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|
/// The renderer: a Nim widget tree, walked into Flutter widgets.
///
/// This knows the tag vocabulary and nothing else — no screens, no state, no
/// idea what "connect" means. Nim decides what the screen is; this decides
/// what a `vbox` looks like.
///
/// The measure of whether the split is honest is how boring this file is. If a
/// feature ever needs a change here AND in Nim, the boundary is in the wrong
/// place. The treatments are `flutter/src/frq/hiccup.cljd`'s, so a tree from
/// Nim paints the way the same tree painted under ClojureDart.
library;
import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:frq_core/frq_core.dart' as core;
import 'nim_theme.dart' as t;
class NimApp extends StatefulWidget {
const NimApp({super.key});
@override
State<NimApp> createState() => _NimAppState();
}
class _NimAppState extends State<NimApp> {
late core.UiNode _tree = core.render();
Timer? _poll;
// One controller and one focus node per keyed entry, kept across rebuilds.
//
// This is why `:key` is on every entry in both the Clojure and the Nim: a
// controller identified by position instead of name meant the host field and
// the port field shared one and both showed the port. The focus node is the
// same bug one layer up — the field is rebuilt from a fresh tree on every
// keystroke, so without a node held per key the caret goes nowhere after the
// first line.
final _controllers = <String, TextEditingController>{};
final _focus = <String, FocusNode>{};
@override
void initState() {
super.initState();
// Polling, because the socket lives on a Nim thread and there is no
// callback into Dart. At ~70µs a render a 100ms timer costs nothing.
_poll = Timer.periodic(const Duration(milliseconds: 100), (_) {
final next = core.poll();
if (next.toString() != _tree.toString()) {
setState(() => _tree = next);
}
});
}
void _send(String id, [String value = '']) {
if (id.isEmpty) return;
setState(() => _tree = core.dispatch(id, value));
if (id == 'send') _focus['draft']?.requestFocus();
}
@override
void dispose() {
_poll?.cancel();
for (final c in _controllers.values) {
c.dispose();
}
for (final f in _focus.values) {
f.dispose();
}
super.dispose();
}
@override
Widget build(BuildContext context) => MaterialApp(
title: 'frq',
debugShowCheckedModeBanner: false,
theme: ThemeData(
useMaterial3: true,
brightness: Brightness.dark,
scaffoldBackgroundColor: t.bg,
colorScheme: const ColorScheme.dark(
primary: t.accent,
onPrimary: t.onAccent,
surface: t.bg,
onSurface: t.onBg,
error: t.destructive,
),
),
home: Scaffold(backgroundColor: t.bg, body: SafeArea(child: _build(_tree))),
);
// ---------------------------------------------------------------- helpers
TextStyle _style(double size, Color color) =>
TextStyle(fontSize: size, color: color, height: 1.35);
double _d(dynamic v, double fallback) =>
v is num ? v.toDouble() : fallback;
/// Gaps between children, as real widgets rather than a `spacing:` — the
/// same layout on every Flutter version this might be built against.
List<Widget> _spaced(List<Widget> kids, double gap, {required bool vertical}) {
if (gap <= 0 || kids.length < 2) return kids;
final out = <Widget>[];
for (var i = 0; i < kids.length; i++) {
if (i > 0) {
out.add(vertical ? SizedBox(height: gap) : SizedBox(width: gap));
}
out.add(kids[i]);
}
return out;
}
/// A source that may be a bundled asset, a file on disk, or a URL — the
/// three the screens hand over, named apart by an `asset:` prefix so they
/// stay one property.
ImageProvider? _imageProvider(String src) {
if (src.isEmpty) return null;
if (src.startsWith('asset:')) return AssetImage(src.substring(6));
if (src.startsWith('http://') || src.startsWith('https://')) {
return NetworkImage(src);
}
return FileImage(File(src));
}
Widget _wrapTap(String onClick, Widget child, {BorderRadius? radius}) {
if (onClick.isEmpty) return child;
return InkWell(
onTap: () => _send(onClick),
borderRadius: radius,
child: child,
);
}
// ------------------------------------------------------------------ build
Widget _build(core.UiNode n) {
final kids = n.children.map(_build).toList();
final spacing = _d(n.props['spacing'], 0);
switch (n.tag) {
case 'page':
return SingleChildScrollView(
child: Center(
child: ConstrainedBox(
constraints:
BoxConstraints(maxWidth: _d(n.props['maxWidth'], 520)),
child: Padding(
padding: const EdgeInsets.all(t.spaceM),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: _spaced(kids, spacing, vertical: true)),
),
),
),
);
case 'vbox':
{
Widget col = Column(
crossAxisAlignment: CrossAxisAlignment.start,
mainAxisSize: MainAxisSize.min,
children: _spaced(kids, spacing, vertical: true),
);
col = _margins(n, col);
final w = _d(n.props['widthRequest'], 0);
if (w > 0) col = SizedBox(width: w, child: col);
// `fillHeight` is what keeps the compose bar at the bottom instead
// of wherever the backlog happens to end.
return n.prop('fillHeight', false) ? Expanded(child: col) : col;
}
case 'hbox':
{
// Wrap and not Row: `:hbox` in the screens means "these go together
// across", not "these fit". The head row of the chat screen asks for
// more than 360 points has, and a Row answers that with an overflow
// rather than a second line.
final wrapping = n.prop('wrap', true);
final align = n.prop('align', 'center');
if (!wrapping) {
return _margins(
n,
Row(
crossAxisAlignment: align == 'end'
? CrossAxisAlignment.end
: CrossAxisAlignment.center,
children: _spaced(kids, spacing, vertical: false),
),
);
}
return _margins(
n,
Wrap(
spacing: spacing,
runSpacing: spacing,
crossAxisAlignment: align == 'end'
? WrapCrossAlignment.end
: WrapCrossAlignment.center,
children: kids,
),
);
}
// Container::Card in the Clojure: padding 12, fills its width.
case 'card':
return Container(
width: double.infinity,
margin: const EdgeInsets.symmetric(vertical: t.spaceXxxs),
padding: const EdgeInsets.all(t.spaceXs),
decoration: BoxDecoration(
color: t.card,
borderRadius: BorderRadius.circular(t.radiusS),
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: _spaced(kids, spacing > 0 ? spacing : t.spaceXxs,
vertical: true)),
);
case 'title':
return Text(n.prop('label', ''),
style: _style(t.textTitle3, t.onBg)
.copyWith(fontWeight: FontWeight.bold));
case 'title-2':
return Padding(
padding: const EdgeInsets.only(top: t.spaceXxs, bottom: t.spaceXxxs),
child: Text(n.prop('label', ''),
style: _style(t.textTitle4, t.onBg)
.copyWith(fontWeight: FontWeight.w600)),
);
case 'label':
return Text(n.prop('label', ''), style: _style(t.textBody, t.onBg));
case 'dim-label':
return Text(n.prop('label', ''), style: _style(t.textCaption, t.dim));
/// Prose, as opposed to a label: this is what a message is, and it
/// wraps. Kept apart from `label` because a wrapping label in a row
/// lays out against the row's width rather than the column's.
case 'text':
return Text(n.prop('text', ''), style: _style(t.textBody, t.onBg));
case 'link':
return _wrapTap(
n.prop('onClick', ''),
Text(
n.prop('label', ''),
style: _style(t.textBody, t.accent)
.copyWith(decoration: TextDecoration.underline,
decorationColor: t.accent),
),
);
case 'separator':
return const Divider(height: 1, thickness: 1, color: t.divider);
case 'spacer':
{
final s = _d(n.props['size'], t.spaceXxs);
return SizedBox(width: s, height: s);
}
case 'spinner':
return Row(
mainAxisSize: MainAxisSize.min,
children: [
const SizedBox(
width: 16,
height: 16,
child: CircularProgressIndicator(
strokeWidth: 2, color: t.accent)),
if (n.prop('label', '').isNotEmpty) ...[
const SizedBox(width: t.spaceXxs),
Text(n.prop('label', ''), style: _style(t.textCaption, t.dim)),
],
],
);
/// A dot that says whether the thing is live, and the words beside it.
case 'status':
return Row(
mainAxisSize: MainAxisSize.min,
children: [
Container(
width: 8,
height: 8,
decoration: BoxDecoration(
color: n.prop('live', false) ? t.success : t.dim,
borderRadius: BorderRadius.circular(t.radiusXs),
),
),
const SizedBox(width: 6),
Text(n.prop('label', ''), style: _style(t.textCaption, t.dim)),
],
);
case 'button':
{
final onClick = n.prop('onClick', '');
final kind = n.prop('kind', 'default');
final label = Text(n.prop('label', ''));
if (kind == 'primary') {
return FilledButton(
onPressed: () => _send(onClick), child: label);
}
if (kind == 'destructive') {
return FilledButton(
style: FilledButton.styleFrom(
backgroundColor: t.destructive,
foregroundColor: t.onDestructive),
onPressed: () => _send(onClick),
child: label,
);
}
return OutlinedButton(onPressed: () => _send(onClick), child: label);
}
case 'checkbutton':
{
// The label is part of the target. 20 logical pixels is a fine tick
// on a desktop pointer and a miss on a thumb, so the whole row taps.
final onToggled = n.prop('onToggled', '');
return InkWell(
onTap: () => _send(onToggled),
child: Row(
mainAxisSize: MainAxisSize.min,
children: [
Checkbox(
value: n.prop('active', false),
onChanged: (_) => _send(onToggled),
),
Text(n.prop('label', ''), style: _style(t.textBody, t.onBg)),
],
),
);
}
case 'emoji':
return _wrapTap(
n.prop('onClick', ''),
Text(n.prop('glyph', n.prop('emoji', '')),
style: TextStyle(fontSize: _d(n.props['size'], 16))),
);
/// A reaction pill: the glyph, and the tally beside it where there is
/// one to show. The same shape whether it is a reaction under a message,
/// a swatch in the picker, or a chip on the sender's row — which is the
/// point: what you press to react and what appears once you have should
/// look like one family.
///
/// A count of zero is no count. The picker passes 0 for every swatch,
/// and a grid of little grey zeroes is noise where a reader is scanning
/// for a face. `mine` is the accent, because the only thing a pill has
/// to say at a glance is whether pressing it again takes yours off.
case 'reaction':
{
final size = _d(n.props['size'], 14);
final count = n.prop('count', 0);
final mine = n.prop('mine', false);
final pad = (0.25 * size).clamp(2.0, 8.0);
return _wrapTap(
n.prop('onClick', ''),
Container(
padding: EdgeInsets.symmetric(horizontal: pad, vertical: pad / 2),
decoration: BoxDecoration(
color: mine ? t.accent : t.component,
borderRadius: BorderRadius.circular(t.radiusS),
),
child: Row(
mainAxisSize: MainAxisSize.min,
children: [
Text(n.prop('emoji', ''), style: TextStyle(fontSize: size)),
if (count > 0) ...[
const SizedBox(width: 4),
Text('$count',
style: _style(t.textCaption,
mine ? t.onAccent : t.dim)),
],
],
),
),
);
}
/// A face is a way in to who someone is, so it takes the press that
/// opens their profile. A picture that will not load is a face that
/// stays its initial and nothing else.
case 'avatar':
{
final size = _d(n.props['size'], 32);
final provider = _imageProvider(n.prop('url', ''));
final fallback = n.prop('fallback', '');
final face = CircleAvatar(
radius: size / 2,
backgroundColor: t.component,
backgroundImage: provider,
onBackgroundImageError: provider == null ? null : (_, __) {},
child: provider == null
? Text(
fallback.isNotEmpty
? fallback.substring(0, 1).toUpperCase()
: '?',
style: _style(t.textBody, t.onBg))
: null,
);
final onClick = n.prop('onClick', '');
if (onClick.isEmpty) return face;
return InkWell(
onTap: () => _send(onClick),
customBorder: const CircleBorder(),
child: face,
);
}
case 'image':
{
final provider = _imageProvider(n.prop('src', ''));
if (provider == null) return const SizedBox.shrink();
final maxW = _d(n.props['maxWidth'], 0);
final maxH = _d(n.props['maxHeight'], 0);
Widget img = Image(
image: provider,
fit: BoxFit.contain,
// A half-written cache file, or one deleted under us: the decoder
// throws during the build, and an exception in a build is a red
// screen for the whole conversation rather than a gap where one
// picture was.
errorBuilder: (_, __, ___) => const SizedBox.shrink(),
);
if (maxW > 0 || maxH > 0) {
img = ConstrainedBox(
constraints: BoxConstraints(
maxWidth: maxW > 0 ? maxW : double.infinity,
maxHeight: maxH > 0 ? maxH : double.infinity,
),
child: img,
);
}
return _wrapTap(n.prop('onClick', ''), img);
}
case 'entry':
{
final key = n.prop('key', '');
final value = n.prop('text', '');
final c = _controllers.putIfAbsent(
key, () => TextEditingController(text: value));
// Only when it actually differs: assigning unconditionally moves the
// caret to the end on every keystroke.
if (c.text != value) {
c.value = c.value.copyWith(
text: value,
selection: TextSelection.collapsed(offset: value.length),
);
}
final field = TextField(
controller: c,
focusNode: _focus.putIfAbsent(key, FocusNode.new),
style: _style(t.textBody, t.onBg),
decoration: InputDecoration(
hintText: n.prop('placeholder', ''),
hintStyle: _style(t.textBody, t.dim),
isDense: true,
filled: true,
fillColor: t.component,
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(t.radiusS),
borderSide: BorderSide.none,
),
),
onChanged: (v) => _send(n.prop('onChange', ''), v),
onSubmitted: (_) => _send(n.prop('onSubmit', '')),
);
final w = _d(n.props['widthRequest'], 0);
// A width request is a minimum in the screens' vocabulary, but here
// it has to be a maximum too: an unconstrained TextField inside a
// Wrap has no width at all to take.
return w > 0 ? SizedBox(width: w, child: field) : Expanded(child: field);
}
case 'scroll':
{
Widget body = SingleChildScrollView(
// The backlog reads from the bottom; a settings list from the top.
reverse: n.prop('stickToBottom', false),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: _spaced(kids, spacing, vertical: true)),
);
body = Scrollbar(child: body);
final h = _d(n.props['height'], 0);
if (h > 0) return SizedBox(height: h, child: body);
// No fixed height: take what the column has left. `reserve` is the
// Clojure's way of saying the same thing to a backend that could not
// do this, and is ignored here on purpose.
return Expanded(child: body);
}
/// A panel over the screen rather than a screen of its own.
case 'dialog':
return Card(
color: t.cardComponent,
child: Padding(
padding: const EdgeInsets.all(t.spaceS),
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.start,
children: [
if (n.prop('title', '').isNotEmpty)
Padding(
padding: const EdgeInsets.only(bottom: t.spaceXxs),
child: Text(n.prop('title', ''),
style: _style(t.textTitle4, t.onCard)
.copyWith(fontWeight: FontWeight.w600)),
),
..._spaced(kids, spacing, vertical: true),
],
),
),
);
default:
// An unknown tag paints as itself rather than crashing or vanishing.
// Nim can add one and see it before this file has heard of it, which
// is what makes the boundary pleasant to work across.
return Container(
padding: const EdgeInsets.all(4),
color: Colors.orange.withValues(alpha: 0.3),
child: Text('?${n.tag}'),
);
}
}
/// `margin`, `marginTop`, `marginBottom`, `marginRight` — the props the
/// screens use to buy air without a wrapper each time.
Widget _margins(core.UiNode n, Widget child) {
final all = _d(n.props['margin'], 0);
final top = _d(n.props['marginTop'], all);
final bottom = _d(n.props['marginBottom'], all);
final right = _d(n.props['marginRight'], all);
final left = _d(n.props['marginLeft'], all);
if (top == 0 && bottom == 0 && right == 0 && left == 0) return child;
return Padding(
padding: EdgeInsets.only(
top: top, bottom: bottom, right: right, left: left),
child: child,
);
}
}
|