From c2ef71ed9215eae0c7e7a20a4e981138c21ba6e4 Mon Sep 17 00:00:00 2001
From: Gergely Polonkai <gergely@polonkai.eu>
Date: Tue, 17 May 2022 17:23:26 +0200
Subject: [PATCH] Add the current Moon phase in the middle

---
 Cargo.lock  |  7 ++++++
 Cargo.toml  |  1 +
 src/main.rs | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index 8b96e66..d860cf8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -491,6 +491,12 @@ dependencies = [
  "wayland-protocols",
 ]
 
+[[package]]
+name = "suncalc"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830c44c596fd2dfa93ad514462622e014c3e58e5d7e6844a87f7d510e8e68045"
+
 [[package]]
 name = "svg"
 version = "0.10.0"
@@ -730,6 +736,7 @@ dependencies = [
  "chrono",
  "resvg",
  "smithay-client-toolkit",
+ "suncalc",
  "svg",
  "tiny-skia",
  "usvg",
diff --git a/Cargo.toml b/Cargo.toml
index 150698c..868a14f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,3 +10,4 @@ svg = "0.10"
 usvg = "0.22"
 tiny-skia = "0.6"
 resvg = "0.22"
+suncalc = "0.4"
diff --git a/src/main.rs b/src/main.rs
index 00f2e51..ef24593 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,8 @@ use chrono::Timelike;
 use sctk::reexports::client::protocol::{wl_shm, wl_surface};
 use sctk::shm::AutoMemPool;
 use sctk::window::{Event as WEvent, FallbackFrame};
-use svg::node::element::{Group, Line, Rectangle, Style, Text};
+use svg::node::element::path::Data as PathData;
+use svg::node::element::{Circle, Group, Line, Path, Rectangle, Style, Text};
 use svg::node::Text as TextNode;
 use svg::Document;
 
@@ -22,6 +23,46 @@ fn time_to_degrees(timestamp: i32, // should be time/timestamp
     seconds_to_degrees(timestamp)
 }
 
+fn get_moon_path(image_width: u32, radius: f32, moon_phase: f64) -> Path {
+    let handle_x_pos = radius as f64 * 1.34;
+    let handle_y_pos = radius * 0.88;
+    let min_x = image_width as f64 / 2.0 - handle_x_pos;
+    let max_x = min_x + 2.0 * handle_x_pos;
+    let top_y = image_width as f32 / 2.0 - handle_y_pos;
+    let bottom_y = image_width as f32 / 2.0 + handle_y_pos;
+
+    let h1_x: f64;
+    let h2_x: f64;
+
+    if moon_phase < 14.0 {
+        h1_x = min_x + 2.0 * handle_x_pos * (1.0 - moon_phase / 14.0);
+        h2_x = max_x;
+    } else {
+        h1_x = min_x;
+        h2_x = max_x + 2.0 * handle_x_pos * (1.0 - moon_phase / 14.0)
+    }
+
+    let path_data = PathData::new()
+        .move_to((image_width as f32 / 2.0, image_width as f32 / 2.0 - radius))
+        .cubic_curve_to((
+            h1_x,
+            top_y,
+            h1_x,
+            bottom_y,
+            image_width as f32 / 2.0,
+            image_width as f32 / 2.0 + radius,
+        ))
+        .cubic_curve_to((
+            h2_x,
+            bottom_y,
+            h2_x,
+            top_y,
+            image_width / 2,
+            image_width as f32 / 2.0 - radius,
+        ));
+    Path::new().set("class", "moon").set("d", path_data)
+}
+
 fn gen_svg() -> Document {
     // These should be calculated
     let local_timestamp = Local::now();
@@ -29,6 +70,13 @@ fn gen_svg() -> Document {
 
     // TODO: These should be calculated instead of hardcoded
     let image_width = 700u32;
+
+    // Calculate the Moon phase
+    let unixtime = suncalc::Timestamp(local_timestamp.timestamp_millis());
+    let moon_illumination = suncalc::moon_illumination(unixtime);
+    let moon_radius = image_width as f32 * 0.071428571;
+    let moon_phase = moon_illumination.phase * 28.0;
+
     let local_hour_font_size = 16.5;
     let hour_name_font_size = 13.37699;
     let outer_r = (image_width as f32) / 2.0 - 3.0 * hour_name_font_size;
@@ -43,6 +91,8 @@ fn gen_svg() -> Document {
         "\
         #border {stroke: none; fill: rgb(19, 17, 30); }
         .local-hour {stroke: none; fill: rgb(238, 187, 85);}
+        .moon-background {stroke: rgb(170, 170, 170); stroke-width: 2px; fill: rgb(19, 17, 30);}
+        .moon {stroke: none; fill: rgb(170, 170, 170);}
         .dial {stroke-width: 2px; stroke: rgb(238, 187, 85);}",
     );
     let mut local_clock = Group::new().set("id", "local-clock");
@@ -69,6 +119,17 @@ fn gen_svg() -> Document {
         local_clock = local_clock.add(hour_node);
     }
 
+    let moon_circle = Circle::new()
+        .set("class", "moon-background")
+        .set("cx", image_width / 2)
+        .set("cy", image_width / 2)
+        .set("r", moon_radius);
+
+    let moon_group = Group::new()
+        .set("id", "moon-container")
+        .add(moon_circle)
+        .add(get_moon_path(image_width, moon_radius, moon_phase));
+
     let dial = Line::new()
         .set("id", "dial")
         .set("class", "dial")
@@ -97,6 +158,7 @@ fn gen_svg() -> Document {
         .add(stylesheet)
         .add(border)
         .add(local_clock)
+        .add(moon_group)
         .add(dial)
 }