feat: add quotations from marked text, with citations and sharing

app/lib/application/pages/quotations_page.dart

@@ -0,0 +1,139 @@
+import '../../database/database.dart';
+import '../../l10n/strings.dart';
+import '../../mews/document.dart';
+import 'mews_urls.dart';
+import 'page_blocks.dart';
+
+/// Every text the reader kept from a page, with the page it came from. The
+/// page mirrors the posts page: a searchable list ordered by the day the
+/// text was kept or by the page it came from, one row per quotation, each
+/// row carrying the citation's author when the page named one.
+Future<MewsPage> buildQuotationsPage(
+  Uri url, {
+  required MewsDatabase db,
+  required Strings strings,
+}) async {
+  final query = url.queryParameters['q'] ?? '';
+  final sort = QuotationSort.parse(url.queryParameters['sort']);
+  final quotations = await db.quotationsList(sort: sort, query: query);
+  final total = await db.countQuotations();
+  final title = strings.t('quotations-title');
+
+  return internalPage(
+    url: url,
+    title: title,
+    strings: strings,
+    body: [
+      ...chrome(title: title, current: url, strings: strings),
+      textForm(
+        action: MewsUrls.quotations,
+        label: strings.t('quotations-search-label'),
+        submitLabel: strings.t('action-search'),
+        field: 'q',
+        value: query,
+      ),
+      ...linkLine([
+        if (query.isNotEmpty)
+          action(MewsUrls.page(url, {'q': null}),
+              strings.t('action-clear-search')),
+      ]),
+      ...choiceLine(
+        label: strings.t('posts-sort-label'),
+        options: [
+          for (final option in const [
+            (QuotationSort.date, 'posts-sort-date'),
+            (QuotationSort.page, 'quotations-sort-page'),
+          ])
+            (
+              href: MewsUrls.page(url, {'sort': option.$1.name}),
+              label: strings.t(option.$2),
+              current: option.$1 == sort,
+            ),
+        ],
+      ),
+      const RuleBlock(),
+      ParagraphBlock([
+        MewsEmphasis(EmphasisStyle.emphasis, [
+          MewsText(countText(strings, total,
+              none: 'count-quotations-none',
+              one: 'count-quotations-one',
+              many: 'count-quotations-many')),
+        ]),
+      ]),
+      if (quotations.isEmpty)
+        ParagraphBlock([
+          MewsText(strings.t(
+              query.isEmpty ? 'quotations-empty' : 'quotations-no-matches')),
+        ])
+      else
+        itemList([
+          for (final quotation in quotations)
+            itemRow(
+              href: quotation.pageUrl,
+              label: quotation.quote,
+              date: dayText(quotation.createdAt),
+              // The row names the page the text came from, not just the
+              // text: the author and the article's title when they are
+              // known, and the site by its own title when the reader's
+              // subscriptions know it, otherwise by its host.
+              note: _rowNote(quotation),
+              actions: [
+                action(
+                    MewsUrls.action('share-quotation', {'id': '${quotation.id}'}),
+                    strings.t('quotations-share')),
+                action(
+                    MewsUrls.action(
+                        'remove-quotation', {'id': '${quotation.id}'}),
+                    strings.t('quotations-remove')),
+              ],
+            ),
+        ]),
+    ],
+  );
+}
+
+/// Who and what the row names behind a quotation: the author and the
+/// article's title when they are known, and the site the page came from by
+/// its own title, or by its host when the subscriptions do not know it.
+/// Nothing is named twice.
+String? _rowNote(Quotation quotation) {
+  final host = Uri.tryParse(quotation.pageUrl)?.host;
+  final source = (quotation.siteTitle?.trim().isNotEmpty ?? false)
+      ? quotation.siteTitle!.trim()
+      : (host != null && host.isNotEmpty ? host : quotation.pageUrl);
+  final named = <String>{};
+  final parts = [
+    for (final part in [
+      quotation.author?.trim(),
+      quotation.pageTitle?.trim(),
+      source,
+    ])
+      if (part != null && part.isNotEmpty && named.add(part)) part,
+  ];
+  return parts.isEmpty ? null : parts.join(actionSeparator);
+}
+
+/// The citation a quotation travels with, shaped as APA names a web page:
+/// the author first when the page's metadata carried one, otherwise the
+/// article's title; the year as a no-date marker, since a page declares no
+/// publication date; then the article's title, the site's own title and the
+/// address. The site is named by its title when the reader's subscriptions
+/// know it, and by its host when they do not; nothing is named twice.
+String citationFor(Quotation quotation, Strings strings) {
+  final noDate = strings.t('quotations-no-date');
+  final uri = Uri.tryParse(quotation.pageUrl);
+  final host =
+      uri != null && uri.host.isNotEmpty ? uri.host : quotation.pageUrl;
+  final author = quotation.author?.trim();
+  final title = quotation.pageTitle?.trim();
+  final site = (quotation.siteTitle?.trim().isNotEmpty ?? false)
+      ? quotation.siteTitle!.trim()
+      : host;
+  final lead = (author != null && author.isNotEmpty) ? author : title ?? site;
+  final named = [
+    if (lead != title && title != null && title.isNotEmpty) title,
+    if (site != lead && site != title) site,
+  ];
+  if (named.isEmpty) return '$lead ($noDate). ${quotation.pageUrl}.';
+  return '$lead ($noDate). ${named.join('. ')}. ${quotation.pageUrl}.';
+}