package main

import (
	"context"
	"errors"
	"fmt"
	"os"
	stdpath "path"
	"strings"
	"time"

	"github.com/alcionai/clues"
	msgraphsdk "github.com/microsoftgraph/msgraph-sdk-go"
	"github.com/microsoftgraph/msgraph-sdk-go/models"
	"github.com/microsoftgraph/msgraph-sdk-go/users"
	"golang.org/x/exp/slices"

	"github.com/alcionai/corso/src/internal/common/dttm"
	"github.com/alcionai/corso/src/internal/common/ptr"
	"github.com/alcionai/corso/src/internal/m365/graph"
	"github.com/alcionai/corso/src/internal/tester"
	"github.com/alcionai/corso/src/pkg/filters"
	"github.com/alcionai/corso/src/pkg/logger"
	"github.com/alcionai/corso/src/pkg/path"
)

// ---------------------------------------------------------------------------
// types, consts, etc
// ---------------------------------------------------------------------------

type permissionInfo struct {
	entityID string
	roles    []string
}

const (
	owner = "owner"
)

// ---------------------------------------------------------------------------
// main
// ---------------------------------------------------------------------------

func main() {
	ls := logger.Settings{
		File:        logger.GetLogFile(""),
		Level:       logger.LLInfo,
		PIIHandling: logger.PIIPlainText,
	}

	ctx, log := logger.Seed(context.Background(), ls)
	defer func() {
		_ = log.Sync() // flush all logs in the buffer
	}()

	adapter, err := graph.CreateAdapter(
		tester.GetM365TenantID(ctx),
		os.Getenv("AZURE_CLIENT_ID"),
		os.Getenv("AZURE_CLIENT_SECRET"))
	if err != nil {
		fatal(ctx, "creating adapter", err)
	}

	var (
		client           = msgraphsdk.NewGraphServiceClient(adapter)
		testUser         = tester.GetM365UserID(ctx)
		testSite         = tester.GetM365SiteID(ctx)
		testService      = os.Getenv("SANITY_RESTORE_SERVICE")
		folder           = strings.TrimSpace(os.Getenv("SANITY_RESTORE_FOLDER"))
		startTime, _     = mustGetTimeFromName(ctx, folder)
		dataFolder       = os.Getenv("TEST_DATA")
		baseBackupFolder = os.Getenv("BASE_BACKUP")
	)

	ctx = clues.Add(
		ctx,
		"resource_owner", testUser,
		"service", testService,
		"sanity_restore_folder", folder,
		"start_time", startTime.Format(time.RFC3339Nano))

	logger.Ctx(ctx).Info("starting sanity test check")

	switch testService {
	case "exchange":
		checkEmailRestoration(ctx, client, testUser, folder, dataFolder, baseBackupFolder, startTime)
	case "onedrive":
		checkOneDriveRestoration(ctx, client, testUser, folder, dataFolder, startTime)
	case "sharepoint":
		checkSharePointRestoration(ctx, client, testSite, testUser, folder, dataFolder, startTime)
	default:
		fatal(ctx, "no service specified", nil)
	}
}

// ---------------------------------------------------------------------------
// exchange
// ---------------------------------------------------------------------------

// checkEmailRestoration verifies that the emails count in restored folder is equivalent to
// emails in actual m365 account
func checkEmailRestoration(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	testUser, folderName, dataFolder, baseBackupFolder string,
	startTime time.Time,
) {
	var (
		restoreFolder    models.MailFolderable
		itemCount        = make(map[string]int32)
		restoreItemCount = make(map[string]int32)
		builder          = client.Users().ByUserId(testUser).MailFolders()
	)

	for {
		result, err := builder.Get(ctx, nil)
		if err != nil {
			fatal(ctx, "getting mail folders", err)
		}

		values := result.GetValue()

		for _, v := range values {
			itemName := ptr.Val(v.GetDisplayName())

			if itemName == folderName {
				restoreFolder = v
				continue
			}

			if itemName == dataFolder || itemName == baseBackupFolder {
				// otherwise, recursively aggregate all child folders.
				getAllMailSubFolders(ctx, client, testUser, v, itemName, dataFolder, itemCount)

				itemCount[itemName] = ptr.Val(v.GetTotalItemCount())
			}
		}

		link, ok := ptr.ValOK(result.GetOdataNextLink())
		if !ok {
			break
		}

		builder = users.NewItemMailFoldersRequestBuilder(link, client.GetAdapter())
	}

	folderID := ptr.Val(restoreFolder.GetId())
	folderName = ptr.Val(restoreFolder.GetDisplayName())
	ctx = clues.Add(
		ctx,
		"restore_folder_id", folderID,
		"restore_folder_name", folderName)

	childFolder, err := client.
		Users().
		ByUserId(testUser).
		MailFolders().
		ByMailFolderId(folderID).
		ChildFolders().
		Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting restore folder child folders", err)
	}

	for _, fld := range childFolder.GetValue() {
		restoreDisplayName := ptr.Val(fld.GetDisplayName())

		// check if folder is the data folder we loaded or the base backup to verify
		// the incremental backup worked fine
		if strings.EqualFold(restoreDisplayName, dataFolder) || strings.EqualFold(restoreDisplayName, baseBackupFolder) {
			count, _ := ptr.ValOK(fld.GetTotalItemCount())

			restoreItemCount[restoreDisplayName] = count
			checkAllSubFolder(ctx, client, fld, testUser, restoreDisplayName, dataFolder, restoreItemCount)
		}
	}

	verifyEmailData(ctx, restoreItemCount, itemCount)
}

func verifyEmailData(ctx context.Context, restoreMessageCount, messageCount map[string]int32) {
	for fldName, expected := range messageCount {
		got := restoreMessageCount[fldName]

		assert(
			ctx,
			func() bool { return expected == got },
			fmt.Sprintf("Restore item counts do not match: %s", fldName),
			expected,
			got)
	}
}

// getAllSubFolder will recursively check for all subfolders and get the corresponding
// email count.
func getAllMailSubFolders(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	testUser string,
	r models.MailFolderable,
	parentFolder,
	dataFolder string,
	messageCount map[string]int32,
) {
	var (
		folderID       = ptr.Val(r.GetId())
		count    int32 = 99
		options        = &users.ItemMailFoldersItemChildFoldersRequestBuilderGetRequestConfiguration{
			QueryParameters: &users.ItemMailFoldersItemChildFoldersRequestBuilderGetQueryParameters{
				Top: &count,
			},
		}
	)

	ctx = clues.Add(ctx, "parent_folder_id", folderID)

	childFolder, err := client.
		Users().
		ByUserId(testUser).
		MailFolders().
		ByMailFolderId(folderID).
		ChildFolders().
		Get(ctx, options)
	if err != nil {
		fatal(ctx, "getting mail subfolders", err)
	}

	for _, child := range childFolder.GetValue() {
		var (
			childDisplayName = ptr.Val(child.GetDisplayName())
			childFolderCount = ptr.Val(child.GetChildFolderCount())
			//nolint:forbidigo
			fullFolderName = stdpath.Join(parentFolder, childDisplayName)
		)

		if filters.PathContains([]string{dataFolder}).Compare(fullFolderName) {
			messageCount[fullFolderName] = ptr.Val(child.GetTotalItemCount())
			// recursively check for subfolders
			if childFolderCount > 0 {
				parentFolder := fullFolderName

				getAllMailSubFolders(ctx, client, testUser, child, parentFolder, dataFolder, messageCount)
			}
		}
	}
}

// checkAllSubFolder will recursively traverse inside the restore folder and
// verify that data matched in all subfolders
func checkAllSubFolder(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	r models.MailFolderable,
	testUser,
	parentFolder,
	dataFolder string,
	restoreMessageCount map[string]int32,
) {
	var (
		folderID       = ptr.Val(r.GetId())
		count    int32 = 99
		options        = &users.ItemMailFoldersItemChildFoldersRequestBuilderGetRequestConfiguration{
			QueryParameters: &users.ItemMailFoldersItemChildFoldersRequestBuilderGetQueryParameters{
				Top: &count,
			},
		}
	)

	childFolder, err := client.
		Users().
		ByUserId(testUser).
		MailFolders().
		ByMailFolderId(folderID).
		ChildFolders().
		Get(ctx, options)
	if err != nil {
		fatal(ctx, "getting mail subfolders", err)
	}

	for _, child := range childFolder.GetValue() {
		var (
			childDisplayName = ptr.Val(child.GetDisplayName())
			//nolint:forbidigo
			fullFolderName = stdpath.Join(parentFolder, childDisplayName)
		)

		if filters.PathContains([]string{dataFolder}).Compare(fullFolderName) {
			childTotalCount, _ := ptr.ValOK(child.GetTotalItemCount())
			restoreMessageCount[fullFolderName] = childTotalCount
		}

		childFolderCount := ptr.Val(child.GetChildFolderCount())

		if childFolderCount > 0 {
			parentFolder := fullFolderName
			checkAllSubFolder(ctx, client, child, testUser, parentFolder, dataFolder, restoreMessageCount)
		}
	}
}

// ---------------------------------------------------------------------------
// oneDrive
// ---------------------------------------------------------------------------

func checkOneDriveRestoration(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	userID, folderName, dataFolder string,
	startTime time.Time,
) {
	drive, err := client.
		Users().
		ByUserId(userID).
		Drive().
		Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting the drive:", err)
	}

	checkDriveRestoration(
		ctx,
		client,
		path.OneDriveService,
		folderName,
		ptr.Val(drive.GetId()),
		ptr.Val(drive.GetName()),
		dataFolder,
		startTime,
		false)
}

// ---------------------------------------------------------------------------
// sharePoint
// ---------------------------------------------------------------------------

func checkSharePointRestoration(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	siteID, userID, folderName, dataFolder string,
	startTime time.Time,
) {
	drive, err := client.
		Sites().
		BySiteId(siteID).
		Drive().
		Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting the drive:", err)
	}

	checkDriveRestoration(
		ctx,
		client,
		path.SharePointService,
		folderName,
		ptr.Val(drive.GetId()),
		ptr.Val(drive.GetName()),
		dataFolder,
		startTime,
		true)
}

// ---------------------------------------------------------------------------
// shared drive tests
// ---------------------------------------------------------------------------

func checkDriveRestoration(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	service path.ServiceType,
	folderName,
	driveID,
	driveName,
	dataFolder string,
	startTime time.Time,
	skipPermissionTest bool,
) {
	var (
		// map itemID -> item size
		fileSizes = make(map[string]int64)
		// map itemID -> permission id -> []permission roles
		folderPermissions         = make(map[string][]permissionInfo)
		restoreFile               = make(map[string]int64)
		restoredFolderPermissions = make(map[string][]permissionInfo)
	)

	var restoreFolderID string

	ctx = clues.Add(ctx, "drive_id", driveID, "drive_name", driveName)

	response, err := client.
		Drives().
		ByDriveId(driveID).
		Items().
		ByDriveItemId("root").
		Children().
		Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting drive by id", err)
	}

	for _, driveItem := range response.GetValue() {
		var (
			itemID   = ptr.Val(driveItem.GetId())
			itemName = ptr.Val(driveItem.GetName())
		)

		if itemName == folderName {
			restoreFolderID = itemID
			continue
		}

		if itemName != dataFolder {
			logAndPrint(ctx, "test data for folder: %s", dataFolder)
			continue
		}

		// if it's a file check the size
		if driveItem.GetFile() != nil {
			fileSizes[itemName] = ptr.Val(driveItem.GetSize())
		}

		if driveItem.GetFolder() == nil && driveItem.GetPackage() == nil {
			continue
		}

		// currently we don't restore blank folders.
		// skip permission check for empty folders
		if ptr.Val(driveItem.GetFolder().GetChildCount()) == 0 {
			logAndPrint(ctx, "skipped empty folder: %s", itemName)
			continue
		}

		folderPermissions[itemName] = permissionIn(ctx, client, driveID, itemID)
		getOneDriveChildFolder(ctx, client, driveID, itemID, itemName, fileSizes, folderPermissions, startTime)
	}

	getRestoredDrive(ctx, client, driveID, restoreFolderID, restoreFile, restoredFolderPermissions, startTime)

	checkRestoredDriveItemPermissions(
		ctx,
		service,
		skipPermissionTest,
		folderPermissions,
		restoredFolderPermissions)

	for fileName, expected := range fileSizes {
		logAndPrint(ctx, "checking for file: %s", fileName)

		got := restoreFile[fileName]

		assert(
			ctx,
			func() bool { return expected == got },
			fmt.Sprintf("different file size: %s", fileName),
			expected,
			got)
	}

	fmt.Println("Success")
}

func checkRestoredDriveItemPermissions(
	ctx context.Context,
	service path.ServiceType,
	skip bool,
	folderPermissions map[string][]permissionInfo,
	restoredFolderPermissions map[string][]permissionInfo,
) {
	if skip {
		return
	}

	/**
		TODO: replace this check with testElementsMatch
		from internal/connecter/graph_connector_helper_test.go
	**/

	for folderName, permissions := range folderPermissions {
		logAndPrint(ctx, "checking for folder: %s", folderName)

		restoreFolderPerm := restoredFolderPermissions[folderName]

		if len(permissions) < 1 {
			logAndPrint(ctx, "no permissions found in: %s", folderName)
			continue
		}

		permCheck := func() bool { return len(permissions) == len(restoreFolderPerm) }

		if service == path.SharePointService {
			permCheck = func() bool { return len(permissions) <= len(restoreFolderPerm) }
		}

		assert(
			ctx,
			permCheck,
			fmt.Sprintf("wrong number of restored permissions: %s", folderName),
			permissions,
			restoreFolderPerm)

		for _, perm := range permissions {
			eqID := func(pi permissionInfo) bool { return strings.EqualFold(pi.entityID, perm.entityID) }
			i := slices.IndexFunc(restoreFolderPerm, eqID)

			assert(
				ctx,
				func() bool { return i >= 0 },
				fmt.Sprintf("permission was restored in: %s", folderName),
				perm.entityID,
				restoreFolderPerm)

			// permissions should be sorted, so a by-index comparison works
			restored := restoreFolderPerm[i]

			assert(
				ctx,
				func() bool { return slices.Equal(perm.roles, restored.roles) },
				fmt.Sprintf("different roles restored: %s", folderName),
				perm.roles,
				restored.roles)
		}
	}
}

func getOneDriveChildFolder(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	driveID, itemID, parentName string,
	fileSizes map[string]int64,
	folderPermission map[string][]permissionInfo,
	startTime time.Time,
) {
	response, err := client.Drives().ByDriveId(driveID).Items().ByDriveItemId(itemID).Children().Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting child folder", err)
	}

	for _, driveItem := range response.GetValue() {
		var (
			itemID   = ptr.Val(driveItem.GetId())
			itemName = ptr.Val(driveItem.GetName())
			fullName = parentName + "/" + itemName
		)

		folderTime, hasTime := mustGetTimeFromName(ctx, itemName)
		if !isWithinTimeBound(ctx, startTime, folderTime, hasTime) {
			continue
		}

		// if it's a file check the size
		if driveItem.GetFile() != nil {
			fileSizes[fullName] = ptr.Val(driveItem.GetSize())
		}

		if driveItem.GetFolder() == nil && driveItem.GetPackage() == nil {
			continue
		}

		// currently we don't restore blank folders.
		// skip permission check for empty folders
		if ptr.Val(driveItem.GetFolder().GetChildCount()) == 0 {
			logAndPrint(ctx, "skipped empty folder: %s", fullName)

			continue
		}

		folderPermission[fullName] = permissionIn(ctx, client, driveID, itemID)
		getOneDriveChildFolder(ctx, client, driveID, itemID, fullName, fileSizes, folderPermission, startTime)
	}
}

func getRestoredDrive(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	driveID, restoreFolderID string,
	restoreFile map[string]int64,
	restoreFolder map[string][]permissionInfo,
	startTime time.Time,
) {
	restored, err := client.
		Drives().
		ByDriveId(driveID).
		Items().
		ByDriveItemId(restoreFolderID).
		Children().
		Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting child folder", err)
	}

	for _, item := range restored.GetValue() {
		var (
			itemID   = ptr.Val(item.GetId())
			itemName = ptr.Val(item.GetName())
			itemSize = ptr.Val(item.GetSize())
		)

		if item.GetFile() != nil {
			restoreFile[itemName] = itemSize
			continue
		}

		if item.GetFolder() == nil && item.GetPackage() == nil {
			continue
		}

		restoreFolder[itemName] = permissionIn(ctx, client, driveID, itemID)
		getOneDriveChildFolder(ctx, client, driveID, itemID, itemName, restoreFile, restoreFolder, startTime)
	}
}

// ---------------------------------------------------------------------------
// permission helpers
// ---------------------------------------------------------------------------

func permissionIn(
	ctx context.Context,
	client *msgraphsdk.GraphServiceClient,
	driveID, itemID string,
) []permissionInfo {
	pi := []permissionInfo{}

	pcr, err := client.
		Drives().
		ByDriveId(driveID).
		Items().
		ByDriveItemId(itemID).
		Permissions().
		Get(ctx, nil)
	if err != nil {
		fatal(ctx, "getting permission", err)
	}

	for _, perm := range pcr.GetValue() {
		if perm.GetGrantedToV2() == nil {
			continue
		}

		var (
			gv2      = perm.GetGrantedToV2()
			permInfo = permissionInfo{}
			entityID string
		)

		// TODO: replace with filterUserPermissions in onedrive item.go
		if gv2.GetUser() != nil {
			entityID = ptr.Val(gv2.GetUser().GetId())
		} else if gv2.GetGroup() != nil {
			entityID = ptr.Val(gv2.GetGroup().GetId())
		}

		roles := filterSlice(perm.GetRoles(), owner)
		for _, role := range roles {
			permInfo.entityID = entityID
			permInfo.roles = append(permInfo.roles, role)
		}

		if len(roles) > 0 {
			slices.Sort(permInfo.roles)
			pi = append(pi, permInfo)
		}
	}

	return pi
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

func fatal(ctx context.Context, msg string, err error) {
	logger.CtxErr(ctx, err).Error("test failure: " + msg)
	fmt.Println(msg+": ", err)
	os.Exit(1)
}

func mustGetTimeFromName(ctx context.Context, name string) (time.Time, bool) {
	t, err := dttm.ExtractTime(name)
	if err != nil && !errors.Is(err, dttm.ErrNoTimeString) {
		fatal(ctx, "extracting time from name: "+name, err)
	}

	return t, !errors.Is(err, dttm.ErrNoTimeString)
}

func isWithinTimeBound(ctx context.Context, bound, check time.Time, hasTime bool) bool {
	if hasTime {
		if bound.Before(check) {
			logger.Ctx(ctx).
				With("boundary_time", bound, "check_time", check).
				Info("skipping restore folder: not older than time bound")

			return false
		}
	}

	return true
}

func filterSlice(sl []string, remove string) []string {
	r := []string{}

	for _, s := range sl {
		if !strings.EqualFold(s, remove) {
			r = append(r, s)
		}
	}

	return r
}

func assert(
	ctx context.Context,
	passes func() bool,
	header string,
	expect, current any,
) {
	if passes() {
		return
	}

	header = "Error: " + header
	expected := fmt.Sprintf("* Expected: %+v", expect)
	got := fmt.Sprintf("* Current: %+v", current)

	logger.Ctx(ctx).Info(strings.Join([]string{header, expected, got}, " "))

	fmt.Println(header)
	fmt.Println(expected)
	fmt.Println(got)

	os.Exit(1)
}

func logAndPrint(ctx context.Context, tmpl string, vs ...any) {
	logger.Ctx(ctx).Infof(tmpl, vs...)
	fmt.Printf(tmpl+"\n", vs...)
}