4 files changed, 254 insertions, 20 deletions

diff --git a/src/app.c b/src/app.c
index 2192e9ae..1164484e 100644
--- a/src/app.c
+++ b/src/app.c
@@ -3,6 +3,7 @@
 #include "ui/window.h"
 #include "ui/inputwidget.h"
 #include "ui/labelwidget.h"
+#include "ui/documentwidget.h"
 #include "ui/util.h"
 #include "ui/text.h"
 #include "ui/color.h"
@@ -290,6 +291,8 @@ iBool handleCommand_App(const char *cmd) {
     iApp *d = &app_;
     iWidget *root = d->window->root;
     if (equal_Command(cmd, "open")) {
+        setUrl_DocumentWidget(findChild_Widget(root, "document"),
+                              collect_String(newCStr_String(valuePtr_Command(cmd, "url"))));
     }
     else if (equal_Command(cmd, "quit")) {
         SDL_Event ev;
diff --git a/src/gmdocument.c b/src/gmdocument.c
index 4132a15e..1aefe133 100644
--- a/src/gmdocument.c
+++ b/src/gmdocument.c
@@ -3,13 +3,31 @@
 #include "ui/text.h"
 #include "ui/metrics.h"
 
-#include <the_Foundation/array.h>
+#include <the_Foundation/ptrarray.h>
+#include <the_Foundation/regexp.h>
+
+iDeclareType(GmLink)
+
+struct Impl_GmLink {
+    iString url;
+};
+
+void init_GmLink(iGmLink *d) {
+    init_String(&d->url);
+}
+
+void deinit_GmLink(iGmLink *d) {
+    deinit_String(&d->url);
+}
+
+iDefineTypeConstruction(GmLink)
 
 struct Impl_GmDocument {
     iObject object;
     iString source;
     iInt2 size;
     iArray layout; /* contents of source, laid out in document space */
+    iPtrArray links;
 };
 
 iDefineObjectConstruction(GmDocument)
@@ -86,15 +104,45 @@ iInt2 measurePreformattedBlock_GmDocument_(const iGmDocument *d, const char *sta
     return measureRange_Text(font, preBlock);
 }
 
+static iRangecc addLink_GmDocument_(iGmDocument *d, iRangecc line, iGmLinkId *linkId) {
+    iRegExp *pattern = new_RegExp("=>\\s*([^\\s]+)(\\s.*)?", caseInsensitive_RegExpOption);
+    iRegExpMatch m;
+    if (matchRange_RegExp(pattern, line, &m)) {
+        iGmLink *link = new_GmLink();
+        setRange_String(&link->url, capturedRange_RegExpMatch(&m, 1));
+        pushBack_PtrArray(&d->links, link);
+        *linkId = size_PtrArray(&d->links); /* index + 1 */
+        iRangecc desc = capturedRange_RegExpMatch(&m, 2);
+        trim_Rangecc(&desc);
+        if (!isEmpty_Range(&desc)) {
+            line = desc; /* Just show the description. */
+        }
+        else {
+            line = capturedRange_RegExpMatch(&m, 1); /* Show the URL. */
+        }
+    }
+    iRelease(pattern);
+    return line;
+}
+
+static void clearLinks_GmDocument_(iGmDocument *d) {
+    iForEach(PtrArray, i, &d->links) {
+        delete_GmLink(i.ptr);
+    }
+    clear_PtrArray(&d->links);
+}
+
 static void doLayout_GmDocument_(iGmDocument *d) {
     if (d->size.x <= 0 || isEmpty_String(&d->source)) {
         return;
     }
     clear_Array(&d->layout);
+    clearLinks_GmDocument_(d);
     iBool isPreformat = iFalse;
     iInt2 pos = zero_I2();
     const iRangecc content = range_String(&d->source);
     iRangecc line = iNullRange;
+    /* TODO: Collect these parameters into a GmTheme. */
     static const int fonts[max_GmLineType] = {
         paragraph_FontId,
         paragraph_FontId, /* bullet */
@@ -151,6 +199,13 @@ static void doLayout_GmDocument_(iGmDocument *d) {
                 /* TODO: store and link the alt text to this run */
                 continue;
             }
+            else if (type == link_GmLineType) {
+                line = addLink_GmDocument_(d, line, &run.linkId);
+                if (!run.linkId) {
+                    /* Invalid formatting. */
+                    type = text_GmLineType;
+                }
+            }
             trimLine_Rangecc_(&line, type);
             run.font = fonts[type];
         }
@@ -175,6 +230,10 @@ static void doLayout_GmDocument_(iGmDocument *d) {
         if (!isPreformat || (prevType != preformatted_GmLineType)) {
             int required =
                 iMax(topMargin[type], bottomMargin[prevType]) * lineHeight_Text(paragraph_FontId);
+            if (type == link_GmLineType && prevType == link_GmLineType) {
+                /* No margin between consecutive links. */
+                required = 0;
+            }
             if (isEmpty_Array(&d->layout)) {
                 required = 0; /* top of document */
             }
@@ -202,6 +261,7 @@ static void doLayout_GmDocument_(iGmDocument *d) {
             isFirstText = iFalse;
         }
         iRangecc runLine = line;
+        /* Create one or more runs for this line. */
         while (!isEmpty_Range(&runLine)) {
             run.bounds.pos = addX_I2(pos, indent * gap_UI);
             const char *contPos;
@@ -222,9 +282,12 @@ void init_GmDocument(iGmDocument *d) {
     init_String(&d->source);
     d->size = zero_I2();
     init_Array(&d->layout, sizeof(iGmRun));
+    init_PtrArray(&d->links);
 }
 
 void deinit_GmDocument(iGmDocument *d) {
+    clearLinks_GmDocument_(d);
+    deinit_PtrArray(&d->links);
     deinit_Array(&d->layout);
     deinit_String(&d->source);
 }
@@ -243,7 +306,7 @@ static void normalize_GmDocument(iGmDocument *d) {
     iRangecc src = range_String(&d->source);
     iRangecc line = iNullRange;
     iBool isPreformat = iFalse;
-    const int preTabWidth = 4; /* TODO: user-configurable parameter */
+    const int preTabWidth = 8; /* TODO: user-configurable parameter */
     while (nextSplit_Rangecc(&src, "\n", &line)) {
         if (isPreformat) {
             /* Replace any tab characters with spaces for visualization. */
@@ -302,6 +365,7 @@ void setSource_GmDocument(iGmDocument *d, const iString *source, int width) {
 void render_GmDocument(const iGmDocument *d, iRangei visRangeY, iGmDocumentRenderFunc render,
                        void *context) {
     iBool isInside = iFalse;
+    /* TODO: Check lookup table for quick starting position. */
     iConstForEach(Array, i, &d->layout) {
         const iGmRun *run = i.value;
         if (isInside) {
@@ -321,4 +385,23 @@ iInt2 size_GmDocument(const iGmDocument *d) {
     return d->size;
 }
 
+const iGmRun *findRun_GmDocument(const iGmDocument *d, iInt2 pos) {
+    /* TODO: Perf optimization likely needed; use a block map? */
+    iConstForEach(Array, i, &d->layout) {
+        const iGmRun *run = i.value;
+        if (contains_Rect(run->bounds, pos)) {
+            return run;
+        }
+    }
+    return NULL;
+}
+
+const iString *linkUrl_GmDocument(const iGmDocument *d, iGmLinkId linkId) {
+    if (linkId > 0 && linkId <= size_PtrArray(&d->links)) {
+        const iGmLink *link = constAt_PtrArray(&d->links, linkId - 1);
+        return &link->url;
+    }
+    return NULL;
+}
+
 iDefineClass(GmDocument)
diff --git a/src/gmdocument.h b/src/gmdocument.h
index 70e912df..b5102044 100644
--- a/src/gmdocument.h
+++ b/src/gmdocument.h
@@ -7,12 +7,14 @@
 
 iDeclareType(GmRun)
 
+typedef uint16_t iGmLinkId;
+
 struct Impl_GmRun {
     iRangecc text;
     iRect bounds; /* advance metrics */
     uint8_t font;
     uint8_t color;
-    uint16_t linkId;
+    iGmLinkId linkId; /* zero for non-links */
 };
 
 iDeclareType(GmDocument)
@@ -27,3 +29,6 @@ typedef void (*iGmDocumentRenderFunc)(void *, const iGmRun *);
 
 void    render_GmDocument       (const iGmDocument *, iRangei visRangeY, iGmDocumentRenderFunc render, void *);
 iInt2   size_GmDocument         (const iGmDocument *);
+
+const iGmRun *  findRun_GmDocument  (const iGmDocument *, iInt2 pos);
+const iString * linkUrl_GmDocument  (const iGmDocument *, iGmLinkId linkId);
diff --git a/src/ui/documentwidget.c b/src/ui/documentwidget.c
index 56726320..ca91d896 100644
--- a/src/ui/documentwidget.c
+++ b/src/ui/documentwidget.c
@@ -7,6 +7,7 @@
 
 #include <the_Foundation/file.h>
 #include <the_Foundation/path.h>
+#include <the_Foundation/ptrarray.h>
 #include <the_Foundation/regexp.h>
 #include <the_Foundation/tlsrequest.h>
 
@@ -17,6 +18,8 @@ enum iDocumentState {
     ready_DocumentState,
 };
 
+
+
 struct Impl_DocumentWidget {
     iWidget widget;
     enum iDocumentState state;
@@ -27,6 +30,9 @@ struct Impl_DocumentWidget {
     iGmDocument *doc;
     int pageMargin;
     int scrollY;
+    iPtrArray visibleLinks;
+    const iGmRun *hoverLink;
+    iClick click;
 };
 
 iDeclareType(Url)
@@ -44,15 +50,15 @@ void init_Url(iUrl *d, const iString *text) {
         new_RegExp("(.+)://([^/:?]*)(:[0-9]+)?([^?]*)(\\?.*)?", caseInsensitive_RegExpOption);
     iRegExpMatch m;
     if (matchString_RegExp(pattern, text, &m)) {
-        capturedRange_RegExpMatch(&m, 1, &d->protocol);
-        capturedRange_RegExpMatch(&m, 2, &d->host);
-        capturedRange_RegExpMatch(&m, 3, &d->port);
+        d->protocol = capturedRange_RegExpMatch(&m, 1);
+        d->host     = capturedRange_RegExpMatch(&m, 2);
+        d->port     = capturedRange_RegExpMatch(&m, 3);
         if (!isEmpty_Range(&d->port)) {
             /* Don't include the colon. */
             d->port.start++;
         }
-        capturedRange_RegExpMatch(&m, 4, &d->path);
-        capturedRange_RegExpMatch(&m, 5, &d->query);
+        d->path  = capturedRange_RegExpMatch(&m, 4);
+        d->query = capturedRange_RegExpMatch(&m, 5);
     }
     else {
         iZap(*d);
@@ -65,6 +71,7 @@ iDefineObjectConstruction(DocumentWidget)
 void init_DocumentWidget(iDocumentWidget *d) {
     iWidget *w = as_Widget(d);
     init_Widget(w);
+    setId_Widget(w, "document");
     setBackgroundColor_Widget(w, gray25_ColorId);
     d->state = blank_DocumentState;
     d->url = new_String();
@@ -74,11 +81,15 @@ void init_DocumentWidget(iDocumentWidget *d) {
     d->doc = new_GmDocument();
     d->pageMargin = 5;
     d->scrollY = 0;
+    init_PtrArray(&d->visibleLinks);
+    d->hoverLink = NULL;
+    init_Click(&d->click, d, SDL_BUTTON_LEFT);
     setUrl_DocumentWidget(
         d, collectNewFormat_String("file://%s/test.gmi", cstr_String(collect_String(home_Path()))));
 }
 
 void deinit_DocumentWidget(iDocumentWidget *d) {
+    deinit_PtrArray(&d->visibleLinks);
     delete_String(d->url);
     delete_String(d->newSource);
     iRelease(d->doc);
@@ -90,6 +101,17 @@ static int documentWidth_DocumentWidget_(const iDocumentWidget *d) {
     return iMini(bounds.size.x - gap_UI * d->pageMargin * 2, fontSize_UI * 40);
 }
 
+static iRect documentBounds_DocumentWidget_(const iDocumentWidget *d) {
+    const iRect bounds = bounds_Widget(constAs_Widget(d));
+    const int   margin = gap_UI * d->pageMargin;
+    iRect       rect;
+    rect.size.x = documentWidth_DocumentWidget_(d);
+    rect.pos.x  = bounds.size.x / 2 - rect.size.x / 2;
+    rect.pos.y  = top_Rect(bounds) + margin;
+    rect.size.y = height_Rect(bounds) - 2 * margin;
+    return rect;
+}
+
 void setSource_DocumentWidget(iDocumentWidget *d, const iString *source) {
     /* TODO: lock source during update */
     setSource_GmDocument(d->doc, source, documentWidth_DocumentWidget_(d));
@@ -114,6 +136,12 @@ static void requestFinished_DocumentWidget_(iAnyObject *obj) {
         d->statusCode = toInt_String(line);
         printf("response (%02d): %s\n", d->statusCode, cstr_String(line));
         /* TODO: post a command with the status code */
+        switch (d->statusCode) {
+            case redirectPermanent_GmStatusCode:
+            case redirectTemporary_GmStatusCode:
+                postCommandf_App("open url:%s", cstr_String(line) + 3);
+                break;
+        }
         delete_String(line);
     }
     setCStrN_String(d->newSource, responseRange.start, size_Range(&responseRange));
@@ -155,19 +183,99 @@ static void fetch_DocumentWidget_(iDocumentWidget *d) {
 }
 
 void setUrl_DocumentWidget(iDocumentWidget *d, const iString *url) {
-    clear_String(d->url);
+    iString *newUrl = new_String();
     if (indexOfCStr_String(url, "://") == iInvalidPos && !startsWithCase_String(url, "gemini:")) {
         /* Prepend default protocol. */
-        setCStr_String(d->url, "gemini://");
+        setCStr_String(newUrl, "gemini://");
+    }
+    append_String(newUrl, url);
+    if (cmpStringSc_String(d->url, newUrl, &iCaseInsensitive)) {
+        set_String(d->url, newUrl);
+        fetch_DocumentWidget_(d);
+    }
+    delete_String(newUrl);
+}
+
+static void addVisibleLink_DocumentWidget_(void *context, const iGmRun *run) {
+    iDocumentWidget *d = context;
+    if (run->linkId) {
+        pushBack_PtrArray(&d->visibleLinks, run);
+    }
+}
+
+static iRangei visibleRange_DocumentWidget_(const iDocumentWidget *d) {
+    const int margin = gap_UI * d->pageMargin;
+    return (iRangei){ d->scrollY - margin,
+                      d->scrollY + height_Rect(bounds_Widget(constAs_Widget(d))) - margin };
+}
+
+static void updateVisible_DocumentWidget_(iDocumentWidget *d) {
+    clear_PtrArray(&d->visibleLinks);
+    render_GmDocument(
+        d->doc,
+        visibleRange_DocumentWidget_(d),
+        addVisibleLink_DocumentWidget_,
+        d);
+}
+
+static iRangecc dirPath_(iRangecc path) {
+    const size_t pos = lastIndexOfCStr_Rangecc(&path, "/");
+    if (pos == iInvalidPos) return path;
+    return (iRangecc){ path.start, path.start + pos };
+}
+
+static const iString *absoluteUrl_DocumentWidget_(const iDocumentWidget *d, const iString *url) {
+    if (indexOfCStr_String(url, "://") != iInvalidPos) {
+        /* Already absolute. */
+        return url;
+    }
+    iUrl parts;
+    init_Url(&parts, d->url);
+    iString *absolute = new_String();
+    appendRange_String(absolute, parts.protocol);
+    appendCStr_String(absolute, "://");
+    appendRange_String(absolute, parts.host);
+    if (!isEmpty_Range(&parts.port)) {
+        appendCStr_String(absolute, ":");
+        appendRange_String(absolute, parts.port);
+    }
+    if (startsWith_String(url, "/")) {
+        append_String(absolute, url);
+    }
+    else {
+        iRangecc relPath = range_String(url);
+        iRangecc dir = dirPath_(parts.path);
+        for (;;) {
+            if (equal_Rangecc(&relPath, ".")) {
+                relPath.start++;
+            }
+            else if (startsWith_Rangecc(&relPath, "./")) {
+                relPath.start += 2;
+            }
+            else if (equal_Rangecc(&relPath, "..")) {
+                relPath.start += 2;
+                dir = dirPath_(dir);
+            }
+            else if (startsWith_Rangecc(&relPath, "../")) {
+                relPath.start += 3;
+                dir = dirPath_(dir);
+            }
+            else break;
+        }
+        appendRange_String(absolute, dir);
+        if (!endsWith_String(absolute, "/")) {
+            appendCStr_String(absolute, "/");
+        }
+        appendRange_String(absolute, relPath);
     }
-    append_String(d->url, url);
-    fetch_DocumentWidget_(d);
+    return collect_String(absolute);
 }
 
 static iBool processEvent_DocumentWidget_(iDocumentWidget *d, const SDL_Event *ev) {
     iWidget *w = as_Widget(d);
     if (isResize_UserEvent(ev)) {
         setWidth_GmDocument(d->doc, documentWidth_DocumentWidget_(d));
+        updateVisible_DocumentWidget_(d);
     }
     if (ev->type == SDL_KEYDOWN) {
         const int mods = keyMods_Sym(ev->key.keysym.mod);
@@ -202,9 +310,46 @@ static iBool processEvent_DocumentWidget_(iDocumentWidget *d, const SDL_Event *e
         else {
             d->scrollY = 0;
         }
+        updateVisible_DocumentWidget_(d);
         postRefresh_App();
         return iTrue;
     }
+    else if (ev->type == SDL_MOUSEMOTION) {
+        const iGmRun *oldHoverLink = d->hoverLink;
+        d->hoverLink = NULL;
+        const iRect docBounds = documentBounds_DocumentWidget_(d);
+        const iInt2 hoverPos =
+            addY_I2(sub_I2(localCoord_Widget(w, init_I2(ev->motion.x, ev->motion.y)),
+                           topLeft_Rect(docBounds)),
+                    d->scrollY);
+        iConstForEach(PtrArray, i, &d->visibleLinks) {
+            const iGmRun *run = i.ptr;
+            if (contains_Rect(run->bounds, hoverPos)) {
+                d->hoverLink = run;
+                break;
+            }
+        }
+        if (d->hoverLink != oldHoverLink) {
+            postRefresh_App();
+        }
+    }
+    switch (processEvent_Click(&d->click, ev)) {
+        case finished_ClickResult:
+            if (d->hoverLink) {
+                iAssert(d->hoverLink->linkId);
+                postCommandf_App("open url:%s",
+                                 cstr_String(absoluteUrl_DocumentWidget_(
+                                     d, linkUrl_GmDocument(d->doc, d->hoverLink->linkId))));
+            }
+            return iTrue;
+        case started_ClickResult:
+        case double_ClickResult:
+        case drag_ClickResult:
+        case aborted_ClickResult:
+            return iTrue;
+        default:
+            break;
+    }
     return processEvent_Widget(w, ev);
 }
 
@@ -223,7 +368,9 @@ static void drawRun_DrawContext_(void *context, const iGmRun *run) {
     initRange_String(&text, run->text);
     iInt2 origin = addY_I2(d->bounds.pos, -d->widget->scrollY);
     drawString_Text(run->font, add_I2(run->bounds.pos, origin), run->color, &text);
-//    drawRect_Paint(&d->paint, moved_Rect(run->bounds, origin), red_ColorId);
+    if (run == d->widget->hoverLink) {
+        drawRect_Paint(&d->paint, moved_Rect(run->bounds, origin), orange_ColorId);
+    }
     deinit_String(&text);
 }
 
@@ -237,18 +384,14 @@ static void draw_DocumentWidget_(const iDocumentWidget *d) {
         setSource_GmDocument(d->doc, d->newSource, documentWidth_DocumentWidget_(d));
         clear_String(d->newSource);
         iConstCast(iDocumentWidget *, d)->state = ready_DocumentState;
+        updateVisible_DocumentWidget_(iConstCast(iDocumentWidget *, d));
     }
     if (d->state != ready_DocumentState) return;
-    iDrawContext ctx = {.widget = d, .bounds = bounds_Widget(w) };
-    const int margin = gap_UI * d->pageMargin;
-    shrink_Rect(&ctx.bounds, init1_I2(margin));
-    ctx.bounds.size.x = documentWidth_DocumentWidget_(d);
-    ctx.bounds.pos.x = bounds_Widget(w).size.x / 2 - ctx.bounds.size.x / 2;
+    iDrawContext ctx = { .widget = d, .bounds = documentBounds_DocumentWidget_(d) };
     init_Paint(&ctx.paint);
-//    drawRect_Paint(&ctx.paint, ctx.bounds, teal_ColorId);
     render_GmDocument(
         d->doc,
-        (iRangei){ d->scrollY - margin, d->scrollY + height_Rect(ctx.bounds) + margin },
+        visibleRange_DocumentWidget_(d),
         drawRun_DrawContext_,
         &ctx);
 }