package app

import (
	"io"
	"strings"
	"testing"

	"github.com/mattermost/mattermost-server/v6/plugin/plugintest/mock"
	"github.com/mattermost/mattermost-server/v6/shared/filestore"
	"github.com/mattermost/mattermost-server/v6/shared/filestore/mocks"
	"github.com/stretchr/testify/assert"
)

const (
	testFileName = "temp-file-name"
	testRootID   = "test-root-id"
	testFilePath = "1/test-root-id/temp-file-name"
)

type TestError struct{}

func (err *TestError) Error() string { return "Mocked File backend error" }

func TestGetFileReader(t *testing.T) {
	th, _ := SetupTestHelper(t)
	mockedReadCloseSeek := &mocks.ReadCloseSeeker{}
	t.Run("should get file reader from filestore successfully", func(t *testing.T) {
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend
		readerFunc := func(path string) filestore.ReadCloseSeeker {
			return mockedReadCloseSeek
		}

		readerErrorFunc := func(path string) error {
			return nil
		}

		fileExistsFunc := func(path string) bool {
			return true
		}

		fileExistsErrorFunc := func(path string) error {
			return nil
		}

		mockedFileBackend.On("Reader", testFilePath).Return(readerFunc, readerErrorFunc)
		mockedFileBackend.On("FileExists", testFilePath).Return(fileExistsFunc, fileExistsErrorFunc)
		actual, _ := th.App.GetFileReader("1", testRootID, testFileName)
		assert.Equal(t, mockedReadCloseSeek, actual)
	})

	t.Run("should get error from filestore when file exists return error", func(t *testing.T) {
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend
		mockedError := &TestError{}
		readerFunc := func(path string) filestore.ReadCloseSeeker {
			return mockedReadCloseSeek
		}

		readerErrorFunc := func(path string) error {
			return nil
		}

		fileExistsFunc := func(path string) bool {
			return false
		}

		fileExistsErrorFunc := func(path string) error {
			return mockedError
		}

		mockedFileBackend.On("Reader", testFilePath).Return(readerFunc, readerErrorFunc)
		mockedFileBackend.On("FileExists", testFilePath).Return(fileExistsFunc, fileExistsErrorFunc)
		actual, err := th.App.GetFileReader("1", testRootID, testFileName)
		assert.Error(t, err, mockedError)
		assert.Nil(t, actual)
	})

	t.Run("should return error, if get reader from file backend returns error", func(t *testing.T) {
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend
		mockedError := &TestError{}
		readerFunc := func(path string) filestore.ReadCloseSeeker {
			return nil
		}

		readerErrorFunc := func(path string) error {
			return mockedError
		}

		fileExistsFunc := func(path string) bool {
			return false
		}

		fileExistsErrorFunc := func(path string) error {
			return nil
		}

		mockedFileBackend.On("Reader", testFilePath).Return(readerFunc, readerErrorFunc)
		mockedFileBackend.On("FileExists", testFilePath).Return(fileExistsFunc, fileExistsErrorFunc)
		actual, err := th.App.GetFileReader("1", testRootID, testFileName)
		assert.Error(t, err, mockedError)
		assert.Nil(t, actual)
	})

	t.Run("should move file from old filepath to new filepath, if file doesnot exists in new filepath and workspace id is 0", func(t *testing.T) {
		filePath := "0/test-root-id/temp-file-name"
		workspaceid := "0"
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend
		readerFunc := func(path string) filestore.ReadCloseSeeker {
			return mockedReadCloseSeek
		}

		readerErrorFunc := func(path string) error {
			return nil
		}

		fileExistsFunc := func(path string) bool {
			// return true for old path
			return path == testFileName
		}

		fileExistsErrorFunc := func(path string) error {
			return nil
		}

		moveFileFunc := func(oldFileName, newFileName string) error {
			return nil
		}

		mockedFileBackend.On("FileExists", filePath).Return(fileExistsFunc, fileExistsErrorFunc)
		mockedFileBackend.On("FileExists", testFileName).Return(fileExistsFunc, fileExistsErrorFunc)
		mockedFileBackend.On("MoveFile", testFileName, filePath).Return(moveFileFunc)
		mockedFileBackend.On("Reader", filePath).Return(readerFunc, readerErrorFunc)

		actual, _ := th.App.GetFileReader(workspaceid, testRootID, testFileName)
		assert.Equal(t, mockedReadCloseSeek, actual)
	})

	t.Run("should return file reader, if file doesnot exists in new filepath and old file path", func(t *testing.T) {
		filePath := "0/test-root-id/temp-file-name"
		fileName := testFileName
		workspaceid := "0"
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend
		readerFunc := func(path string) filestore.ReadCloseSeeker {
			return mockedReadCloseSeek
		}

		readerErrorFunc := func(path string) error {
			return nil
		}

		fileExistsFunc := func(path string) bool {
			// return true for old path
			return false
		}

		fileExistsErrorFunc := func(path string) error {
			return nil
		}

		moveFileFunc := func(oldFileName, newFileName string) error {
			return nil
		}

		mockedFileBackend.On("FileExists", filePath).Return(fileExistsFunc, fileExistsErrorFunc)
		mockedFileBackend.On("FileExists", testFileName).Return(fileExistsFunc, fileExistsErrorFunc)
		mockedFileBackend.On("MoveFile", fileName, filePath).Return(moveFileFunc)
		mockedFileBackend.On("Reader", filePath).Return(readerFunc, readerErrorFunc)

		actual, _ := th.App.GetFileReader(workspaceid, testRootID, testFileName)
		assert.Equal(t, mockedReadCloseSeek, actual)
	})
}

func TestSaveFile(t *testing.T) {
	th, _ := SetupTestHelper(t)
	mockedReadCloseSeek := &mocks.ReadCloseSeeker{}
	t.Run("should save file to file store using file backend", func(t *testing.T) {
		fileName := "temp-file-name.txt"
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend

		writeFileFunc := func(reader io.Reader, path string) int64 {
			paths := strings.Split(path, "/")
			assert.Equal(t, "1", paths[0])
			assert.Equal(t, testRootID, paths[1])
			fileName = paths[2]
			return int64(10)
		}

		writeFileErrorFunc := func(reader io.Reader, filePath string) error {
			return nil
		}

		mockedFileBackend.On("WriteFile", mockedReadCloseSeek, mock.Anything).Return(writeFileFunc, writeFileErrorFunc)
		actual, err := th.App.SaveFile(mockedReadCloseSeek, "1", testRootID, fileName)
		assert.Equal(t, fileName, actual)
		assert.Nil(t, err)
	})

	t.Run("should save .jpeg file as jpg file to file store using file backend", func(t *testing.T) {
		fileName := "temp-file-name.jpeg"
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend

		writeFileFunc := func(reader io.Reader, path string) int64 {
			paths := strings.Split(path, "/")
			assert.Equal(t, "1", paths[0])
			assert.Equal(t, "test-root-id", paths[1])
			assert.Equal(t, "jpg", strings.Split(paths[2], ".")[1])
			return int64(10)
		}

		writeFileErrorFunc := func(reader io.Reader, filePath string) error {
			return nil
		}

		mockedFileBackend.On("WriteFile", mockedReadCloseSeek, mock.Anything).Return(writeFileFunc, writeFileErrorFunc)
		actual, err := th.App.SaveFile(mockedReadCloseSeek, "1", "test-root-id", fileName)
		assert.Nil(t, err)
		assert.NotNil(t, actual)
	})

	t.Run("should return error when fileBackend.WriteFile returns error", func(t *testing.T) {
		fileName := "temp-file-name.jpeg"
		mockedFileBackend := &mocks.FileBackend{}
		th.App.filesBackend = mockedFileBackend
		mockedError := &TestError{}

		writeFileFunc := func(reader io.Reader, path string) int64 {
			paths := strings.Split(path, "/")
			assert.Equal(t, "1", paths[0])
			assert.Equal(t, "test-root-id", paths[1])
			assert.Equal(t, "jpg", strings.Split(paths[2], ".")[1])
			return int64(10)
		}

		writeFileErrorFunc := func(reader io.Reader, filePath string) error {
			return mockedError
		}

		mockedFileBackend.On("WriteFile", mockedReadCloseSeek, mock.Anything).Return(writeFileFunc, writeFileErrorFunc)
		actual, err := th.App.SaveFile(mockedReadCloseSeek, "1", "test-root-id", fileName)
		assert.Equal(t, "", actual)
		assert.Equal(t, "unable to store the file in the files storage: Mocked File backend error", err.Error())
	})
}