Fix #206 and make (most) emotes embed in comments (#209)

* Fix links not being converted when multiple emojis are in one comment

* Make (most) emotes embed within comments

* Restore the behavior that the "rewrite_urls_removes_backslashes_and_rewrites_url" test looks for

* Listen to cargo fmt and cargo clippy's suggestions as well as removing some leftover comments and code

---------

Co-authored-by: Matthew Esposito <matt@matthew.science>

src/utils.rs

@@ -12,6 +12,7 @@ use once_cell::sync::Lazy;
 use regex::Regex;
 use rust_embed::RustEmbed;
 use serde_json::Value;
+use serde_json_path::{JsonPath, JsonPathExt};
 use std::collections::{HashMap, HashSet};
 use std::env;
 use std::str::FromStr;
@@ -919,12 +920,19 @@ pub fn rewrite_urls(input_text: &str) -> String {
 		// Rewrite Reddit links to Redlib
 		REDDIT_REGEX.replace_all(input_text, r#"href="/"#)
 			.to_string();
-	text1 = REDDIT_EMOJI_REGEX
-		.replace_all(&text1, format_url(REDDIT_EMOJI_REGEX.find(&text1).map(|x| x.as_str()).unwrap_or_default()))
-		.to_string()
-		// Remove (html-encoded) "\" from URLs.
-		.replace("%5C", "")
-		.replace("\\_", "_");
+
+	loop {
+		if REDDIT_EMOJI_REGEX.find(&text1).is_none() {
+			break;
+		} else {
+			text1 = REDDIT_EMOJI_REGEX
+				.replace_all(&text1, format_url(REDDIT_EMOJI_REGEX.find(&text1).map(|x| x.as_str()).unwrap_or_default()))
+				.to_string()
+		}
+	}
+
+	// Remove (html-encoded) "\" from URLs.
+	text1 = text1.replace("%5C", "").replace("\\_", "_");
 
 	// Rewrite external media previews to Redlib
 	loop {
@@ -980,6 +988,83 @@ pub fn rewrite_urls(input_text: &str) -> String {
 	}
 }
 
+// These links all follow a pattern of "https://reddit-econ-prod-assets-permanent.s3.amazonaws.com/asset-manager/SUBREDDIT_ID/RANDOM_FILENAME.png"
+static REDDIT_EMOTE_LINK_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r#"https://reddit-econ-prod-assets-permanent.s3.amazonaws.com/asset-manager/(.*)"#).unwrap());
+
+// These all follow a pattern of '"emote|SUBREDDIT_IT|NUMBER"', we want the number
+static REDDIT_EMOTE_ID_NUMBER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r#""emote\|.*\|(.*)""#).unwrap());
+
+pub fn rewrite_emotes(media_metadata: &Value, comment: String) -> String {
+	/* Create the paths we'll use to look for our data inside the json.
+	Because we don't know the name of any given emote we use a wildcard to parse them. */
+	let link_path = JsonPath::parse("$[*].s.u").expect("valid JSON Path");
+	let id_path = JsonPath::parse("$[*].id").expect("valid JSON Path");
+	let size_path = JsonPath::parse("$[*].s.y").expect("valid JSON Path");
+
+	// Extract all of the results from those json paths
+	let link_nodes = media_metadata.json_path(&link_path);
+	let id_nodes = media_metadata.json_path(&id_path);
+
+	// Initialize our vectors
+	let mut id_vec = Vec::new();
+	let mut link_vec = Vec::new();
+
+	// Add the relevant data to each of our vectors so we can access it by number later
+	for current_id in id_nodes {
+		id_vec.push(current_id)
+	}
+	for current_link in link_nodes {
+		link_vec.push(current_link)
+	}
+
+	/* Set index to the length of link_vec.
+	This is one larger than we'll actually be looking at, but we correct that later */
+	let mut index = link_vec.len();
+
+	// Comment needs to be in scope for when we call rewrite_urls()
+	let mut comment = comment;
+
+	/* Loop until index hits zero.
+	This also prevents us from trying to do anything on an empty vector */
+	while index != 0 {
+		/* Subtract 1 from index to get the real index we should be looking at.
+		Then continue on each subsequent loop to continue until we hit the last entry in the vector.
+		This is how we get this to deal with multiple emotes in a single message and properly replace each ID with it's link */
+		index -= 1;
+
+		// Convert our current index in id_vec into a string so we can search through it with regex
+		let current_id = id_vec[index].to_string();
+
+		/* The ID number can be multiple lengths, so we capture it with regex.
+		We also want to only attempt anything when we get matches to avoid panicking */
+		if let Some(id_capture) = REDDIT_EMOTE_ID_NUMBER_REGEX.captures(&current_id) {
+			// Format the ID to include the colons it has in the comment text
+			let id = format!(":{}:", &id_capture[1]);
+
+			// Convert current link to string to search through it with the regex
+			let link = link_vec[index].to_string();
+
+			// Make sure we only do operations when we get matches, otherwise we panic when trying to access the first match
+			if let Some(link_capture) = REDDIT_EMOTE_LINK_REGEX.captures(&link) {
+				/* Reddit sends a size for the image based on whether it's alone or accompanied by text.
+				It's a good idea and makes everything look nicer, so we'll do the same. */
+				let size = media_metadata.json_path(&size_path).first().unwrap().to_string();
+
+				// Replace the ID we found earlier in the comment with the respective image and it's link from the regex capture
+				let to_replace_with = format!(
+					"<img loading=\"lazy\" src=\"/emote/{} width=\"{size}\" height=\"{size}\" style=\"vertical-align:text-bottom\">",
+					&link_capture[1]
+				);
+
+				// Inside the comment replace the ID we found with the string that will embed the image
+				comment = comment.replace(&id, &to_replace_with).to_string();
+			}
+		}
+	}
+	// Call rewrite_urls() to transform any other Reddit links
+	rewrite_urls(&comment)
+}
+
 // Format vote count to a string that will be displayed.
 // Append `m` and `k` for millions and thousands respectively, and
 // round to the nearest tenth.
@@ -1301,3 +1386,11 @@ fn test_url_path_basename() {
 	// empty path
 	assert_eq!(url_path_basename("/"), "");
 }
+
+#[test]
+fn test_rewriting_emotes() {
+	let json_input = serde_json::from_str(r#"{"emote|t5_31hpy|2028":{"e":"Image","id":"emote|t5_31hpy|2028","m":"image/png","s":{"u":"https://reddit-econ-prod-assets-permanent.s3.amazonaws.com/asset-manager/t5_31hpy/PW6WsOaLcd.png","x":60,"y":60},"status":"valid","t":"sticker"}}"#).expect("Valid JSON");
+	let comment_input = r#"<div class="comment_body "><div class="md"><p>:2028:</p></div></div>"#;
+	let output = r#"<div class="comment_body "><div class="md"><p><img loading="lazy" src="/emote/t5_31hpy/PW6WsOaLcd.png" width="60" height="60" style="vertical-align:text-bottom"></p></div></div>"#;
+	assert_eq!(rewrite_emotes(&json_input, comment_input.to_string()), output);
+}