refactor: thumbnail process flow

- I think we can just use `dicom` schema
to get median instance
- So I remove `getSeriesOfMedianIndex`
- and replace `getInstanceOfMedianIndex`'s args to query object
- that you can pass studyUID, or (studyUID, seriesUID)
- and use sort to make same UID together to get current median instance

api/dicom-web/controller/WADO-RS/service/thumbnail.service.js

@@ -104,15 +104,14 @@ class StudyThumbnailFactory extends ThumbnailFactory {
      * @param {import("../../../../../utils/typeDef/dicom").Uids} uids 
      */
     async getThumbnailInstance() {
-        let medianSeries = await dicomSeriesModel.getSeriesOfMedianIndex(this.uids.studyUID);
-        if (!medianSeries) return undefined;
-
-        let medianInstance = await dicomModel.getInstanceOfMedianIndex(this.uids.studyUID, medianSeries.seriesUID);
+        let medianInstance = await dicomModel.getInstanceOfMedianIndex({
+            studyUID: this.uids.studyUID
+        });
         if (!medianInstance) return undefined;
 
         let instanceFramesObj = await renderedService.getInstanceFrameObj({
             studyUID: this.uids.studyUID,
-            seriesUID: medianSeries.seriesUID,
+            seriesUID: medianInstance.seriesUID,
             instanceUID: medianInstance.instanceUID
         });
 
@@ -131,7 +130,10 @@ class SeriesThumbnailFactory extends ThumbnailFactory {
      * @param {import("../../../../../utils/typeDef/dicom").Uids} uids 
      */
     async getThumbnailInstance() {
-        let medianInstance = await dicomModel.getInstanceOfMedianIndex(this.uids.studyUID, this.uids.seriesUID);
+        let medianInstance = await dicomModel.getInstanceOfMedianIndex({
+            studyUID: this.uids.studyUID,
+            seriesUID: this.uids.seriesUID
+        });
         if (!medianInstance) return undefined;
 
         let instanceFramesObj = await renderedService.getInstanceFrameObj({

models/mongodb/models/dicom.js

@@ -402,21 +402,22 @@ dicomModelSchema.statics.getPathOfInstance = async function(iParam) {
  * @param {string} studyUID 
  * @param {string} seriesUID 
  */
-dicomModelSchema.statics.getInstanceOfMedianIndex = async function (studyUID, seriesUID) {
-    let instanceCountOfSeries = await mongoose.model("dicomSeries").countDocuments({
-        studyUID,
-        seriesUID
+dicomModelSchema.statics.getInstanceOfMedianIndex = async function (query) {
+    let instanceCountOfStudy = await mongoose.model("dicom").countDocuments({
+        studyUID: query.studyUID
     });
 
-    return await mongoose.model("dicom").findOne({
-        studyUID
-    }, {
+    return await mongoose.model("dicom").findOne(query, {
         studyUID: 1,
         seriesUID: 1,
         instanceUID: 1,
         instancePath: 1
     })
-    .skip(instanceCountOfSeries >> 1)
+    .sort({
+        studyUID: 1,
+        seriesUID: 1
+    })
+    .skip(instanceCountOfStudy >> 1)
     .limit(1)
     .exec();
 };

models/mongodb/models/dicomSeries.js

@@ -152,26 +152,6 @@ dicomSeriesSchema.statics.getPathGroupOfInstances = async function(iParam) {
     }
 };
 
-/**
- * 
- * @param {string} studyUID 
- */
-dicomSeriesSchema.statics.getSeriesOfMedianIndex = async function (studyUID) {
-    let seriesCountOfStudy = await mongoose.model("dicomSeries").countDocuments({
-        studyUID
-    });
-
-    return await mongoose.model("dicomSeries").findOne({
-        studyUID
-    }, {
-        studyUID: 1,
-        seriesUID: 1
-    })
-    .skip(seriesCountOfStudy >> 1)
-    .limit(1)
-    .exec();
-};
-
 
 /**
  * @typedef { mongoose.Model<dicomSeriesSchema> & { 
@@ -180,7 +160,6 @@ dicomSeriesSchema.statics.getSeriesOfMedianIndex = async function (studyUID) {
  *      seriesUID: string
  *   }): Promise<import("../../../utils/typeDef/WADO-RS/WADO-RS.def").ImagePathObj[]>;
  * getDicomJson: function(queryOptions: import("../../../utils/typeDef/dicom").DicomJsonMongoQueryOptions): Promise<JSON[]>;
- * getSeriesOfMedianIndex: function(studyUID: string): Promise<any>
  * }} DicomSeriesModel
 */