feat: build v1 Mews client: reader UI, gestures, Drift store, fetch actor

app/lib/mews/document.dart

@@ -0,0 +1,291 @@
+/// Document model for Mews pages (mews-spec/SPEC.md sections 3 to 6).
+/// Pure data: no Flutter imports, so it can be built inside an isolate.
+library;
+
+/// The `body` variant class a page carries (spec 5.3), or [plain] when absent.
+enum MewsVariant { plain, warm, cool, green, mono }
+
+/// A parsed page. [specVersion] holds the conformance marker's value and is
+/// null on a page without the marker, which must be shown plainly (spec 8.1).
+class MewsPage {
+  const MewsPage({
+    required this.url,
+    required this.body,
+    required this.lang,
+    required this.direction,
+    required this.variant,
+    required this.entries,
+    this.specVersion,
+    this.title,
+    this.description,
+    this.author,
+    this.atomFeedHref,
+  });
+
+  final String url;
+  final List<MewsBlock> body;
+  final String lang;
+  final TextDirection direction;
+  final MewsVariant variant;
+  final List<MewsEntry> entries;
+  final String? specVersion;
+  final String? title;
+  final String? description;
+  final String? author;
+  final String? atomFeedHref;
+
+  bool get isMews => specVersion != null;
+}
+
+/// TextDirection without importing Flutter: pages with dir="rtl" render
+/// right-to-left (spec 3).
+enum TextDirection { ltr, rtl }
+
+/// A dated link that starts a list item (spec 6.1).
+class MewsEntry {
+  const MewsEntry({required this.url, required this.date, required this.title});
+
+  final String url;
+  final DateTime date;
+  final String title;
+}
+
+sealed class MewsBlock {
+  const MewsBlock();
+}
+
+class HeadingBlock extends MewsBlock {
+  const HeadingBlock(this.level, this.inline);
+
+  final int level; // 1 to 6
+  final List<MewsInline> inline;
+}
+
+class ParagraphBlock extends MewsBlock {
+  const ParagraphBlock(this.inline);
+
+  final List<MewsInline> inline;
+}
+
+class QuoteBlock extends MewsBlock {
+  const QuoteBlock(this.children);
+
+  final List<MewsBlock> children;
+}
+
+class PreBlock extends MewsBlock {
+  const PreBlock(this.text);
+
+  final String text;
+}
+
+class AddressBlock extends MewsBlock {
+  const AddressBlock(this.inline);
+
+  final List<MewsInline> inline;
+}
+
+class RuleBlock extends MewsBlock {
+  const RuleBlock();
+}
+
+class ListBlock extends MewsBlock {
+  const ListBlock({required this.ordered, required this.start, required this.items});
+
+  final bool ordered;
+  final int start;
+  final List<MewsListItem> items;
+}
+
+class MewsListItem {
+  const MewsListItem(this.blocks);
+
+  final List<MewsBlock> blocks;
+}
+
+class DefinitionItem {
+  const DefinitionItem(this.term, this.definition);
+
+  final List<MewsInline> term;
+  final List<MewsInline> definition;
+}
+
+class DefinitionListBlock extends MewsBlock {
+  const DefinitionListBlock(this.items);
+
+  final List<DefinitionItem> items;
+}
+
+class TableBlock extends MewsBlock {
+  const TableBlock({required this.rows, this.caption, this.summary});
+
+  final List<MewsTableRow> rows;
+  final String? caption;
+  final String? summary;
+}
+
+class MewsTableRow {
+  const MewsTableRow(this.cells);
+
+  final List<MewsTableCell> cells;
+}
+
+class MewsTableCell {
+  const MewsTableCell({
+    required this.header,
+    required this.inline,
+    this.colspan = 1,
+    this.rowspan = 1,
+  });
+
+  final bool header;
+  final List<MewsInline> inline;
+  final int colspan;
+  final int rowspan;
+}
+
+/// Same-site images load normally; off-site or data: sources are refused by
+/// the client without reader action (specs 4.2 and 8.1), and the alt text is
+/// shown in their place.
+class ImageBlock extends MewsBlock {
+  const ImageBlock({required this.src, required this.alt, required this.allowed});
+
+  final String src;
+  final String alt;
+  final bool allowed;
+}
+
+class FormBlock extends MewsBlock {
+  const FormBlock({
+    required this.action,
+    required this.method,
+    required this.fields,
+    required this.submitLabel,
+  });
+
+  final String action;
+  final String method;
+  final List<MewsFormField> fields;
+  final String? submitLabel;
+}
+
+sealed class MewsFormField {
+  const MewsFormField({required this.name, this.label});
+
+  final String name;
+  final String? label;
+}
+
+class MewsTextField extends MewsFormField {
+  const MewsTextField({
+    required super.name,
+    required this.password,
+    this.value = '',
+    this.maxLength,
+    this.inputMode,
+    super.label,
+  });
+
+  final bool password;
+  final String value;
+  final int? maxLength;
+  final String? inputMode;
+}
+
+class MewsCheckboxField extends MewsFormField {
+  const MewsCheckboxField({
+    required super.name,
+    required this.checked,
+    this.value = 'on',
+    super.label,
+  });
+
+  final bool checked;
+  final String value;
+}
+
+class MewsRadioField extends MewsFormField {
+  const MewsRadioField({
+    required super.name,
+    required this.checked,
+    required this.value,
+    super.label,
+  });
+
+  final bool checked;
+  final String value;
+}
+
+class MewsSelectField extends MewsFormField {
+  const MewsSelectField({required super.name, required this.options, super.label});
+
+  final List<MewsSelectOption> options;
+}
+
+class MewsSelectOption {
+  const MewsSelectOption({required this.value, required this.selected});
+
+  final String value;
+  final bool selected;
+}
+
+class MewsTextAreaField extends MewsFormField {
+  const MewsTextAreaField({
+    required super.name,
+    required this.value,
+    this.rows = 3,
+    super.label,
+  });
+
+  final String value;
+  final int rows;
+}
+
+/// A hidden input; kept in the model so it round-trips on submit.
+class MewsHiddenField extends MewsFormField {
+  const MewsHiddenField({required super.name, required this.value});
+
+  final String value;
+}
+
+/// One or more inputs of kind submit/reset collapse into this control.
+class MewsSubmitField extends MewsFormField {
+  const MewsSubmitField({required this.reset, super.label, super.name = ''});
+
+  final bool reset;
+}
+
+sealed class MewsInline {
+  const MewsInline();
+}
+
+class MewsText extends MewsInline {
+  const MewsText(this.text);
+
+  final String text;
+}
+
+enum EmphasisStyle { emphasis, strong, code, sample, variable, term, quote }
+
+/// em, i, cite and abbr map to [EmphasisStyle.emphasis]; strong and b to
+/// [EmphasisStyle.strong]; kbd and samp to [EmphasisStyle.sample]; var to
+/// [EmphasisStyle.variable]; dfn to [EmphasisStyle.term]; q to
+/// [EmphasisStyle.quote]. The distinction keeps the renderer honest about what
+/// authors meant, per the reader-controls-presentation principle.
+class MewsEmphasis extends MewsInline {
+  const MewsEmphasis(this.style, this.children);
+
+  final EmphasisStyle style;
+  final List<MewsInline> children;
+}
+
+class MewsLink extends MewsInline {
+  const MewsLink(this.href, this.children);
+
+  final String href;
+  final List<MewsInline> children;
+}
+
+class MewsLineBreak extends MewsInline {
+  const MewsLineBreak();
+}