import 'dart:convert';
import 'package:dio/dio.dart';
import 'package:isekai_wiki/api/base_api.dart';
import 'package:isekai_wiki/api/response/csrf_token.dart';

import 'package:isekai_wiki/global.dart';
import 'package:json_annotation/json_annotation.dart';

part 'mw_api.g.dart';

@JsonSerializable()
class MWApiErrorException implements Exception {
  String code;

  String? info;

  @JsonKey(name: "docref")
  String? detail;

  MWApiErrorException({required this.code, this.info, this.detail});

  factory MWApiErrorException.fromJson(Map<String, dynamic> json) =>
      _$MWApiErrorExceptionFromJson(json);

  Map<String, dynamic> toJson() => _$MWApiErrorExceptionToJson(this);

  @override
  String toString() {
    return "MediaWiki Api Error: ${info ?? code}";
  }
}

class MWApiEmptyBodyException implements Exception {
  dynamic resData;

  MWApiEmptyBodyException(this.resData);

  @override
  String toString() {
    return "MediaWiki Api Response body is empty";
  }
}

class CannotFetchCSRFTokenException implements Exception {
  String? message;
  CannotFetchCSRFTokenException([this.message]);

  @override
  String toString() {
    if (message != null) {
      return message!;
    } else {
      return "Cannot fetch CSRF token from MediaWiki API";
    }
  }
}

class MWResponse<T> {
  Map<String, String>? warnings;
  T data;
  Map<String, String>? continueInfo;

  MWResponse(this.data, {this.warnings, this.continueInfo});

  MWResponse<N> replaceData<N>(N data) {
    return MWResponse<N>(
      data,
      warnings: warnings,
      continueInfo: continueInfo,
    );
  }
}

class MWApi {
  static Future<MWResponse<Map<String, dynamic>>> get(String action,
      {Map<String, dynamic>? params, bool returnRoot = false}) async {
    Map<String, String> paramsStr =
        params?.map((key, value) => MapEntry(key, value.toString())) ?? {};
    paramsStr.addAll({
      "action": action,
      "format": "json",
      "formatversion": "2",
      "uselang": Global.wikiLang,
    });
    if (Global.webOrigin != null) {
      paramsStr["origin"] = Global.webOrigin!;
    }

    var resText = "";
    try {
      var apiBaseUri = Uri.parse(Global.siteConfig.apiUrl);
      resText = await BaseApi.get(apiBaseUri, search: paramsStr);
    } on DioError catch (err) {
      if (err.type == DioErrorType.response) {
        if (err.response != null) {
          var response = err.response!;
          var contentType = response.headers[Headers.contentTypeHeader];
          if (contentType != null &&
              contentType.contains("application/json") &&
              response.data is String) {
            resText = response.data as String;
          }
        }
      }

      if (resText.isEmpty) {
        // 没有捕获到服务器返回的错误，则抛给上一层
        rethrow;
      }
    }

    return parseMWResponse(action, resText, returnRoot);
  }

  static Future<MWResponse<Map<String, dynamic>>> post<T>(String action,
      {Map<String, dynamic>? params, String? withToken, bool returnRoot = false}) async {
    params ??= {};
    params.addAll({
      "action": action,
      "format": "json",
      "formatversion": 2,
      "uselang": Global.wikiLang,
    });
    if (Global.webOrigin != null) {
      params["origin"] = Global.webOrigin!;
    }

    var resText = "";
    try {
      if (withToken != null) {
        // 获取CSRF Token
        params["token"] = await getToken(type: withToken);
      }

      var apiBaseUri = Uri.parse(Global.siteConfig.apiUrl);

      resText = await BaseApi.post(apiBaseUri, data: params);
    } on DioError catch (err) {
      if (err.type == DioErrorType.response) {
        if (err.response != null) {
          var response = err.response!;
          var contentType = response.headers[Headers.contentTypeHeader];
          if (contentType != null &&
              contentType.contains("application/json") &&
              response.data is String) {
            resText = response.data as String;
          }
        }
      }

      if (resText.isEmpty) {
        // 没有捕获到服务器返回的错误，则抛给上一层
        rethrow;
      }
    }

    return parseMWResponse(action, resText, returnRoot);
  }

  static MWResponse<Map<String, dynamic>> parseMWResponse(
      String action, String resJson, bool returnRoot) {
    var resData = jsonDecode(resJson);
    if (resData is! Map<String, dynamic>) {
      throw MWApiEmptyBodyException(resData);
    }

    // 处理请求错误
    if (resData.containsKey("error")) {
      throw MWApiErrorException.fromJson(resData["error"]!);
    }

    // 请求结果
    MWResponse<Map<String, dynamic>> mwRes;

    if (returnRoot) {
      var filteredResData = <String, dynamic>{}..addAll(resData);
      filteredResData
        ..remove("error")
        ..remove("warnings")
        ..remove("batchcomplete");
      mwRes = MWResponse(filteredResData);
    } else {
      if (!resData.containsKey(action) || resData[action] is! Map<String, dynamic>) {
        throw MWApiEmptyBodyException(resData);
      }
      mwRes = MWResponse(resData[action] as Map<String, dynamic>);
    }

    // warnings
    if (resData.containsKey("warnings") && resData["warnings"] is Map<String, dynamic>) {
      var warnings = resData["warnings"] as Map<String, dynamic>;
      Map<String, String> warningMap = {};
      warnings.forEach((key, value) {
        if (value is Map<String, String> && value.containsKey("*")) {
          var valueStr = value["*"] as String;
          warningMap[key] = valueStr;
        }
      });
      if (warningMap.isNotEmpty) {
        mwRes.warnings = warningMap;
      }
    }

    // continue参数
    var batchcomplete = resData["batchcomplete"];
    if (batchcomplete is bool && batchcomplete) {
      var continueInfo = resData["continue"];
      if (continueInfo is Map<String, dynamic>) {
        mwRes.continueInfo = {};
        continueInfo.forEach((key, value) {
          var keyStr = key;
          mwRes.continueInfo![keyStr] = value.toString();
        });
      }
    }

    return mwRes;
  }

  /// 获取Token，Token可能为空
  static Future<MWResponse<String?>> getTokenRaw({String type = "csrf"}) async {
    var query = {
      "meta": "tokens",
      "type": type,
    };

    var mwRes = await MWApi.get("query", params: query);

    var data = CSRFTokenResponse.fromJson(mwRes.data);
    var tokenKey = "${type}token";
    var token = data.tokens[tokenKey];

    return mwRes.replaceData(token);
  }

  /// 获取Token，并在无法获取时抛出异常
  static Future<String> getToken({String type = "csrf"}) async {
    var tokenRes = await getTokenRaw(type: type);
    if (tokenRes.data == null) {
      if (tokenRes.warnings != null && tokenRes.warnings!.containsKey("tokens")) {
        throw CannotFetchCSRFTokenException(tokenRes.warnings!["tokens"]);
      } else {
        throw CannotFetchCSRFTokenException();
      }
    }
    return tokenRes.data!;
  }
}