fine-tuning notes in preparation for release

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/routes/notes/Index.svelte

@@ -0,0 +1,83 @@
+<script>
+    import { onMount }       from 'svelte';
+    import { useTinyRouter } from 'svelte-tiny-router';
+
+    import { api }           from '../../urls.svelte.js';
+    import { t }             from '../../translations.svelte.js';
+    import { user }          from '../../user.svelte.js';
+
+    import List   from './List.svelte';
+
+    let authors  = $state({});
+    let error    = $state(null);
+    let loader       = {
+        offset : 0,
+        limit  : 5,
+        active : true
+    }
+    let note     = $state({source:null,rendered:null});
+    let notes    = $state(null);
+    let {
+        module = null,
+        entity_id = null
+    } = $props();
+
+
+
+
+    async function loadNotes(){
+        const url  = api(`notes?offset=${loader.offset}&limit=${loader.limit}`);
+
+        const resp = await fetch(url,{credentials:'include'});
+        if (resp.ok){
+            const data = await resp.json();
+            if (!notes) notes = [];
+            notes.push(...Object.values(data.notes).sort((a, b) => b.id - a.id));
+            authors    = {...authors, ...data.authors};
+            loader.offset += loader.limit;
+            loader.active  = false;
+            error = null;
+            if (Object.keys(data.notes).length) onscroll(null); // when notes were received, check whether they fill up the page
+
+        } else {
+            error = await resp.text();
+        }
+    }
+
+    async function saveNote(){
+        const url  = api(`notes/${module}/${entity_id}`);
+        const resp = await fetch(url,{
+            credentials : 'include',
+            method      : 'POST',
+            body        : note.source
+        });
+        if (resp.ok){
+            let newNote       = await resp.json();
+            authors[user.id]  = user;
+            notes[newNote.id] = newNote;
+            note              = {source:'',rendered:''};
+            error             = null;
+            return true;
+        } else {
+            error = await resp.text();
+            return false;
+        }
+    }
+
+
+
+    function onscroll(ev){
+        if (window.innerHeight + window.scrollY >= document.body.offsetHeight && !loader.active) {
+            loader.active = true;
+            loadNotes();
+        }
+    }
+
+    loadNotes(loadNotes)
+</script>
+
+<svelte:window {onscroll} />
+{#if error}
+<span class="error">{error}</span>
+{/if}
+<List {notes} />