Playlist system creation

Added a way to deal with playlist. Also now autoscroll to keep new playing kara on top. Fixed wrong command name

common/db.js

 const logger = require.main.require('./common/logger.js');
 const config = require.main.require('./common/config.js');
+const MiniSearch = require("minisearch")
 var sqlite3 = require.main.require('sqlite3').verbose();
 
 /* The kara table is defined as follows:
@@ -47,6 +48,28 @@ class KaraDatabase {
     constructor() {
         this.m_karaPath = config.content.database.path;
         this.m_db = new sqlite3.Database(this.m_karaPath);
+        this.m_db.configure('busyTimeout', 50000);
+        this.m_search_engine = new MiniSearch({
+            fields: [
+                "id",
+                "cat",
+                "type",
+                "language",
+                "author",
+                "title",
+                "source"
+            ], // fields to index for full-text search
+            storeFields: [
+                "id",
+                "cat",
+                "type",
+                "language",
+                "author",
+                "title",
+                "source",
+		"available"
+            ] // fields to return with search results
+          })
         logger.info('db', 'Create database from file ' + config.content.database.path);
     }
 
@@ -56,55 +79,28 @@ class KaraDatabase {
         logger.info('db', `Close database ${this.m_karaPath}`);
     }
 
-    /* Search from the kara table, a string. Can be anything (query, name,
-     * language, source, etc).
+    /* Search for karas with the search engine
      *  - queryString: String
-     *  - limit: Int | null -> maximal number of results
-     *  - offset: Int | null -> offset in the search
-     * => a promize, callback with [(id: Int, string, cat, type, language, author, title, source)] */
-    search(queryString, offset = null, limit = null) {
-        var __ret = [];
-        var __sqlQuery = `SELECT id, string,
-                            category AS cat,
-                            (song_type || song_number) AS type,
-                            language, author_name AS author,
-                            song_name AS title, source_name AS source
-                          FROM kara
-                          WHERE string LIKE ? OR author_name COLLATE nocase = ?`;
-        if (offset != null && limit != null) __sqlQuery += ` LIMIT ${offset}, ${limit}`;
-
-        function __getRecords(db) {
-            return new Promise(resolv => {
-                db.all(__sqlQuery, [`%${queryString}%`, queryString], (err, rows) => {
-                    if (err) {
-                        logger.error('db', err);
-                        throw err;
-                    }
-                    rows.forEach(row => {
-                        __ret.push(row);
-                    });
-                    resolv(__ret);
-                });
-            });
-        }
-
-        return __getRecords(this.m_db);
+     * => A list of search results [(id: Int, string, cat, type, language, author, title, source)] */
+    search(queryString) {
+        let searchResult = this.m_search_engine.search(queryString, {
+            prefix: term => term.length,
+            fuzzy: term => term.length > 3 ? 0.2 : null,
+            combineWith: 'AND'
+        }).slice(0,200);
+        return searchResult;
     }
 
-    /* List all the kara in the db.
-     *  - limit: Int | null -> maximal number of results
-     *  - offset: Int | null -> offset in the search
-     * => a promize, callback with [(id: Int, string, cat, type, language, author, title, source)] */
-    all(offset = null, limit = null) {
+    /* Initiate the search engine with the db
+     * => a promize */
+    setup_search_engine() {
         var __ret = [];
-        var __sqlQuery = `SELECT id, string,
+        var __sqlQuery = `SELECT id,
                             category AS cat,
                             (song_type || song_number) AS type,
                             language, author_name AS author,
-                            song_name AS title, source_name AS source
+                            song_name AS title, source_name AS source, available
                           FROM kara`;
-        if (offset != null && limit != null) __sqlQuery += ` LIMIT ${offset}, ${limit}`;
-
         function __getRecords(db) {
             return new Promise(resolv => {
                 db.all(__sqlQuery, [], (err, rows) => {
@@ -120,7 +116,14 @@ class KaraDatabase {
             });
         }
 
-        return __getRecords(this.m_db);
+        function __SetupSE(karas, search_engine = db.m_search_engine){
+            search_engine.removeAll()
+            logger.info("db", karas.length)
+            search_engine.addAll(karas)
+            logger.info("db", search_engine.documentCount)
+        }
+
+        return __getRecords(this.m_db).then(__SetupSE);
     }
 
     /* List all the next karas in the queue.