// SPDX-License-Identifier: Apache-2.0
//
// Copyright The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build windows

package lazyproc_test

import (
	"errors"
	"strings"
	"testing"

	"github.com/prometheus-community/windows_exporter/internal/headers/lazyproc"
	"github.com/stretchr/testify/require"
	"golang.org/x/sys/windows"
)

func TestFind(t *testing.T) {
	t.Parallel()

	kernel32 := windows.NewLazySystemDLL("kernel32.dll")
	missingDLL := windows.NewLazySystemDLL("windows_exporter_missing.dll")

	t.Run("all present", func(t *testing.T) {
		t.Parallel()

		require.NoError(t, lazyproc.Find(kernel32, kernel32.NewProc("GetTickCount64"), kernel32.NewProc("GetSystemInfo")))
		require.NoError(t, lazyproc.Find(kernel32))
	})

	t.Run("missing export", func(t *testing.T) {
		t.Parallel()

		err := lazyproc.Find(kernel32, kernel32.NewProc("GetTickCount64"), kernel32.NewProc("WindowsExporterMissingExport"))
		require.ErrorIs(t, err, errors.ErrUnsupported)
		require.ErrorContains(t, err, "WindowsExporterMissingExport")
	})

	t.Run("missing DLL is reported once", func(t *testing.T) {
		t.Parallel()

		err := lazyproc.Find(missingDLL, missingDLL.NewProc("A"), missingDLL.NewProc("B"))
		require.ErrorIs(t, err, errors.ErrUnsupported)
		require.Equal(t, 1, strings.Count(err.Error(), "windows_exporter_missing.dll"), err.Error())

		// The loader error stays text only, so the error has a single cause.
		require.NotErrorIs(t, err, windows.ERROR_MOD_NOT_FOUND)

		var lazyErr *lazyproc.Error

		require.ErrorAs(t, err, &lazyErr)
		require.Equal(t, "windows_exporter_missing.dll", lazyErr.DLL)
		require.Len(t, lazyErr.Missing, 1)
	})

	t.Run("Once", func(t *testing.T) {
		t.Parallel()

		load := lazyproc.Once(kernel32, kernel32.NewProc("WindowsExporterMissingExport"))

		first := load()
		require.ErrorIs(t, first, errors.ErrUnsupported)
		// The cached error is returned again.
		require.Same(t, first, load())
	})
}