Resolve "Handle CandidateList"

Closes #29 (closed)

web/services/model/candidateList-model.js

+import * as Messages from "/services/messages/messages.js";
+
+let candidateListModel;
+
+export function getCandidateListModel() {
+  if (candidateListModel == null) {
+    candidateListModel = new CandidateListModel();
+  }
+  return candidateListModel;
+}
+
+class CandidateListModel {
+  constructor() {}
+
+  async getCandidateList(id) {
+    if (this.candidateLists == null) await this.refreshCandidateLists();
+    let candidateListToGet;
+    this.candidateLists.forEach((candidateList) => {
+      if (candidateList.ID == id) candidateListToGet = candidateList;
+    });
+    return candidateListToGet;
+  }
+
+  async getCandidateLists() {
+    if (this.candidateLists == null) {
+      try {
+        const response = await fetch("/api/CandidateList/", {
+          method: "GET",
+          headers: new Headers({
+            "XSRF-Token": this.current_user.xsrftoken,
+          }),
+        });
+        if (response.status !== 200) {
+          throw new Error(
+            `CandidateLists could not be fetched (status ${response.status})`
+          );
+        }
+        this.candidateLists = await response.json();
+      } catch (e) {
+        Messages.Show("is-warning", e.message);
+        console.error(e);
+      }
+    }
+    return this.candidateLists;
+  }
+
+  async saveCandidateList(method, ID, Name, PartyID, RoundID, AreaID) {
+    try {
+      const response = await fetch(
+        "/api/CandidateList/" + ID,
+        {
+          method: method,
+          headers: new Headers({
+            "XSRF-Token": this.current_user.xsrftoken,
+          }),
+          body: JSON.stringify({
+            ID: ID,
+            Name: Name,
+            PartyID: PartyID,
+            RoundID: RoundID,
+            AreaID : AreaID
+          }),
+        }
+      );
+      if (response.status !== 200) {
+        throw new Error(
+          `CandidateList could not be updated or created (status ${response.status})`
+        );
+      }
+      this.refreshCandidateLists();
+      return await response.json();
+    } catch (e) {
+      Messages.Show("is-warning", e.message);
+      console.error(e);
+      return;
+    }
+  }
+
+  async deleteCandidateList(ID) {
+    try {
+      const response = await fetch("/api/CandidateList/" + ID, {
+        method: "delete",
+        headers: new Headers({
+          "XSRF-Token": this.current_user.xsrftoken,
+        }),
+      });
+      if (response.status !== 200) {
+        throw new Error(
+          `CandidateList could not be deleted (status ${response.status})`
+        );
+      }
+    } catch (e) {
+      Messages.Show("is-warning", e.message);
+      console.error(e);
+    }
+  }
+
+  async refreshCandidateLists() {
+    this.candidateLists = null;
+    await this.getCandidateLists();
+  }
+}