import 'dart:async';

import 'package:aves/model/image_entry.dart';
import 'package:aves/model/metadata_service.dart';
import 'package:aves/widgets/fullscreen/info/info_page.dart';
import 'package:flutter/material.dart';

class MetadataSection extends StatefulWidget {
  final ImageEntry entry;

  const MetadataSection({this.entry});

  @override
  State<StatefulWidget> createState() => MetadataSectionState();
}

class MetadataSectionState extends State<MetadataSection> {
  Future<Map> _metadataLoader;

  static const int maxValueLength = 140;

  @override
  void initState() {
    super.initState();
    initMetadataLoader();
  }

  @override
  void didUpdateWidget(MetadataSection oldWidget) {
    super.didUpdateWidget(oldWidget);
    initMetadataLoader();
  }

  initMetadataLoader() async {
    _metadataLoader = MetadataService.getAllMetadata(widget.entry);
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _metadataLoader,
      builder: (futureContext, AsyncSnapshot<Map> snapshot) {
        if (snapshot.hasError) return Text(snapshot.error);
        if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
        final metadataMap = snapshot.data.cast<String, Map>();
        final directoryNames = metadataMap.keys.toList()..sort();

        Widget content;
        if (MediaQuery.of(context).size.width > 400) {
          final threshold = (2 * directoryNames.length + directoryNames.map((k) => metadataMap[k].length).reduce((v, e) => v + e)) / 2;
          final first = <String>[], second = <String>[];
          var processed = 0;
          for (int i = 0; i < directoryNames.length; i++) {
            final directoryName = directoryNames[i];
            if (processed <= threshold)
              first.add(directoryName);
            else
              second.add(directoryName);
            processed += 2 + metadataMap[directoryName].length;
          }
          content = Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(child: getMetadataColumn(metadataMap, first)),
              SizedBox(width: 8),
              Expanded(child: getMetadataColumn(metadataMap, second)),
            ],
          );
        } else {
          content = getMetadataColumn(metadataMap, directoryNames);
        }

        return Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            SectionRow('Metadata'),
            content,
          ],
        );
      },
    );
  }

  Widget getMetadataColumn(Map<String, Map> metadataMap, List<String> directoryNames) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        ...directoryNames.expand((directoryName) {
          final directory = metadataMap[directoryName];
          final tagKeys = directory.keys.toList()..sort();
          return [
            if (directoryName.isNotEmpty)
              Padding(
                padding: EdgeInsets.symmetric(vertical: 4.0),
                child: Text(directoryName,
                    style: TextStyle(
                      fontSize: 18,
                      fontFamily: 'Concourse Caps',
                    )),
              ),
            ...tagKeys.map((tagKey) {
              final value = directory[tagKey] as String;
              if (value == null || value.isEmpty) return SizedBox.shrink();
              return InfoRow(tagKey, value.length > maxValueLength ? '${value.substring(0, maxValueLength)}…' : value);
            }),
            SizedBox(height: 16),
          ];
        }),
      ],
    );
  }
}