1 files changed, 89 insertions, 0 deletions
diff --git a/components/embedding.rb b/components/embedding.rb
new file mode 100644
index 0000000..f08ff3d
--- /dev/null
+++ b/components/embedding.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require 'sweet-moon'
+
+require 'open3'
+require 'json'
+require 'tempfile'
+
+module NanoBot
+  module Components
+    class Embedding
+      def self.ensure_safety!(safety)
+        raise 'missing safety definitions' unless safety.key?(:sandboxed)
+      end
+
+      def self.lua(source:, parameters:, values:, safety:)
+        ensure_safety!(safety)
+
+        allowed = ''
+        allowed = ', {math=math,string=string,table=table}' if safety[:sandboxed]
+
+        state = SweetMoon::State.new
+        code = "_, embedded = pcall(load([[\nreturn function(#{parameters.join(', ')})\n#{source}\nend\n]], nil, 't'#{allowed}))"
+
+        state.eval(code)
+        embedded = state.get(:embedded)
+        embedded.call(values)
+      end
+
+      def self.fennel(source:, parameters:, values:, safety:)
+        ensure_safety!(safety)
+
+        path = "#{File.expand_path('../static/fennel', __dir__)}/?.lua"
+        state = SweetMoon::State.new(package_path: path).fennel
+
+        # TODO: `global` is deprecated.
+        state.fennel.eval(
+          "(global embedded (fn [#{parameters.join(' ')}] #{source}))", 1,
+          safety[:sandboxed] ? { allowedGlobals: %w[math string table] } : nil
+        )
+        embedded = state.get(:embedded)
+        embedded.call(values)
+      end
+
+      def self.clojure(source:, parameters:, values:, safety:)
+        ensure_safety!(safety)
+
+        raise 'TODO: sandboxed Clojure through Babashka not implemented' if safety[:sandboxed]
+
+        raise 'invalid Clojure parameter name' if parameters.include?('injected-parameters')
+
+        key_value = {}
+
+        parameters.each_with_index { |key, index| key_value[key] = values[index] }
+
+        parameters_json = key_value.to_json
+
+        json_file = Tempfile.new(['nano-bot', '.json'])
+        clojure_file = Tempfile.new(['nano-bot', '.clj'])
+
+        begin
+          json_file.write(parameters_json)
+          json_file.close
+
+          clojure_source = <<~CLOJURE
+            (require '[cheshire.core :as json])
+            (def injected-parameters (json/parse-string (slurp (java.io.FileReader. "#{json_file.path}"))))
+
+            #{parameters.map { |p| "(def #{p} (get injected-parameters \"#{p}\"))" }.join("\n")}
+
+            #{source}
+          CLOJURE
+
+          clojure_file.write(clojure_source)
+          clojure_file.close
+
+          bb_command = "bb --prn #{clojure_file.path} | bb -e \"(->> *in* slurp read-string print)\""
+
+          stdout, stderr, status = Open3.capture3(bb_command)
+
+          status.success? ? stdout : stderr
+        ensure
+          json_file&.unlink
+          clojure_file&.unlink
+        end
+      end
+    end
+  end
+end