format floats in dosage strings

Use correct approach into formatting float values during converting them to strings with up-scaling to complete values.

Cargo.toml

@@ -42,6 +42,8 @@ chrono-english = "0.1.7"
 clap-verbosity-flag = "3.0.1"
 clap_complete = "4.5.40"
 atty = "0.2.14"
+ryu = "1.0.18"
+float-pretty-print = "0.1.1"
 [dependencies.sea-orm-migration]
 version = "1.1.0"
 features = [

src/lib/dosage.rs

@@ -1,18 +1,26 @@
-use measurements::Mass;
+use clap::builder::TypedValueParser;
+use float_pretty_print::PrettyPrintFloat;
+use measurements::{Mass, Measurement};
 use miette::IntoDiagnostic;
 use std::str::FromStr;
 
 pub type Dosage = Mass;
 
-// TODO: This is not what it's meant to be, there is a still work needed on sane
-// approach to automatic scaling of units.
 /// Function will take human-readable input as representation of mass of
 /// substance that was ingested (also referred as Dosage)
 pub fn parse_dosage(input: &str) -> miette::Result<Dosage>
 {
     Mass::from_str(input).into_diagnostic()
 }
 
+pub fn format_dosage(input: &Dosage) -> miette::Result<String> {
+    let suggested_unit = input.get_appropriate_units();
+    let float = format!("{:4.4}", PrettyPrintFloat(suggested_unit.1));
+    let unit = suggested_unit.0;
+    Ok(format!("{} {}", float.trim_start(), unit))
+}
+
+
 #[cfg(test)]
 mod tests
 {
@@ -28,4 +36,10 @@ mod tests
             Mass::from_micrograms(100f64)
         )
     }
+
+    #[test]
+    fn test_print_dosage() {
+        let dosage = Mass::from_grams(0.1);
+        assert_eq!(format_dosage(&dosage).unwrap(), "100 mg");
+    }
 }

src/view_model/ingestion.rs

@@ -1,6 +1,8 @@
+use crate::lib::dosage::format_dosage;
 use crate::lib::dosage::Dosage;
 use crate::lib::orm::ingestion;
 use crate::lib::output::Formatter;
+use core::convert::From;
 use measurements::Measurement;
 use serde::Deserialize;
 use serde::Serialize;
@@ -26,11 +28,13 @@ impl From<ingestion::Model> for ViewModel
 {
     fn from(model: ingestion::Model) -> Self
     {
+        let dosage = Dosage::from_base_units(model.dosage.into());
+
         Self::builder()
             .id(model.id)
             .substance_name(model.substance_name)
             .route(model.route_of_administration)
-            .dosage(Dosage::from_base_units(model.dosage as f64).to_string())
+            .dosage(format_dosage(&dosage).unwrap())
             .ingested_at(model.ingested_at.to_string())
             .build()
     }