1 files changed, 78 insertions, 0 deletions
diff --git a/src/proto/serializer.rs b/src/proto/serializer.rs
new file mode 100644
index 0000000..603cc0b
--- /dev/null
+++ b/src/proto/serializer.rs
@@ -0,0 +1,78 @@
+use crate::proto::message::{IrcMessage, Prefix};
+use std::fmt::Write;
+
+pub fn serialize(msg: &IrcMessage) -> String {
+    let mut out = String::with_capacity(512);
+
+    // tags
+    if !msg.tags.is_empty() {
+        out.push('@');
+        let mut first = true;
+        for (key, value) in &msg.tags {
+            if !first {
+                out.push(';');
+            }
+            first = false;
+            out.push_str(key);
+            if let Some(v) = value {
+                out.push('=');
+                escape_tag_value(&mut out, v);
+            }
+        }
+        out.push(' ');
+    }
+
+    // prefix
+    if let Some(prefix) = &msg.prefix {
+        out.push(':');
+        match prefix {
+            Prefix::Server(s) => out.push_str(s),
+            Prefix::User { nick, user, host } => {
+                out.push_str(nick);
+                if let Some(u) = user {
+                    out.push('!');
+                    out.push_str(u);
+                }
+                if let Some(h) = host {
+                    out.push('@');
+                    out.push_str(h);
+                }
+            }
+        }
+        out.push(' ');
+    }
+
+    // command
+    let _ = write!(out, "{}", msg.command);
+
+    // params
+    let last_idx = msg.params.len().saturating_sub(1);
+    for (i, param) in msg.params.iter().enumerate() {
+        out.push(' ');
+        // The last param must be trailing if it contains spaces or starts with ':'
+        let needs_trailing = i == last_idx
+            && (param.contains(' ')
+                || param.starts_with(':')
+                || param.is_empty()
+                || msg.params.len() > 1);
+        if needs_trailing {
+            out.push(':');
+        }
+        out.push_str(param);
+    }
+
+    out
+}
+
+fn escape_tag_value(out: &mut String, value: &str) {
+    for ch in value.chars() {
+        match ch {
+            ';' => out.push_str(r"\:"),
+            ' ' => out.push_str(r"\s"),
+            '\\' => out.push_str(r"\\"),
+            '\r' => out.push_str(r"\r"),
+            '\n' => out.push_str(r"\n"),
+            c => out.push(c),
+        }
+    }
+}