add a roll command, relax semver requirements on dependencies

1 files changed, 60 insertions, 0 deletions

diff --git a/src/commands/roll.rs b/src/commands/roll.rs
new file mode 100644
index 0000000..fb5c71a
--- /dev/null
+++ b/src/commands/roll.rs
@@ -0,0 +1,60 @@
+use serenity::prelude::*;
+use serenity::framework::standard::Args;
+use serenity::model::channel::Message;
+use regex::Regex;
+use rand::prelude::*;
+
+use Result;
+
+use super::send;
+
+lazy_static! {
+    static ref ROLL_REGEX: Regex = Regex::new(r"([0-9]+)?(?:d([0-9]+)(?:\s+\+\s+([0-9]+))?)")
+                                        .expect("error parsing roll regex");
+}
+
+pub fn roll(_ctx: &mut Context, msg: &Message, args: Args) -> Result<()> {
+    let captures = match ROLL_REGEX.captures(args.full()) {
+        Some(captures) => captures,
+        None => return send(msg.channel_id, "conway is a goldfish", msg.tts),
+    };
+
+    let dice_count = match captures.get(1) {
+        Some(x) => {
+            match x.as_str().parse::<usize>() {
+                Ok(x) => x,
+                Err(e) => {
+                    send(msg.channel_id, "conway is a goldfish", msg.tts)?;
+                    return Err(e.into());
+                },
+            }
+        },
+        None => 1,
+    };
+
+    if dice_count > 1000000 {
+        send(msg.channel_id, "no.", msg.tts)?;
+        return Ok(());
+    }
+
+    let faces = match captures.get(2).unwrap().as_str().parse::<usize>() {
+        Ok(faces) => faces,
+        Err(e) => {
+            send(msg.channel_id, "conway is a goldfish", msg.tts)?;
+            return Err(e.into())
+        },
+    };
+
+    let adjust = match captures.get(3).map(|adjust| adjust.as_str().parse::<usize>()).transpose() {
+        Ok(adjust) => adjust.unwrap_or(0),
+        Err(e) => {
+            send(msg.channel_id, "conway is a goldfish", msg.tts)?;
+            return Err(e.into())
+        },
+    };
+
+    let mut rng = thread_rng();
+    let total = (0..dice_count).map(|_| rng.gen_range(0, faces)).sum::<usize>() + adjust + 1;
+
+    send(msg.channel_id, &format!("{}", total), msg.tts)
+}