import 'package:flutter/material.dart';
import 'package:flutter_hooks/flutter_hooks.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';

import '../../shared/identity_names/identity_names.dart';
import '../../shared/identity_names/identity_names_provider.dart';
import '../../shared/mentions/mention_tags.dart';
import '../../shared/theme/theme.dart';
import '../../shared/widgets/avatar_image.dart';
import '../../shared/widgets/buzz_loading_indicator.dart';
import '../../shared/widgets/frosted_app_bar.dart';
import '../../shared/widgets/frosted_scaffold.dart';
import '../channels/message_content.dart';
import '../profile/profile_provider.dart';
import '../../shared/profile/user_cache_provider.dart';
import 'note_card.dart';
import 'pulse_actions.dart';
import 'pulse_models.dart';

/// Full-screen page for composing a new note or replying to one.
///
/// When [replyTo] is null this composes a new top-level note; when set the
/// page shows the note being replied to as context and the action button
/// reads "Reply". The text field auto-focuses on open so the keyboard is
/// ready immediately.
class ComposeNotePage extends HookConsumerWidget {
  final UserNote? replyTo;

  /// The comparison context of the surface that opened the reply, so the
  /// reply context names people as they were shown there. Its labels are
  /// resolved against live naming facts while this page is open.
  final IdentityNames? names;

  const ComposeNotePage({super.key, this.replyTo, this.names});

  bool get _isReply => replyTo != null;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final controller = useTextEditingController();
    final focusNode = useFocusNode();
    final isSending = useState(false);
    final hasText = useListenableSelector(
      controller,
      () => controller.text.trim().isNotEmpty,
    );
    final profile = ref.watch(profileProvider).asData?.value;

    // Auto-focus the field once the page has mounted.
    useEffect(() {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        focusNode.requestFocus();
      });
      return null;
    }, const []);

    Future<void> submit() async {
      if (!hasText || isSending.value) return;
      isSending.value = true;
      try {
        await publishNote(ref, content: controller.text, replyTo: replyTo);
        if (context.mounted) Navigator.of(context).pop(true);
      } catch (_) {
        // Keep the page open so the draft isn't lost; re-enable the button.
        isSending.value = false;
        rethrow;
      }
    }

    return FrostedScaffold(
      resizeToAvoidBottomInset: true,
      appBar: FrostedAppBar(
        nativeTitle: _isReply ? 'Reply' : 'New note',
        nativeActions: [
          IosNavigationAction(
            label: isSending.value
                ? 'Sending…'
                : _isReply
                ? 'Reply'
                : 'Post',
            onPressed: hasText && !isSending.value ? submit : null,
          ),
        ],
        leading: TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: Grid.xxs),
            child: FilledButton(
              onPressed: hasText && !isSending.value ? submit : null,
              style: FilledButton.styleFrom(
                padding: const EdgeInsets.symmetric(horizontal: Grid.gutter),
                minimumSize: const Size(0, 36),
                shape: const StadiumBorder(),
              ),
              child: isSending.value
                  ? SizedBox(
                      width: 16,
                      height: 16,
                      child: BuzzLoadingIndicator(
                        size: 16,
                        semanticLabel: _isReply
                            ? 'Sending reply'
                            : 'Publishing post',
                      ),
                    )
                  : Text(_isReply ? 'Reply' : 'Post'),
            ),
          ),
        ],
      ),
      body: SafeArea(
        top: false,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            SizedBox(height: frostedAppBarHeight(context)),
            if (_isReply) _ReplyContext(note: replyTo!, names: names),
            Expanded(
              child: SingleChildScrollView(
                padding: const EdgeInsets.all(Grid.xs),
                child: Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    AvatarImage(
                      imageUrl: profile?.avatarUrl,
                      radius: 18,
                      backgroundColor: context.colors.primaryContainer,
                      fallback: Text(
                        profile?.initial ?? '?',
                        style: context.textTheme.labelMedium?.copyWith(
                          color: context.colors.onPrimaryContainer,
                        ),
                      ),
                    ),
                    const SizedBox(width: Grid.xxs),
                    Expanded(
                      child: TextField(
                        controller: controller,
                        focusNode: focusNode,
                        minLines: 3,
                        maxLines: null,
                        autofocus: true,
                        keyboardType: TextInputType.multiline,
                        textInputAction: TextInputAction.newline,
                        style: context.textTheme.bodyLarge,
                        decoration: InputDecoration(
                          hintText: _isReply
                              ? 'Post your reply'
                              : 'What’s on your mind?',
                          border: InputBorder.none,
                          enabledBorder: InputBorder.none,
                          focusedBorder: InputBorder.none,
                          isDense: true,
                          contentPadding: const EdgeInsets.symmetric(
                            vertical: Grid.half,
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

/// A read-only preview of the note being replied to, laid out like a list
/// row (avatar + name + time + content) but non-interactive. Capped in
/// height so a long note doesn't push the editor off-screen.
class _ReplyContext extends ConsumerWidget {
  final UserNote note;
  final IdentityNames? names;

  const _ReplyContext({required this.note, this.names});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final pubkey = note.pubkey.toLowerCase();
    final profile =
        ref.watch(userCacheProvider.select((cache) => cache[pubkey])) ??
        ref.read(userCacheProvider.notifier).get(pubkey);
    final mentionPubkeys = mentionedPubkeysFromTags(note.tags);
    final labels =
        names?.withSources(ref.watch(identityNameSourcesProvider)) ??
        watchIdentityNames(ref, {pubkey, ...mentionPubkeys});
    final displayName = labels.labelFor(pubkey);

    return Padding(
      padding: const EdgeInsets.fromLTRB(Grid.gutter, Grid.xs, Grid.gutter, 0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            'Replying to $displayName',
            style: context.textTheme.labelMedium?.copyWith(
              color: context.colors.onSurfaceVariant,
            ),
          ),
          const SizedBox(height: Grid.xs),
          // Mirror the NoteCard list-row layout, read-only. Shrink-wraps to
          // the content; long notes are capped to ~3 lines via the parent
          // page scroll + ellipsis on the content.
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              AvatarImage(
                imageUrl: profile?.avatarUrl,
                radius: 18,
                backgroundColor: context.colors.primaryContainer,
                fallback: Text(
                  // Name-derived when the profile is cached; keyed to the
                  // hex public key when it isn't, so the compact-npub
                  // fallback label doesn't render `N` for every unnamed
                  // author.
                  profile?.initial ??
                      (pubkey.isNotEmpty ? pubkey[0].toUpperCase() : '?'),
                  style: context.textTheme.labelMedium?.copyWith(
                    color: context.colors.onPrimaryContainer,
                  ),
                ),
              ),
              const SizedBox(width: Grid.xs),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Row(
                      children: [
                        Expanded(
                          child: Text(
                            displayName,
                            maxLines: 1,
                            style: messageUsernameTextStyle,
                            overflow: TextOverflow.ellipsis,
                          ),
                        ),
                        const SizedBox(width: Grid.half),
                        ConstrainedBox(
                          constraints: const BoxConstraints(maxWidth: Grid.xxl),
                          child: Text(
                            formatPulseRelativeTime(note.createdAt),
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                            style: messageTimestampTextStyle.copyWith(
                              color: context.colors.onSurfaceVariant,
                            ),
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: Grid.half),
                    // Rich content (images, links, mentions) like the list
                    // row, but clipped to a compact max height so a tall
                    // image or long note can't blow up the page.
                    ConstrainedBox(
                      constraints: const BoxConstraints(maxHeight: 132),
                      child: ClipRect(
                        child: Align(
                          alignment: Alignment.topLeft,
                          heightFactor: 1,
                          child: MessageContent(
                            content: note.content,
                            mentionLabels: {
                              for (final key in mentionPubkeys)
                                key: labels.labelFor(key),
                            },
                            tags: note.tags,
                            baseStyle: messageBodyTextStyle.copyWith(
                              color: context.colors.onSurface,
                            ),
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
          const SizedBox(height: Grid.xs),
          Divider(
            height: 1,
            color: context.colors.outlineVariant.withValues(alpha: 0.5),
          ),
        ],
      ),
    );
  }
}