1 files changed, 51 insertions, 0 deletions
diff --git a/static/redirect.js b/static/redirect.js
new file mode 100644
index 0000000..338e98b
--- /dev/null
+++ b/static/redirect.js
@@ -0,0 +1,51 @@
+function getRandomSite(ignore) {
+    // get random index from sites
+    var index = Math.floor(Math.random() * sites.length);
+    // if random site is referrer, retry
+    return (index === ignore) ? generateRandom(ignore) : sites[index];
+}
+
+var validRedirectTypes = ['next', 'previous', 'random']
+
+// parse url params
+var params = new URLSearchParams(window.location.search);
+var referrerUrl = params.get('referrer')
+var type = params.get('type') || 'random' // default to random if no type given
+
+if (!validRedirectTypes.includes(type)) { // default to random is type not valid
+    type = 'random'
+}
+
+if (!sites.includes(referrerUrl)) {
+    // referrer url is incorrect, select random referrer from sites list,
+    referrerUrl = sites[Math.floor(Math.random() * sites.length)]
+    // select random site, and redirect to it
+    window.location.href = sites[Math.floor(Math.random() * sites.length)]
+}
+
+// get index of the referrer url
+var referrerIndex =  sites.indexOf(referrerUrl);
+
+if (type === 'random') {
+    var redirect = getRandomSite(referrerIndex)
+} else if (type === 'next') {
+    // get index of next website in list
+     var nextIndex = referrerIndex + 1
+     console.log(nextIndex)
+
+    // if index is greater than the length of list, loop back to 0 index
+    if (nextIndex > sites.length - 1) {
+        nextIndex = 0
+    }
+
+    var redirect = sites[nextIndex]
+} else { // redirect to previous
+    var previousIndex = referrerIndex - 1
+    if (previousIndex < 0) { // if previous index is less than 0, loop around to last index
+        previousIndex = sites.length - 1
+    }
+
+    var redirect = sites[previousIndex]
+}
+
+window.location.href = redirect
+\ No newline at end of file