package driveroot

import (
	"strings"

	"github.com/ultisuite/ulti-backend/internal/nextcloud"
)

// NormalizeMountBackend maps stored backend_type to a provider family.
func NormalizeMountBackend(backendType string) string {
	switch strings.TrimSpace(strings.ToLower(backendType)) {
	case "googledrive", "google":
		return "google"
	case "onedrive", "microsoft":
		return "microsoft"
	default:
		return strings.TrimSpace(strings.ToLower(backendType))
	}
}

func isGoogleWorkspaceNativeMime(mimeType string) bool {
	switch strings.TrimSpace(mimeType) {
	case "application/vnd.google-apps.document",
		"application/vnd.google-apps.spreadsheet",
		"application/vnd.google-apps.presentation":
		return true
	default:
		return false
	}
}

func isMicrosoftOfficeMime(mimeType, name string) bool {
	mime := strings.ToLower(strings.TrimSpace(mimeType))
	switch mime {
	case "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
		"application/msword",
		"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
		"application/vnd.ms-excel",
		"application/vnd.openxmlformats-officedocument.presentationml.presentation",
		"application/vnd.ms-powerpoint":
		return true
	}
	ext := ""
	if dot := strings.LastIndex(name, "."); dot >= 0 {
		ext = strings.ToLower(name[dot+1:])
	}
	switch ext {
	case "doc", "docx", "xls", "xlsx", "ppt", "pptx":
		return true
	default:
		return false
	}
}

func providerIDFromETag(etag string) string {
	id := strings.Trim(strings.TrimSpace(etag), "\"")
	if id == "" {
		return ""
	}
	// Google Drive file ids are alphanumeric plus _ and -.
	for _, r := range id {
		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' || r == '-' {
			continue
		}
		return ""
	}
	if len(id) < 10 {
		return ""
	}
	return id
}

// GoogleWorkspaceWebURL builds a browser editor URL for native Google Workspace files.
func GoogleWorkspaceWebURL(mimeType, fileID string) string {
	fileID = strings.TrimSpace(fileID)
	if fileID == "" {
		return ""
	}
	switch strings.TrimSpace(mimeType) {
	case "application/vnd.google-apps.document":
		return "https://docs.google.com/document/d/" + fileID + "/edit"
	case "application/vnd.google-apps.spreadsheet":
		return "https://docs.google.com/spreadsheets/d/" + fileID + "/edit"
	case "application/vnd.google-apps.presentation":
		return "https://docs.google.com/presentation/d/" + fileID + "/edit"
	default:
		return ""
	}
}

func shouldOpenMountExternally(backend, mimeType, name string) bool {
	backend = NormalizeMountBackend(backend)
	if backend == "google" && isGoogleWorkspaceNativeMime(mimeType) {
		return true
	}
	if backend == "microsoft" && isMicrosoftOfficeMime(mimeType, name) {
		return true
	}
	return false
}

// EnrichMountCloudNative marks mount files that should open in the provider's web editor.
func EnrichMountCloudNative(file *nextcloud.FileInfo, mountBackend string) {
	if file == nil || file.Type == "directory" {
		return
	}
	backend := NormalizeMountBackend(mountBackend)
	if backend == "" {
		return
	}
	file.MountBackend = backend
	if !shouldOpenMountExternally(backend, file.MimeType, file.Name) {
		return
	}
	file.OpenExternally = true
	if backend == "google" && isGoogleWorkspaceNativeMime(file.MimeType) {
		if id := providerIDFromETag(file.ETag); id != "" {
			file.ExternalURL = GoogleWorkspaceWebURL(file.MimeType, id)
		}
	}
}

func EnrichMountCloudNativeFiles(files []nextcloud.FileInfo, mountBackend string) []nextcloud.FileInfo {
	for i := range files {
		EnrichMountCloudNative(&files[i], mountBackend)
	}
	return files
}