From 446b1659de36158651ca628a42c3201248042330 Mon Sep 17 00:00:00 2001
From: Anton Vakhrushev <a.vakhrushev@elama.ru>
Date: Thu, 3 Oct 2019 17:10:13 +0300
Subject: [PATCH] Add resource exception

---
 spec/world_spec.cr |  9 +++++++++
 src/command.cr     |  8 ++++++--
 src/exception.cr   |  2 ++
 src/resources.cr   | 12 +++++++++++-
 4 files changed, 28 insertions(+), 3 deletions(-)
 create mode 100644 src/exception.cr

diff --git a/spec/world_spec.cr b/spec/world_spec.cr
index 176a1bc..b3253dc 100644
--- a/spec/world_spec.cr
+++ b/spec/world_spec.cr
@@ -10,4 +10,13 @@ describe "World" do
     world.run(100)
     world.map.get(point).has_role(TileRole::CrystalHarvester)
   end
+
+  it "should fail when not enought resources" do
+    world = World.new
+    point = Point.new(2, 3)
+    cmd = BuildCrystalRestorerCommand.new(point)
+    expect_raises(NotEnoughtResources) do
+      world.push(cmd)
+    end
+  end
 end
diff --git a/src/command.cr b/src/command.cr
index 6a80ba8..2867542 100644
--- a/src/command.cr
+++ b/src/command.cr
@@ -62,12 +62,14 @@ class HarvestCrystalCommand < Command
 end
 
 class BuildCrystalRestorerCommand < Command
-  BUILD_TIME = 50
+  CRYSTALS_COST = 100
+  BUILD_TIME    =  50
 
   def initialize(@point : Point)
   end
 
   def start(world : World) : Int32
+    world.resources.dec(ResourceType::Crystal, CRYSTALS_COST)
     BUILD_TIME
   end
 
@@ -112,12 +114,14 @@ class RestoreCrystalCommand < Command
 end
 
 class BuildTerraformerCommand < Command
-  BUILD_TIME = 120
+  CRYSTALS_COST = 100
+  BUILD_TIME    = 120
 
   def initialize(@point : Point)
   end
 
   def start(world : World) : Int32
+    world.resources.dec(ResourceType::Crystal, CRYSTALS_COST)
     BUILD_TIME
   end
 
diff --git a/src/exception.cr b/src/exception.cr
new file mode 100644
index 0000000..9dcf0f3
--- /dev/null
+++ b/src/exception.cr
@@ -0,0 +1,2 @@
+class NotEnoughtResources < Exception
+end
diff --git a/src/resources.cr b/src/resources.cr
index e9cdf14..6da26ec 100644
--- a/src/resources.cr
+++ b/src/resources.cr
@@ -1,3 +1,5 @@
+require "./exception"
+
 enum ResourceType
   Crystal
   Terraformation
@@ -16,6 +18,14 @@ class Resources
   end
 
   def inc(t : ResourceType, value : Int32)
-    @values[t] = @values[t] + value
+    new_value = @values[t] + value
+    if new_value < 0
+      raise NotEnoughtResources.new
+    end
+    @values[t] = new_value
+  end
+
+  def dec(t : ResourceType, value : Int32)
+    inc(t, -value)
   end
 end