From 3a7a603e67651966965b691cc8c5aa59a88f8a21 Mon Sep 17 00:00:00 2001
From: Vladislav Mamon <norskeld@gmail.com>
Date: Mon, 26 Feb 2024 12:10:20 +0300
Subject: [PATCH] refactor: find distance in km, slightly clean up filters

---
 src/coord.rs   |  7 +++++--
 src/filters.rs | 20 ++++++++++++--------
 src/main.rs    |  4 ++--
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/src/coord.rs b/src/coord.rs
index 02d0499..61f67ab 100644
--- a/src/coord.rs
+++ b/src/coord.rs
@@ -48,7 +48,7 @@ impl Coord {
       .ok_or_else(|| CoordError::GetCoordsFailed)
   }
 
-  /// Finds the distance (in meters) between two coordinates using the haversine formula.
+  /// Finds the distance (in kilometers) between two coordinates using the haversine formula.
   pub fn distance_to(&self, other: &Self) -> f64 {
     // Earth radius in meters. This is *average*, since Earth is not a sphere, but a spheroid.
     const R: f64 = 6_371_000f64;
@@ -66,6 +66,9 @@ impl Coord {
     let hav_delta_lam = phi1.cos() * phi2.cos() * haversine(lam2 - lam1);
     let hav_delta = hav_delta_phi + hav_delta_lam;
 
-    (2.0 * R * hav_delta.sqrt().asin() * 1_000.0).round() / 1_000.0
+    // The distance in meters.
+    let distance = (2.0 * R * hav_delta.sqrt().asin() * 1_000.0).round() / 1_000.0;
+
+    distance / 1_000.0
   }
 }
diff --git a/src/filters.rs b/src/filters.rs
index 6eac381..c8ef8de 100644
--- a/src/filters.rs
+++ b/src/filters.rs
@@ -20,15 +20,16 @@ pub trait Filter: Debug {
   fn matches(&self, relay: &Relay) -> bool;
 }
 
+/// Filter by distance. The distance is in kilometers.
 #[derive(Debug)]
 pub struct FilterByDistance {
-  user: Coord,
+  coord: Coord,
   distance: f64,
 }
 
 impl FilterByDistance {
-  pub fn new(user: Coord, distance: f64) -> Self {
-    Self { user, distance }
+  pub fn new(coord: Coord, distance: f64) -> Self {
+    Self { coord, distance }
   }
 }
 
@@ -38,16 +39,19 @@ impl Filter for FilterByDistance {
   }
 
   fn matches(&self, relay: &Relay) -> bool {
-    (relay.coord.distance_to(&self.user) / 1_000.0) < self.distance
+    relay.coord.distance_to(&self.coord) < self.distance
   }
 }
 
+/// Filter by protocol. `None` means any protocol.
 #[derive(Debug)]
-pub struct FilterByProtocol(Option<Protocol>);
+pub struct FilterByProtocol {
+  protocol: Option<Protocol>,
+}
 
 impl FilterByProtocol {
   pub fn new(protocol: Option<Protocol>) -> Self {
-    Self(protocol)
+    Self { protocol }
   }
 }
 
@@ -58,8 +62,8 @@ impl Filter for FilterByProtocol {
 
   fn matches(&self, relay: &Relay) -> bool {
     self
-      .0
+      .protocol
       .as_ref()
-      .map_or(true, |use_protocol| relay.protocol == *use_protocol)
+      .map_or(true, |protocol| relay.protocol == *protocol)
   }
 }
diff --git a/src/main.rs b/src/main.rs
index 99ac4e0..9e7d571 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -14,7 +14,7 @@ async fn main() -> anyhow::Result<()> {
   let spinner = Spinner::new();
 
   // -----------------------------------------------------------------------------------------------
-  // 1. Get current location, either via arguments or via Mullvad API.
+  // 1. Get the current location, either via arguments or via Mullvad API.
   spinner.set_message("Getting current location");
 
   let user = match cli.latitude.zip(cli.longitude) {
@@ -41,7 +41,7 @@ async fn main() -> anyhow::Result<()> {
   thread::sleep(std::time::Duration::from_secs(1));
 
   // -----------------------------------------------------------------------------------------------
-  // 3. Pinging relays.
+  // 3. Ping relays.
   spinner.set_message("Pinging relays");
 
   let mut tasks = Vec::new();