// @dart=2.9

/*
Copyright 2020-2021 Vishesh Handa <me@vhanda.in>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import 'dart:convert';

import 'package:flutter_emoji/flutter_emoji.dart';
import 'package:yaml/yaml.dart';

import 'package:gitjournal/core/notes_folder.dart';
import 'package:gitjournal/settings.dart';
import 'package:gitjournal/utils/datetime.dart';
import 'package:gitjournal/utils/logger.dart';
import 'md_yaml_doc.dart';
import 'note.dart';

abstract class NoteSerializerInterface {
  void encode(Note note, MdYamlDoc data);
  void decode(MdYamlDoc data, Note note);
}

var emojiParser = EmojiParser();

class NoteSerializationSettings {
  String modifiedKey = "modified";
  String createdKey = "created";
  String titleKey = "title";
  String typeKey = "type";
  String tagsKey = "tags";

  bool tagsInString = false;
  bool tagsHaveHash = false;

  SettingsTitle titleSettings = SettingsTitle.Default;
}

class NoteSerializer implements NoteSerializerInterface {
  var settings = NoteSerializationSettings();

  NoteSerializer.fromConfig(NotesFolderConfig config) {
    settings.modifiedKey = config.yamlModifiedKey;
    settings.createdKey = config.yamlCreatedKey;
    settings.tagsKey = config.yamlTagsKey;
    settings.titleSettings = config.titleSettings;
  }

  NoteSerializer.raw();

  @override
  void encode(Note note, MdYamlDoc data) {
    data.body = emojiParser.unemojify(note.body);

    if (note.created != null) {
      data.props[settings.createdKey] = toIso8601WithTimezone(note.created);
    } else {
      data.props.remove(settings.createdKey);
    }

    if (note.modified != null) {
      data.props[settings.modifiedKey] = toIso8601WithTimezone(note.modified);
    } else {
      data.props.remove(settings.modifiedKey);
    }

    if (note.title != null) {
      var title = emojiParser.unemojify(note.title.trim());
      if (settings.titleSettings == SettingsTitle.InH1) {
        if (title.isNotEmpty) {
          data.body = '# $title\n\n${data.body}';
          data.props.remove(settings.titleKey);
        }
      } else {
        if (title.isNotEmpty) {
          data.props[settings.titleKey] = title;
        } else {
          data.props.remove(settings.titleKey);
        }
      }
    } else {
      data.props.remove(settings.titleKey);
    }

    if (note.type != NoteType.Unknown) {
      var type = note.type.toString().substring(9); // Remove "NoteType."
      data.props[settings.typeKey] = type;
    } else {
      data.props.remove(settings.typeKey);
    }

    if (note.tags.isEmpty) {
      data.props.remove(settings.tagsKey);
    } else {
      data.props[settings.tagsKey] = note.tags.toList();
      if (settings.tagsInString) {
        var tags = note.tags;
        if (settings.tagsHaveHash) {
          tags = tags.map((e) => '#$e').toSet();
        }
        data.props[settings.tagsKey] = tags.join(' ');
      }
    }

    note.extraProps.forEach((key, value) {
      data.props[key] = value;
    });
  }

  @override
  void decode(MdYamlDoc data, Note note) {
    var propsUsed = <String>{};

    var modifiedKeyOptions = [
      "modified",
      "mod",
      "lastModified",
      "lastMod",
      "lastmodified",
      "lastmod",
    ];
    for (var possibleKey in modifiedKeyOptions) {
      var val = data.props[possibleKey];
      if (val != null) {
        note.modified = parseDateTime(val.toString());
        settings.modifiedKey = possibleKey;

        propsUsed.add(possibleKey);
        break;
      }
    }

    note.body = emojiParser.emojify(data.body);

    var createdKeyOptions = [
      "created",
      "date",
    ];
    for (var possibleKey in createdKeyOptions) {
      var val = data.props[possibleKey];
      if (val != null) {
        note.created = parseDateTime(val.toString());
        settings.createdKey = possibleKey;

        propsUsed.add(possibleKey);
        break;
      }
    }

    //
    // Title parsing
    //
    if (data.props.containsKey(settings.titleKey)) {
      var title = data.props[settings.titleKey]?.toString() ?? "";
      note.title = emojiParser.emojify(title);

      propsUsed.add(settings.titleKey);
      settings.titleSettings = SettingsTitle.InYaml;
    } else {
      var startsWithH1 = false;
      for (var line in LineSplitter.split(note.body)) {
        if (line.trim().isEmpty) {
          continue;
        }
        startsWithH1 = line.startsWith('#');
        break;
      }

      if (startsWithH1) {
        var titleStartIndex = note.body.indexOf('#');
        var titleEndIndex = note.body.indexOf('\n', titleStartIndex);
        if (titleEndIndex == -1 || titleEndIndex == note.body.length) {
          note.title = note.body.substring(titleStartIndex + 1).trim();
          note.body = "";
        } else {
          note.title =
              note.body.substring(titleStartIndex + 1, titleEndIndex).trim();
          note.body = note.body.substring(titleEndIndex + 1).trim();
        }
      }
    }

    var type = data.props[settings.typeKey];
    switch (type) {
      case "Checklist":
        note.type = NoteType.Checklist;
        break;
      case "Journal":
        note.type = NoteType.Journal;
        break;
      default:
        note.type = NoteType.Unknown;
        break;
    }
    if (type != null) {
      propsUsed.add(settings.typeKey);
    }

    try {
      var tagKeyOptions = [
        "tags",
        "categories",
        "keywords",
      ];
      for (var possibleKey in tagKeyOptions) {
        var tags = data.props[possibleKey];
        if (tags != null) {
          if (tags is YamlList) {
            note.tags = tags.map((t) => t.toString()).toSet();
          } else if (tags is List) {
            note.tags = tags.map((t) => t.toString()).toSet();
          } else if (tags is String) {
            settings.tagsInString = true;
            var allTags = tags.split(' ');
            settings.tagsHaveHash = allTags.every((t) => t.startsWith('#'));
            if (settings.tagsHaveHash) {
              allTags.removeWhere((e) => e.length <= 1);
              allTags = allTags.map((e) => e.substring(1)).toList();
            }

            note.tags = allTags.toSet();
          } else {
            Log.e("Note Tags Decoding Failed: $tags");
          }

          settings.tagsKey = possibleKey;
          propsUsed.add(settings.tagsKey);
          break;
        }
      }
    } catch (e) {
      Log.e("Note Decoding Failed: $e");
    }

    // Extra Props
    note.extraProps = {};
    data.props.forEach((key, val) {
      if (propsUsed.contains(key)) {
        return;
      }

      note.extraProps[key] = val;
    });
  }
}