feat/add dominant color to embed

Cargo.toml

@@ -39,6 +39,10 @@ scraper = "0.19"
 # Discord
 serenity = "=0.12.4"
 
+# Image processing
+image = { version = "0.25", default-features = false, features = ["png", "jpeg", "webp", "gif"] }
+color-thief = "0.2.2"
+
 # Utils
 uuid = { version = "1.11.1", features = ["v4"] }
 chrono = "0.4.40"

src/discord/api.rs

@@ -57,6 +57,8 @@ pub enum DiscordError {
     Api,
 }
 
+const FALLBACK_EMBED_COLOR: u32 = 0x005eeb;
+
 impl DiscordAPI {
     pub async fn default() -> Self {
         DiscordAPI::new(
@@ -107,7 +109,7 @@ impl DiscordAPI {
         info!(channel_id = %channel_id, event = %event.title, "Sending event");
 
         let title = event.title.clone();
-        let embed = Self::build_event_embed(event, ticket_shop_url, ticket_shop_icon_url);
+        let embed = Self::build_event_embed(event, ticket_shop_url, ticket_shop_icon_url).await;
 
         let message_builder = CreateMessage::new().add_embed(embed.clone());
 
@@ -120,7 +122,7 @@ impl DiscordAPI {
             })
     }
 
-    fn build_event_embed(
+    async fn build_event_embed(
         event: Event,
         ticket_shop_url: Option<String>,
         ticket_shop_icon_url: &str,
@@ -138,17 +140,57 @@ impl DiscordAPI {
         }
 
         let embed_description = Self::truncate_embed_description(description);
+        let color = Self::get_image_dominant_color(&event.details.image_url)
+            .await
+            .unwrap_or_else(|| Colour::new(FALLBACK_EMBED_COLOR));
 
         CreateEmbed::new()
             .title(event.title)
             .url(event.link)
             .description(embed_description)
             .author(author)
-            .color(Colour::new(0x005eeb))
+            .color(color)
             .field("Datas", event.occurring_at.dates, true)
             .image(event.details.image_url)
     }
 
+    pub async fn get_image_dominant_color(image_url: &str) -> Option<Colour> {
+        let bytes = reqwest::get(image_url)
+            .await
+            .map_err(|e| warn!("Failed fetching event image '{}': {}", image_url, e))
+            .ok()?
+            .bytes()
+            .await
+            .map_err(|e| warn!("Failed reading event image bytes '{}': {}", image_url, e))
+            .ok()?;
+
+        let rgba = image::load_from_memory(&bytes)
+            .map_err(|e| warn!("Failed decoding event image '{}': {}", image_url, e))
+            .ok()?
+            .to_rgba8();
+
+        let palette =
+            color_thief::get_palette(rgba.as_raw(), color_thief::ColorFormat::Rgba, 10, 8)
+                .map_err(|e| warn!("Failed extracting palette for '{}': {:?}", image_url, e))
+                .ok()?;
+
+        let dominant = palette
+            .iter()
+            .find(|c| Self::is_colorful(c.r, c.g, c.b))
+            .or_else(|| palette.first())?;
+
+        Some(Colour::from_rgb(dominant.r, dominant.g, dominant.b))
+    }
+
+    /// Excludes near-grayscale colors so a vivid palette entry wins over a washed-out background.
+    fn is_colorful(r: u8, g: u8, b: u8) -> bool {
+        const SATURATION_THRESHOLD: u8 = 30;
+        let max = r.max(g).max(b);
+        let min = r.min(g).min(b);
+
+        max - min > SATURATION_THRESHOLD
+    }
+
     pub async fn add_custom_reaction(&self, message: &Message, emoji: &EmojiConfig) {
         trace!("Adding reaction");
 
@@ -618,9 +660,9 @@ impl DiscordAPI {
             Ok(false) => {}
         }
 
-        let mut embed =
-            Self::build_event_embed(event, ticket_shop_url, ticket_shop_icon_url)
-                .field("Voto", vote_emoji.to_string(), true);
+        let mut embed = Self::build_event_embed(event, ticket_shop_url, ticket_shop_icon_url)
+            .await
+            .field("Voto", vote_emoji.to_string(), true);
 
         if let Some(comment) = comment {
             embed = embed.field("Comentários", comment, true);

tests/discord_embed_color_tests.rs

@@ -0,0 +1,62 @@
+mod discord_embed_color {
+    use alertaemcena::agenda_cultural::api::AgendaCulturalAPI;
+    use alertaemcena::discord::api::DiscordAPI;
+    use serenity::all::Colour;
+
+    async fn assert_dominant_color_extracted(event_url: &str, expected_hex: u32) {
+        let event = AgendaCulturalAPI::scrape_event(event_url)
+            .await
+            .unwrap_or_else(|| panic!("Failed to scrape event '{}'", event_url));
+
+        let color = DiscordAPI::get_image_dominant_color(&event.details.image_url).await;
+
+        match color {
+            Some(color) => assert_eq!(
+                color,
+                Colour::new(expected_hex),
+                "Dominant color for '{}' did not match expected",
+                event.details.image_url
+            ),
+            None => panic!(
+                "Failed to extract dominant color from event image '{}'",
+                event.details.image_url
+            ),
+        }
+    }
+
+    #[test_log::test(tokio::test)]
+    async fn should_extract_dominant_color_for_sonho_de_uma_noite_de_verao() {
+        assert_dominant_color_extracted(
+            "https://www.agendalx.pt/events/event/sonho-de-uma-noite-de-verao-5/",
+            0x1B80B4,
+        )
+        .await;
+    }
+
+    #[test_log::test(tokio::test)]
+    async fn should_extract_dominant_color_for_o_filho() {
+        assert_dominant_color_extracted(
+            "https://www.agendalx.pt/events/event/o-filho-2/",
+            0x785D55,
+        )
+        .await;
+    }
+
+    #[test_log::test(tokio::test)]
+    async fn should_extract_dominant_color_for_o_coracao_de_um_pugilista() {
+        assert_dominant_color_extracted(
+            "https://www.agendalx.pt/events/event/o-coracao-de-um-pugilista/",
+            0xCEB2A7,
+        )
+        .await;
+    }
+
+    #[test_log::test(tokio::test)]
+    async fn should_extract_dominant_color_for_a_ratoeira() {
+        assert_dominant_color_extracted(
+            "https://www.agendalx.pt/events/event/a-ratoeira-5/",
+            0xC07A4F,
+        )
+        .await;
+    }
+}