From ab994d027a1bf110f158b363fceb6b5a6c0ae27c Mon Sep 17 00:00:00 2001
From: Alex Mikhalev <alexmikhalevalex@gmail.com>
Date: Tue, 18 Aug 2020 20:55:53 -0600
Subject: [PATCH] Implement SectionRunner pause/unpause

---
 src/section_runner.rs | 121 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 108 insertions(+), 13 deletions(-)

diff --git a/src/section_runner.rs b/src/section_runner.rs
index 14e07b1..53536e2 100644
--- a/src/section_runner.rs
+++ b/src/section_runner.rs
@@ -16,7 +16,7 @@ use tokio::{
     sync::mpsc,
     time::{delay_for, Instant},
 };
-use tracing::{debug, trace, trace_span};
+use tracing::{debug, trace, trace_span, warn};
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct RunHandle(i32);
@@ -40,14 +40,22 @@ enum RunnerMsg {
     QueueRun(RunHandle, SectionRef, Duration),
     CancelRun(RunHandle),
     CancelAll,
+    Pause,
+    Unpause,
 }
 
 #[derive(Clone, Debug, PartialEq)]
 enum RunState {
     Waiting,
-    Running { start_time: Instant },
+    Running {
+        start_time: Instant,
+    },
     Finished,
     Cancelled,
+    Paused {
+        start_time: Instant,
+        pause_time: Instant,
+    },
 }
 
 #[derive(Debug)]
@@ -55,10 +63,21 @@ struct SecRun {
     handle: RunHandle,
     section: SectionRef,
     duration: Duration,
+    total_duration: Duration,
     state: RunState,
 }
 
 impl SecRun {
+    fn new(handle: RunHandle, section: SectionRef, duration: Duration) -> Self {
+        Self {
+            handle,
+            section,
+            duration,
+            total_duration: duration,
+            state: RunState::Waiting,
+        }
+    }
+
     fn start(&mut self, interface: &dyn SectionInterface) {
         use RunState::*;
         debug!(section_id = self.section.id, "starting running section");
@@ -72,11 +91,21 @@ impl SecRun {
         matches!(self.state, RunState::Running{..})
     }
 
+    fn is_paused(&self) -> bool {
+        matches!(self.state, RunState::Paused{..})
+    }
+
     fn finish(&mut self, interface: &dyn SectionInterface) {
         if self.is_running() {
             debug!(section_id = self.section.id, "finished running section");
             interface.set_section_state(self.section.interface_id, false);
             self.state = RunState::Finished;
+        } else {
+            warn!(
+                section_id = self.section.id,
+                state = debug(&self.state),
+                "cannot finish run which is not running"
+            );
         }
     }
 
@@ -87,6 +116,53 @@ impl SecRun {
         }
         self.state = RunState::Cancelled;
     }
+
+    fn pause(&mut self, interface: &dyn SectionInterface) {
+        use RunState::*;
+        match self.state {
+            Running { start_time } => {
+                debug!(section_id = self.section.id, "pausing running section");
+                interface.set_section_state(self.section.interface_id, false);
+                self.state = Paused {
+                    start_time,
+                    pause_time: Instant::now(),
+                };
+            }
+            Waiting => {
+                debug!(section_id = self.section.id, "pausing waiting section");
+                self.state = Paused {
+                    start_time: Instant::now(),
+                    pause_time: Instant::now(),
+                };
+            }
+            Finished | Cancelled | Paused { .. } => {}
+        }
+    }
+
+    fn unpause(&mut self, interface: &dyn SectionInterface) {
+        use RunState::*;
+        match self.state {
+            Paused {
+                start_time,
+                pause_time,
+            } => {
+                debug!(section_id = self.section.id, "unpausing section");
+                interface.set_section_state(self.section.interface_id, true);
+                self.state = Running {
+                    start_time: Instant::now(),
+                };
+                let ran_for = pause_time - start_time;
+                self.duration = self.duration - ran_for;
+            }
+            Waiting | Finished | Cancelled | Running { .. } => {
+                warn!(
+                    section_id = self.section.id,
+                    state = debug(&self.state),
+                    "can only unpause paused section"
+                );
+            }
+        }
+    }
 }
 
 mod option_future {
@@ -143,16 +219,25 @@ async fn runner_task(
     let mut running = true;
     let mut run_queue: VecDeque<SecRun> = VecDeque::new();
     let mut delay_future: OptionFuture<_> = None.into();
+    let mut paused = false;
     while running {
         if let Some(current_run) = run_queue.front_mut() {
             let done = match current_run.state {
                 Waiting => {
-                    current_run.start(&*interface);
-                    delay_future = Some(delay_for(current_run.duration)).into();
+                    if paused {
+                        current_run.pause(&*interface);
+                    } else {
+                        current_run.start(&*interface);
+                        delay_future = Some(delay_for(current_run.duration)).into();
+                    }
                     false
                 }
                 Running { start_time } => {
-                    if start_time.elapsed() >= current_run.duration {
+                    if paused {
+                        current_run.pause(&*interface);
+                        delay_future = None.into();
+                        false
+                    } else if start_time.elapsed() >= current_run.duration {
                         current_run.finish(&*interface);
                         delay_future = None.into();
                         true
@@ -160,6 +245,13 @@ async fn runner_task(
                         false
                     }
                 }
+                Paused { .. } => {
+                    if !paused {
+                        current_run.unpause(&*interface);
+                        delay_future = Some(delay_for(current_run.duration)).into();
+                    }
+                    false
+                }
                 Cancelled | Finished => true,
             };
 
@@ -176,12 +268,7 @@ async fn runner_task(
             match msg {
                 Quit => running = false,
                 QueueRun(handle, section, duration) => {
-                    run_queue.push_back(SecRun {
-                        handle,
-                        section,
-                        duration,
-                        state: Waiting,
-                    });
+                    run_queue.push_back(SecRun::new(handle, section, duration));
                 }
                 CancelRun(handle) => {
                     for run in &mut run_queue {
@@ -200,6 +287,12 @@ async fn runner_task(
                         run.cancel(&*interface);
                     }
                 }
+                Pause => {
+                    paused = true;
+                }
+                Unpause => {
+                    paused = false;
+                }
             }
         };
         let delay_done = || {
@@ -270,11 +363,13 @@ impl SectionRunner {
     }
 
     pub async fn pause(&mut self) -> Result<()> {
-        todo!()
+        self.msg_send.send(RunnerMsg::Pause).await?;
+        Ok(())
     }
 
     pub async fn unpause(&mut self) -> Result<()> {
-        todo!()
+        self.msg_send.send(RunnerMsg::Unpause).await?;
+        Ok(())
     }
 }