From 19106501aab1903358c5b62a5b547eb0b70e8b65 Mon Sep 17 00:00:00 2001
From: Egor Aristov <ef@efprojects.com>
Date: Tue, 4 Feb 2025 19:31:25 +0300
Subject: [PATCH] url encoding and decoding

---
 .../wizard-vue/src/components/Copyable.vue    |  2 +
 frontend/wizard-vue/src/pages/WizardPage.vue  | 28 ++++++++-
 frontend/wizard-vue/src/urlmaker/index.ts     | 63 +++++++++++++++++++
 frontend/wizard-vue/tsconfig.json             |  7 ++-
 4 files changed, 96 insertions(+), 4 deletions(-)
 create mode 100644 frontend/wizard-vue/src/urlmaker/index.ts

diff --git a/frontend/wizard-vue/src/components/Copyable.vue b/frontend/wizard-vue/src/components/Copyable.vue
index 7e46352..7b8da9a 100644
--- a/frontend/wizard-vue/src/components/Copyable.vue
+++ b/frontend/wizard-vue/src/components/Copyable.vue
@@ -41,6 +41,8 @@ div.copyable {
   span.contents {
     flex: 1;
     padding: 4px;
+    overflow: hidden;
+    text-align: left;
   }
 
   span.copy {
diff --git a/frontend/wizard-vue/src/pages/WizardPage.vue b/frontend/wizard-vue/src/pages/WizardPage.vue
index 1091206..46c0a6a 100644
--- a/frontend/wizard-vue/src/pages/WizardPage.vue
+++ b/frontend/wizard-vue/src/pages/WizardPage.vue
@@ -5,6 +5,7 @@ import {type Field, fields, type Specs} from "@/urlmaker/specs.ts";
 import Btn from "@/components/Btn.vue";
 import Copyable from "@/components/Copyable.vue";
 import EditUrlModal from "@/components/EditUrlModal.vue";
+import {decodeUrl, encodeUrl} from "@/urlmaker";
 
 const emptySpecs = fields.reduce((o, f) => {
   o[f.name] = f.default;
@@ -13,9 +14,9 @@ const emptySpecs = fields.reduce((o, f) => {
 const specs = reactive(emptySpecs);
 const formValid = ref(false);
 
-watch(specs, (value, oldValue) => {
+watch(specs, (value) => {
   formValid.value = fields.every(field => (
-    specs[field.name].length === 0 && !(field as Field).required || field.validate(specs[field.name]).ok
+    value[field.name].length === 0 && !(field as Field).required || field.validate(value[field.name]).ok
   ));
 });
 
@@ -23,12 +24,33 @@ const existingLink = ref("");
 const link = ref("");
 const editModalVisible = ref(false);
 
+watch(existingLink, async (value) => {
+  if(!value) return;
+  existingLink.value = "";
+  try {
+    Object.assign(specs, await decodeUrl(value));
+    link.value = "";
+  } catch (e) {
+    console.log(e);
+    alert(`Decoding error: ${e}`);
+  }
+});
+
+async function generateLink() {
+  try {
+    link.value = await encodeUrl(specs);
+  } catch (e) {
+    console.log(e);
+    alert(`Encoding error: ${e}`);
+  }
+}
+
 </script>
 
 <template>
   <div class="wrapper">
     <SpecsForm v-model="specs" class="specs-form"></SpecsForm>
-    <Btn :active="formValid">Generate link</Btn>
+    <Btn :active="formValid" @click="generateLink">Generate link</Btn>
     <Btn :active="formValid">Screenshot</Btn>
     <Btn @click="editModalVisible = true">Edit existing task</Btn>
     <Copyable v-if="link" :contents="link" class="link-view"></Copyable>
diff --git a/frontend/wizard-vue/src/urlmaker/index.ts b/frontend/wizard-vue/src/urlmaker/index.ts
new file mode 100644
index 0000000..626863e
--- /dev/null
+++ b/frontend/wizard-vue/src/urlmaker/index.ts
@@ -0,0 +1,63 @@
+import type {Specs} from "@/urlmaker/specs.ts";
+
+const apiEndpoint = '/api/v1/render/';
+
+export async function decodeUrl(url: string): Promise<Specs> {
+  const splitUrl = url.split(apiEndpoint);
+  if(splitUrl.length !== 2) {
+    throw 'Split failed';
+  }
+  let encodedData = splitUrl[1];
+  console.log('Data len=' + encodedData.length);
+  const m = encodedData.match(/(\d*):?([A-Za-z0-9+/=]+)/);
+  if(!m) {
+    throw 'Regex failed';
+  }
+  const version = m[1] ? parseInt(m[1]) : 0;
+  console.log('Decoding url using version: ' + version);
+  encodedData = m[2];
+
+  let buf = b64decode(encodedData);
+  if (version === 0) {
+    const jsonData = await decompress(buf);
+    return JSON.parse(jsonData);
+  }
+  throw 'Unknown version'
+}
+
+export async function encodeUrl(specs: Specs): Promise<string> {
+  const jsonData = JSON.stringify(specs);
+  const buf = await compress(jsonData);
+  const encodedData = b64encode(buf);
+  console.log('Data len=' + encodedData.length);
+  const version = 0;
+  return `${document.location.origin}${apiEndpoint}${version}:${encodedData}`
+}
+
+function b64encode(buf: Uint8Array): string {
+  const b64str = btoa(String.fromCharCode.apply(null, buf));
+  return b64str.replaceAll('=', '');
+}
+
+function b64decode(s: string): Uint8Array {
+  return Uint8Array.from(atob(s), c => c.charCodeAt(0));
+}
+
+async function compress(s: string): Promise<Uint8Array> {
+  let byteArray = new TextEncoder().encode(s);
+  let cs = new CompressionStream('deflate-raw');
+  let writer = cs.writable.getWriter();
+  writer.write(byteArray);
+  writer.close();
+  let response = new Response(cs.readable);
+  return new Uint8Array(await response.arrayBuffer());
+}
+
+async function decompress(buf: Uint8Array): Promise<string> {
+  let ds = new DecompressionStream('deflate-raw');
+  let writer = ds.writable.getWriter();
+  writer.write(buf);
+  writer.close();
+  let response = new Response(ds.readable);
+  return response.text();
+}
diff --git a/frontend/wizard-vue/tsconfig.json b/frontend/wizard-vue/tsconfig.json
index 66b5e57..ab48de1 100644
--- a/frontend/wizard-vue/tsconfig.json
+++ b/frontend/wizard-vue/tsconfig.json
@@ -7,5 +7,10 @@
     {
       "path": "./tsconfig.app.json"
     }
-  ]
+  ],
+  "compilerOptions": {
+    "lib": [
+      "es2021"
+    ]
+  }
 }