diff --git a/src/types.rs b/src/types.rs
index e99ad5a..f203f45 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -3,6 +3,7 @@ use anyhow;
 // A simple type alias so as to DRY.
 
 pub type Result<T> = anyhow::Result<T>;
+pub type TimeSerie = Vec<(u64, f64)>;
 
 #[derive(Clone)]
 pub struct PrometheusConfig {
@@ -39,3 +40,5 @@ pub struct QueryConfig {
     pub to: u64,
     pub step: u64,
 }
+
+
diff --git a/src/utils.rs b/src/utils.rs
index f3ed790..55e2435 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -2,7 +2,7 @@ use bytes::{buf::Reader, Buf};
 use hyper::{body, Body, Client, Method, Request, StatusCode};
 use std::{collections::HashMap, io::Read};
 
-use crate::types;
+use crate::types::{self, TimeSerie};
 
 pub fn print_buf(mut reader: Reader<impl Buf>) {
     let mut dst = [0; 1024];
@@ -82,6 +82,54 @@ pub async fn post_with_headers(
     let body = hyper::body::aggregate(res).await?;
     let reader = body.reader();
 
-    // Err(anyhow::format_err!("bad"))
     Ok((status, reader))
 }
+
+
+// TODO: cover this function with tests
+pub fn interpolate_nans_and_gaps_with_zeros(ts: &TimeSerie, from: u64, to: u64, step: u64) -> TimeSerie {
+    // add zeros in the begining
+    let mut result: TimeSerie = Vec::new();
+    let mut t = from;
+
+    if ts.len() == 0 {
+        while t + step < to {
+            result.push((t, 0.0));
+            t += step;
+        }
+        return result;
+    }
+
+    while t + step < ts[0].0 {
+        result.push((t, 0.0));
+        t += step;
+    }
+
+    let mut i = 0usize;
+    while i + 1 < ts.len() {
+        let mut my_t = ts[i].0;
+        let v = if f64::is_nan(ts[i].1) { 0.0 } else { ts[i].1 };
+        result.push((my_t, v));
+
+        let next_t = ts[i + 1].0;
+
+        while my_t + step < next_t {
+            my_t += step;
+            result.push((my_t, 0.0));
+        }
+
+        i += 1;
+    }
+
+    let mut t = ts.last().unwrap().0;
+    let v = if f64::is_nan(ts.last().unwrap().1) { 0.0 } else { ts.last().unwrap().1 };
+
+    result.push((t, v));
+
+    while t + step < to {
+        t += step;
+        result.push((t, 0.0));
+    }
+
+    return result;
+}