From b9cfe0f4409928de92210e4f9602f28b137e7294 Mon Sep 17 00:00:00 2001
From: Karl F <karlfogel@gmail.com>
Date: Tue, 16 Aug 2016 10:51:27 +0200
Subject: [PATCH] Ship knows when a hyperjump is legal or not

---
 data/libs/Ship.lua | 105 ++++++++++++++++++++++++++++++++++++++++++++-
 src/WorldView.cpp  |   5 ++-
 2 files changed, 107 insertions(+), 3 deletions(-)

diff --git a/data/libs/Ship.lua b/data/libs/Ship.lua
index 9873524e61e..9a92b020fa5 100644
--- a/data/libs/Ship.lua
+++ b/data/libs/Ship.lua
@@ -367,14 +367,117 @@ Ship.RemoveEquip = function (self, item, count, slot)
 	return ret
 end
 
-Ship.HyperjumpTo = function (self, path)
+
+--
+-- Method: IsHyperjumpAllowed
+--
+-- Check if hyperjump is allowed, return bool and minimum allowed
+-- altitude / distance.
+--
+-- > is_allowed, distance = ship:IsHyperjumpAllowed()
+--
+--
+-- Return:
+--
+--   is_allowed - Boolean. True if allowed at ships current position,
+--                flase otherwise
+--
+--   distance - The minimum allowed altitude from planetary body, or
+--              distance from orbital space station, for a legal hyper juump.
+--
+-- Availability:
+--
+--  2016 August
+--
+-- Status:
+--
+--  experimental
+--
+Ship.IsHyperjumpAllowed = function(self)
+
+	-- in meters
+	local MIN_PLANET_HYPERJUMP_ALTITUDE = 10000
+	local MIN_SPACESTATION_HYPERJUMP_DISTANCE = 1000
+
+	-- get closest non-dynamic (not ships, cargo, missiles) body of ship
+	local body = self.frameBody
+
+	-- If no body close by, anything goes
+	if not body then
+		return true, 0
+	end
+
+	-- if alt is nil, then outside frame of ref -> OK to jump
+	local check = function(alt, dist) return not alt or alt >= dist, dist end
+
+	-- if body exists and not a planet -> allowed
+	if body and body.type == 'STARPORT_ORBITAL' then
+		return check(body:DistanceTo(self), MIN_SPACESTATION_HYPERJUMP_DISTANCE)
+	end
+
+	-- if on a planet:
+	-- always allowed if not body.hasAtmosphere?
+
+	-- if body is a planet or a star:
+	if body and body.type ~= 'GRAVPOINT' then
+		local lat, long, altitude = self:GetGroundPosition()
+		return check(altitude, MIN_PLANET_HYPERJUMP_ALTITUDE)
+	end
+end
+
+--
+-- Method: HyperjumpTo
+--
+-- Hyperjump ship to system. Makes sure the ship has a hyper drive,
+-- that target is withn range, and ship has enough fuel, before
+-- initiating the hyperjump countdown. In addition, through the
+-- optional argument, the ship can fly to a safe distance, compliant
+-- with local authorities' regulation, before initiating the jump.
+--
+-- > status = ship:HyperjumpTo(path)
+-- > status = ship:HyperjumpTo(path, is_legal)
+--
+-- Parameters:
+--
+--   path - a <SystemPath> for the destination system
+--
+--   isLegal - an optional Boolean argument, defaults to false. If
+--             true AI will fly the ship ship to legal distance
+--             before jumping
+--
+-- Return:
+--
+--   status - a <Constants.ShipJumpStatus> string that tells if the ship can
+--            hyperspace and if not, describes the reason
+--
+-- Availability:
+--
+--  2015
+--
+-- Status:
+--
+--  experimental
+--
+Ship.HyperjumpTo = function (self, path, is_legal)
 	local engine = self:GetEquip("engine", 1)
 	if not engine then
 		return "NO_DRIVE"
 	end
+
+	-- default to false, if nil:
+	is_legal = not (is_legal == nil) or is_legal
+
+	-- only jump from safe distance
+	local is_allowed, distance = self:IsHyperjumpAllowed()
+	if is_legal and self.frameBody and not is_allowed then
+		print("---> Engage AI for safe distance of hyperjump")
+		self:AIEnterLowOrbit(self.frameBody)
+	end
+
 	return engine:HyperjumpTo(self, path)
 end
 
+
 Ship.CanHyperjumpTo = function(self, path)
 	return self:GetHyperspaceDetails(path) == 'OK'
 end
diff --git a/src/WorldView.cpp b/src/WorldView.cpp
index 4f27575986c..205d6d72f69 100644
--- a/src/WorldView.cpp
+++ b/src/WorldView.cpp
@@ -582,14 +582,15 @@ void WorldView::RefreshHyperspaceButton() {
 
 	SystemPath target = m_game->GetSectorView()->GetHyperspaceTarget();
 	if (LuaObject<Ship>::CallMethod<bool>(Pi::player, "CanHyperjumpTo", &target)){
-
+//		std::cout << "ONE" << std::endl;
 		if(Pi::player->GetFlightState() == Ship::FLYING || Pi::player->GetFlightState() == Ship::JUMPING)
 		{
+//			std::cout << "TWO" << std::endl;
 			// leave the "disabled" state if not landed:
 			if(m_hyperspaceButton->GetState() == 0)
 				m_hyperspaceButton->StateNext();
 
-			if(!Pi::player->IsHyperspaceAllowed()){
+			if(!LuaObject<Ship>::CallMethod<bool>(Pi::player, "IsHyperjumpAllowed")){
 				// If crossing boundary from above
 				if(3 <= m_hyperspaceButton->GetState()){
 					m_hyperspaceButton->StatePrev();