From 97ca48b1fe121e9311189e2fbfa5c737c8ca337a Mon Sep 17 00:00:00 2001
From: SimonBrazell <simon@brazell.com.au>
Date: Sun, 23 Feb 2020 16:19:32 +1100
Subject: OSM redirects (experimental)

---
 background.js | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

(limited to 'background.js')

diff --git a/background.js b/background.js
index ab04f950..70fc0c2b 100644
--- a/background.js
+++ b/background.js
@@ -7,30 +7,40 @@ const twitterRegex = /((www|mobile)\.)?twitter\.com/;
 const bibliogramDefault = 'https://bibliogram.art';
 const instagramRegex = /((www|about|help)\.)?instagram\.com/;
 const instagramPathsRegex = /(\/a|\/admin|\/api|\/favicon.ico|\/static|\/imageproxy|\/p|\/u|\/developer|\/about|\/legal|\/explore|\/director)/;
+const osmDefault = 'https://openstreetmap.org';
+const googleMapsRegex = /(google).*(\/maps)/;
+const latLngZoomRegex = /@(-?\d[0-9.]*),(-?\d[0-9.]*),(\d{1,2})[.z]/;
+const dataLatLngRegex = /(!3d|!4d)(-?[0-9]{1,10}.[0-9]{1,10})/g;
 
 let nitterInstance;
 let invidiousInstance;
 let bibliogramInstance;
+let osmInstance;
 let disableNitter;
 let disableInvidious;
 let disableBibliogram;
+let disableOsm;
 
 chrome.storage.sync.get(
   [
     'nitterInstance',
     'invidiousInstance',
     'bibliogramInstance',
+    'osmInstance',
     'disableNitter',
     'disableInvidious',
     'disableBibliogram',
+    'disableOsm'
   ],
   result => {
     disableNitter = result.disableNitter;
     disableInvidious = result.disableInvidious;
     disableBibliogram = result.disableBibliogram;
+    disableOsm = result.disableOsm;
     nitterInstance = result.nitterInstance || nitterDefault;
     invidiousInstance = result.invidiousInstance || invidiousDefault;
     bibliogramInstance = result.bibliogramInstance || bibliogramDefault;
+    osmInstance = result.osmInstance || osmDefault;
   }
 );
 
@@ -44,6 +54,9 @@ chrome.storage.onChanged.addListener(changes => {
   if ('bibliogramInstance' in changes) {
     bibliogramInstance = changes.bibliogramInstance.newValue || bibliogramDefault;
   }
+  if ('osmInstance' in changes) {
+    osmInstance = changes.osmInstance.newValue || osmDefault;
+  }
   if ('disableNitter' in changes) {
     disableNitter = changes.disableNitter.newValue;
   }
@@ -53,8 +66,61 @@ chrome.storage.onChanged.addListener(changes => {
   if ('disableBibliogram' in changes) {
     disableBibliogram = changes.disableBibliogram.newValue;
   }
+  if ('disableOsm' in changes) {
+    disableOsm = changes.disableOsm.newValue;
+  }
 });
 
+// https://github.com/tankaru/ReplaceG2O
+function deg2rad(deg) {
+  return deg / 360 * 2 * Math.PI;
+}
+
+function rad2deg(rad) {
+  return rad / 2 / Math.PI * 360.0;
+}
+
+function getTileNumber(lat, lon, zoom) {
+  xtile = Math.round((lon + 180.0) / 360.0 * 2 ** zoom);
+  ytile = Math.round((1 - Math.log(Math.tan(deg2rad(lat)) + 1 / (Math.cos(deg2rad(lat)))) / Math.PI) / 2 * 2 ** zoom);
+  return [xtile, ytile];
+}
+
+function getLonLat(xtile, ytile, zoom) {
+  n = 2 ** zoom;
+  lon = xtile / n * 360.0 - 180.0;
+  lat = rad2deg(Math.atan(Math.sinh(Math.PI * (1 - 2 * ytile / n))));
+  return [lon, lat];
+}
+
+function LonLat_to_bbox(lat, lon, zoom) {
+  width = 600;
+  height = 450;
+  tile_size = 256;
+
+  [xtile, ytile] = getTileNumber(lat, lon, zoom);
+
+  xtile_s = (xtile * tile_size - width / 2) / tile_size;
+  ytile_s = (ytile * tile_size - height / 2) / tile_size;
+  xtile_e = (xtile * tile_size + width / 2) / tile_size;
+  ytile_e = (ytile * tile_size + height / 2) / tile_size;
+
+  [lon_s, lat_s] = getLonLat(xtile_s, ytile_s, zoom);
+  [lon_e, lat_e] = getLonLat(xtile_e, ytile_e, zoom);
+
+  return [lon_s, lat_s, lon_e, lat_e];
+}
+
+//make a bbox, 0.001 should be modified based on zoom value
+function bbox(lat, lon, zoom) {
+  return LonLat_to_bbox(lat, lon, zoom);
+
+}
+
+function zoom(satelliteZoom) {
+  return -1.4436 * Math.log(satelliteZoom) + 28.7;
+}
+
 function redirectYouTube(url) {
   if (url.host.split('.')[0] === 'studio') {
     // Avoid redirecting `studio.youtube.com`
@@ -90,6 +156,34 @@ function redirectInstagram(url) {
   }
 }
 
+function redirectGoogleMaps(url, type) {
+  let query = '';
+  let lat = '';
+  let lon = '';
+  let zoom = '';
+  if (url.pathname.match(latLngZoomRegex)) {
+    [, lat, lon, zoom] = url.pathname.match(latLngZoomRegex);
+  }
+  if (type === 'main_frame') {
+    if (url.pathname.includes('data=')) {
+      const [mlat, mlon] = url.pathname.match(dataLatLngRegex);
+      return `${osmInstance}/?mlat=${mlat.replace('!3d', '')}&mlon=${mlon.replace('!4d', '')}#map=${zoom}/${lat}/${lon}`;
+    } else if (url.search.includes('q=')) {
+      query = encodeURI(url.searchParams.get('q'));
+    } else {
+      query = url.pathname.split('/')[3];
+    }
+    return `${osmInstance}/search?query=${query}#map=${zoom}/${lat}/${lon}`;
+  } else if (type === 'sub_frame' && url.pathname.match(latLngZoomRegex)) {
+    const [mapleft, mapbottom, mapright, maptop] = bbox(Number(lat), Number(lon), zoom(z));
+    if (url.pathname.includes('data=')) {
+      const [mlat, mlon] = url.pathname.match(dataLatLngRegex);
+      return `${osmInstance}/export/embed.html?bbox=${mapleft}%2C${mapbottom}'%2C'${mapright}'%2C'${maptop}'&amp;layer=mapnik&amp;marker=${mlat}%2C${mlon}'`;
+    }
+    return `${osmInstance}/export/embed.html?bbox=${mapleft}%2C${mapbottom}'%2C'${mapright}'%2C'${maptop}'&amp;layer=mapnik'`;
+  }
+}
+
 chrome.webRequest.onBeforeRequest.addListener(
   details => {
     const url = new URL(details.url);
@@ -112,6 +206,12 @@ chrome.webRequest.onBeforeRequest.addListener(
           redirectUrl: redirectInstagram(url)
         };
       }
+    } else if (url.href.match(googleMapsRegex)) {
+      if (!disableOsm) {
+        redirect = {
+          redirectUrl: redirectGoogleMaps(url, details.type)
+        };
+      }
     }
     if (redirect && redirect.redirectUrl) {
       console.log(
-- 
cgit 1.4.1