// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0

package users

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
)

func TestAddFirst(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	user, err := u.AddFirst("admin", "a-very-good-passphrase", "cs", "plasma", "Petr Balvín")
	if err != nil {
		t.Fatalf("AddFirst: %v", err)
	}
	if user.Role != "admin" || user.Language != "cs" || user.Theme != "plasma" || user.Name != "Petr Balvín" {
		t.Fatalf("first account = %+v", user)
	}
	if _, err := u.AddFirst("other", "another-good-passphrase", "", "", ""); !errors.Is(err, ErrUsersExist) {
		t.Fatalf("second first account: err = %v", err)
	}
	if len(u.All()) != 1 {
		t.Fatalf("accounts = %v", u.All())
	}
}

// The wizard claim is serialised: two concurrent AddFirst calls create
// exactly one account, never two admins racing for the installation.
func TestAddFirstIsSerialised(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	var wg sync.WaitGroup
	var mu sync.Mutex
	ok := 0
	for range 4 {
		wg.Go(func() {
			if _, err := u.AddFirst("claim", "a-very-good-passphrase", "", "", ""); err == nil {
				mu.Lock()
				ok++
				mu.Unlock()
			}
		})
	}
	wg.Wait()
	if ok != 1 {
		t.Fatalf("%d claims won", ok)
	}
	if len(u.All()) != 1 {
		t.Fatalf("accounts = %v", u.All())
	}
}

func stat(path string) (os.FileInfo, error) { return os.Stat(path) }

// The helpers below keep the tests readable now that every mutation
// reports why it failed.

func addSucceeded(u *Users, username, secret, role string) bool {
	_, err := u.Add(username, secret, role)
	return err == nil
}

func addFailed(u *Users, username, secret, role string) bool {
	return !addSucceeded(u, username, secret, role)
}

func mustAdd(t *testing.T, u *Users, username, secret, role string) {
	t.Helper()
	if _, err := u.Add(username, secret, role); err != nil {
		t.Fatalf("Add(%q): %v", username, err)
	}
}

func renameSucceeded(u *Users, from, to string) bool {
	_, err := u.Rename(from, to)
	return err == nil
}

func renameFailed(u *Users, from, to string) bool { return !renameSucceeded(u, from, to) }

func writeFile(t *testing.T, path, content string) {
	t.Helper()
	if err := os.WriteFile(path, []byte(content), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
}

func TestNoAccountsBeforeFirstAdd(t *testing.T) {
	u := New(filepath.Join(t.TempDir(), "users.toml"))
	if u.Any() {
		t.Fatal("a missing file must hold no accounts: the first-run wizard is the only creator")
	}
}

func TestAddAndPersist(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	added, err := u.Add("petr", "heslo12345", "admin")
	if err != nil {
		t.Fatalf("Add: %v", err)
	}
	if added == nil {
		t.Fatal("Add failed")
	}
	if added.Role != "admin" {
		t.Fatalf("role = %q", added.Role)
	}
	// Invalid role falls back to the default.
	if second, err := u.Add("joe", "heslo12345", "root"); err != nil || second.Role != DefaultRole {
		t.Fatalf("second = %v", second)
	}
	// Duplicate and empty names are rejected.
	if addSucceeded(u, "petr", "x", "admin") {
		t.Fatal("duplicate accepted")
	}
	if addSucceeded(u, "", "x", "admin") {
		t.Fatal("empty name accepted")
	}

	reopened := New(path)
	if len(reopened.All()) != 2 {
		t.Fatalf("reopened users = %v", reopened.All())
	}
	if reopened.Authenticate("petr", "heslo12345") == nil {
		t.Fatal("authenticate failed after reopen")
	}
	info, err := stat(path)
	if err != nil {
		t.Fatalf("stat: %v", err)
	}
	if info.Mode().Perm() != 0o600 {
		t.Fatalf("mode = %v, want 0600", info.Mode().Perm())
	}
}

func TestUpdates(t *testing.T) {
	u := New(filepath.Join(t.TempDir(), "users.toml"))
	if addFailed(u, "petr", "heslo12345", "admin") {
		t.Fatal("Add failed")
	}
	if got, err := u.UpdateName("petr", "Petr Balvín"); err != nil || got.Name != "Petr Balvín" {
		t.Fatalf("UpdateName = %v", got)
	}
	if got, err := u.UpdateName("petr", ""); err != nil || got.Name != "" {
		t.Fatalf("clear name = %v", got)
	}
	if got, err := u.UpdateFediverseCreator("petr", "@petr@social"); err != nil || got.FediverseCreator != "@petr@social" {
		t.Fatalf("UpdateFediverseCreator = %v", got)
	}
	if got, err := u.UpdatePhoto("petr", "/media/p.webp"); err != nil || got.Photo != "/media/p.webp" {
		t.Fatalf("UpdatePhoto = %v", got)
	}
	if _, err := u.UpdatePassword("petr", "noveheslo123"); err != nil {
		t.Fatal("UpdatePassword failed")
	}
	if u.Authenticate("petr", "noveheslo123") == nil {
		t.Fatal("new password does not verify")
	}
	if _, err := u.UpdateName("missing", "x"); err == nil {
		t.Fatal("update of missing user succeeded")
	}
}

func TestUpdateLanguage(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	mustAdd(t, u, "petr", "heslo12345", "admin")
	if got, err := u.UpdateLanguage("petr", "cs"); err != nil || got.Language != "cs" {
		t.Fatalf("UpdateLanguage = %v, %v", got, err)
	}
	// The choice survives the round trip through the users file, and an
	// unknown language is refused rather than stored.
	if u.Find("petr").Language != "cs" {
		t.Fatal("language did not persist")
	}
	if _, err := u.UpdateLanguage("petr", "de"); err == nil {
		t.Fatal("unsupported language accepted")
	}
}

func TestUpdateTheme(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	mustAdd(t, u, "petr", "heslo12345", "admin")
	if got, err := u.UpdateTheme("petr", "plasma"); err != nil || got.Theme != "plasma" {
		t.Fatalf("UpdateTheme = %v, %v", got, err)
	}
	// The choice survives the round trip through the users file, and an
	// unknown scheme is refused rather than stored.
	if u.Find("petr").Theme != "plasma" {
		t.Fatal("theme did not persist")
	}
	if _, err := u.UpdateTheme("petr", "sepia"); err == nil {
		t.Fatal("unsupported colour scheme accepted")
	}
}

func TestUpdateOrcid(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	mustAdd(t, u, "petr", "heslo12345", "admin")
	// A valid iD persists, normalised to its upper-case form.
	if got, err := u.UpdateOrcid("petr", "0000-0002-1825-0097"); err != nil ||
		got.Orcid != "0000-0002-1825-0097" {
		t.Fatalf("UpdateOrcid = %v, %v", got, err)
	}
	if u.Find("petr").Orcid != "0000-0002-1825-0097" {
		t.Fatal("orcid did not persist")
	}
	// A broken check digit is refused and the old value stays.
	if _, err := u.UpdateOrcid("petr", "0000-0002-1825-0098"); err == nil {
		t.Fatal("invalid orcid accepted")
	}
	if u.Find("petr").Orcid != "0000-0002-1825-0097" {
		t.Fatal("refused orcid overwrote the stored one")
	}
	// Empty clears it.
	if got, err := u.UpdateOrcid("petr", ""); err != nil || got.Orcid != "" {
		t.Fatalf("UpdateOrcid clear = %v, %v", got, err)
	}
}

func TestRename(t *testing.T) {
	u := New(filepath.Join(t.TempDir(), "users.toml"))
	mustAdd(t, u, "petr", "heslo12345", "admin")
	mustAdd(t, u, "joe", "heslo12345", "author")
	if got, err := u.Rename("petr", "balvin"); err != nil || got.Username != "balvin" {
		t.Fatalf("Rename = %v", got)
	}
	if u.Find("petr") != nil {
		t.Fatal("old name still present")
	}
	if renameSucceeded(u, "balvin", "joe") {
		t.Fatal("rename onto existing user succeeded")
	}
	if renameSucceeded(u, "balvin", "") {
		t.Fatal("rename to empty succeeded")
	}
}

func TestLastAdminProtection(t *testing.T) {
	u := New(filepath.Join(t.TempDir(), "users.toml"))
	mustAdd(t, u, "petr", "heslo12345", "admin")
	mustAdd(t, u, "joe", "heslo12345", "author")

	if got, err := u.SetRole("petr", "author"); err == nil && got != nil {
		t.Fatal("demoting the last admin succeeded")
	}
	if got, err := u.SetRole("petr", "wizard"); err == nil && got != nil {
		t.Fatal("invalid role accepted")
	}
	if got, err := u.Delete("petr"); err == nil || got != "" {
		t.Fatal("deleting the last admin succeeded")
	}
	if got, err := u.Delete("joe"); err != nil || got != "joe" {
		t.Fatalf("Delete = %q", got)
	}
	if got, err := u.Delete("joe"); err == nil || got != "" {
		t.Fatal("deleting the last user succeeded")
	}

	// With two admins, demotion and deletion are allowed.
	mustAdd(t, u, "second", "heslo12345", "admin")
	if got, err := u.SetRole("petr", "author"); err != nil || got == nil {
		t.Fatal("demoting with two admins failed")
	}
	if got, err := u.SetRole("petr", "admin"); err != nil || got == nil {
		t.Fatal("re-promoting failed")
	}
	if got, err := u.Delete("second"); err != nil || got != "second" {
		t.Fatalf("Delete = %q", got)
	}
}

func TestCacheInvalidationOnOutOfBandEdit(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	mustAdd(t, u, "petr", "heslo12345", "admin")
	if len(u.All()) != 1 {
		t.Fatal("want 1 user")
	}
	other := New(path)
	other.Add("joe", "heslo12345", "author")
	if got := len(u.All()); got != 2 {
		t.Fatalf("cache not invalidated: %d users", got)
	}
}

func TestUnreadableFileYieldsNoUsers(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	writeFile(t, path, "not = valid = toml")
	u := New(path)
	if len(u.All()) != 0 {
		t.Fatalf("users = %v, want none", u.All())
	}
}

func TestWeakStoredHashRejected(t *testing.T) {
	// N=1024 hash: below the policy floor, must not authenticate.
	path := filepath.Join(t.TempDir(), "users.toml")
	weak := `[[users]]
username = "old"
password_hash = "scrypt$1024$8$1$c2FsdHNhbHRzYWx0c2E=$aGFzaGhhc2hoYXNoaGFzaGhhc2hoYXNoaGFzaA=="
role = "admin"
`
	writeFile(t, path, weak)
	u := New(path)
	if len(u.All()) != 1 {
		t.Fatalf("users = %v", u.All())
	}
	if u.Authenticate("old", "anything") != nil {
		t.Fatal("weak hash authenticated")
	}
	if !strings.Contains(u.All()[0].PasswordHash, "scrypt$1024") {
		t.Fatal("hash not loaded")
	}
}

// A users file that exists but cannot be parsed fails closed: no
// account is served, a mutation refuses rather than write the empty
// list back, and the unreadable file is left untouched. The first-run
// wizard gate reads the health separately, so a corrupted file never
// turns into an open setup page.
func TestUnreadableFileFailsClosed(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	if u.Any() {
		t.Fatal("no account is expected while the file is absent")
	}
	if err := os.WriteFile(path, []byte("this is not TOML [[["), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	u.Invalidate()
	if got := u.All(); len(got) != 0 {
		t.Fatalf("a corrupted file yielded %d account(s)", len(got))
	}
	if err := u.Health(); err == nil {
		t.Fatal("Health reported no problem with a corrupted file")
	}
	// A mutation must refuse rather than write the empty list back.
	if addSucceeded(u, "joe", "joes-good-passphrase", "author") {
		t.Fatal("Add wrote over an unreadable file")
	}
	raw, err := os.ReadFile(path)
	if err != nil || string(raw) != "this is not TOML [[[" {
		t.Fatalf("the unreadable file was overwritten: %q", raw)
	}
}

func TestRenameIsSerialised(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	if addFailed(u, "first", "first-good-passphrase", "admin") {
		t.Fatal("Add failed")
	}
	if addFailed(u, "second", "second-good-passphrase", "author") {
		t.Fatal("Add failed")
	}
	var wg sync.WaitGroup
	for range 8 {
		wg.Go(func() {
			u.Rename("first", "merged")
			u.Rename("second", "merged")
		})
	}
	wg.Wait()
	merged := 0
	for _, user := range u.All() {
		if user.Username == "merged" {
			merged++
		}
	}
	if merged > 1 {
		t.Fatalf("%d accounts share one username", merged)
	}
}

// TestWritersDoNotRaceReaders exercises a mutation against concurrent
// readers: loadLocked writes the cache fields readers read under u.mu,
// so a writer that called it without u.mu would be a data race.
func TestWritersDoNotRaceReaders(t *testing.T) {
	path := filepath.Join(t.TempDir(), "users.toml")
	u := New(path)
	if addFailed(u, "admin", "admin-good-passphrase", "admin") {
		t.Fatal("Add failed")
	}
	var wg sync.WaitGroup
	for i := range 4 {
		wg.Go(func() {
			u.UpdateName("admin", fmt.Sprintf("name-%d", i))
		})
	}
	for range 4 {
		wg.Go(func() {
			u.All()
			u.Health()
			u.Find("admin")
		})
	}
	wg.Wait()
}