package authn

import (
	"errors"
	"path/filepath"
	"testing"

	"golang.org/x/crypto/bcrypt"
)

func openTestStore(t *testing.T) (*Store, string) {
	t.Helper()
	path := filepath.Join(t.TempDir(), DatabaseFile)
	store, err := Open(path)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = store.Close() })
	return store, path
}

func TestPasswordRecordPersistsAndAuthenticates(t *testing.T) {
	store, path := openTestStore(t)
	created, wasCreated, err := store.SetPassword("Kami", "correct horse battery")
	if err != nil || !wasCreated || created.Username != "Kami" {
		t.Fatalf("created=%+v new=%v err=%v", created, wasCreated, err)
	}
	if _, err := store.Authenticate("KAMI", "correct horse battery"); err != nil {
		t.Fatalf("authenticate: %v", err)
	}
	if _, err := store.Authenticate("Kami", "wrong password"); !errors.Is(err, ErrInvalidCredentials) {
		t.Fatalf("wrong password error = %v", err)
	}
	if err := store.Close(); err != nil {
		t.Fatal(err)
	}
	reopened, err := Open(path)
	if err != nil {
		t.Fatal(err)
	}
	defer reopened.Close()
	if _, err := reopened.Authenticate("kami", "correct horse battery"); err != nil {
		t.Fatalf("persisted authentication: %v", err)
	}
}

func TestUpdateRequiresCurrentPasswordAndMovesUsername(t *testing.T) {
	store, _ := openTestStore(t)
	if _, _, err := store.SetPassword("operator", "original password"); err != nil {
		t.Fatal(err)
	}
	if _, err := store.Update("operator", "wrong password", "kami", "replacement password"); !errors.Is(err, ErrInvalidCredentials) {
		t.Fatalf("wrong current password error = %v", err)
	}
	updated, err := store.Update("operator", "original password", "kami", "replacement password")
	if err != nil || updated.Username != "kami" {
		t.Fatalf("updated=%+v err=%v", updated, err)
	}
	if _, err := store.Authenticate("operator", "original password"); !errors.Is(err, ErrInvalidCredentials) {
		t.Fatalf("old credential error = %v", err)
	}
	if _, err := store.Authenticate("kami", "replacement password"); err != nil {
		t.Fatalf("new credential: %v", err)
	}
}

func TestUpdateRefusesExistingUsername(t *testing.T) {
	store, _ := openTestStore(t)
	if _, _, err := store.SetPassword("one", "password one"); err != nil {
		t.Fatal(err)
	}
	if _, _, err := store.SetPassword("two", "password two"); err != nil {
		t.Fatal(err)
	}
	if _, err := store.Update("one", "password one", "TWO", ""); !errors.Is(err, ErrUsernameExists) {
		t.Fatalf("collision error = %v", err)
	}
}

func TestLegacyHashImportsOnlyIntoEmptyDatabase(t *testing.T) {
	store, _ := openTestStore(t)
	hash, err := bcrypt.GenerateFromPassword([]byte("legacy password"), bcrypt.MinCost)
	if err != nil {
		t.Fatal(err)
	}
	if imported, err := store.ImportBcrypt("legacy", string(hash)); err != nil || !imported {
		t.Fatalf("imported=%v err=%v", imported, err)
	}
	if imported, err := store.ImportBcrypt("intruder", string(hash)); err != nil || imported {
		t.Fatalf("second import=%v err=%v", imported, err)
	}
	if _, err := store.Authenticate("legacy", "legacy password"); err != nil {
		t.Fatalf("imported credential: %v", err)
	}
}

func TestCredentialValidation(t *testing.T) {
	store, _ := openTestStore(t)
	if _, _, err := store.SetPassword("", "a sufficiently long password"); err == nil {
		t.Fatal("blank username accepted")
	}
	if _, _, err := store.SetPassword("operator", "short"); err == nil {
		t.Fatal("short password accepted")
	}
	if _, _, err := store.SetPassword("operator", string(make([]byte, maximumPassword+1))); err == nil {
		t.Fatal("oversized bcrypt password accepted")
	}
}