From 84b0a5a912a9f2ab809158968da339c29ae32cd2 Mon Sep 17 00:00:00 2001
From: Jannis R <mail@jannisr.de>
Date: Wed, 7 Mar 2018 16:53:33 +0100
Subject: [PATCH] storage interface

---
 .gitignore     |  2 ++
 lib/storage.js | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++
 package.json   |  2 ++
 3 files changed, 66 insertions(+)
 create mode 100644 lib/storage.js

diff --git a/.gitignore b/.gitignore
index 808662f..45d061e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,5 @@ pnpm-debug.log
 
 package-lock.json
 shrinkwrap.yaml
+
+vbb-telegram.ldb
diff --git a/lib/storage.js b/lib/storage.js
new file mode 100644
index 0000000..89fc5a5
--- /dev/null
+++ b/lib/storage.js
@@ -0,0 +1,62 @@
+'use strict'
+
+const level = require('level')
+const path = require('path')
+const hifo = require('hifo')
+
+const last = '\xff'
+
+const db = level(path.join(__dirname, '..', 'vbb-telegram.ldb'), {
+	valueEncoding: 'json'
+})
+
+const getCommand = (user) => {
+	return db.get(user + ':cmd')
+	.catch((err) => {
+		if (err.notFound) return null
+		else throw err
+	})
+}
+
+const putCommand = (user, cmd) => {
+	return db.put(user + ':cmd', cmd)
+}
+
+// todo: sth more efficient
+const getTopLocations = (user) => {
+	const ns = user + ':locations:'
+	const top = hifo(hifo.highest('count'), 3)
+
+	const onItem = ({key, value}) => {
+		const id = key.slice(ns.length)
+		top.add({id, count: value})
+	}
+
+	const items = db.createReadStream({gt: ns, lt: ns + last})
+	return new Promise((resolve, reject) => {
+		items.once('error', (err) => {
+			reject(err)
+			items.destroy()
+		})
+		items.once('end', () => {
+			resolve(top.data)
+		})
+		items.on('data', onItem)
+	})
+}
+
+const incLocation = async (user, id) => {
+	const key = user + ':locations:' + id
+	try {
+		const count = await db.get(key)
+		await db.put(key, count + 1)
+	} catch (err) {
+		if (err.notFound) await db.put(key, 1)
+		else throw err
+	}
+}
+
+module.exports = {
+	getCommand, putCommand,
+	getTopLocations, incLocation
+}
diff --git a/package.json b/package.json
index 1b1f338..1be7b94 100644
--- a/package.json
+++ b/package.json
@@ -21,5 +21,7 @@
 		"node": ">=8"
 	},
 	"dependencies": {
+		"hifo": "^1.0.0",
+		"level": "^3.0.0"
 	}
 }