link map WIP

src/routes/api/link_map.js

@@ -0,0 +1,52 @@
+"use strict";
+
+const sql = require('../../services/sql');
+
+async function getLinks(noteIds) {
+    return await sql.getManyRows(`
+        SELECT noteId, targetNoteId, type
+        FROM links
+        WHERE (noteId IN (???) OR targetNoteId IN (???))
+          AND isDeleted = 0
+        UNION
+        SELECT noteId, value, 'relation'
+        FROM attributes
+        WHERE (noteId IN (???) OR value IN (???))
+          AND type = 'relation'
+          AND isDeleted = 0
+    `, noteIds);
+}
+
+async function getLinkMap(req) {
+    const {noteId} = req.params;
+
+    let noteIds = new Set([noteId]);
+    let links = [];
+
+    while (true) {
+        const newLinks = await getLinks(noteIds);
+        const newNoteIds = new Set(newLinks.map(l => l.noteId).concat(newLinks.map(l => l.targetNoteId)));
+
+        if (newNoteIds.length === noteIds.length) {
+            // no new note discovered, no need to search any further
+            break;
+        }
+
+        if (newNoteIds.length > 50) {
+            // to many notes to display
+            break;
+        }
+
+        noteIds = newNoteIds;
+        links = newLinks;
+    }
+
+    // keep only links coming from and targetting some note in the noteIds set
+    links = links.filter(l => noteIds.has(l.noteId) && noteIds.has(l.targetNoteId));
+
+    return links;
+}
+
+module.exports = {
+    getLinkMap
+};