:sparkles: ProgressStats introduced

2 files changed, 81 insertions, 1 deletions

diff --git a/index.js b/index.js
index 879016d..7564b59 100644
--- a/index.js
+++ b/index.js
@@ -14,6 +14,9 @@ var overpass = require('query-overpass')
 var osmBoundarySources = require('./osmBoundarySources.json')
 var zoneCfg = require('./timezones.json')
 
+const ProgressStats = require('./progressStats')
+var progressStats = new ProgressStats(Object.keys(osmBoundarySources).length)
+
 // allow building of only a specified zones
 var filteredIndex = process.argv.indexOf('--filtered-zones')
 if (filteredIndex > -1 && process.argv[filteredIndex + 1]) {
@@ -161,7 +164,8 @@ var downloadOsmBoundary = function (boundaryId, boundaryCallback) {
 
   asynclib.auto({
     downloadFromOverpass: function (cb) {
-      console.log('downloading from overpass')
+      progressStats.logNext()
+      console.log('downloading from overpass; overall progress ' + progressStats.getPercentage() + '% done - ' + progressStats.getTimeLeft(5) + ' left')
       fetchIfNeeded(boundaryFilename, boundaryCallback, cb, function () {
         var overpassResponseHandler = function (err, data) {
           if (err) {
diff --git a/progressStats.js b/progressStats.js
new file mode 100644
index 0000000..64b50e1
--- /dev/null
+++ b/progressStats.js
@@ -0,0 +1,76 @@
+class ProgressStats {
+
+    constructor(totalDownloads) {
+        this.totalDownloads = totalDownloads
+        this.downloadCounter = 0
+        this.timestamps = []
+    }
+
+    logNext() {
+        this.downloadCounter++
+        this.timestamps.push({
+            "index": this.downloadCounter,
+            "timestamp": Date.now()
+        })
+    }
+
+    /**
+     * calculates the percentage of finished downloads
+     * @returns {string}
+     */
+    getPercentage() {
+        var current = (this.downloadCounter / this.totalDownloads)
+        return Math.round(current * 1000.0) / 10.0
+    }
+
+    /**
+     * calculates the time left and outputs it in human readable format
+     * calculation is based on a reference length, that can be defined.
+     *
+     * @returns {string}
+     */
+    getTimeLeft(referenceLength) {
+        if(this.downloadCounter <= referenceLength){
+            //number of reference downloads must exist before left time can be predicted
+            return "? minutes"
+        }
+        var processDurationInSeconds = (Date.now() - this.timestamps[0].timestamp) / 1000
+        if(processDurationInSeconds < 60){
+            //process must run longer than 60seconds before left time can be predicted
+            return "? minutes"
+        }
+
+        var indexOfStepsBefore = this.timestamps.findIndex((t) => {
+            return t.index == (this.downloadCounter - referenceLength)
+        })
+        var lastSteps = this.timestamps[indexOfStepsBefore];
+        var millisOflastSteps = Date.now() - lastSteps.timestamp
+        var downloadsLeft = this.totalDownloads - this.downloadCounter
+        var millisecondsLeft = (millisOflastSteps / referenceLength) * downloadsLeft
+        return this.formatMilliseconds(millisecondsLeft)
+    }
+
+    /**
+     * inspired from https://stackoverflow.com/questions/19700283/how-to-convert-time-milliseconds-to-hours-min-sec-format-in-javascript
+     * @param millisec
+     * @returns {string}
+     */
+    formatMilliseconds(millisec) {
+        var seconds = (millisec / 1000).toFixed(1);
+        var minutes = (millisec / (1000 * 60)).toFixed(1);
+        var hours = (millisec / (1000 * 60 * 60)).toFixed(1);
+        var days = (millisec / (1000 * 60 * 60 * 24)).toFixed(1);
+        if (seconds < 60) {
+            return seconds + " seconds";
+        } else if (minutes < 60) {
+            return minutes + " minutes";
+        } else if (hours < 24) {
+            return hours + " hours";
+        } else {
+            return days + " days"
+        }
+    }
+
+}
+
+module.exports = ProgressStats
\ No newline at end of file