cache handler

structure/Cache.js

@@ -0,0 +1,100 @@
+const fs = require('fs');
+
+class Cache {
+
+    constructor(client) {
+
+        const opts = client._options;
+        this.client = client;
+        this.logger = client.logger;
+
+        this.saveInterval = opts.saveInterval;
+        this._ready = false;
+
+        this.queue = [];
+        this.channels = {};
+        this.lastActivity = {};
+
+        this.modmail = {};
+        this.updatedThreads = [];
+
+    }
+
+    load() {
+
+        if (this._ready) return;
+
+        if (fs.existsSync('./persistent_cache.json')) {
+            this.logger.info('Loading cache');
+            const raw = JSON.parse(fs.readFileSync('./persistent_cache.json', { encoding: 'utf-8' }));
+            const entries = Object.entries(raw);
+            for (const [key, val] of entries) this[key] = val;
+        } else {
+            this.logger.info('Cache file missing, creating...');
+            this.save();
+        }
+
+        this.cacheSaveInterval = setInterval(this.save.bind(this), 10 * 60 * 1000);
+        this.modmailSaveInterval = setInterval(this.save.bind(this), this.saveInterval * 60 * 1000, this.client.modmail);
+        this._ready = true;
+
+    }
+
+    save() {
+        this.logger.debug('Saving cache');
+        fs.writeFileSync('./persistent_cache.json', JSON.stringify(this.json));
+    }
+
+    saveModmailHistory() {
+
+        if (!this.updatedThreads.length) return;
+        const toSave = [...this.updatedThreads];
+        this.updatedThreads = [];
+        this.client.logger.debug(`Saving modmail data`);
+        if (!fs.existsSync('./modmail_cache')) fs.mkdirSync('./modmail_cache');
+
+        for (const id of toSave) {
+            const path = `./modmail_cache/${id}.json`;
+            try {
+                fs.writeFileSync(path, JSON.stringify(this.modmail[id]));
+            } catch (err) {
+                this.client.logger.error(`Error during saving of history\n${id}\n${JSON.stringify(this.modmail)}\n${err.stack}`);
+            }
+        }
+
+    }
+
+    loadModmailHistory(userId) {
+
+        return new Promise((resolve, reject) => {
+
+            if (this.modmail[userId]) return resolve(this.modmail[userId]);
+
+            const path = `./modmail_cache/${userId}.json`;
+            if (!fs.existsSync(path)) {
+                this.modmail[userId] = [];
+                return resolve(this.modmail[userId]);
+            }
+
+            fs.readFile(path, { encoding: 'utf-8' }, (err, data) => {
+                if (err) reject(err);
+                const parsed = JSON.parse(data);
+                this.modmail[userId] = parsed;
+                resolve(parsed);
+            });
+
+        });
+
+    }
+
+    get json() {
+        return {
+            queue: this.queue,
+            channels: this.channels,
+            lastActivity: this.lastActivity
+        };
+    }
+
+}
+
+module.exports = Cache;