From 1b73718780284f6711c9e6327fb25a8e86014708 Mon Sep 17 00:00:00 2001
From: Milan Rother <milan.rother@gmx.de>
Date: Sat, 28 Mar 2026 13:12:58 +0100
Subject: [PATCH] Add Send to Codegen button with compressed URL hash transfer

---
 src/lib/components/icons/Icon.svelte |  6 +++
 src/routes/+page.svelte              | 61 ++++++++++++++++++++++++++--
 2 files changed, 64 insertions(+), 3 deletions(-)

diff --git a/src/lib/components/icons/Icon.svelte b/src/lib/components/icons/Icon.svelte
index 510f8f94..e2f68cc8 100644
--- a/src/lib/components/icons/Icon.svelte
+++ b/src/lib/components/icons/Icon.svelte
@@ -427,6 +427,12 @@
 		<line x1="12" y1="15" x2="12" y2="3"/>
 		<line x1="4" y1="21" x2="20" y2="21"/>
 	</svg>
+{:else if name === 'codegen'}
+	<svg width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+		<path d="M7 4H6a2 2 0 0 0-2 2v4a2 2 0 0 1-2 2 2 2 0 0 1 2 2v4a2 2 0 0 0 2 2h1"/>
+		<path d="M17 4h1a2 2 0 0 1 2 2v4a2 2 0 0 0 2 2 2 2 0 0 0-2 2v4a2 2 0 0 1-2 2h-1"/>
+		<text x="12" y="16" text-anchor="middle" fill="currentColor" stroke="none" font-size="12" font-weight="700" font-family="var(--font-mono), monospace">C</text>
+	</svg>
 {:else if name === 'font-size-increase'}
 	<svg width={size} height={size} viewBox="0 0 24 24" fill="currentColor" stroke="none">
 		<text x="2" y="18" font-size="16" font-weight="700" font-family="system-ui, sans-serif">A</text>
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index 1847eb93..f7cb8b21 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -42,7 +42,7 @@
 	import { pyodideState, simulationState, initPyodide, stopSimulation, continueStreamingSimulation, stageMutations } from '$lib/pyodide/bridge';
 	import { pendingMutationCount } from '$lib/pyodide/mutationQueue';
 	import { initBackendFromUrl, autoDetectBackend } from '$lib/pyodide/backend';
-	import { runGraphStreamingSimulation, validateGraphSimulation } from '$lib/pyodide/pathsimRunner';
+	import { runGraphStreamingSimulation, validateGraphSimulation, exportToPython } from '$lib/pyodide/pathsimRunner';
 	import { consoleStore } from '$lib/stores/console';
 	import { newGraph, saveFile, saveAsFile, setupAutoSave, clearAutoSave, debouncedAutoSave, openImportDialog, importFromUrl, currentFileName } from '$lib/schema/fileOps';
 	import { confirmationStore } from '$lib/stores/confirmation';
@@ -59,10 +59,10 @@
 	let mousePosition = $state({ x: 0, y: 0 });
 
 	// Save feedback animation state
-	let saveFlash = $state<'save' | 'save-as' | null>(null);
+	let saveFlash = $state<'save' | 'save-as' | 'codegen' | null>(null);
 	let saveFlashTimeout: ReturnType<typeof setTimeout> | undefined;
 
-	function flashSaveButton(which: 'save' | 'save-as') {
+	function flashSaveButton(which: 'save' | 'save-as' | 'codegen') {
 		clearTimeout(saveFlashTimeout);
 		saveFlash = which;
 		saveFlashTimeout = setTimeout(() => { saveFlash = null; }, 1500);
@@ -78,6 +78,58 @@
 		if (success) flashSaveButton('save-as');
 	}
 
+	// Codegen export — compress Python code into URL hash and open codegen
+	const CODEGEN_URL = import.meta.env.VITE_CODEGEN_URL ?? 'https://code.pathsim.org/app';
+	const CODEGEN_MAX_BYTES = 100_000; // 100 KB raw Python limit
+
+	async function compressAndEncode(text: string): Promise<string> {
+		const data = new TextEncoder().encode(text);
+		const cs = new CompressionStream('deflate-raw');
+		const writer = cs.writable.getWriter();
+		writer.write(data);
+		writer.close();
+		const compressed = new Uint8Array(await new Response(cs.readable).arrayBuffer());
+		let binary = '';
+		for (const b of compressed) binary += String.fromCharCode(b);
+		return btoa(binary).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
+	}
+
+	async function handleSendToCodegen() {
+		const { nodes, connections } = graphStore.toJSON();
+
+		if (nodes.length === 0) {
+			await confirmationStore.show({
+				title: 'No Model',
+				message: 'There are no blocks in the current graph. Add blocks to your simulation before exporting to Codegen.',
+				confirmText: 'OK',
+				cancelText: 'Cancel'
+			});
+			return;
+		}
+
+		const settings = settingsStore.get();
+		const codeContext = codeContextStore.getCode();
+		const events = eventStore.toJSON();
+		const pythonCode = exportToPython(nodes, connections, settings, codeContext, events);
+
+		const rawBytes = new TextEncoder().encode(pythonCode).length;
+		if (rawBytes > CODEGEN_MAX_BYTES) {
+			const sizeKB = Math.round(rawBytes / 1024);
+			const openExport = await confirmationStore.show({
+				title: 'Model Too Large',
+				message: `The generated Python code is ${sizeKB} KB, which exceeds the transfer limit. Use the Python Code export (Ctrl+E) to copy the code and paste it into Codegen manually.`,
+				confirmText: 'Open Python Export',
+				cancelText: 'Cancel'
+			});
+			if (openExport) exportDialogOpen = true;
+			return;
+		}
+
+		const encoded = await compressAndEncode(pythonCode);
+		window.open(`${CODEGEN_URL}#code=${encoded}`, '_blank');
+		flashSaveButton('codegen');
+	}
+
 	// Panel visibility state
 	let showProperties = $state(false);
 	let showNodeLibrary = $state(false);
@@ -1049,6 +1101,9 @@
 			<button class="toolbar-btn" onclick={() => exportDialogOpen = true} use:tooltip={{ text: "Python Code", shortcut: "Ctrl+E" }} aria-label="View Python Code">
 				<Icon name="braces" size={16} />
 			</button>
+			<button class="toolbar-btn" onclick={handleSendToCodegen} use:tooltip={"Send to Codegen"} aria-label="Send to Codegen">
+				<Icon name={saveFlash === 'codegen' ? 'check' : 'codegen'} size={16} />
+			</button>
 		</div>
 
 		<!-- Help -->