1 files changed, 94 insertions, 0 deletions
diff --git a/src/main/java/ch/fhnw/thga/gradleplugins/InitFregeTask.java b/src/main/java/ch/fhnw/thga/gradleplugins/InitFregeTask.java
new file mode 100644
index 0000000..c2926aa
--- /dev/null
+++ b/src/main/java/ch/fhnw/thga/gradleplugins/InitFregeTask.java
@@ -0,0 +1,94 @@
+package ch.fhnw.thga.gradleplugins;
+
+import static ch.fhnw.thga.gradleplugins.SharedTaskLogic.NEW_LINE;
+
+import java.io.IOException;
+import java.nio.file.Paths;
+
+import org.gradle.api.DefaultTask;
+import org.gradle.api.file.DirectoryProperty;
+import org.gradle.api.file.RegularFile;
+import org.gradle.api.provider.Property;
+import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.Internal;
+import org.gradle.api.tasks.OutputDirectory;
+import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.TaskAction;
+import org.gradle.api.tasks.options.Option;
+
+public abstract class InitFregeTask extends DefaultTask
+{
+    private static final String EMPTY_LINE = "";
+    private static final String HELLO_FREGE_CODE_WITHOUT_MODULE = String.join(NEW_LINE,
+        "import Test.QuickCheck",
+        EMPTY_LINE,
+        "--- compute digit sum",
+        "digitSum :: Integer -> Integer",
+        "digitSum 0 = 0",
+        "digitSum n = (n `rem` 10) + digitSum (n `div` 10)",
+        EMPTY_LINE,
+        "--- compute the reduced digit sum",
+        "reducedDigitSum :: Integer -> Integer",
+        "reducedDigitSum n = if n < 10 then n else reducedDigitSum $ digitSum n",
+        EMPTY_LINE,
+        "main = do",
+        "    let answer = digitSum 6666666",
+        "    println $",
+        "        \"The answer to life, the universe and everything is \"",
+        "        ++ show answer",
+        "        ++ \".\"",
+        EMPTY_LINE,
+        "{--",
+        "    The property 'p_reduced_digit_sum_of_multiple_of_9_is_always_9' checks",
+        "    the famous claim that every multiple of 9 number has also the reduced",
+        "    digit sum of 9, e.g. 9, 27, 36, ...", 
+        "-}",
+        "p_reduced_digit_sum_of_multiple_of_9_is_always_9 = ",
+        "    property $ \\(n :: Integer) -> (n > 0) ==> (reducedDigitSum $ 9 * n) == 9"
+    );
+
+    @Input
+    @Option(option = "moduleName",
+           description = "The module name of the default frege file"
+    )
+    public abstract Property<String> getFregeModuleName();
+
+    @Internal
+    final Provider<String> getHelloFregeCode()
+    {
+        return getFregeModuleName()
+            .map(moduleName -> String.format("module %s where", moduleName))
+            .map(firstLine  -> String.join(
+                NEW_LINE, 
+                firstLine, HELLO_FREGE_CODE_WITHOUT_MODULE
+            ));
+    }
+
+    @Internal
+    final Provider<String> getFregeFilePath()
+    {
+        return getFregeModuleName()
+            .map(moduleName -> moduleName.replace(".", "/"))
+            .map(filePath   -> Paths.get(filePath).normalize())
+            .map(filePath   -> String.format("%s.fr", filePath.toString()));
+    }
+    
+    @OutputDirectory
+    public abstract DirectoryProperty getFregeMainSourceDir();
+
+    @OutputFile
+    final Provider<RegularFile> getHelloFregeFile()
+    {
+        return getFregeMainSourceDir().file(getFregeFilePath());
+    }
+
+    @TaskAction
+    public void writeHelloFregeFile() throws IOException
+    {
+        SharedTaskLogic.writeToFile(
+            getHelloFregeFile().get().getAsFile(),
+            getHelloFregeCode().get()
+        );
+    }
+}