Report MPC horizon and drop any cycles at the beginning which are 0

This lets us start firing faster.

Change-Id: Idda068e3b0ca78da6ec5ab422d217d10d9c65e1c
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/y2022/control_loops/superstructure/catapult/catapult.cc b/y2022/control_loops/superstructure/catapult/catapult.cc
index 8b5c7eb..e662f30 100644
--- a/y2022/control_loops/superstructure/catapult/catapult.cc
+++ b/y2022/control_loops/superstructure/catapult/catapult.cc
@@ -300,10 +300,19 @@
     return std::nullopt;
   }
 
-  const double u = problems_[current_controller_]->U(0);
+  double u;
+  size_t solution_horizon = 0;
+  if (current_controller_ == 0u) {
+    while (solution_horizon < problems_[current_controller_]->horizon() &&
+           problems_[current_controller_]->U(solution_horizon) < 0.01) {
+      ++solution_horizon;
+    }
+  } else {
+    u = problems_[current_controller_]->U(0);
+  }
 
-  if (current_controller_ + 1u < problems_.size()) {
-    problems_[current_controller_ + 1]->WarmStart(
+  if (current_controller_ + 1u + solution_horizon < problems_.size()) {
+    problems_[current_controller_ + solution_horizon + 1]->WarmStart(
         *problems_[current_controller_]);
   }
   ++current_controller_;
@@ -360,8 +369,9 @@
           Eigen::Vector2d(latched_shot_position, latched_shot_velocity));
 
       const bool solved = catapult_mpc_.Solve();
-
-      if (solved || catapult_mpc_.started()) {
+      current_horizon_ = catapult_mpc_.current_horizon();
+      const bool started = catapult_mpc_.started();
+      if (solved || started) {
         std::optional<double> solution = catapult_mpc_.Next();
 
         if (!solution.has_value()) {
@@ -419,6 +429,7 @@
     // Select the controller designed for when we have no ball.
     catapult_.set_controller_index(1);
 
+    current_horizon_ = 0u;
     const double output_voltage = catapult_.UpdateController(catapult_disabled);
     if (catapult_voltage != nullptr) {
       *catapult_voltage = output_voltage;
diff --git a/y2022/control_loops/superstructure/catapult/catapult.h b/y2022/control_loops/superstructure/catapult/catapult.h
index 6a2c834..12c0116 100644
--- a/y2022/control_loops/superstructure/catapult/catapult.h
+++ b/y2022/control_loops/superstructure/catapult/catapult.h
@@ -159,6 +159,15 @@
   // Returns the time in seconds it last took Solve to run.
   double solve_time() const { return solve_time_; }
 
+  // Returns the horizon of the current controller.
+  size_t current_horizon() const {
+    if (current_controller_ >= problems_.size()) {
+      return 0u;
+    } else {
+      return problems_[current_controller_]->horizon();
+    }
+  }
+
   // Returns the controller value if there is a controller to run, or nullopt if
   // we finished the last controller.  Advances the controller pointer to the
   // next controller and warms up the next controller.
@@ -182,7 +191,7 @@
 class Catapult {
  public:
   Catapult(const constants::Values &values)
-      : catapult_(values.catapult.subsystem_params), catapult_mpc_(35) {}
+      : catapult_(values.catapult.subsystem_params), catapult_mpc_(30) {}
 
   using PotAndAbsoluteEncoderSubsystem =
       ::frc971::control_loops::StaticZeroingSingleDOFProfiledSubsystem<
@@ -198,6 +207,8 @@
   bool estopped() const { return catapult_.estopped(); }
   double solve_time() const { return catapult_mpc_.solve_time(); }
 
+  uint8_t mpc_horizon() const { return current_horizon_; }
+
   bool mpc_active() const { return !use_profile_; }
 
   // Returns the number of shots taken.
@@ -230,6 +241,7 @@
   bool use_profile_ = true;
 
   int shot_count_ = 0;
+  uint8_t current_horizon_ = 0u;
 };
 
 }  // namespace catapult