diff --git a/src/main.rs b/src/main.rs
index 0f85acd..d4b0055 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,9 +1,12 @@
 use clap::Parser;
+use fit_file as fit;
+use fit_file::{fit_file, FitFieldValue, FitRecordMsg, FitSessionMsg};
 use geo_types::{coord, Point};
 use gpx::{Gpx, GpxVersion, Track, TrackSegment, Waypoint};
 use std::{fs::File, io::BufWriter};
 use time::OffsetDateTime;
 
+/// universal Result
 type Res<T> = Result<T, Box<dyn std::error::Error>>;
 
 #[derive(Parser)]
@@ -14,22 +17,20 @@ struct Args {
 
 // FitRecordMsg to gpx Waypoint
 fn frm_to_gwp(frm: FitRecordMsg) -> Waypoint {
-    // "Time: {}\tLat: {}\tLon: {}\tAlt: {:.1}m\tDist: {:.3}km\tSpeed: {:.1}km/h\tHR: {}",
-    // eprintln!("time: {:?}", frm.timestamp);
     let time = frm.timestamp.unwrap_or(0);
     let time = OffsetDateTime::from_unix_timestamp(time.into()).ok();
 
-    let lat = fit_file::semicircles_to_degrees(frm.position_lat.unwrap_or(0));
-    let lon = fit_file::semicircles_to_degrees(frm.position_long.unwrap_or(0));
+    let lat = fit::semicircles_to_degrees(frm.position_lat.unwrap_or(0));
+    let lon = fit::semicircles_to_degrees(frm.position_long.unwrap_or(0));
 
     let alt = if let Some(enh_alt) = frm.enhanced_altitude {
         Some(enh_alt)
     } else {
         frm.altitude.map(|alt| alt.into())
     }
-    .map(|alt| alt as f32 / 5. - 500.);
+    .map(|alt| alt as f32 / 5. - 500.); // m
 
-    // let dist = frm.distance.unwrap_or(0) as f32 / 100000.;
+    // let dist = frm.distance.unwrap_or(0) as f32 / 100000.; // km
 
     let speed = if let Some(enh_spd) = frm.enhanced_speed {
         Some(enh_spd)
@@ -37,7 +38,7 @@ fn frm_to_gwp(frm: FitRecordMsg) -> Waypoint {
         frm.speed.map(|spd| spd.into())
     }
     .map(|spd| spd as f64);
-    // .map(|spd| spd as f64 / 1000. * 3.6);
+    // .map(|spd| spd as f64 / 1000. * 3.6); // km/h
 
     // let hr = frm
     //     .heart_rate
@@ -60,27 +61,22 @@ fn no_lat_lon(frm: &FitRecordMsg) -> bool {
     frm.position_long.is_none() && frm.position_lat.is_none()
 }
 
-use fit_file::{fit_file, FitRecordMsg, FitSessionMsg};
-
 /// Called for each record message as it is processed.
 fn callback(
     timestamp: u32,
     global_message_num: u16,
     _local_msg_type: u8,
     _message_index: u16,
-    fields: Vec<fit_file::FitFieldValue>,
+    fields: Vec<FitFieldValue>,
     data: &mut Context,
 ) {
-    if global_message_num == fit_file::GLOBAL_MSG_NUM_DEVICE_INFO {
-        // let msg = FitDeviceInfoMsg::new(fields);
-        // println!("{msg:#?}");
-    } else if global_message_num == fit_file::GLOBAL_MSG_NUM_SESSION {
+    if global_message_num == fit::GLOBAL_MSG_NUM_SESSION {
         let msg = FitSessionMsg::new(fields);
         let sport_names = fit_file::init_sport_name_map();
         let sport_id = msg.sport.unwrap();
 
         println!("Sport: {}", sport_names.get(&sport_id).unwrap());
-    } else if global_message_num == fit_file::GLOBAL_MSG_NUM_RECORD {
+    } else if global_message_num == fit::GLOBAL_MSG_NUM_RECORD {
         let mut msg = FitRecordMsg::new(fields);
 
         data.num_records_processed += 1;
@@ -95,30 +91,8 @@ fn callback(
             data.no_lat_lon_sum += 1;
         }
 
-        // println!(
-        //     "timestamp: {:?}|{:?}|{:?}|{}",
-        //     msg.timestamp, msg.time128, msg.time_from_course, timestamp
-        // );
         let wp = frm_to_gwp(msg);
         data.track_segment.points.push(wp);
-        // assert!(msg.timestamp.is_some());
-
-        // println!("{msg:#?}");
-
-        // println!(
-        //     // "Timestamp: {} Latitude: {} Longitude: {} Altitude: {} Distance: {} Speed: {} HeartRate: {}",
-        //     "Time: {}\tLat: {}\tLon: {}\tAlt: {:.1}m\tDist: {:.3}km\tSpeed: {:.1}km/h\tHR: {}",
-        //     msg.timestamp.unwrap_or(0),
-        //     fit_file::semicircles_to_degrees(msg.position_lat.unwrap_or(0)),
-        //     fit_file::semicircles_to_degrees(msg.position_long.unwrap_or(0)),
-        //     msg.enhanced_altitude.unwrap_or(0) as f32 / 5. - 500.,
-        //     msg.distance.unwrap_or(0) as f32 / 100000.,
-        //     msg.enhanced_speed.unwrap_or(0) as f32 / 1000. * 3.6,
-        //     msg.heart_rate
-        //         .map(|hr| hr.checked_add(1))
-        //         .unwrap_or(Some(0))
-        //         .unwrap_or(0),
-        // );
     }
 }
 
@@ -176,33 +150,6 @@ fn fit2gpx(f_in: &str) -> Res<()> {
     Ok(())
 }
 
-//                 if let MessageType::Record = msg.data.message_type {
-//                     let rec_dat: RecordData = msg.data.clone().into();
-//                     if rec_dat.no_lat_lon() {
-//                         no_lat_lon_sum += 1;
-//                         // eprintln!("doesn't contain lat/lon data: {:?}", msg.data);
-//                         // continue;
-//                     }
-//                     // eprintln!("{rec_dat:#?}");
-//                     // Add track point
-//                     let wp: Waypoint = rec_dat.into();
-//                     // if wp.point().x_y() == (0., 0.) {
-//                     //     eprintln!("warn: guess it's invalid: {msg:#?}");
-//                     // }
-//                     if ongoing_activity {
-//                         track_segment.points.push(wp);
-//                     } else {
-//                         eprintln!("warn: NOT in an activity right now");
-//                         // std::io::stdin().read_line(&mut String::new())?;
-//                     }
-//                 } else if let MessageType::Activity = msg.data.message_type {
-//                     let start_stop = df_at(&msg.data, 4);
-//                     if let Some(Value::Enum(start_stop)) = start_stop {
-//                         if start_stop == &"start" {
-//                             ongoing_activity = true;
-//                         } else if start_stop == &"stop" {
-//                             ongoing_activity = false;
-
 fn main() {
     // collecting cli args
     let args = Args::parse();