ScopeMesh}},
		Serves: map[string]map[string]any{"bucket": {"name": "b-${consumer:as:dns}"}}}
	if b := serving.IdentityBoundOf("bucket"); b.Max != DefaultIdentityLimit {
		t.Errorf("a provider deriving a name from its consumers is not bounded: %+v", b)
	}
	// And `false` says it outright, even for a provider that receives.
	routes := Manifest{Module: "routes", Provides: []Offer{{Name: "route", Scope: ScopeMesh,
		Identity: &OfferIdentity{None: true}}},
		Receives: map[string]string{"route": "/var/lib/mesh/routes/mesh.json"}}
	if b := routes.IdentityBoundOf("route"); b.Bounded() {
		t.Errorf("`identity: false` still bounds: %+v", b)
	}
}

// The field reads as written and writes back the same, and refuses what says nothing.
func TestAnOffersIdentityIsParsedStrictly(t *testing.T) {
	for _, raw := range []string{
		`{"name":"s3-bucket","scope":"mesh","identity":{"max":20,"in":"an S3 access key"}}`,
		`{"name":"wildcard-resolution","scope":"mesh","identity":false}`,
		`{"name":"redis-cache","scope":"mesh","identity":{"in":"a Redis ACL user"}}`,
	} {
		var o Offer
		if err := json.Unmarshal([]byte(raw), &o); err != nil {
			t.Fatalf("%s: %v", raw, err)
		}
		back, err := json.Marshal(o)
		if err != nil || string(back) != raw {
			t.Errorf("did not round-trip:\n%s\n%s (%v)", raw, back, err)
		}
	}
	for _, raw := range []string{
		`{"name":"x","identity":true}`,
		`{"name":"x","identity":{"max":20,"in":"y","most":3}}`,
	} {
		var o Offer
		if err := json.Unmarshal([]byte(raw), &o); err == nil {
			t.Errorf("accepted %s", raw)
		}
	}
	bad := Manifest{Module: "bad", Version: "1", Provides: []Offer{
		{Name: "unsaid", Scope: ScopeMesh, Identity: &OfferIdentity{Max: 20}},
		{Name: "tiny", Scope: ScopeMesh, Identity: &OfferIdentity{Max: 4, In: "nothing usable"}},
	}}
	raw, err := json.Marshal(bad)
	if err != nil {
		t.Fatal(err)
	}
	_, err = ParseManifest(raw)
	if err == nil || !strings.Contains(err.Error(), "without saying what keeps them") ||
		!strings.Contains(err.Error(), "the shortest the mesh makes") {
		t.Fatalf("a bound with no `in`, or too short for any identity, was accepted: %v", err)
	}
}

// Refused before merge: the catalogue check judges each module's identity, on the longest machine
// name, against the bound of every provision it wants — and names the module and the slug to set.
func TestTheCatalogueCheckRefusesAnIdentityThatOverflowsWhatItRequires(t *testing.T) {
	shelf := Shelf{
		"objects": {Module: "objects", Provides: []Offer{{Name: "s3-bucket", Scope: ScopeMesh,
			Identity: &OfferIdentity{Max: 20, In: "an S3 access key"}}},
			Receives: map[string]string{"s3-bucket": "/var/lib/mesh/objects/mesh.json"}},
		"photoalbum": {Module: "photoalbum", Requires: []string{"s3-bucket"}},
		"files":      {Module: "files", Requires: []string{"s3-bucket"}},
	}
	problems := IdentityProblems(shelf, 6)
	if len(problems) != 1 || !strings.Contains(problems[0], "photoalbum wants s3-bucket") ||
		!strings.Contains(problems[0], `"mesh_nnnnnn_photoalbum", 22`) ||
		!strings.Contains(problems[0], "`slug` of at most 8 characters") {
		t.Fatalf("one overflow, named with its remedy, was expected: %q", problems)
	}
	// A longer machine name refuses more: the check is about the mesh's machines, not one.
	if got := IdentityProblems(shelf, 10); len(got) != 2 {
		t.Fatalf("on a 10-character name both overflow (mesh_nnnnnnnnnn_files is 21): %q", got)
	}
	// And a slug is the remedy it names.
	album := shelf["photoalbum"]
	album.Slug = "album"
	shelf["photoalbum"] = album
	if got := IdentityProblems(shelf, 6); len(got) != 0 {
		t.Fatalf("a slug that fits is still refused: %q", got)
	}
}

// Tonight's case (issue 263): networkmanager, no slug, requiring the mesh's resolver provision on a
// machine with a six-character name. Under ADR 0049's one bound it was refused, and its provider's
// whole machine with it; the resolver keeps no name, so it is not refused at all.
func TestARequirementOnAKeylessProvisionComposesWithALongName(t *testing.T) {
	shelf := Shelf{
		"resolver":       {Module: "resolver", Provides: []Offer{{Name: "wildcard-resolution", Scope: ScopeMesh}}},
		"networkmanager": {Module: "networkmanager", Requires: []string{"wildcard-resolution"}},
	}
	if CheckIdentity("laptop", "networkmanager") == nil {
		t.Fatal("the regression is not reproduced: mesh_laptop_networkmanager fits the old global bound")
	}
	if got := IdentityProblems(shelf, 6); len(got) != 0 {
		t.Fatalf("a requirement on a keyless provision was refused for its length: %q", got)
	}
	r := Resolution{Node: "laptop", Modules: []Manifest{shelf["networkmanager"]},
		Needs: []Needed{{Name: "wildcard-resolution", From: "anchor", For: "networkmanager",
			Identity: shelf["resolver"].IdentityBoundOf("wildcard-resolution")}}}
	if got := r.Overflowing(); len(got) != 0 {
		t.Fatalf("a keyless requirement is reported as overflowing: %+v", got)
	}
}

// The consumer's side of the same judgement the provider's composition makes: what `status` says.
func TestAnOverflowingRequirementIsNamedFromTheConsumersSide(t *testing.T) {
	bound := IdentityBound{Max: 20, In: "an S3 access key"}
	r := Resolution{Node: "laptop",
		Modules: []Manifest{{Module: "photoalbum"}, {Module: "files"}, {Module: "gallery", Slug: "gal"}},
		Needs: []Needed{
			{Name: "s3-bucket", From: "anchor", For: "photoalbum", Identity: bound},
			{Name: "s3-bucket", From: "anchor", For: "photoalbum", Local: "second", Identity: bound},
			{Name: "s3-bucket", From: "anchor", For: "files", Identity: bound},
			{Name: "s3-bucket", From: "anchor", For: "gallery", Identity: bound},
			{Name: "licence", From: "records", For: "photoalbum", ByRecord: true, Identity: bound},
		}}
	got := r.Overflowing()
	if len(got) != 1 || got[0].Module != "photoalbum" || got[0].Identity != "mesh_laptop_photoalbum" ||
		got[0].Provider != "anchor" {
		t.Fatalf("one overflow, once, was expected: %+v", got)
	}
	if said := got[0].String(); !strings.Contains(said, "an S3 access key keeps 20") ||
		!strings.Contains(said, "slug") {
		t.Fatalf("the overflow does not say what keeps it or the remedy: %s", said)
	}
}

// An identity served as a DNS label is never truncated, so the offer's bound must keep it in one.
func TestAnIdentityServedAsADNSLabelIsBoundedToOne(t *testing.T) {
	serves := map[string]map[string]any{"bucket": {"name": "${consumer:as:dns}"}}
	wide := Manifest{Module: "wide", Serves: serves, Provides: []Offer{{Name: "bucket", Scope: ScopeMesh,
		Identity: &OfferIdentity{Max: 255, In: "a client id"}}}}
	if got := CheckServes(wide); len(got) != 1 || !strings.Contains(got[0], "a label keeps 63") {
		t.Fatalf("a 255-character bound on a DNS label passed: %q", got)
	}
	unsaid := Manifest{Module: "unsaid", Serves: serves, Provides: []Offer{{Name: "bucket", Scope: ScopeMesh}}}
	if got := CheckServes(unsaid); len(got) != 0 {
		t.Fatalf("the default bound (20) on a DNS label was refused: %q", got)
	}
}