package enroll

import (
	"crypto/ed25519"
	"encoding/base64"
	"encoding/json"
	"strings"
	"testing"
)

// The two artefacts have to agree, and that agreement is the whole reason this is a package rather
// than two commands: the config carries the private signing key, the registration carries the public
// one, and a node whose relay entry was minted from a different key pair authenticates nowhere.
func TestTheConfigAndTheRegistrationDescribeTheSameNode(t *testing.T) {
	result, err := Generate(Options{
		RelayURL:  "https://relay.example",
		LocalPort: 3000,
		AuditPath: "/var/log/msa-agent/audit.log",
	})
	if err != nil {
		t.Fatalf("Generate: %v", err)
	}

	var cfg struct {
		NodeID     string `json:"nodeId"`
		RelayURL   string `json:"relayUrl"`
		AgentToken string `json:"agentToken"`
		LocalPort  int    `json:"localPort"`
		SignKey    string `json:"signKey"`
		KxKey      string `json:"kxKey"`
		AuditPath  string `json:"auditPath"`
		Devices    []any  `json:"devices"`
	}
	if err := json.Unmarshal(result.Config, &cfg); err != nil {
		t.Fatalf("the config is not valid JSON: %v", err)
	}
	var reg Registration
	if err := json.Unmarshal(result.Registration, &reg); err != nil {
		t.Fatalf("the registration is not valid JSON: %v", err)
	}

	if cfg.NodeID != reg.NodeID || cfg.NodeID != result.NodeID {
		t.Fatalf("node ids disagree: config=%q registration=%q result=%q", cfg.NodeID, reg.NodeID, result.NodeID)
	}
	if cfg.AgentToken != reg.Token {
		t.Fatal("the config's bearer and the registration's token differ; the agent would 401")
	}
	if cfg.RelayURL != "https://relay.example" || cfg.LocalPort != 3000 {
		t.Fatalf("relay or port lost: %+v", cfg)
	}
	if cfg.Devices == nil || len(cfg.Devices) != 0 {
		t.Fatalf("devices must start empty, got %v", cfg.Devices)
	}

	// The private key is 64 bytes; its last 32 are the public key, which is what the relay verifies.
	private, err := base64.StdEncoding.DecodeString(cfg.SignKey)
	if err != nil || len(private) != ed25519.PrivateKeySize {
		t.Fatalf("signKey is not a base64 ed25519 private key: %v (%d bytes)", err, len(private))
	}
	public, err := base64.StdEncoding.DecodeString(reg.SignKey)
	if err != nil || len(public) != ed25519.PublicKeySize {
		t.Fatalf("the registration's signKey is not a base64 ed25519 public key: %v (%d bytes)", err, len(public))
	}
	if string(private[ed25519.PrivateKeySize-ed25519.PublicKeySize:]) != string(public) {
		t.Fatal("the relay's registration carries a key that does not belong to the config's private key")
	}
}

// The node password is the one secret this tool must not invent. An unprotected node needs no value;
// a protected one needs the real one, or every command fails with node_auth_failed and the cause is
// not obvious from the phone.
func TestTheNodePasswordIsOnlyWrittenWhenGiven(t *testing.T) {
	without, err := Generate(Options{RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a"})
	if err != nil {
		t.Fatal(err)
	}
	if strings.Contains(string(without.Config), "nodePassword") {
		t.Fatal("a config with no password claims one")
	}
	with, err := Generate(Options{
		RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a", NodePassword: "hunter2",
	})
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(string(with.Config), `"nodePassword": "hunter2"`) {
		t.Fatal("the given password was not written")
	}
}

// Re-enrolling a node has to be able to keep the identifiers the relay already knows, or the operator
// has two edits to make instead of one.
func TestGivenIdentifiersAreKept(t *testing.T) {
	result, err := Generate(Options{
		RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a",
		NodeID: "nd_keepme0001", AgentToken: strings.Repeat("a", 64), ProvisionSecret: "kept-secret",
	})
	if err != nil {
		t.Fatal(err)
	}
	var reg Registration
	if err := json.Unmarshal(result.Registration, &reg); err != nil {
		t.Fatal(err)
	}
	if reg.NodeID != "nd_keepme0001" || reg.Token != strings.Repeat("a", 64) {
		t.Fatalf("identifiers were regenerated: %+v", reg)
	}
	if result.ProvisionSecret != "kept-secret" {
		t.Fatal("the pairing secret was regenerated")
	}
}

// Two enrollments must not produce the same keys or ids. A generator that repeated a key would make
// two nodes able to impersonate each other, and it is the kind of bug a seeded RNG introduces once.
func TestTwoEnrollmentsDiffer(t *testing.T) {
	first, err := Generate(Options{RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a"})
	if err != nil {
		t.Fatal(err)
	}
	second, err := Generate(Options{RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a"})
	if err != nil {
		t.Fatal(err)
	}
	if first.NodeID == second.NodeID {
		t.Fatal("two enrollments produced the same node id")
	}
	if string(first.Config) == string(second.Config) {
		t.Fatal("two enrollments produced the same config, so the same keys")
	}
}

func TestMissingInputIsRefused(t *testing.T) {
	cases := map[string]Options{
		"no relay":  {LocalPort: 3000, AuditPath: "/a"},
		"bad port":  {RelayURL: "https://relay.example", LocalPort: 0, AuditPath: "/a"},
		"huge port": {RelayURL: "https://relay.example", LocalPort: 70000, AuditPath: "/a"},
		"no audit":  {RelayURL: "https://relay.example", LocalPort: 3000},
	}
	for name, opts := range cases {
		if _, err := Generate(opts); err == nil {
			t.Fatalf("%s was accepted", name)
		}
	}
}

// The node records how it got into the relay, because `uninstall` cannot work it out any other way: the
// agent holds no admin token, so it cannot remove its own entry, and the operator has to be told which
// of the relay's two records mentions this node.
func TestEnrollmentRecordsItsOwnProvenance(t *testing.T) {
	withCode, err := Generate(Options{
		RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a", SelfEnrolled: true,
	})
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(string(withCode.Config), `"selfEnrolled": true`) {
		t.Fatal("a self-enrolled node does not say so")
	}
	// And a node an operator wrote into agents.json does not claim to have enrolled itself, or the
	// uninstall would send the operator to the app to remove an entry that is not there.
	manual, err := Generate(Options{RelayURL: "https://relay.example", LocalPort: 3000, AuditPath: "/a"})
	if err != nil {
		t.Fatal(err)
	}
	if strings.Contains(string(manual.Config), "selfEnrolled") {
		t.Fatal("a manually registered node claims to be self-enrolled")
	}
}