package testutil

import (
	"bytes"
	"flag"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"github.com/spf13/cobra"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// UpdateGolden writes out the golden files with the latest values, rather than failing the test.
var shouldUpdateGolden = flag.Bool("update", false, "update golden files")

const (
	testdataDir      = "testdata"
	goldenDirSuffix  = "GoldenOutput"
	goldenFileSuffix = ".golden"
)

// CmdTest is a command to be run on the command line as a test
type CmdTest struct {
	// The name of the test. This will be used when generating golden
	// files
	Name string

	// The values that would be inputted to airshipctl as commands, flags,
	// and arguments. The initial "airshipctl" is implied
	CmdLine string

	// The instantiated version of the root airshipctl command to test
	Cmd *cobra.Command

	// The expected error
	Error error
}

// RunTest either asserts that a specific command's output matches the expected
// output from its golden file, or generates golden files if the -update flag
// is passed
func RunTest(t *testing.T, test *CmdTest) {
	t.Helper()
	cmd := test.Cmd

	actual := &bytes.Buffer{}
	cmd.SetOut(actual)

	args := strings.Fields(test.CmdLine)
	cmd.SetArgs(args)

	err := cmd.Execute()
	checkError(t, err, test.Error)

	if *shouldUpdateGolden {
		updateGolden(t, test, actual.Bytes())
	} else {
		assertEqualGolden(t, test, actual.Bytes())
	}
}

func updateGolden(t *testing.T, test *CmdTest, actual []byte) {
	t.Helper()
	goldenDir := filepath.Join(testdataDir, t.Name()+goldenDirSuffix)
	err := os.MkdirAll(goldenDir, 0775)
	require.NoErrorf(t, err, "Failed to create golden directory %s", goldenDir)
	t.Logf("Created %s", goldenDir)
	goldenFilePath := filepath.Join(goldenDir, test.Name+goldenFileSuffix)
	t.Logf("Updating golden file: %s", goldenFilePath)
	err = ioutil.WriteFile(goldenFilePath, normalize(actual), 0666)
	require.NoErrorf(t, err, "Failed to update golden file at %s", goldenFilePath)
}

func assertEqualGolden(t *testing.T, test *CmdTest, actual []byte) {
	t.Helper()
	goldenDir := filepath.Join(testdataDir, t.Name()+goldenDirSuffix)
	goldenFilePath := filepath.Join(goldenDir, test.Name+goldenFileSuffix)
	golden, err := ioutil.ReadFile(goldenFilePath)
	require.NoErrorf(t, err, "Failed while reading golden file at %s", goldenFilePath)
	assert.Equal(t, string(golden), string(actual))
}

func checkError(t *testing.T, actual, expected error) {
	t.Helper()
	if expected == nil {
		require.NoError(t, actual)
	} else {
		require.Error(t, actual)
	}
}

func normalize(in []byte) []byte {
	return bytes.Replace(in, []byte("\r\n"), []byte("\n"), -1)
}