From 87e273fe00ce5fa5dc33060bfe78eab92a1d16ea Mon Sep 17 00:00:00 2001
From: w6vvn <vivienne@w6vvn.net>
Date: Thu, 4 Sep 2025 20:40:36 -0700
Subject: [PATCH] handle relative links and unspecified schemes

---
 gem300.rkt | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/gem300.rkt b/gem300.rkt
index 8bb47aa..99fd096 100644
--- a/gem300.rkt
+++ b/gem300.rkt
@@ -3,6 +3,8 @@
 (require (prefix-in net: "net.rkt")
          (prefix-in gmi: "gmi.rkt"))
 
+(require net/url-string)
+
 ;; global state variable which will be an input port containing the
 ;; rendered out gemtext document as it shall be shown to the user
 (define document-buffer null)
@@ -10,22 +12,31 @@
 ;; global state which will be the document structure, before rendering
 (define document null)
 
+;; global state for the url of the currently visited document
+(define current-url null)
+
 (define (go-cmd url)
   (if (non-empty-string? url)
-      (let-values ([(status meta c-in) (net:get url)])
-        (let-values ([(doc) (gmi:parse (port->lines c-in))]
-                     [(db-in db-out) (make-pipe #f)])
+      (let ()
+        (when (not (string-contains? url "://"))
+          (set! url (string-append "gemini://" url)))
 
-          (set! document doc)
+        (let-values ([(status meta c-in) (net:get url)])
+          (let-values ([(doc) (gmi:parse (port->lines c-in))]
+                       [(db-in db-out) (make-pipe #f)])
 
-          (set! document-buffer db-in)
-          (parameterize ([current-output-port db-out])
-            (gmi:render doc))
+            (set! document doc)
 
-          (let ([remaining (pipe-content-length db-in)])
-            (printf "document retrieved. ~a bytes\n" remaining))
+            (set! document-buffer db-in)
+            (parameterize ([current-output-port db-out])
+              (gmi:render doc))
 
-          (next-cmd)))
+            (set! current-url url)
+
+            (let ([remaining (pipe-content-length db-in)])
+              (printf "document retrieved. ~a bytes\n" remaining))
+
+            (next-cmd))))
 
       (displayln "go where?")))
 
@@ -43,7 +54,11 @@
     (printf "~a bytes remaining\n" remaining)))
 
 (define (visit-cmd line)
-  (go-cmd (gmi:match-link document (string->number line))))
+  (define url (gmi:match-link document (string->number line)))
+  (set! url
+        (url->string (combine-url/relative (string->url current-url)
+                                           url)))
+  (go-cmd url))
 
 (define (repl)
   (display "G-300 > ")