PDF Salad with repetition allowed

projects/pdf-salad/build.hxml

@@ -3,4 +3,4 @@
 -cp src
 --main Main
 -js index.js
---cmd node index.js example-input
+--cmd node index.js example-input 5

projects/pdf-salad/src/Externs.hx

@@ -8,4 +8,10 @@ extern class PDFDocument {
     public static function create():Promise<PDFDocument>;
     public static function load(bytes:Buffer):Promise<PDFDocument>;
     public function save():Promise<Buffer>;
+    public function getPageCount():Int;
+    public function copyPages(srcDoc:PDFDocument, indices:Array<Int>):Array<PDFPage>;
+    public function addPage(page:PDFPage):Void;
 }
+
+@:jsRequire("pdf-lib", "PDFPage")
+extern class PDFPage {}

projects/pdf-salad/src/Main.hx

@@ -2,6 +2,7 @@ package;
 
 import js.lib.Uint8Array;
 import js.node.Fs;
+import js.lib.Promise;
 import kiss.Kiss;
 import kiss.Prelude;
 import Externs;

projects/pdf-salad/src/Main.kiss

@@ -1,5 +1,21 @@
 (defun main []
-    (let [bytesIn (Fs.readFileSync "example-input/antique-phone-shop.pdf")]
+    (let [[sourceDir numPages] (Sys.args)]
-        (.then (PDFDocument.load bytesIn) (lambda [pdfToModify]
+        (.then
-            (.then (pdfToModify.save) (lambda [bytesOut]
+            (Promise.all
-                (Fs.writeFileSync "out.pdf" bytesOut)))))))
+                (for file (Fs.readdirSync sourceDir)
+                    (PDFDocument.load (Fs.readFileSync (+ sourceDir "/" file)))))
+            (lambda [inputPdfs]
+                // TODO make an awaitLet macro that .thens a promise or all() of promises into a binding
+                (.then (PDFDocument.create) (lambda [saladPdf]
+                    (.then 
+                        (Promise.all
+                            (for _ #|0... Std.parseInt(numPages)|# 
+                                (let [:PDFDocument pdf (nth inputPdfs (Std.random inputPdfs.length))
+                                        page (Std.random (pdf.getPageCount))]
+                                    (saladPdf.copyPages pdf [page]))))
+                        (lambda [pages]
+                            (doFor page pages (saladPdf.addPage (first page)))
+                            (.then (saladPdf.save) (lambda [bytesOut]
+                                (Fs.writeFileSync "out.pdf" bytesOut)))))))))))
+                            
+