From 9f1811975e996a3bf70c3e834a872e59c8ade984 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Fri, 14 Apr 2023 08:37:14 +0100
Subject: Load the map list from a JSON file

---
 data/maps.json  |  5 +++++
 src/Game.hs     | 11 +++++------
 src/Game/Map.hs |  9 +++++++++
 3 files changed, 19 insertions(+), 6 deletions(-)
 create mode 100644 data/maps.json

diff --git a/data/maps.json b/data/maps.json
new file mode 100644
index 0000000..2b56827
--- /dev/null
+++ b/data/maps.json
@@ -0,0 +1,5 @@
+[
+    "data/map1.json",
+    "data/map2.json",
+    "data/map1.json"
+]
diff --git a/src/Game.hs b/src/Game.hs
index be34a08..c2f6083 100644
--- a/src/Game.hs
+++ b/src/Game.hs
@@ -32,10 +32,6 @@ windowWidth, windowHeight :: CInt
 version :: String
 version = "0.1.0"
 
--- XXX: placeholder for the map list, perhaps should be loaded from a JSON
-maps :: [String]
-maps = ["data/map1.json", "data/map2.json"]
-
 data Env = Env
   { window :: SDL.Window,
     renderer :: SDL.Renderer,
@@ -43,6 +39,7 @@ data Env = Env
     fullscreen :: Bool,
     renderRect :: SDL.Rectangle CInt,
     tsTexture :: SDL.Texture,
+    mapList :: [String],
     map :: M.Map,
     sprites :: S.SpriteSheet,
     font :: BF.BitmapFont,
@@ -75,7 +72,8 @@ main = do
   tsTexture <- SDL.Image.loadTexture renderer "data/tiles.png"
   ssTexture <- SDL.Image.loadTexture renderer "data/sprites.png"
   bfTexture <- SDL.Image.loadTexture renderer "data/font.png"
-  map' <- M.load (head maps) tsTexture
+  mapList <- M.loadMapList "data/maps.json"
+  map' <- M.load (head mapList) tsTexture
   sprites <- S.load "data/sprites.json" ssTexture
   font <- BF.load "data/font.json" bfTexture
   controls <- newIORef C.init
@@ -89,6 +87,7 @@ main = do
         fullscreen = False,
         renderRect = defaultRenderRect,
         tsTexture = tsTexture,
+        mapList = mapList,
         map = map',
         sprites = sprites,
         font = font,
@@ -167,7 +166,7 @@ gameLoop e = do
           es <- E.addExit env.entities x (y - 8) -- adjusted to player's height
           pure env {entities = es, state = state {GS.exit = True}}
       | state.levelCompleted == GS.ExitDone = do
-          map' <- M.load (maps !! (env.state.currentLevel + 1)) env.tsTexture
+          map' <- M.load (env.mapList !! (env.state.currentLevel + 1)) env.tsTexture
           entities <- E.mkEntities env.sprites map' env.controls
           pure $
             env
diff --git a/src/Game/Map.hs b/src/Game/Map.hs
index ea20b17..9616971 100644
--- a/src/Game/Map.hs
+++ b/src/Game/Map.hs
@@ -3,6 +3,7 @@ module Game.Map
     Object (..),
     objects,
     totalBatteries,
+    loadMapList,
     load,
     render,
     isBlocked,
@@ -117,6 +118,14 @@ data Viewport = Viewport Int Int Int Int
 
 data Map = Map MapData SDL.Texture
 
+-- | Loads a list of maps from JSON file.
+loadMapList :: String -> IO [String]
+loadMapList filename = do
+  d <- readFile filename
+  case decode d :: Result [String] of
+    Ok s -> pure s
+    Error e -> error e
+
 -- | Loads a map from a JSON file.
 load :: String -> SDL.Texture -> IO Map
 load filename tex = do
-- 
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