From 7944fd3f7fa00c1c3067d4102e9bfb5b623fc9b1 Mon Sep 17 00:00:00 2001
From: Sebastian Moser <sebastian@c2vi.dev>
Date: Thu, 23 May 2024 00:24:09 +0200
Subject: [PATCH] added hello-world wasm example and npmPackage nix derivation

---
 flake.nix                  | 47 ++++++++++++++++++++++++++++++++++----
 src/lib.rs                 |  9 +++++++-
 src/platform/wasm/mod.rs   | 19 +++++++++++++++
 src/platform/wasm/utils.rs |  0
 4 files changed, 69 insertions(+), 6 deletions(-)
 create mode 100644 src/platform/wasm/mod.rs
 create mode 100644 src/platform/wasm/utils.rs

diff --git a/flake.nix b/flake.nix
index d0fb590..341e727 100644
--- a/flake.nix
+++ b/flake.nix
@@ -21,23 +21,56 @@
 let
   pkgs = nixpkgs.legacyPackages.${system};
   wasmToolchain = fenix.packages.${system}.combine [
-    fenix.packages.${system}.targets.wasm32-unknown-unknown.stable.toolchain
-    fenix.packages.${system}.complete.toolchain
+    fenix.packages.${system}.targets.wasm32-unknown-unknown.latest.toolchain
+    fenix.packages.${system}.latest.toolchain
   ];
-  osToolchain = fenix.packages.${system}.complete.toolchain;
+  osToolchain = fenix.packages.${system}.latest.toolchain;
   wasmCrane = crane.lib.${system}.overrideToolchain wasmToolchain;
   osCrane = crane.lib.${system}.overrideToolchain osToolchain;
 
+  wasmArtifacts = wasmCrane.buildDepsOnly ({
+    src = self;
+    doCheck = false; # tests does not work in wasm
+    CARGO_BUILD_TARGET = "wasm32-unknown-unknown";
+  });
+
 in {
 ############################## PACKAGES ##############################
     packages.default = osCrane.buildPackage {
       src = "${self}";
+      cargoExtraArgs = "--bin mize --features os-binary";
     };
 
-    packages = {
+    packages = rec {
       wasm = wasmCrane.buildPackage {
         src = "${self}";
+        CARGO_BUILD_TARGET = "wasm32-unknown-unknown";
+        doCheck = false;
       };
+
+      # Thanks to:
+      # - https://github.com/dl-solarity/hardhat-diamond-tools/blob/e5b8bc9624fbf89eda83a8ce4f6b6672ea83f550/flake.nix#L103
+      # - https://github.com/ipetkov/crane/issues/362#issuecomment-1683220603
+      npmPackage = wasmCrane.mkCargoDerivation {
+        name = "mize-npm-package";
+
+        # i can't use CARGO_BUILD_TARGET to set the target
+        # because then the cargo install run by wasm-pack tries to build the wasm-bindgen-cli for a wasm target...
+        cargoExtraArgs = "--target wasm32-unknown-unknown --features wasm-target";
+        src = self;
+
+        cargoArtifacts = wasmArtifacts;
+        doCheck = false;
+
+        buildPhaseCargoCommand = ''
+            mkdir -p $out/pkg
+
+            HOME=$(mktemp -d fake-homeXXXX) wasm-pack build --out-dir $out/pkg --scope=c2vi -- --features wasm-target
+        '';
+
+        buildInputs = with pkgs; [ wasm-bindgen-cli binaryen wasm-pack wasmToolchain ];
+      };
+
     };
 
 ############################## DEV SHELLS ##############################
@@ -58,6 +91,10 @@ in {
       ];
     };
 
-  });
+  }) // {
+
+############################## SOME GLOBAL OUTPUTS ##############################
+    inherit inputs;
+  };
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 9698367..8b98d18 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,6 +3,8 @@
 
 static PROTO_VERSION: u8 = 1;
 
+// the core part houses the code that can run on any platform
+/*
 pub mod core {
     pub mod memstore;
     pub mod instance;
@@ -14,7 +16,12 @@ pub mod core {
 }
 
 pub use core::*;
-
+// */
+
+pub mod platform {
+    #[cfg(feature = "wasm-target")]
+    pub mod wasm;
+}
 
 
 
diff --git a/src/platform/wasm/mod.rs b/src/platform/wasm/mod.rs
new file mode 100644
index 0000000..0241800
--- /dev/null
+++ b/src/platform/wasm/mod.rs
@@ -0,0 +1,19 @@
+mod utils;
+
+use wasm_bindgen::prelude::*;
+
+// When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
+// allocator.
+#[cfg(feature = "wee_alloc")]
+#[global_allocator]
+static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
+
+#[wasm_bindgen]
+extern {
+    fn alert(s: &str);
+}
+
+#[wasm_bindgen]
+pub fn greet() {
+    alert("Hello, wasm-game-of-life!");
+}
diff --git a/src/platform/wasm/utils.rs b/src/platform/wasm/utils.rs
new file mode 100644
index 0000000..e69de29