// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package credstore

import (
	"encoding/base64"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"github.com/zalando/go-keyring"
)

// newLargeTestToken builds a token whose access token is several KB,
// mimicking real JWTs with large groups claims that exceed the Windows
// Credential Manager 2560-byte blob limit.
func newLargeTestToken(clientID string) Token {
	return Token{
		AccessToken:  "header." + strings.Repeat("groups-claim-payload-", 300) + ".sig",
		RefreshToken: "test-refresh-token",
		TokenType:    "Bearer",
		ExpiresAt:    time.Now().Add(1 * time.Hour).Truncate(time.Second),
		ClientID:     clientID,
	}
}

func newTestEncryptedStore(t *testing.T) (*EncryptedFileStore[Token], string) {
	t.Helper()
	keyring.MockInit()
	path := filepath.Join(t.TempDir(), "tokens.enc")
	return NewEncryptedFileStore[Token]("test-service", path, JSONCodec[Token]{}), path
}

func TestEncryptedFileStoreSaveAndLoad(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	tok := newLargeTestToken("test-client")
	require.NoError(t, store.Save(tok.ClientID, tok))

	loaded, err := store.Load("test-client")
	require.NoError(t, err)
	assert.Equal(t, tok.AccessToken, loaded.AccessToken)
	assert.Equal(t, tok.RefreshToken, loaded.RefreshToken)
	assert.True(t, tok.ExpiresAt.Equal(loaded.ExpiresAt))
}

func TestEncryptedFileStoreFileContainsNoPlaintext(t *testing.T) {
	store, path := newTestEncryptedStore(t)

	tok := newLargeTestToken("test-client")
	require.NoError(t, store.Save(tok.ClientID, tok))

	raw, err := os.ReadFile(path)
	require.NoError(t, err)
	assert.NotContains(t, string(raw), "groups-claim-payload")
	assert.NotContains(t, string(raw), tok.RefreshToken)
}

func TestEncryptedFileStoreKeyringHoldsOnlySmallMasterKey(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	tok := newLargeTestToken("test-client")
	require.NoError(t, store.Save(tok.ClientID, tok))

	// The token itself must not be in the keyring.
	_, err := keyring.Get("test-service", "test-client")
	assert.ErrorIs(t, err, keyring.ErrNotFound)

	// Only the 44-byte base64 master key may live in the keyring —
	// well under the Windows Credential Manager 2560-byte blob limit.
	encoded, err := keyring.Get("test-service", masterKeyUser)
	require.NoError(t, err)
	assert.Len(t, encoded, 44)
	key, err := base64.StdEncoding.DecodeString(encoded)
	require.NoError(t, err)
	assert.Len(t, key, 32)
}

func TestEncryptedFileStoreLoadNotFound(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	_, err := store.Load("nonexistent")
	assert.ErrorIs(t, err, ErrNotFound)
}

func TestEncryptedFileStoreDelete(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	tok := newLargeTestToken("test-client")
	require.NoError(t, store.Save(tok.ClientID, tok))
	require.NoError(t, store.Delete("test-client"))

	_, err := store.Load("test-client")
	assert.ErrorIs(t, err, ErrNotFound)
}

func TestEncryptedFileStoreSaveEmptyClientID(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	err := store.Save("", newLargeTestToken("x"))
	assert.ErrorIs(t, err, ErrEmptyClientID)
}

func TestEncryptedFileStoreProbe(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	assert.True(t, store.Probe())
}

func TestEncryptedFileStoreCorruptMasterKeyFailsLoad(t *testing.T) {
	store, _ := newTestEncryptedStore(t)

	tok := newLargeTestToken("test-client")
	require.NoError(t, store.Save(tok.ClientID, tok))

	// A fresh store whose keyring holds a corrupted key must fail to decrypt
	// rather than return garbage or mint a new key.
	require.NoError(t, keyring.Set("test-service", masterKeyUser, "not-base64!"))
	fresh := NewEncryptedFileStore[Token]("test-service", store.file.filePath, JSONCodec[Token]{})
	assert.False(t, fresh.Probe())
	_, err := fresh.Load("test-client")
	require.Error(t, err)
	assert.NotErrorIs(t, err, ErrNotFound)
}

func TestEncryptedFileStoreNilCodecPanics(t *testing.T) {
	assert.Panics(t, func() {
		NewEncryptedFileStore[string]("svc", "path", nil)
	})
}

func TestEncryptedFileStoreString(t *testing.T) {
	store, path := newTestEncryptedStore(t)
	assert.Equal(t, "encrypted-file: "+path, store.String())
}