From 0ddd9d91eaa59ddd76f0cb62644dc9894a0a8e60 Mon Sep 17 00:00:00 2001
From: Dan Paulat <dpaulat@gmail.com>
Date: Fri, 26 May 2023 16:14:33 -0500
Subject: [PATCH] Timeline step back

---
 .../scwx/qt/manager/timeline_manager.cpp      | 63 +++++++++++++++++++
 wxdata/include/scwx/util/map.hpp              | 39 ++++++++----
 2 files changed, 90 insertions(+), 12 deletions(-)

diff --git a/scwx-qt/source/scwx/qt/manager/timeline_manager.cpp b/scwx-qt/source/scwx/qt/manager/timeline_manager.cpp
index 7269aee1..4d25f09b 100644
--- a/scwx-qt/source/scwx/qt/manager/timeline_manager.cpp
+++ b/scwx-qt/source/scwx/qt/manager/timeline_manager.cpp
@@ -33,6 +33,7 @@ public:
    TimelineManager* self_;
 
    void SelectTime(std::chrono::system_clock::time_point selectedTime = {});
+   void StepBack();
 
    std::string                           radarSite_ {"?"};
    std::string                           previousRadarSite_ {"?"};
@@ -51,6 +52,12 @@ TimelineManager::~TimelineManager() = default;
 
 void TimelineManager::SetRadarSite(const std::string& radarSite)
 {
+   if (p->radarSite_ == radarSite)
+   {
+      // No action needed
+      return;
+   }
+
    logger_->debug("SetRadarSite: {}", radarSite);
 
    p->radarSite_ = radarSite;
@@ -123,6 +130,8 @@ void TimelineManager::AnimationStepBegin()
 void TimelineManager::AnimationStepBack()
 {
    logger_->debug("AnimationStepBack");
+
+   p->StepBack();
 }
 
 void TimelineManager::AnimationPlay()
@@ -217,6 +226,60 @@ void TimelineManager::Impl::SelectTime(
       });
 }
 
+void TimelineManager::Impl::StepBack()
+{
+   scwx::util::async(
+      [this]()
+      {
+         // Take a lock for time selection
+         std::unique_lock lock {selectTimeMutex_};
+
+         // Determine time to get active volume times
+         std::chrono::system_clock::time_point queryTime = adjustedTime_;
+         if (queryTime == std::chrono::system_clock::time_point {})
+         {
+            queryTime = std::chrono::system_clock::now();
+         }
+
+         // Request active volume times
+         auto radarProductManager =
+            manager::RadarProductManager::Instance(radarSite_);
+         auto volumeTimes =
+            radarProductManager->GetActiveVolumeTimes(queryTime);
+
+         std::set<std::chrono::system_clock::time_point>::const_iterator it;
+
+         if (adjustedTime_ == std::chrono::system_clock::time_point {})
+         {
+            // If the adjusted time is live, get the last element in the set
+            it = volumeTimes.cend();
+            if (!volumeTimes.empty())
+            {
+               --it;
+            }
+         }
+         else
+         {
+            // Get the current element in the set
+            it = scwx::util::GetBoundedElementIterator(volumeTimes,
+                                                       adjustedTime_);
+         }
+
+         // Only if we aren't at the beginning of the volume times set
+         if (it != volumeTimes.cbegin())
+         {
+            // Select the previous time
+            adjustedTime_ = *(--it);
+            selectedTime_ = adjustedTime_;
+
+            logger_->debug("Volume time updated: {}",
+                           scwx::util::TimeString(adjustedTime_));
+
+            emit self_->VolumeTimeUpdated(adjustedTime_);
+         }
+      });
+}
+
 std::shared_ptr<TimelineManager> TimelineManager::Instance()
 {
    static std::weak_ptr<TimelineManager> timelineManagerReference_ {};
diff --git a/wxdata/include/scwx/util/map.hpp b/wxdata/include/scwx/util/map.hpp
index b6282807..f35e2abf 100644
--- a/wxdata/include/scwx/util/map.hpp
+++ b/wxdata/include/scwx/util/map.hpp
@@ -8,14 +8,13 @@ namespace scwx
 namespace util
 {
 
-template<class Container, class ReturnType = Container::const_pointer>
-ReturnType GetBoundedElementPointer(Container& container,
-                                    const typename Container::key_type& key)
+template<class Container>
+Container::const_iterator
+GetBoundedElementIterator(Container&                          container,
+                          const typename Container::key_type& key)
 {
-   ReturnType elementPtr {nullptr};
-
    // Find the first element greater than the key requested
-   auto it = container.upper_bound(key);
+   typename Container::const_iterator it = container.upper_bound(key);
 
    // An element with a key greater was found
    if (it != container.cend())
@@ -25,19 +24,34 @@ ReturnType GetBoundedElementPointer(Container& container,
       {
          // Get the element immediately preceding, this the element we are
          // looking for
-         elementPtr = &(*(--it));
+         --it;
       }
       else
       {
          // The current element is a good substitute
-         elementPtr = &(*it);
       }
    }
    else if (container.size() > 0)
    {
       // An element with a key greater was not found. If it exists, it must be
-      // the last element.
-      elementPtr = &(*container.rbegin());
+      // the last element. Decrement the end iterator.
+      --it;
+   }
+
+   return it;
+}
+
+template<class Container, class ReturnType = Container::const_pointer>
+ReturnType GetBoundedElementPointer(Container& container,
+                                    const typename Container::key_type& key)
+{
+   ReturnType elementPtr {nullptr};
+
+   auto it = GetBoundedElementIterator(container, key);
+
+   if (it != container.cend())
+   {
+      elementPtr = &(*(it));
    }
 
    return elementPtr;
@@ -48,9 +62,10 @@ ReturnType GetBoundedElement(std::map<Key, T>& map, const Key& key)
 {
    ReturnType element;
 
-   typename std::map<Key, T>::pointer elementPtr =
+   typename std::map<Key, T>::const_pointer elementPtr =
       GetBoundedElementPointer<std::map<Key, T>,
-                               typename std::map<Key, T>::pointer>(map, key);
+                               typename std::map<Key, T>::const_pointer>(map,
+                                                                         key);
    if (elementPtr != nullptr)
    {
       element = elementPtr->second;