package broker

import (
	"strings"
	"testing"
)

// Deriving the bus's user list from the mesh's records.
//
// Every test here is about a way the list could be wrong that the server would not tell anybody
// about: a user missing, a user named twice, a user with authority it did not declare.

func someRecords() Records {
	return Records{
		Nodes: []string{"two", "one"},
		Assigned: map[string][]Declared{
			"one": {{Module: "telegram", Serves: []string{"status"}}},
			"two": {{Module: "shop", Emits: []string{"order.placed"}}},
		},
		Enrolling: []string{"three"},
		People:    map[string][]string{"ada": {"mesh-catalog.catalog_tools"}},
	}
}

func namesOf(t *testing.T, r Records) []string {
	t.Helper()
	users, err := Users(r)
	if err != nil {
		t.Fatal(err)
	}
	out := make([]string, 0, len(users))
	for _, u := range users {
		out = append(out, u.Username())
	}
	return out
}

// The controller is always there. A mesh whose own controller is not in the file is a mesh that
// cannot be told anything, and there is no state of the records in which that is correct.
func TestTheControllerIsAlwaysInTheList(t *testing.T) {
	for _, r := range []Records{{}, someRecords()} {
		names := namesOf(t, r)
		if len(names) == 0 || names[0] != "controller" {
			t.Fatalf("the controller is not first in %v", names)
		}
	}
}

// One user per node, one per module per node, one per live token and one per person — and nothing
// else, because a user nobody derived is a user nobody can explain.
func TestEveryRecordBecomesExactlyOneUser(t *testing.T) {
	names := namesOf(t, someRecords())
	want := []string{
		"controller",
		"node.one", "one.telegram",
		"node.two", "two.shop",
		"enrol.three",
		"person.ada",
	}
	if strings.Join(names, ",") != strings.Join(want, ",") {
		t.Fatalf("derived %v\n    want %v", names, want)
	}
}

// Two users with one name is a file the server reads as one of them, and which one depends on the
// order. Refused here, where both can be named, rather than left to be whichever the server picked.
func TestTwoUsersWithOneNameAreRefused(t *testing.T) {
	r := someRecords()
	r.Assigned["one"] = append(r.Assigned["one"], Declared{Module: "telegram"})
	_, err := Users(r)
	if err == nil {
		t.Fatal("a module assigned twice to one node composed two users with one name")
	}
	if !strings.Contains(err.Error(), "one.telegram") {
		t.Fatalf("the refusal does not name the user: %v", err)
	}
}

// A module's authority is what it declared and nothing more, carried through the derivation intact —
// because this is the step where a mistake would grant something no manifest asked for.
func TestAModulesAuthorityIsWhatItDeclared(t *testing.T) {
	seat := Seat{Name: "telegram-sender", Accepts: []string{"send"}, Emits: []string{"delivered"}}
	users, err := Users(Records{
		Nodes: []string{"one"},
		Assigned: map[string][]Declared{"one": {{
			Module: "shop", Emits: []string{"order.placed"}, Uses: []Seat{seat},
		}}},
	})
	if err != nil {
		t.Fatal(err)
	}
	perms, err := PermissionsFor(users[len(users)-1])
	if err != nil {
		t.Fatal(err)
	}
	has(t, perms.Publish, "mesh.mod.shop.event.order.placed")
	has(t, perms.Publish, "mesh.seat.telegram-sender.accept.send")
	// A seat it uses, not one it holds: it may submit work and may not publish the seat's own
	// events, or it could lie about outcomes on a role somebody else fills.
	hasNot(t, perms.Publish, "mesh.seat.telegram-sender.event.delivered")
	hasNot(t, perms.Subscribe, "mesh.seat.telegram-sender.accept.send")
}

// A user the mesh has never minted a password for is named rather than silently dropped or
// composed as a user anybody is. It is an ordinary situation — a module assigned a moment ago — and
// the remedy is to mint one, so the caller decides whether to write a partial file.
func TestAUserWithNoPasswordIsNamedRatherThanWritten(t *testing.T) {
	users, err := Users(someRecords())
	if err != nil {
		t.Fatal(err)
	}
	filled, missing := WithPasswords(users, map[string]string{
		"controller": "$2a$hash", "node.one": "$2a$hash",
	})
	if len(filled) != 2 {
		t.Fatalf("composed %d users from two hashes", len(filled))
	}
	if len(missing) != len(users)-2 {
		t.Fatalf("%d users are missing a password, of %d: %v", len(missing), len(users), missing)
	}
	for _, p := range filled {
		if p.PasswordHash == "" {
			t.Fatalf("%s was kept with no password, which is a user anybody is", p.Username())
		}
	}
}

// And the whole thing composes: records in, a file the server would read out.
func TestRecordsComposeIntoAFile(t *testing.T) {
	users, err := Users(someRecords())
	if err != nil {
		t.Fatal(err)
	}
	hashes := map[string]string{}
	for _, u := range users {
		hashes[u.Username()] = "$2a$11$" + strings.Repeat("x", 22)
	}
	filled, missing := WithPasswords(users, hashes)
	if len(missing) != 0 {
		t.Fatalf("users with no password: %v", missing)
	}
	got, err := Compose(Server{ClientPort: 4222, MonitoringPort: 8222, StoreDir: "/data",
		TLSCert: "/tls/tls.crt", TLSKey: "/tls/tls.key", TLSCA: "/tls/ca.crt"}, filled)
	if err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{
		`user: "controller"`, `user: "node.one"`, `user: "one.telegram"`,
		`user: "enrol.three"`, `user: "person.ada"`,
		`"_INBOX.enrol.three.>"`, `"mesh.mod.mesh-catalog.tool.catalog_tools"`,
	} {
		if !strings.Contains(got, want) {
			t.Errorf("the composed file does not contain %s", want)
		}
	}
}

// The accounts block alone is what the mesh writes, and it holds nothing about the server.
//
// **The split is the whole design decision** (ComposeAccounts): ports, TLS paths and a store
// directory are properties of the container the module raises, and a controller that wrote them
// would have to be kept in step with a Dockerfile it never sees. So this test says what must not be
// in the file as plainly as what must.
func TestWhatTheMeshWritesIsUsersAndNothingAboutTheServer(t *testing.T) {
	users, err := Users(someRecords())
	if err != nil {
		t.Fatal(err)
	}
	hashes := map[string]string{}
	for _, u := range users {
		hashes[u.Username()] = "$2a$11$" + strings.Repeat("x", 22)
	}
	filled, missing := WithPasswords(users, hashes)
	if len(missing) != 0 {
		t.Fatalf("users with no password: %v", missing)
	}
	got, err := ComposeAccounts(filled)
	if err != nil {
		t.Fatal(err)
	}

	for _, want := range []string{"accounts {", `user: "controller"`, `user: "one.telegram"`} {
		if !strings.Contains(got, want) {
			t.Errorf("the accounts file does not contain %s", want)
		}
	}
	// None of the server's own settings. Each of these in the mesh's file is a value the controller
	// would then own, and the module could no longer change its own image without the mesh agreeing.
	// `jetstream {` is the server's block (its store, its limits); `jetstream: enabled` inside the
	// account is the account's, and the mesh owns the account — a user in it is told "JetStream
	// not enabled for account" without it (2026-09-28).
	if !strings.Contains(got, "jetstream: enabled") {
		t.Errorf("the account does not enable JetStream, so no user in it can bind a consumer")
	}
	for _, absent := range []string{"port:", "http:", "jetstream {", "tls {", "store_dir", "cert_file"} {
		if strings.Contains(got, absent) {
			t.Errorf("the accounts file contains %q, which belongs to the module that raises the "+
				"server, not to the mesh", absent)
		}
	}
}

// A user with no password is refused here too, not only by the whole-file composition: this is the
// function the controller actually calls, and a user without a password is a user anybody is.
func TestTheAccountsFileRefusesAUserWithNoPassword(t *testing.T) {
	if _, err := ComposeAccounts([]Principal{{Kind: KindController}}); err == nil {
		t.Fatal("a user with no password hash was written")
	}
}

// **A user list is composed for a bus the mesh has not moved onto yet**, and that is the whole of
// step 2 (novox/hq ADR 0116): the server stands in the mesh carrying nothing, on its own ports, while
// every node is still on the bus it was on.
//
// Pinned because the first version of the composing step got it backwards — it wrote the list only
// once the controller was already on the new bus, which is a step that cannot be taken: the module
// comes up, finds no accounts file, and waits for one the controller had decided not to write.
func TestAUserListIsComposedBeforeAnythingMovesOntoTheBus(t *testing.T) {
	// Exactly the records of a mesh mid-change: everything running, nothing on the new bus.
	users, err := Users(Records{
		Nodes:    []string{"anchor"},
		Assigned: map[string][]Declared{"anchor": {{Module: "nats"}}},
	})
	if err != nil {
		t.Fatal(err)
	}
	hashes := map[string]string{}
	for _, u := range users {
		hashes[u.Username()] = "$2a$11$" + strings.Repeat("x", 22)
	}
	filled, missing := WithPasswords(users, hashes)
	if len(missing) != 0 {
		t.Fatalf("users with no credential: %v", missing)
	}
	accounts, err := ComposeAccounts(filled)
	if err != nil {
		t.Fatal(err)
	}
	// The controller's own user above all: a file without it is a bus its writer cannot connect to,
	// which is what the server would be left holding the moment it starts.
	if !strings.Contains(accounts, `user: "controller"`) {
		t.Fatalf("the composed list does not contain the controller:\n%s", accounts)
	}
	if !strings.Contains(accounts, `user: "node.anchor"`) {
		t.Errorf("the composed list does not contain the machine running the bus")
	}
}