1 files changed, 91 insertions, 0 deletions
diff --git a/azalea-brigadier/src/exceptions/command_syntax_exception.rs b/azalea-brigadier/src/exceptions/command_syntax_exception.rs
new file mode 100644
index 00000000..4bfe9cda
--- /dev/null
+++ b/azalea-brigadier/src/exceptions/command_syntax_exception.rs
@@ -0,0 +1,91 @@
+use std::{cmp, fmt};
+
+use super::builtin_exceptions::BuiltInExceptions;
+use crate::message::Message;
+
+#[derive(Clone, PartialEq)]
+pub struct CommandSyntaxException {
+    pub type_: BuiltInExceptions,
+    message: Message,
+    input: Option<String>,
+    cursor: Option<usize>,
+}
+
+const CONTEXT_AMOUNT: usize = 10;
+
+impl CommandSyntaxException {
+    pub fn new(type_: BuiltInExceptions, message: Message, input: &str, cursor: usize) -> Self {
+        Self {
+            type_,
+            message,
+            input: Some(input.to_string()),
+            cursor: Some(cursor),
+        }
+    }
+
+    pub fn create(type_: BuiltInExceptions, message: Message) -> Self {
+        Self {
+            type_,
+            message,
+            input: None,
+            cursor: None,
+        }
+    }
+
+    pub fn message(&self) -> String {
+        let mut message = self.message.string();
+        let context = self.context();
+        if let Some(context) = context {
+            message.push_str(&format!(
+                " at position {}: {}",
+                self.cursor.unwrap_or(usize::MAX),
+                context
+            ));
+        }
+        message
+    }
+
+    pub fn raw_message(&self) -> &Message {
+        &self.message
+    }
+
+    pub fn context(&self) -> Option<String> {
+        if let Some(input) = &self.input {
+            if let Some(cursor) = self.cursor {
+                let mut builder = String::new();
+                let cursor = cmp::min(input.len(), cursor);
+
+                if cursor > CONTEXT_AMOUNT {
+                    builder.push_str("...");
+                }
+
+                builder.push_str(
+                    &input
+                        [(cmp::max(0, cursor as isize - CONTEXT_AMOUNT as isize) as usize)..cursor],
+                );
+                builder.push_str("<--[HERE]");
+
+                return Some(builder);
+            }
+        }
+        None
+    }
+
+    pub fn get_type(&self) -> &BuiltInExceptions {
+        &self.type_
+    }
+
+    pub fn input(&self) -> &Option<String> {
+        &self.input
+    }
+
+    pub fn cursor(&self) -> Option<usize> {
+        self.cursor
+    }
+}
+
+impl fmt::Debug for CommandSyntaxException {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.message())
+    }
+}