package inventory

import (
	"os"
	"strings"
	"testing"

	"github.com/novox/mesh-controller/internal/broker"
	"github.com/novox/mesh-controller/internal/catalogue"
)

// grantMatches is a NATS subject pattern matching a subject: `*` one token, `>` the rest.
func grantMatches(pattern, subject string) bool {
	p, s := strings.Split(pattern, "."), strings.Split(subject, ".")
	for i, tok := range p {
		if tok == ">" {
			return len(s) > i
		}
		if i >= len(s) || (tok != "*" && tok != s[i]) {
			return false
		}
	}
	return len(p) == len(s)
}

func grantsAny(patterns []string, subject string) bool {
	for _, p := range patterns {
		if grantMatches(p, subject) {
			return true
		}
	}
	return false
}

// novox/hq ADR 0259 §8 (confirmation review of 2026-10-09): the router honours a verified sender only on the
// controller's `root-free` word, asked on the bus. So only the serving controller may answer that verb — be
// subscribed to its subject — and nobody may publish into the router's inbox but by answering a request it
// made (allow_responses). Composed here from the controller's own manifest, on a machine where the machine's
// runtime carries it beside an ordinary module, with the router, a channel, a person and an administrator: a
// runtime carrying the controller's module, a node-engine, a channel or anybody else answering `root-free` is
// an agent answering it.
func TestOnlyTheServingControllerMayAnswerRootFree(t *testing.T) {
	raw, err := os.ReadFile("../../module.json")
	if err != nil {
		t.Fatal(err)
	}
	controller, err := catalogue.ParseManifest(raw)
	if err != nil {
		t.Fatal(err)
	}
	parse := func(s string) catalogue.Manifest {
		m, err := catalogue.ParseManifest([]byte(s))
		if err != nil {
			t.Fatal(err)
		}
		return m
	}
	dir := `"resources": [{"id": "state", "type": "directory", "mode": "0700", "place": "."}]`
	router := parse(`{"module": "messenger", "version": "1", "runs-as": "messenger",
	  "seats": [{"name": "operator-channel", "scope": "mesh", "serves": ["open"], "accepts": ["ask"],
	             "emits": ["decided"], "by-caller": ["ask", "decided"]}],
	  "claims": [{"name": "operator-channel", "scope": "mesh", "serves": ["open"]}],
	  "invokes": ["seat:mesh-controller.root-free", "seat:mesh-controller.conditions"],
	  "own-secrets": {"broker": "${dir:state}/broker"}, "secrets-owner": "messenger",
	  "resources": [{"id": "account", "type": "user", "name": "messenger", "shell": "/usr/bin/nologin", "home": "/var/lib/messenger"},
	                {"id": "state", "type": "directory", "mode": "0700", "place": ".", "owner": "messenger"}]}`)
	ordinary := parse(`{"module": "lab-bystander", "version": "1", "own-secrets": {"broker": "${dir:state}/broker"}, ` + dir + `}`)
	runtime := catalogue.Manifest{Module: broker.RuntimeModule}

	manifests := []catalogue.Manifest{controller, router, ordinary, runtime}
	seats := map[string]catalogue.SeatDeclaration{}
	declarers := map[string]string{}
	for _, m := range manifests {
		for _, s := range m.DefinesSeats {
			seats[s.Name], declarers[s.Name] = s, m.Module
		}
	}
	for _, own := range catalogue.SeatsWithAProtocol() {
		seats[own.Name] = catalogue.SeatDeclaration{Name: own.Name, Scope: own.Scope, Accepts: own.Accepts,
			Emits: own.Emits, Serves: own.Serves}
	}
	records := broker.Records{Nodes: []string{"anchor", "laptop"}, Assigned: map[string][]broker.Declared{},
		People:          map[string][]string{"operator": {"*"}, "guest": {"mesh-controller.status"}},
		Interchangeable: map[string]bool{}}
	for _, m := range manifests {
		records.Assigned["anchor"] = append(records.Assigned["anchor"], declaredFor(m, seats, declarers))
	}
	// And a second machine whose runtime carries an ordinary module: where agents run as the operator.
	records.Assigned["laptop"] = []broker.Declared{declaredFor(ordinary, seats, declarers), declaredFor(runtime, seats, declarers)}
	users, err := broker.Users(records)
	if err != nil {
		t.Fatal(err)
	}
	const verb = "mesh.seat.mesh-controller.tool.root-free"
	answerers := 0
	for _, u := range users {
		p, err := broker.PermissionsFor(u)
		if err != nil {
			t.Fatal(err)
		}
		answers := grantsAny(p.Subscribe, verb)
		if answers != (u.Kind == broker.KindController) {
			t.Errorf("%s (%s) %s subscribe to %s", u.Username(), u.Kind,
				map[bool]string{true: "may", false: "may not"}[answers], verb)
		}
		if answers {
			answerers++
		}
		// Nobody publishes into the router's inbox but as an answer to what it asked.
		for _, inbox := range []string{"_INBOX.anchor.messenger.x1.y", "_INBOX.anchor.messenger.>"} {
			if u.Username() != "anchor.messenger" && grantsAny(p.Publish, inbox) {
				t.Errorf("%s may publish into the router's inbox (%s) without being asked", u.Username(), inbox)
			}
		}
	}
	if answerers != 1 {
		t.Errorf("%d principals may answer root-free, want the controller alone", answerers)
	}
}