import 'package:easy_localization/easy_localization.dart';
import 'package:flutter/material.dart';
import 'package:html/parser.dart';
import 'package:http/http.dart';
import 'package:obtainium/components/generated_form.dart';
import 'package:obtainium/custom_errors.dart';
import 'package:obtainium/providers/source_provider.dart';

String ensureAbsoluteUrl(String ambiguousUrl, Uri referenceAbsoluteUrl) {
  try {
    Uri.parse(ambiguousUrl).origin;
    return ambiguousUrl;
  } catch (err) {
    // is relative
  }
  var currPathSegments = referenceAbsoluteUrl.path
      .split('/')
      .where((element) => element.trim().isNotEmpty)
      .toList();
  if (ambiguousUrl.startsWith('/') || currPathSegments.isEmpty) {
    return '${referenceAbsoluteUrl.origin}/$ambiguousUrl';
  } else if (ambiguousUrl.split('/').where((e) => e.isNotEmpty).length == 1) {
    return '${referenceAbsoluteUrl.origin}/${currPathSegments.join('/')}/$ambiguousUrl';
  } else {
    return '${referenceAbsoluteUrl.origin}/${currPathSegments.sublist(0, currPathSegments.length - 1).join('/')}/$ambiguousUrl';
  }
}

int compareAlphaNumeric(String a, String b) {
  List<String> aParts = _splitAlphaNumeric(a);
  List<String> bParts = _splitAlphaNumeric(b);

  for (int i = 0; i < aParts.length && i < bParts.length; i++) {
    String aPart = aParts[i];
    String bPart = bParts[i];

    bool aIsNumber = _isNumeric(aPart);
    bool bIsNumber = _isNumeric(bPart);

    if (aIsNumber && bIsNumber) {
      int aNumber = int.parse(aPart);
      int bNumber = int.parse(bPart);
      int cmp = aNumber.compareTo(bNumber);
      if (cmp != 0) {
        return cmp;
      }
    } else if (!aIsNumber && !bIsNumber) {
      int cmp = aPart.compareTo(bPart);
      if (cmp != 0) {
        return cmp;
      }
    } else {
      // Alphanumeric strings come before numeric strings
      return aIsNumber ? 1 : -1;
    }
  }

  return aParts.length.compareTo(bParts.length);
}

List<String> _splitAlphaNumeric(String s) {
  List<String> parts = [];
  StringBuffer sb = StringBuffer();

  bool isNumeric = _isNumeric(s[0]);
  sb.write(s[0]);

  for (int i = 1; i < s.length; i++) {
    bool currentIsNumeric = _isNumeric(s[i]);
    if (currentIsNumeric == isNumeric) {
      sb.write(s[i]);
    } else {
      parts.add(sb.toString());
      sb.clear();
      sb.write(s[i]);
      isNumeric = currentIsNumeric;
    }
  }

  parts.add(sb.toString());

  return parts;
}

bool _isNumeric(String s) {
  return s.codeUnitAt(0) >= 48 && s.codeUnitAt(0) <= 57;
}

class HTML extends AppSource {
  HTML() {
    additionalSourceAppSpecificSettingFormItems = [
      [
        GeneratedFormSwitch('sortByFileNamesNotLinks',
            label: tr('sortByFileNamesNotLinks'))
      ],
      [
        GeneratedFormTextField('customLinkFilterRegex',
            label: tr('customLinkFilterRegex'),
            hint: 'download/(.*/)?(android|apk|mobile)',
            required: false,
            additionalValidators: [
              (value) {
                return regExValidator(value);
              }
            ])
      ],
      [
        GeneratedFormTextField('intermediateLinkRegex',
            label: tr('intermediateLinkRegex'),
            hint: '([0-9]+\.)*[0-9]+/\$',
            required: false,
            additionalValidators: [(value) => regExValidator(value)])
      ],
      [
        GeneratedFormTextField('versionExtractionRegEx',
            label: tr('versionExtractionRegEx'),
            required: false,
            additionalValidators: [(value) => regExValidator(value)]),
        GeneratedFormTextField('matchGroupToUse',
            label: tr('matchGroupToUse'),
            required: false,
            hint: '1',
            textInputType: const TextInputType.numberWithOptions(),
            additionalValidators: [
              (value) {
                value ??= '1';
                if (int.tryParse(value) == null) {
                  return tr('invalidInput');
                }
                return null;
              }
            ])
      ]
    ];
    overrideVersionDetectionFormDefault('noVersionDetection',
        disableStandard: true, disableRelDate: true);
  }

  @override
  Future<Map<String, String>?> getRequestHeaders(
      {Map<String, dynamic> additionalSettings = const <String, dynamic>{},
      bool forAPKDownload = false}) async {
    return {
      "User-Agent":
          "Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Mobile Safari/537.36"
    };
  }

  @override
  String sourceSpecificStandardizeURL(String url) {
    return url;
  }

  @override
  Future<APKDetails> getLatestAPKDetails(
    String standardUrl,
    Map<String, dynamic> additionalSettings,
  ) async {
    var uri = Uri.parse(standardUrl);
    Response res = await sourceRequest(standardUrl);
    if (res.statusCode == 200) {
      var html = parse(res.body);
      List<String> allLinks = html
          .querySelectorAll('a')
          .map((element) => element.attributes['href'] ?? '')
          .toList();
      List<String> links = [];
      if ((additionalSettings['intermediateLinkRegex'] as String?)
              ?.isNotEmpty ==
          true) {
        var reg = RegExp(additionalSettings['intermediateLinkRegex']);
        links = allLinks.where((element) => reg.hasMatch(element)).toList();
        links.sort((a, b) => compareAlphaNumeric(a, b));
        if (links.isEmpty) {
          throw ObtainiumError(tr('intermediateLinkNotFound'));
        }
        Map<String, dynamic> additionalSettingsTemp =
            Map.from(additionalSettings);
        additionalSettingsTemp['intermediateLinkRegex'] = null;
        return getLatestAPKDetails(
            ensureAbsoluteUrl(links.last, uri), additionalSettingsTemp);
      }
      if ((additionalSettings['customLinkFilterRegex'] as String?)
              ?.isNotEmpty ==
          true) {
        var reg = RegExp(additionalSettings['customLinkFilterRegex']);
        links = allLinks.where((element) => reg.hasMatch(element)).toList();
      } else {
        links = allLinks
            .where((element) =>
                Uri.parse(element).path.toLowerCase().endsWith('.apk'))
            .toList();
      }
      links.sort((a, b) => additionalSettings['sortByFileNamesNotLinks'] == true
          ? compareAlphaNumeric(a.split('/').where((e) => e.isNotEmpty).last,
              b.split('/').where((e) => e.isNotEmpty).last)
          : compareAlphaNumeric(a, b));
      if ((additionalSettings['apkFilterRegEx'] as String?)?.isNotEmpty ==
          true) {
        var reg = RegExp(additionalSettings['apkFilterRegEx']);
        links = links.where((element) => reg.hasMatch(element)).toList();
      }
      if (links.isEmpty) {
        throw NoReleasesError();
      }
      var rel = links.last;
      String? version = rel.hashCode.toString();
      var versionExtractionRegEx =
          additionalSettings['versionExtractionRegEx'] as String?;
      if (versionExtractionRegEx?.isNotEmpty == true) {
        var match = RegExp(versionExtractionRegEx!).allMatches(rel);
        if (match.isEmpty) {
          throw NoVersionError();
        }
        version = match.last
            .group(int.parse(additionalSettings['matchGroupToUse'] as String));
        if (version?.isEmpty == true) {
          throw NoVersionError();
        }
      }
      List<String> apkUrls =
          [rel].map((e) => ensureAbsoluteUrl(e, uri)).toList();
      return APKDetails(version!, apkUrls.map((e) => MapEntry(e, e)).toList(),
          AppNames(uri.host, tr('app')));
    } else {
      throw getObtainiumHttpError(res);
    }
  }
}