package sharepoint

import (
	"context"
	"net/http"
	"strings"

	"github.com/microsoftgraph/msgraph-sdk-go/drives"
	"github.com/microsoftgraph/msgraph-sdk-go/models"

	"github.com/alcionai/corso/src/internal/common/ptr"
	"github.com/alcionai/corso/src/internal/m365/onedrive"
	odConsts "github.com/alcionai/corso/src/internal/m365/onedrive/consts"
	"github.com/alcionai/corso/src/pkg/backup/details"
	"github.com/alcionai/corso/src/pkg/control"
	"github.com/alcionai/corso/src/pkg/path"
	"github.com/alcionai/corso/src/pkg/selectors"
	"github.com/alcionai/corso/src/pkg/services/m365/api"
)

var _ onedrive.BackupHandler = &libraryBackupHandler{}

type libraryBackupHandler struct {
	ac    api.Drives
	scope selectors.SharePointScope
}

func (h libraryBackupHandler) Get(
	ctx context.Context,
	url string,
	headers map[string]string,
) (*http.Response, error) {
	return h.ac.Get(ctx, url, headers)
}

func (h libraryBackupHandler) PathPrefix(
	tenantID, resourceOwner, driveID string,
) (path.Path, error) {
	return path.Build(
		tenantID,
		resourceOwner,
		path.SharePointService,
		path.LibrariesCategory,
		false,
		odConsts.DrivesPathDir,
		driveID,
		odConsts.RootPathDir)
}

func (h libraryBackupHandler) CanonicalPath(
	folders *path.Builder,
	tenantID, resourceOwner string,
) (path.Path, error) {
	return folders.ToDataLayerSharePointPath(tenantID, resourceOwner, path.LibrariesCategory, false)
}

func (h libraryBackupHandler) ServiceCat() (path.ServiceType, path.CategoryType) {
	return path.SharePointService, path.LibrariesCategory
}

func (h libraryBackupHandler) NewDrivePager(
	resourceOwner string,
	fields []string,
) api.DrivePager {
	return h.ac.NewSiteDrivePager(resourceOwner, fields)
}

func (h libraryBackupHandler) NewItemPager(
	driveID, link string,
	fields []string,
) api.DriveItemEnumerator {
	return h.ac.NewItemPager(driveID, link, fields)
}

func (h libraryBackupHandler) AugmentItemInfo(
	dii details.ItemInfo,
	item models.DriveItemable,
	size int64,
	parentPath *path.Builder,
) details.ItemInfo {
	return augmentItemInfo(dii, item, size, parentPath)
}

// constructWebURL is a helper function for recreating the webURL
// for the originating SharePoint site. Uses the additionalData map
// from a models.DriveItemable that possesses a downloadURL within the map.
// Returns "" if the map is nil or key is not present.
func constructWebURL(adtl map[string]any) string {
	var (
		desiredKey = "@microsoft.graph.downloadUrl"
		sep        = `/_layouts`
		url        string
	)

	if adtl == nil {
		return url
	}

	r := adtl[desiredKey]
	point, ok := r.(*string)

	if !ok {
		return url
	}

	value := ptr.Val(point)
	if len(value) == 0 {
		return url
	}

	temp := strings.Split(value, sep)
	url = temp[0]

	return url
}

func (h libraryBackupHandler) FormatDisplayPath(
	driveName string,
	pb *path.Builder,
) string {
	return "/" + driveName + "/" + pb.String()
}

func (h libraryBackupHandler) NewLocationIDer(
	driveID string,
	elems ...string,
) details.LocationIDer {
	return details.NewSharePointLocationIDer(driveID, elems...)
}

func (h libraryBackupHandler) GetItemPermission(
	ctx context.Context,
	driveID, itemID string,
) (models.PermissionCollectionResponseable, error) {
	return h.ac.GetItemPermission(ctx, driveID, itemID)
}

func (h libraryBackupHandler) GetItem(
	ctx context.Context,
	driveID, itemID string,
) (models.DriveItemable, error) {
	return h.ac.GetItem(ctx, driveID, itemID)
}

func (h libraryBackupHandler) IsAllPass() bool {
	return h.scope.IsAny(selectors.SharePointLibraryFolder)
}

func (h libraryBackupHandler) IncludesDir(dir string) bool {
	return h.scope.Matches(selectors.SharePointLibraryFolder, dir)
}

// ---------------------------------------------------------------------------
// Restore
// ---------------------------------------------------------------------------

var _ onedrive.RestoreHandler = &libraryRestoreHandler{}

type libraryRestoreHandler struct {
	ac api.Drives
}

func NewRestoreHandler(ac api.Client) *libraryRestoreHandler {
	return &libraryRestoreHandler{ac.Drives()}
}

func (h libraryRestoreHandler) AugmentItemInfo(
	dii details.ItemInfo,
	item models.DriveItemable,
	size int64,
	parentPath *path.Builder,
) details.ItemInfo {
	return augmentItemInfo(dii, item, size, parentPath)
}

func (h libraryRestoreHandler) NewItemContentUpload(
	ctx context.Context,
	driveID, itemID string,
) (models.UploadSessionable, error) {
	return h.ac.NewItemContentUpload(ctx, driveID, itemID)
}

func (h libraryRestoreHandler) DeleteItemPermission(
	ctx context.Context,
	driveID, itemID, permissionID string,
) error {
	return h.ac.DeleteItemPermission(ctx, driveID, itemID, permissionID)
}

func (h libraryRestoreHandler) PostItemPermissionUpdate(
	ctx context.Context,
	driveID, itemID string,
	body *drives.ItemItemsItemInvitePostRequestBody,
) (drives.ItemItemsItemInviteResponseable, error) {
	return h.ac.PostItemPermissionUpdate(ctx, driveID, itemID, body)
}

func (h libraryRestoreHandler) PostItemInContainer(
	ctx context.Context,
	driveID, parentFolderID string,
	newItem models.DriveItemable,
	onCollision control.CollisionPolicy,
) (models.DriveItemable, error) {
	return h.ac.PostItemInContainer(ctx, driveID, parentFolderID, newItem, onCollision)
}

func (h libraryRestoreHandler) GetFolderByName(
	ctx context.Context,
	driveID, parentFolderID, folderName string,
) (models.DriveItemable, error) {
	return h.ac.GetFolderByName(ctx, driveID, parentFolderID, folderName)
}

func (h libraryRestoreHandler) GetRootFolder(
	ctx context.Context,
	driveID string,
) (models.DriveItemable, error) {
	return h.ac.GetRootFolder(ctx, driveID)
}

// ---------------------------------------------------------------------------
// Common
// ---------------------------------------------------------------------------

func augmentItemInfo(
	dii details.ItemInfo,
	item models.DriveItemable,
	size int64,
	parentPath *path.Builder,
) details.ItemInfo {
	var driveName, siteID, driveID, weburl, creatorEmail string

	// TODO: we rely on this info for details/restore lookups,
	// so if it's nil we have an issue, and will need an alternative
	// way to source the data.

	if item.GetCreatedBy() != nil && item.GetCreatedBy().GetUser() != nil {
		// User is sometimes not available when created via some
		// external applications (like backup/restore solutions)
		additionalData := item.GetCreatedBy().GetUser().GetAdditionalData()

		ed, ok := additionalData["email"]
		if !ok {
			ed = additionalData["displayName"]
		}

		if ed != nil {
			creatorEmail = *ed.(*string)
		}
	}

	gsi := item.GetSharepointIds()
	if gsi != nil {
		siteID = ptr.Val(gsi.GetSiteId())
		weburl = ptr.Val(gsi.GetSiteUrl())

		if len(weburl) == 0 {
			weburl = constructWebURL(item.GetAdditionalData())
		}
	}

	if item.GetParentReference() != nil {
		driveID = ptr.Val(item.GetParentReference().GetDriveId())
		driveName = strings.TrimSpace(ptr.Val(item.GetParentReference().GetName()))
	}

	var pps string
	if parentPath != nil {
		pps = parentPath.String()
	}

	dii.SharePoint = &details.SharePointInfo{
		Created:    ptr.Val(item.GetCreatedDateTime()),
		DriveID:    driveID,
		DriveName:  driveName,
		ItemName:   ptr.Val(item.GetName()),
		ItemType:   details.SharePointLibrary,
		Modified:   ptr.Val(item.GetLastModifiedDateTime()),
		Owner:      creatorEmail,
		ParentPath: pps,
		SiteID:     siteID,
		Size:       size,
		WebURL:     weburl,
	}

	return dii
}