From 1cee3956d224f869bc55827b30459b237ae14d45 Mon Sep 17 00:00:00 2001
From: Jonathan Strong <jonathan.strong@gmail.com>
Date: Thu, 26 Mar 2020 03:32:12 -0400
Subject: [PATCH] begin adding case study

---
 Cargo.toml        |   2 +
 src/case_study.rs | 137 ++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs        |  37 +++++++------
 3 files changed, 160 insertions(+), 16 deletions(-)
 create mode 100644 src/case_study.rs

diff --git a/Cargo.toml b/Cargo.toml
index 6c68a51..1b07623 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,5 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+chrono = "0.4"
+uuid = { version = "0.7", features = ["v4"] }
diff --git a/src/case_study.rs b/src/case_study.rs
new file mode 100644
index 0000000..6724a84
--- /dev/null
+++ b/src/case_study.rs
@@ -0,0 +1,137 @@
+use std::net::Ipv4Addr;
+use chrono::{DateTime, Utc};
+use uuid::Uuid;
+
+pub struct Event<T> {
+    pub time: DateTime<Utc>,
+    pub id: Uuid,
+    pub event: T,
+}
+
+pub struct Pending{
+    pub recipient: Ipv4Addr,
+}
+
+pub struct Sending {
+    pub payload: Vec<u8>,
+    pub bytes_sent: usize,
+    pub prev: Event<Ipv4Addr>,
+}
+
+pub struct Sent {
+    pub ack_req: bool,
+    pub prev: Event<Sending>,
+}
+
+pub struct Ack {
+    pub data: Vec<u8>,
+    pub prev: Event<Sent>,
+}
+
+pub struct Finished<T> {
+    pub prev: Event<T>,
+}
+
+pub enum Active {
+    Pending(Event<Pending>),
+    Sending(Event<Sending>),
+    Sent(Event<Sent>),
+    Acked(Event<Ack>),
+    FinishedNoAck(Event<Finished<Sent>>),
+    FinishedAcked(Event<Finished<Ack>>),
+}
+
+pub trait Timestamped {
+    fn time(&self) -> DateTime<Utc>;
+}
+
+pub trait Chronological {
+    type Prev;
+    type Next;
+
+    fn prev(&self) -> Self::Prev;
+    fn next(&self) -> Self::Next;
+}
+
+pub trait Elapsed<P, N>: Chronological<Prev = P, Next = N> {
+    fn elapsed(&self) -> chrono::Duration;
+}
+
+impl<T> Timestamped for Event<T> {
+    fn time(&self) -> DateTime<Utc> { self.time }
+}
+
+impl<P, N, T> Elapsed<P, N> for T
+    where T: Chronological<Prev = P, Next = N>,
+          P: Timestamped,
+          N: Timestamped
+{
+    fn elapsed(&self) -> chrono::Duration {
+        self.next().time().signed_duration_since(self.prev().time())
+    }
+}
+
+impl<N, T> Elapsed<(), N> for T
+    where T: Chronological<Prev = (), Next = N>
+{
+    fn elapsed(&self) -> chrono::Duration {
+        chrono::Duration::seconds(0)
+    }
+}
+
+impl Timestamped for Active {
+    fn time(&self) -> DateTime<Utc> {
+        use Active::*;
+        match self {
+            Pending(event) => event.time,
+            Sending(event) => event.time,
+            Sent(event) => event.time,
+            Acked(event) => event.time,
+            FinishedNoAck(event) => event.time,
+            FinishedAcked(event) => event.time,
+        }
+    }
+}
+
+macro_rules! event_attr {
+    ($method:ident, $t:ident, $attr:ident) => {
+        fn $method(&self) -> $t {
+            use Active::*;
+            match self {
+                Pending(event) => event.$attr,
+                Sending(event) => event.$attr,
+                Sent(event) => event.$attr,
+                Acked(event) => event.$attr,
+                FinishedNoAck(event) => event.$attr,
+                FinishedAcked(event) => event.$attr,
+            }
+        }
+    }
+}
+
+impl Active {
+    event_attr!(id, Uuid, id);
+}
+
+#[allow(unused)]
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::str::FromStr;
+
+    #[test]
+    fn event_attr_accessors_work() {
+        let pending = Pending { recipient: "0.0.0.0".parse().unwrap() };
+        let now = Utc::now();
+        let id = Uuid::new_v4();
+        let pending_event = Event {
+            time: now,
+            id,
+            event: pending,
+        };
+        let pending_active = Active::Pending(pending_event);
+        assert_eq!(pending_active.time(), now);
+        assert_eq!(pending_active.id(), id);
+    }
+}
+
diff --git a/src/lib.rs b/src/lib.rs
index 67edbac..e3db6e5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -44,7 +44,12 @@
 //! }
 //! make_adder_fn!(42);
 //! ```
+//!
+
+pub mod case_study;
 
+
+#[allow(unused)]
 #[cfg(test)]
 mod tests {
 
@@ -319,26 +324,26 @@ mod tests {
                 <A as Devious>::abc(&$x)
             }
         }
-        let c = <A as ::tests::example_for_why_you_should_use_fully_qualified_names::Devious>::abc(&a);
+        //let c = <A as ::tests::example_for_why_you_should_use_fully_qualified_names::Devious>::abc(&a);
 
-        macro_rules! you_gotta_be_wiser {
-            { [[ $x:ident ]] } => {
-                <A as ::tests::example_for_why_you_should_use_fully_qualified_names::Devious>::abc(&$x)
-            }
-            //{ [[ $x:ident ]] } => {
-            //    <A as crate::tests::example_for_why_you_should_use_fully_qualified_names::Devious>::abc(&$x)
-            //};
-
-            //{ -^-^- $x:ident -^-^- } => {{ 
-            //    // invoking the version that's inside `the_upside_down`
-            //    use crate::tests::example_for_why_you_should_use_fully_qualified_names::the_upside_down::Devious as OtherDevious;
-            //    <A as crate::tests::example_for_why_you_should_use_fully_qualified_names::the_upside_down::OtherDevious>::xyz(&$x)
-            //}};
-        }
+        //macro_rules! you_gotta_be_wiser {
+        //    { [[ $x:ident ]] } => {
+        //        <A as ::tests::example_for_why_you_should_use_fully_qualified_names::Devious>::abc(&$x)
+        //    }
+        //    //{ [[ $x:ident ]] } => {
+        //    //    <A as crate::tests::example_for_why_you_should_use_fully_qualified_names::Devious>::abc(&$x)
+        //    //};
+
+        //    //{ -^-^- $x:ident -^-^- } => {{ 
+        //    //    // invoking the version that's inside `the_upside_down`
+        //    //    use crate::tests::example_for_why_you_should_use_fully_qualified_names::the_upside_down::Devious as OtherDevious;
+        //    //    <A as crate::tests::example_for_why_you_should_use_fully_qualified_names::the_upside_down::OtherDevious>::xyz(&$x)
+        //    //}};
+        //}
 
         assert_eq!(didnt_see_it_coming!{ a <-> }, 42);
 
-        assert_eq!(you_gotta_be_wiser!{ [[ a ]] }, 42);
+        //assert_eq!(you_gotta_be_wiser!{ [[ a ]] }, 42);
         //assert_eq!(you_gotta_be_wiser!{ -^-^- a -^-^- }, -42);
 
         /// muhaha