1 files changed, 47 insertions, 0 deletions
diff --git a/lib/utils/progress.js b/lib/utils/progress.js
new file mode 100644
index 0000000..b66aea9
--- /dev/null
+++ b/lib/utils/progress.js
@@ -0,0 +1,47 @@
+var _ = require("lodash");
+
+// Returns from a navigation and a current file, a snapshot of current detailed state
+var calculProgress = function(navigation, current) {
+    var n = _.size(navigation);
+    var percent = 0, prevPercent = 0, currentChapter = null;
+    var done = true;
+
+    var chapters = _.chain(navigation)
+    .map(function(nav, path) {
+        nav.path = path;
+        return nav;
+    })
+    .map(function(nav, i) {
+        // Calcul percent
+        nav.percent = (i * 100) / Math.max((n - 1), 1);
+
+        // Is it done
+        nav.done = done;
+        if (nav.path == current) {
+            currentChapter = nav;
+            percent = nav.percent;
+            done = false;
+        } else if (done) {
+            prevPercent = nav.percent;
+        }
+
+        return nav;
+    })
+    .value();
+
+    return {
+        // Previous percent
+        prevPercent: prevPercent,
+
+        // Current percent
+        percent: percent,
+
+        // List of chapter with progress
+        chapters: chapters,
+
+        // Current chapter
+        current: currentChapter
+    };
+}
+
+module.exports = calculProgress;