Added basic categorization functionality in the server & UI

backend/categories.js

@@ -0,0 +1,112 @@
+const config_api = require('./config');
+
+var logger = null;
+var db = null;
+var users_db = null;
+var db_api = null;
+
+function setDB(input_db, input_users_db, input_db_api) { db = input_db; users_db = input_users_db; db_api = input_db_api }
+function setLogger(input_logger) { logger = input_logger; }
+
+function initialize(input_db, input_users_db, input_logger, input_db_api) {
+    setDB(input_db, input_users_db, input_db_api);
+    setLogger(input_logger);
+}
+
+/*
+
+Categories:
+
+    Categories are a way to organize videos based on dynamic rules set by the user. Categories are universal (so not per-user).
+    
+    Categories, besides rules, have an optional custom output. This custom output can help users create their
+        desired directory structure.
+
+Rules:
+    A category rule consists of a property, a comparison, and a value. For example, "uploader includes 'VEVO'"
+
+    Rules are stored as an object with the above fields. In addition to those fields, it also has a preceding_operator, which
+        is either OR or AND, and signifies whether the rule should be ANDed with the previous rules, or just ORed. For the first
+        rule, this field is null.
+
+    Ex. (title includes 'Rihanna' OR title includes 'Beyonce' AND uploader includes 'VEVO')
+
+*/
+
+async function categorize(file_json) {
+    return new Promise(resolve => {
+        let selected_category = null;
+        const categories = getCategories();
+        if (!categories) {
+            logger.warn('Categories could not be found. Initializing categories...');
+            db.assign({categories: []}).write();
+            resolve(null);
+            return;
+        }
+
+        for (let i = 0; i < categories.length; i++) {
+            const category = categories[i];
+            const rules = category['rules'];
+
+            // if rules for current category apply, then that is the selected category
+            if (applyCategoryRules(file_json, rules, category['name'])) {
+                selected_category = category;
+                logger.verbose(`Selected category ${category['name']} for ${file_json['webpage_url']}`);
+            }
+        }
+
+        resolve(selected_category);
+        
+    });
+}
+
+function getCategories() {
+    const categories = db.get('categories').value();
+    return categories ? categories : null;
+}
+
+function applyCategoryRules(file_json, rules, category_name) {
+    let rules_apply = false;
+    for (let i = 0; i < rules.length; i++) {
+        const rule = rules[i];
+        let rule_applies = null;
+
+        let preceding_operator = rule['preceding_operator'];
+
+        switch (rule['comparator']) {
+            case 'includes':
+                rule_applies = file_json[rule['property']].includes(rule['value']);
+                break;
+            case 'not_includes':
+                rule_applies = !(file_json[rule['property']].includes(rule['value']));
+                break;
+            case 'equals':
+                rule_applies = file_json[rule['property']] === rule['value'];
+                break;
+            case 'not_equals':
+                rule_applies = file_json[rule['property']] !== rule['value'];
+                break;
+            default:
+                logger.warn(`Invalid comparison used for category ${category_name}`)
+                break;
+        }
+
+        // OR the first rule with rules_apply, which will be initially false
+        if (i === 0) preceding_operator = 'or';
+
+        // update rules_apply based on current rule
+        if (preceding_operator === 'or')
+            rules_apply = rules_apply || rule_applies;
+        else
+            rules_apply = rules_apply && rule_applies;
+    }
+
+    return rules_apply;
+}
+
+
+
+module.exports = {
+    initialize: initialize,
+    categorize: categorize,
+}