8 files changed, 202 insertions, 12 deletions

diff --git a/src/history.c b/src/history.c
index 740830e9..f6ad4771 100644
--- a/src/history.c
+++ b/src/history.c
@@ -284,6 +284,36 @@ void add_History(iHistory *d, const iString *url ){
     unlock_Mutex(d->mtx);
 }
 
+iBool preceding_History(iHistory *d, iRecentUrl *recent_out) {
+    iBool ok = iFalse;
+    lock_Mutex(d->mtx);
+    if (!isEmpty_Array(&d->recent) && d->recentPos < size_Array(&d->recent) - 1) {
+        const iRecentUrl *recent = constAt_Array(&d->recent, d->recentPos + 1);
+        set_String(&recent_out->url, &recent->url);
+        recent_out->normScrollY = recent->normScrollY;
+        recent_out->cachedDoc = ref_Object(recent->cachedDoc);
+        /* Cached response is not returned, would involve a deep copy. */
+        ok = iTrue;
+    }
+    unlock_Mutex(d->mtx);
+    return ok;
+}
+
+iBool following_History(iHistory *d, iRecentUrl *recent_out) {
+    iBool ok = iFalse;
+    lock_Mutex(d->mtx);
+    if (!isEmpty_Array(&d->recent) && d->recentPos > 0) {
+        const iRecentUrl *recent = constAt_Array(&d->recent, d->recentPos - 1);
+        set_String(&recent_out->url, &recent->url);
+        recent_out->normScrollY = recent->normScrollY;
+        recent_out->cachedDoc = ref_Object(recent->cachedDoc);
+        /* Cached response is not returned, would involve a deep copy. */
+        ok = iTrue;
+    }
+    unlock_Mutex(d->mtx);
+    return ok;
+}
+
 iBool goBack_History(iHistory *d) {
     lock_Mutex(d->mtx);
     if (!isEmpty_Array(&d->recent) && d->recentPos < size_Array(&d->recent) - 1) {
diff --git a/src/history.h b/src/history.h
index eb35b1df..9c900b82 100644
--- a/src/history.h
+++ b/src/history.h
@@ -63,6 +63,8 @@ void        setCachedResponse_History   (iHistory *, const iGmResponse *response
 void        setCachedDocument_History   (iHistory *, iGmDocument *doc);
 iBool       goBack_History              (iHistory *);
 iBool       goForward_History           (iHistory *);
+iBool       preceding_History           (iHistory *d, iRecentUrl *recent_out);
+iBool       following_History           (iHistory *d, iRecentUrl *recent_out);
 iRecentUrl *recentUrl_History           (iHistory *, size_t pos);
 iRecentUrl *mostRecentUrl_History       (iHistory *);
 iRecentUrl *findUrl_History             (iHistory *, const iString *url);
diff --git a/src/ui/documentwidget.c b/src/ui/documentwidget.c
index 936c3cb7..70201d7b 100644
--- a/src/ui/documentwidget.c
+++ b/src/ui/documentwidget.c
@@ -315,6 +315,10 @@ void init_DocumentWidget(iDocumentWidget *d) {
     init_Widget(w);
     setId_Widget(w, format_CStr("document%03d", ++docEnum_));
     setFlags_Widget(w, hover_WidgetFlag | noBackground_WidgetFlag, iTrue);
+    if (deviceType_App() != desktop_AppDeviceType) {
+        setFlags_Widget(w, leftEdgeDraggable_WidgetFlag | rightEdgeDraggable_WidgetFlag |
+                        horizontalOffset_WidgetFlag, iTrue);
+    }
     init_PersistentDocumentState(&d->mod);
     d->flags           = 0;
     d->phoneToolbar    = NULL;
@@ -977,6 +981,9 @@ static void updateTimestampBuf_DocumentWidget_(const iDocumentWidget *d) {
 }
 
 static void invalidate_DocumentWidget_(iDocumentWidget *d) {
+    if (flags_Widget(as_Widget(d)) & destroyPending_WidgetFlag) {
+        return;
+    }
     invalidate_VisBuf(d->visBuf);
     clear_PtrSet(d->invalidRuns);
 }
@@ -2237,6 +2244,133 @@ static iBool handlePinch_DocumentWidget_(iDocumentWidget *d, const char *cmd) {
     return iTrue;
 }
 
+static void swap_DocumentWidget_(iDocumentWidget *d, iGmDocument *doc,
+                                 iDocumentWidget *swapBuffersWith) {
+    if (doc) {
+        iAssert(isInstance_Object(doc, &Class_GmDocument));
+        iGmDocument *copy = ref_Object(doc);
+        iRelease(d->doc);
+        d->doc = copy;
+        d->scrollY = swapBuffersWith->scrollY;
+        updateVisible_DocumentWidget_(d);
+        iSwap(iVisBuf *,     d->visBuf,     swapBuffersWith->visBuf);
+        iSwap(iVisBufMeta *, d->visBufMeta, swapBuffersWith->visBufMeta);
+        iSwap(iDrawBufs *,   d->drawBufs,   swapBuffersWith->drawBufs);
+        invalidate_DocumentWidget_(swapBuffersWith);
+    }
+}
+
+static iWidget *swipeParent_DocumentWidget_(iDocumentWidget *d) {
+    return findChild_Widget(as_Widget(d)->root->widget, "doctabs");
+}
+
+static iBool handleSwipe_DocumentWidget_(iDocumentWidget *d, const char *cmd) {
+    iWidget *w = as_Widget(d);
+    if (equal_Command(cmd, "edgeswipe.moved")) {
+        as_Widget(d)->offsetRef = NULL;
+        const int side = argLabel_Command(cmd, "side");
+        const int offset = arg_Command(cmd);
+        if (side == 1) {
+            if (atOldest_History(d->mod.history)) {
+                return iTrue;
+            }
+            iWidget *swipeParent = swipeParent_DocumentWidget_(d);
+            /* The temporary "swipeIn" will display the previous page until the finger is lifted. */
+            iDocumentWidget *swipeIn = findChild_Widget(swipeParent, "swipein");
+            if (!swipeIn) {
+                swipeIn = new_DocumentWidget();
+                setId_Widget(as_Widget(swipeIn), "swipein");
+                setFlags_Widget(as_Widget(swipeIn),
+                                disabled_WidgetFlag | refChildrenOffset_WidgetFlag |
+                                fixedPosition_WidgetFlag | fixedSize_WidgetFlag, iTrue);
+                swipeIn->widget.rect.pos = windowToInner_Widget(swipeParent, localToWindow_Widget(w, w->rect.pos));
+                swipeIn->widget.rect.size = d->widget.rect.size;
+                swipeIn->widget.offsetRef = w;
+                iRecentUrl *recent = new_RecentUrl();
+                preceding_History(d->mod.history, recent);
+                if (recent->cachedDoc) {
+                    iChangeRef(swipeIn->doc, recent->cachedDoc);
+                    updateScrollMax_DocumentWidget_(d);
+                    setValue_Anim(&swipeIn->scrollY.pos, size_GmDocument(swipeIn->doc).y * recent->normScrollY, 0);
+                    updateVisible_DocumentWidget_(swipeIn);
+                }
+                delete_RecentUrl(recent);
+                addChildPos_Widget(swipeParent, iClob(swipeIn), front_WidgetAddPos);
+            }
+        }
+        if (side == 2) {
+            if (offset < -get_Window()->pixelRatio * 10) {
+                if (!atLatest_History(d->mod.history) &&
+                    ~flags_Widget(w) & dragged_WidgetFlag) {
+                    postCommand_Widget(d, "navigate.forward");
+                    setFlags_Widget(w, dragged_WidgetFlag, iTrue);
+                    /* Set up the swipe dummy. */
+                    iWidget *swipeParent = swipeParent_DocumentWidget_(d);
+                    iDocumentWidget *target = new_DocumentWidget();
+                    setId_Widget(as_Widget(target), "swipeout");
+                    /* The target takes the old document and jumps on top. */
+                    target->widget.rect.pos = windowToInner_Widget(swipeParent, localToWindow_Widget(w, w->rect.pos));
+                    target->widget.rect.size = d->widget.rect.size;
+                    setFlags_Widget(as_Widget(target), fixedPosition_WidgetFlag | fixedSize_WidgetFlag, iTrue);
+                    swap_DocumentWidget_(target, d->doc, d);
+                    addChildPos_Widget(swipeParent, iClob(target), front_WidgetAddPos);
+                    setFlags_Widget(as_Widget(target), refChildrenOffset_WidgetFlag, iTrue);
+                    as_Widget(target)->offsetRef = parent_Widget(w);
+                    destroy_Widget(as_Widget(target)); /* will be actually deleted after animation finishes */
+                }
+                if (flags_Widget(w) & dragged_WidgetFlag) {
+                    setVisualOffset_Widget(w, width_Widget(w) + offset, 10, 0);
+                }
+                else {
+                    setVisualOffset_Widget(w, offset / 4, 10, 0);
+                }
+            }
+            return iTrue;
+        }
+    }
+    if (equal_Command(cmd, "edgeswipe.ended") && argLabel_Command(cmd, "side") == 2) {
+        if (argLabel_Command(cmd, "abort") && flags_Widget(w) & dragged_WidgetFlag) {
+            postCommand_Widget(d, "navigate.back");
+        }
+        setFlags_Widget(w, dragged_WidgetFlag, iFalse);
+        setVisualOffset_Widget(w, 0, 100, 0);
+        return iTrue;
+    }
+    if (equal_Command(cmd, "edgeswipe.ended") && argLabel_Command(cmd, "side") == 1) {
+        iWidget *swipeParent = swipeParent_DocumentWidget_(d);
+        iWidget *swipeIn = findChild_Widget(swipeParent, "swipein");
+        if (swipeIn) {
+            swipeIn->offsetRef = NULL;
+            destroy_Widget(swipeIn);
+        }
+    }
+    if (equal_Command(cmd, "swipe.back")) {
+        if (atOldest_History(d->mod.history)) {
+            setVisualOffset_Widget(w, 0, 100, 0);
+            return iTrue;
+        }
+        iWidget *swipeParent = swipeParent_DocumentWidget_(d);
+        iDocumentWidget *target = new_DocumentWidget();
+        setId_Widget(as_Widget(target), "swipeout");
+        /* The target takes the old document and jumps on top. */
+        target->widget.rect.pos = windowToInner_Widget(swipeParent, innerToWindow_Widget(w, zero_I2()));
+        /* Note: `innerToWindow_Widget` does not apply visual offset. */
+        target->widget.rect.size = w->rect.size;
+        setFlags_Widget(as_Widget(target), fixedPosition_WidgetFlag | fixedSize_WidgetFlag, iTrue);
+        swap_DocumentWidget_(target, d->doc, d);
+        addChildPos_Widget(swipeParent, iClob(target), back_WidgetAddPos);
+        setFlags_Widget(as_Widget(d), refChildrenOffset_WidgetFlag, iTrue);
+        as_Widget(d)->offsetRef = swipeParent;
+        setVisualOffset_Widget(as_Widget(target), value_Anim(&w->visualOffset), 0, 0);
+        setVisualOffset_Widget(as_Widget(target), width_Widget(target), 150, 0);
+        destroy_Widget(as_Widget(target)); /* will be actually deleted after animation finishes */
+        setVisualOffset_Widget(w, 0, 0, 0);
+        postCommand_Widget(d, "navigate.back");
+        return iTrue;
+    }
+    return iFalse;
+}
+
 static iBool handleCommand_DocumentWidget_(iDocumentWidget *d, const char *cmd) {
     iWidget *w = as_Widget(d);
     if (equal_Command(cmd, "document.openurls.changed")) {
@@ -2842,7 +2976,7 @@ static iBool handleCommand_DocumentWidget_(iDocumentWidget *d, const char *cmd)
                     uiHeading_ColorEscape "${heading.import.bookmarks}",
                     formatCStrs_Lang("dlg.import.found.n", count),
                     (iMenuItem[]){ { "${cancel}", 0, 0, NULL },
-                                   { format_CStr(cstrCount_Lang("dlg.import.add.n", count),
+                                   { format_CStr(cstrCount_Lang("dlg.import.add.n", (int) count),
                                                  uiTextAction_ColorEscape,
                                                  count),
                                      0,
@@ -2901,6 +3035,10 @@ static iBool handleCommand_DocumentWidget_(iDocumentWidget *d, const char *cmd)
     else if (startsWith_CStr(cmd, "pinch.") && document_Command(cmd) == d) {
         return handlePinch_DocumentWidget_(d, cmd);
     }
+    else if ((startsWith_CStr(cmd, "edgeswipe.") || startsWith_CStr(cmd, "swipe.")) &&
+             document_App() == d) {
+        return handleSwipe_DocumentWidget_(d, cmd);
+    }
     return iFalse;
 }
 
@@ -4306,7 +4444,8 @@ static iBool render_DocumentWidget_(const iDocumentWidget *d, iDrawContext *ctx,
     /* Swap buffers around to have room available both before and after the visible region. */
     allocVisBuffer_DocumentWidget_(d);
     reposition_VisBuf(visBuf, vis);
-    /* Redraw the invalid ranges. */ {
+    /* Redraw the invalid ranges. */
+    if (~flags_Widget(constAs_Widget(d)) & destroyPending_WidgetFlag) {
         iPaint *p = &ctx->paint;
         init_Paint(p);
         iForIndices(i, visBuf->buffers) {
@@ -4490,6 +4629,7 @@ static void draw_DocumentWidget_(const iDocumentWidget *d) {
         .vis             = vis,
         .showLinkNumbers = (d->flags & showLinkNumbers_DocumentWidgetFlag) != 0,
     };
+    init_Paint(&ctx.paint);
     render_DocumentWidget_(d, &ctx, iFalse /* just the mandatory parts */);
     setClip_Paint(&ctx.paint, bounds);
     int yTop = docBounds.pos.y - pos_SmoothScroll(&d->scrollY);
diff --git a/src/ui/mobile.c b/src/ui/mobile.c
index 1bf289a7..7c0c8b60 100644
--- a/src/ui/mobile.c
+++ b/src/ui/mobile.c
@@ -447,7 +447,7 @@ void finalizeSheet_Mobile(iWidget *sheet) {
         }
         addChild_Widget(topPanel, iClob(makePadding_Widget(lineHeight_Text(labelFont_()))));
         /* Slide top panel with detail panels. */ {
-            setFlags_Widget(topPanel, refChildrenOffset_WidgetFlag, iTrue);
+        setFlags_Widget(topPanel, refChildrenOffset_WidgetFlag, iTrue);
             topPanel->offsetRef = detailStack;
         }
         if (prefsTabs) {
diff --git a/src/ui/root.c b/src/ui/root.c
index 2d69970d..e279a048 100644
--- a/src/ui/root.c
+++ b/src/ui/root.c
@@ -271,7 +271,8 @@ void destroyPending_Root(iRoot *d) {
     setCurrent_Root(d);
     iForEach(PtrSet, i, d->pendingDestruction) {
         iWidget *widget = *i.value;
-        if (!isFinished_Anim(&widget->visualOffset)) {
+        if (!isFinished_Anim(&widget->visualOffset) ||
+            isBeingVisuallyOffsetByReference_Widget(widget)) {
             continue;
         }
         if (widget->flags & keepOnTop_WidgetFlag) {
@@ -1169,11 +1170,11 @@ void createUserInterface_Root(iRoot *d) {
         setId_Widget(mainStack, "stack");
         addChildFlags_Widget(div, iClob(mainStack), resizeChildren_WidgetFlag | expand_WidgetFlag |
                                                         unhittable_WidgetFlag);
-        iWidget *tabBar = makeTabs_Widget(mainStack);
-        setId_Widget(tabBar, "doctabs");
-        setBackgroundColor_Widget(tabBar, uiBackground_ColorId);
-        appendTabPage_Widget(tabBar, iClob(new_DocumentWidget()), "Document", 0, 0);
-        iWidget *buttons = findChild_Widget(tabBar, "tabs.buttons");
+        iWidget *docTabs = makeTabs_Widget(mainStack);
+        setId_Widget(docTabs, "doctabs");
+        setBackgroundColor_Widget(docTabs, uiBackground_ColorId);
+        appendTabPage_Widget(docTabs, iClob(new_DocumentWidget()), "Document", 0, 0);
+        iWidget *buttons = findChild_Widget(docTabs, "tabs.buttons");
         setFlags_Widget(buttons, collapse_WidgetFlag | hidden_WidgetFlag |
                                      drawBackgroundToHorizontalSafeArea_WidgetFlag, iTrue);
         if (deviceType_App() == phone_AppDeviceType) {
diff --git a/src/ui/touch.c b/src/ui/touch.c
index 236601e8..36bac267 100644
--- a/src/ui/touch.c
+++ b/src/ui/touch.c
@@ -273,8 +273,9 @@ static void update_TouchState_(void *ptr) {
 //                                     touch->edge == right_TouchEdge && swipeDir < 0 ? SDL_BUTTON_X2 : 0);
 //                setHover_Widget(NULL);
                 postCommandf_App("edgeswipe.ended abort:1 side:%d id:%llu", touch->edge, touch->id);
-                touch->edge = none_TouchEdge;                
-                remove_ArrayIterator(&i);
+                touch->edge = none_TouchEdge;
+                /* May be a regular drag along the edge so don't remove. */
+                //remove_ArrayIterator(&i);
             }
             continue;
         }
@@ -516,6 +517,7 @@ iBool processEvent_Touch(const SDL_Event *ev) {
     else if (ev->type == SDL_FINGERMOTION) {
         iTouch *touch = find_TouchState_(d, fing->fingerId);
         if (touch && touch->edge) {
+            clear_Array(d->moms);
             pushPos_Touch_(touch, pos, nowTime);
             postCommandf_App("edgeswipe.moved arg:%d side:%d id:%llu",
                              (int) (x_F3(pos) - x_F3(touch->startPos)),
diff --git a/src/ui/widget.c b/src/ui/widget.c
index f1d1dae4..3b67684b 100644
--- a/src/ui/widget.c
+++ b/src/ui/widget.c
@@ -759,6 +759,19 @@ void arrange_Widget(iWidget *d) {
     }
 }
 
+iBool isBeingVisuallyOffsetByReference_Widget(const iWidget *d) {
+    if (d->flags & refChildrenOffset_WidgetFlag) {
+        iConstForEach(ObjectList, i, children_Widget(d->offsetRef)) {
+            const iWidget *child = i.object;
+            if (child == d) continue;
+            if (child->flags & (visualOffset_WidgetFlag | dragged_WidgetFlag)) {
+                return iTrue;
+            }
+        }
+    }
+    return iFalse;
+}
+
 static void applyVisualOffset_Widget_(const iWidget *d, iInt2 *pos) {
     if (d->flags & (visualOffset_WidgetFlag | dragged_WidgetFlag)) {
         const int off = iRound(value_Anim(&d->visualOffset));
@@ -1075,12 +1088,12 @@ iBool processEvent_Widget(iWidget *d, const SDL_Event *ev) {
                 if (d->flags & dragged_WidgetFlag && equal_Command(cmd, "edgeswipe.ended")) {
                     if (argLabel_Command(cmd, "abort")) {
                         setVisualOffset_Widget(d, 0, 200, easeOut_AnimFlag);
-                        setFlags_Widget(d, dragged_WidgetFlag, iFalse);
                     }
                     else {
                         postCommand_Widget(
                             d, argLabel_Command(cmd, "side") == 1 ? "swipe.back" : "swipe.forward");
                     }
+                    setFlags_Widget(d, dragged_WidgetFlag, iFalse);
                 }
                 if (d->commandHandler && d->commandHandler(d, ev->user.data1)) {
                     iAssert(get_Root() == d->root);
diff --git a/src/ui/widget.h b/src/ui/widget.h
index 7255b975..b2310f21 100644
--- a/src/ui/widget.h
+++ b/src/ui/widget.h
@@ -244,6 +244,8 @@ iBool   isCommand_Widget            (const iWidget *d, const SDL_Event *ev, cons
 iBool   hasParent_Widget            (const iWidget *d, const iWidget *someParent);
 iBool   isAffectedByVisualOffset_Widget
                                     (const iWidget *);
+iBool   isBeingVisuallyOffsetByReference_Widget
+                                    (const iWidget *);
 void    setId_Widget                (iWidget *, const char *id);
 void    setFlags_Widget             (iWidget *, int64_t flags, iBool set);
 void    setPos_Widget               (iWidget *, iInt2 pos);