1 files changed, 136 insertions, 0 deletions
diff --git a/lib/fetchPackwizModpack.nix b/lib/fetchPackwizModpack.nix
new file mode 100644
index 0000000..a12d098
--- /dev/null
+++ b/lib/fetchPackwizModpack.nix
@@ -0,0 +1,136 @@
+{
+  lib,
+  stdenvNoCC,
+  fetchurl,
+  packwiz-installer-bootstrap,
+  packwiz-installer,
+  jre_headless,
+  jq,
+  moreutils,
+  curl,
+  cacert,
+}: let
+  fetchPackwizModpack = {
+    pname ? "packwiz-pack",
+    version ? "",
+    url ? null,
+    hash ? "",
+    # Either 'server' or 'both' (to get client mods as well)
+    side ? "server",
+    # The derivation passes through a 'manifest' expression, that includes
+    # useful metadata (such as MC version). When providing the manifest file itself,
+    # this metadata can be used to automatically assign 'pname' and 'version'
+    #
+    # By default, if you access the 'manifest' expression, IFD will be used.
+    # If you want to use 'manifest' without IFD or a manifest file, you can
+    # also pass a manifestHash, which allows us to fetch it with
+    # builtins.fetchurl instead.
+    manifest ? null,
+    manifestHash ? null,
+    useManifest ? manifest != null,
+    ...
+  } @ args:
+    assert lib.assertMsg (url == null -> manifest != null) "a url or manifest must be provided!";
+      stdenvNoCC.mkDerivation (finalAttrs:
+        {
+          pname =
+            if useManifest
+            then finalAttrs.passthru.manifest.name
+            else pname;
+
+          version =
+            if useManifest
+            then finalAttrs.passthru.manifest.version
+            else version;
+
+          dontUnpack = true;
+
+          buildInputs = [jre_headless jq moreutils curl cacert];
+
+          buildPhase = ''
+            ${lib.optionalString (!useManifest) "curl -L \"${url}\" > pack.toml"}
+
+            java -jar ${packwiz-installer-bootstrap} \
+              --bootstrap-main-jar ${packwiz-installer} \
+              --bootstrap-no-update \
+              --no-gui \
+              --side ${side} \
+              "${
+              if useManifest
+              then manifest
+              else url
+            }"
+          '';
+
+          installPhase = ''
+            runHook preInstall
+
+            # Fix non-determinism
+            rm env-vars -r
+            jq -Sc '.' packwiz.json | sponge packwiz.json
+
+            mkdir -p $out
+            cp * -r $out/
+
+            runHook postInstall
+          '';
+
+          passthru = let
+            drv = fetchPackwizModpack args;
+          in {
+            # Pack manifest as a nix expression
+            # If manifestHash is not null or the manifest is directly provided,
+            # then we can do this without IFD.
+            # Otherwise, fallback to IFD.
+            manifest = lib.importTOML (
+              if manifestHash != null
+              then
+                builtins.fetchurl
+                {
+                  inherit url;
+                  sha256 = manifestHash;
+                }
+              else if useManifest
+              then manifest
+              else "${drv}/pack.toml"
+            );
+
+            # Adds an attribute set of files to the derivation.
+            # Useful to add server-specific mods not part of the pack.
+            addFiles = files:
+              stdenvNoCC.mkDerivation {
+                inherit (drv) pname version;
+                src = null;
+                dontUnpack = true;
+                dontConfig = true;
+                dontBuild = true;
+                dontFixup = true;
+
+                installPhase =
+                  ''
+                    cp -as "${drv}" $out
+                    chmod u+w -R $out
+                  ''
+                  + lib.concatLines (
+                    lib.mapAttrsToList
+                    (name: file: ''
+                      mkdir -p "$out/$(dirname "${name}")"
+                      cp -as "${file}" "$out/${name}"
+                    '')
+                    files
+                  );
+
+                passthru = {inherit (drv) manifest;};
+                meta = drv.meta or {};
+              };
+          };
+
+          dontFixup = true;
+
+          outputHashMode = "recursive";
+          outputHashAlgo = "sha256";
+          outputHash = hash;
+        }
+        // args);
+in
+  fetchPackwizModpack