working v1.

extension/background.js

@@ -2,8 +2,41 @@ import browser from 'webextension-polyfill'
 import {Buffer} from 'buffer'
 import {validateEvent, signEvent, getEventHash, getPublicKey} from 'nostr-tools'
 
+import {
+  PERMISSIONS_REQUIRED,
+  readPermissionLevel,
+  updatePermission
+} from './common'
+
+const prompts = {}
+
 browser.runtime.onMessage.addListener(async (req, sender) => {
-  let {type, params, host} = req
+  let {prompt} = req
+
+  if (prompt) {
+    return handlePromptMessage(req, sender)
+  } else {
+    return handleContentScriptMessage(req)
+  }
+})
+
+async function handleContentScriptMessage({type, params, host}) {
+  let level = await readPermissionLevel(host)
+
+  if (level >= PERMISSIONS_REQUIRED[type]) {
+    // authorized, proceed
+  } else {
+    // ask for authorization
+    try {
+      await promptPermission(host, PERMISSIONS_REQUIRED[type])
+      // authorized, proceed
+    } catch (_) {
+      // not authorized, stop here
+      return {
+        error: `insufficient permissions, required ${PERMISSIONS_REQUIRED[type]}`
+      }
+    }
+  }
 
   try {
     switch (type) {
@@ -38,4 +71,42 @@ browser.runtime.onMessage.addListener(async (req, sender) => {
   } catch (error) {
     return {error}
   }
-})
+}
+
+function handlePromptMessage({id, condition, host, level}, sender) {
+  switch (condition) {
+    case 'forever':
+    case 'expirable':
+      prompts[id]?.resolve?.()
+      updatePermission(host, {
+        level,
+        condition
+      })
+      break
+    case 'single':
+      prompts[id]?.resolve?.()
+      break
+    case 'no':
+      prompts[id]?.reject?.()
+      break
+  }
+
+  delete prompts[id]
+  browser.windows.remove(sender.tab.windowId)
+}
+
+function promptPermission(host, level) {
+  let id = Math.random().toString().slice(4)
+  let qs = new URLSearchParams({host, level, id})
+
+  return new Promise((resolve, reject) => {
+    browser.windows.create({
+      url: `${browser.runtime.getURL('prompt.html')}?${qs.toString()}`,
+      type: 'popup',
+      width: 340,
+      height: 230
+    })
+
+    prompts[id] = {resolve, reject}
+  })
+}