import 'dart:async';
import 'dart:convert';
import 'dart:ui' as ui;
import 'dart:typed_data';

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

import '../animated_avatar.dart';
import '../community/community_provider.dart';
import '../emoji/emoji_avatar.dart';
import '../emoji/native_emoji_glyph.dart';
import '../push/push_presentation_cache.dart';
import '../relay/relay.dart';

part 'avatar_image_native.dart';

/// An avatar that supports both remote URLs and inline image data.
///
/// Flutter's [NetworkImage] only loads network URLs, while desktop browsers also
/// accept `data:image/*` sources directly. Agent emoji avatars are inline SVGs,
/// so mobile must decode those before rendering them.
class AvatarImage extends StatelessWidget {
  final String? imageUrl;
  final double radius;
  final Color? backgroundColor;
  final Widget fallback;
  final bool isAgent;

  const AvatarImage({
    super.key,
    required this.imageUrl,
    required this.radius,
    required this.fallback,
    this.backgroundColor,
    this.isAgent = false,
  });

  @override
  Widget build(BuildContext context) {
    final animatedAvatar = parseAnimatedAvatarUrl(imageUrl);
    final color = animatedAvatar == null ? backgroundColor : Colors.transparent;
    final content = SizedBox.square(
      dimension: radius * 2,
      child: AvatarImageContent(
        imageUrl: animatedAvatar?.posterUrl ?? imageUrl,
        fallback: fallback,
      ),
    );
    if (!isAgent) {
      return CircleAvatar(
        radius: radius,
        backgroundColor: color,
        child: ClipOval(child: content),
      );
    }

    final borderRadius = BorderRadius.circular(radius * 0.6);
    return DecoratedBox(
      decoration: BoxDecoration(color: color, borderRadius: borderRadius),
      child: ClipRRect(borderRadius: borderRadius, child: content),
    );
  }
}

/// Image content for avatar surfaces whose shape is supplied by their parent.
class AvatarImageContent extends ConsumerStatefulWidget {
  final String? imageUrl;
  final Widget fallback;
  final BoxFit fit;

  const AvatarImageContent({
    super.key,
    required this.imageUrl,
    required this.fallback,
    this.fit = BoxFit.cover,
  });

  @override
  ConsumerState<AvatarImageContent> createState() => _AvatarImageContentState();
}

class _AvatarImageContentState extends ConsumerState<AvatarImageContent> {
  late _AvatarSource? _source = _AvatarSource.parse(widget.imageUrl);
  String? _scheduledPushAvatar;

  @override
  void didUpdateWidget(AvatarImageContent oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.imageUrl != oldWidget.imageUrl) {
      _source = _AvatarSource.parse(widget.imageUrl);
    }
  }

  @override
  Widget build(BuildContext context) {
    final centeredFallback = Center(child: widget.fallback);
    final communityID = ref.watch(activeCommunityProvider).value?.id;

    return switch (_source) {
      _EmojiAvatarSource(:final emoji, :final color) => ColoredBox(
        color: color,
        child: LayoutBuilder(
          builder: (_, constraints) {
            final glyphSize = constraints.biggest.shortestSide * 258 / 512;
            return Center(
              child: NativeEmojiGlyph(
                emoji: emoji,
                size: glyphSize,
                opticalBoxSize: glyphSize,
              ),
            );
          },
        ),
      ),
      _SvgAvatarSource(:final svg) => SvgPicture.string(
        svg,
        fit: widget.fit,
        placeholderBuilder: (_) => centeredFallback,
        errorBuilder: (_, _, _) => centeredFallback,
      ),
      _RasterDataAvatarSource(:final bytes) => _rasterImage(
        communityID: communityID,
        sourceURL: widget.imageUrl,
        bytes: bytes,
        fallback: centeredFallback,
      ),
      _NetworkAvatarSource(:final url) => MediaImage(
        url: url,
        fit: widget.fit,
        onBytesLoaded: communityID == null
            ? null
            : (bytes) => unawaited(
                cacheBuzzPushAvatarFromLoadedBytes(communityID, url, bytes),
              ),
        errorBuilder: (_, _, _) => centeredFallback,
      ),
      null => centeredFallback,
    };
  }

  Widget _rasterImage({
    required String? communityID,
    required String? sourceURL,
    required Uint8List bytes,
    required Widget fallback,
  }) {
    if (communityID != null && sourceURL != null) {
      final identity = '$communityID\u0000$sourceURL';
      if (_scheduledPushAvatar != identity) {
        _scheduledPushAvatar = identity;
        WidgetsBinding.instance.addPostFrameCallback((_) {
          if (!mounted || _scheduledPushAvatar != identity) return;
          unawaited(
            cacheBuzzPushAvatarFromLoadedBytes(communityID, sourceURL, bytes),
          );
        });
      }
    }
    return Image.memory(
      bytes,
      fit: widget.fit,
      errorBuilder: (_, _, _) => fallback,
    );
  }
}

sealed class _AvatarSource {
  const _AvatarSource();

  static _AvatarSource? parse(String? value) {
    final url = value?.trim();
    if (url == null || url.isEmpty) return null;
    if (!url.startsWith('data:image/')) return _NetworkAvatarSource(url);

    try {
      final data = UriData.parse(url);
      if (data.mimeType == 'image/svg+xml') {
        final Uint8List bytes = data.contentAsBytes();
        final svg = utf8.decode(bytes);
        final emojiAvatar = parseEmojiAvatarSvg(svg);
        return emojiAvatar == null
            ? _SvgAvatarSource(svg)
            : _EmojiAvatarSource(
                emojiAvatar.emoji,
                Color(emojiAvatar.colorValue),
              );
      }
      return _RasterDataAvatarSource(data.contentAsBytes());
    } on FormatException {
      return null;
    }
  }
}

class _EmojiAvatarSource extends _AvatarSource {
  final String emoji;
  final Color color;
  const _EmojiAvatarSource(this.emoji, this.color);
}

class _SvgAvatarSource extends _AvatarSource {
  final String svg;
  const _SvgAvatarSource(this.svg);
}

class _RasterDataAvatarSource extends _AvatarSource {
  final Uint8List bytes;
  const _RasterDataAvatarSource(this.bytes);
}

class _NetworkAvatarSource extends _AvatarSource {
  final String url;
  const _NetworkAvatarSource(this.url);
}