add contrast requirements for colors

Cargo.lock

@@ -151,6 +151,15 @@ dependencies = [
  "syn 0.15.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "contrast"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rgb 0.8.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "cookie"
 version = "0.12.0"
@@ -1007,14 +1016,21 @@ dependencies = [
  "webpki-roots 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rgb"
+version = "0.8.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "rgbot"
 version = "0.1.0"
 dependencies = [
+ "contrast 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "err-derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rgb 0.8.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "serenity 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1620,6 +1636,7 @@ dependencies = [
 "checksum chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "45912881121cb26fad7c38c17ba7daa18764771836b34fab7d3fbd93ed633878"
 "checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
 "checksum command_attr 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5406ee18de55f66abb90533af259d0adbc9f629c02fecc8e6ddd8ae986ab990b"
+"checksum contrast 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e9e2e6885a8c59c03522edaa351a7ad5b6d47ed2632fcfbc0f2b00fcce520eb1"
 "checksum cookie 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "888604f00b3db336d2af898ec3c1d5d0ddf5e6d462220f2ededc33a87ac4bbd5"
 "checksum cookie_store 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "46750b3f362965f197996c4448e4a0935e791bf7d6631bfce9ee0af3d24c919c"
 "checksum crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d663548de7f5cca343f1e0a48d14dcfb0e9eb4e079ec58883b7251539fa10aeb"
@@ -1712,6 +1729,7 @@ dependencies = [
 "checksum regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7d707a4fa2637f2dca2ef9fd02225ec7661fe01a53623c1e6515b6916511f7a7"
 "checksum regex-syntax 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)" = "9d76410686f9e3a17f06128962e0ecc5755870bb890c34820c7af7f1db2e1d48"
 "checksum reqwest 0.9.18 (registry+https://github.com/rust-lang/crates.io-index)" = "00eb63f212df0e358b427f0f40aa13aaea010b470be642ad422bcbca2feff2e4"
+"checksum rgb 0.8.14 (registry+https://github.com/rust-lang/crates.io-index)" = "2089e4031214d129e201f8c3c8c2fe97cd7322478a0d1cdf78e7029b0042efdb"
 "checksum ring 0.14.6 (registry+https://github.com/rust-lang/crates.io-index)" = "426bc186e3e95cac1e4a4be125a4aca7e84c2d616ffc02244eef36e2a60a093c"
 "checksum rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "a7f4dccf6f4891ebcc0c39f9b6eb1a83b9bf5d747cb439ec6fba4f3b977038af"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"

Cargo.toml

@@ -8,5 +8,7 @@ edition = "2018"
 serenity = { version = "0.6", features = ["cache"] }
 regex = "1.1"
 err-derive = "0.1"
-env_logger = "~0.4"
+env_logger = "0.4"
-log = "~0.3"
+log = "0.3"
+contrast = "0.1"
+rgb = "0.8"

src/main.rs

@@ -1,18 +1,20 @@
 use std::env;
 
+use contrast::contrast;
+use err_derive::Error;
+use regex::Regex;
+use rgb::RGB8;
+use serenity::model::guild::{Guild, Role};
+use serenity::model::id::RoleId;
+use serenity::model::user::User;
 use serenity::{
     model::{channel::Message, gateway::Ready},
-    utils::Colour,
     prelude::*,
+    utils::Colour,
     Error as DiscordError,
 };
-use regex::Regex;
-use serenity::model::guild::{Role, Guild};
-use serenity::model::id::RoleId;
-use err_derive::Error;
-use serenity::model::user::User;
-use std::u8;
 use std::sync::Arc;
+use std::u8;
 
 #[derive(Debug, Error)]
 enum BotError {
@@ -28,16 +30,30 @@ impl From<DiscordError> for BotError {
     }
 }
 
+fn background_contrast(color: Colour) -> f32 {
+    let background_dark: Colour = Colour::from(0x36393E);
+    let background_light: Colour = Colour::from(0xFFFFFF);
+
+    let rgb = RGB8::from(color.tuple());
+    let contrast_light = contrast(RGB8::from(background_light.tuple()), rgb);
+    let contrast_dark = contrast(RGB8::from(background_dark.tuple()), rgb);
+
+    f32::min(contrast_dark, contrast_light)
+}
+
 type Result<T> = std::result::Result<T, BotError>;
 
 struct Handler {
-    color_regex: Regex
+    color_regex: Regex,
+    min_contrast: f32,
 }
 
 impl Handler {
-    pub fn new() -> Self {
+    pub fn new(min_contrast: f32) -> Self {
         Handler {
-            color_regex: Regex::new(r"^#([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})$").unwrap()
+            color_regex: Regex::new(r"^#([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})$")
+                .unwrap(),
+            min_contrast,
         }
     }
 
@@ -50,31 +66,46 @@ impl Handler {
     }
 
     fn get_color_role_position(&self, guild: &Guild) -> Result<u8> {
-        guild.role_by_name("colors").map(|r| r.position as u8)
+        guild
+            .role_by_name("colors")
+            .map(|r| r.position as u8)
             .ok_or(BotError::NoColorRole)
     }
 
-    fn get_or_create_role(&self, context: &Context, color: Colour, guild: &RwLock<Guild>) -> Result<Role> {
+    fn get_or_create_role(
+        &self,
+        context: &Context,
+        color: Colour,
+        guild: &RwLock<Guild>,
+    ) -> Result<Role> {
         let name = format!("#{}", color.hex());
         let color_position = self.get_color_role_position(&mut guild.read())?;
         if let Some(role) = guild.read().role_by_name(&name) {
             return Ok(role.clone());
         }
 
-        let role = guild.write().create_role(context, |r| r
+        let role = guild.write().create_role(context, |r| {
-            .name(&name)
+            r.name(&name)
                 .colour(color.0 as u64)
-            .position(color_position),
+                .position(color_position)
-        )?;
+        })?;
 
         Ok(role)
     }
 
-    fn assign_color(&self, context: Context, user: User, guild: Arc<RwLock<Guild>>, color: Colour) -> Result<(String, String)> {
+    fn assign_color<'a>(
-        let role = self.get_or_create_role(&context, color, &guild)?;
+        &self,
-        let mut member = guild.read().member(&context, user.id)?;
+        context: &Context,
+        user: &'a User,
+        guild: Arc<RwLock<Guild>>,
+        color: Colour,
+    ) -> Result<(String, &'a String)> {
+        let role = self.get_or_create_role(context, color, &guild)?;
+        let mut member = guild.read().member(context, user.id)?;
 
-        let old_colors: Vec<RoleId> = member.roles(&context.cache).unwrap_or_default()
+        let old_colors: Vec<RoleId> = member
+            .roles(&context.cache)
+            .unwrap_or_default()
             .iter()
             .filter(|r| self.color_regex.is_match(&r.name))
             .map(|r| r.id)
@@ -82,16 +113,21 @@ impl Handler {
         member.remove_roles(&context.http, &old_colors)?;
         member.add_role(&context.http, role.id)?;
         self.cleanup_roles(context, &guild, role.id)?;
-        Ok((role.name, user.name))
+        Ok((role.name, &user.name))
     }
 
-    fn cleanup_roles(&self, context: Context, guild: &RwLock<Guild>, used: RoleId) -> Result<()> {
+    fn cleanup_roles(&self, context: &Context, guild: &RwLock<Guild>, used: RoleId) -> Result<()> {
-        let used_roles: Vec<RoleId> = guild.read().members.values()
+        let used_roles: Vec<RoleId> = guild
+            .read()
+            .members
+            .values()
             .flat_map(|member| member.roles.iter())
             .map(|role| role.clone())
             .collect();
 
-        let empty_roles: Vec<RoleId> = guild.read().roles
+        let empty_roles: Vec<RoleId> = guild
+            .read()
+            .roles
             .values()
             .filter(|role| self.color_regex.is_match(&role.name))
             .filter(|role| !used_roles.contains(&role.id))
@@ -110,9 +146,11 @@ impl Handler {
 impl EventHandler for Handler {
     fn message(&self, context: Context, msg: Message) {
         if let Some(color) = self.parse_color(&msg.content) {
+            if background_contrast(color) > self.min_contrast {
                 if let Some(guild) = msg.guild(context.cache.clone()) {
-                match self.assign_color(context, msg.author, guild, color) {
+                    match self.assign_color(&context, &msg.author, guild, color) {
                         Ok((role, user)) => {
+                            let _ = msg.react(&context, '☑');
                             println!("Assigned role {} for {}", role, user);
                         }
                         Err(err) => {
@@ -122,6 +160,9 @@ impl EventHandler for Handler {
                 } else {
                     println!("Failed to get guild");
                 }
+            } else {
+                let _ = msg.react(&context, '❌');
+            }
         }
     }
 
@@ -133,10 +174,13 @@ impl EventHandler for Handler {
 fn main() {
     env_logger::init().expect("Unable to init env_logger");
 
-    let token = env::var("DISCORD_TOKEN")
+    let token = env::var("DISCORD_TOKEN").expect("Expected a token in the environment");
-        .expect("Expected a token in the environment");
+    let min_contrast: f32 = env::var("MIN_CONTRAST")
+        .unwrap_or_else(|_| "2".to_string())
+        .parse()
+        .expect("Failed to parse min contrast");
 
-    let mut client = Client::new(&token, Handler::new()).expect("Err creating client");
+    let mut client = Client::new(&token, Handler::new(min_contrast)).expect("Err creating client");
 
     if let Err(why) = client.start() {
         println!("Client error: {:?}", why);