import { Inject, Service } from '@tsed/di';

import axios from 'axios';
import { addHours } from 'date-fns';

import { REQUEST_TIMEOUT_FOR_PTOG, getSupportedGrowiActionsRegExp } from '@growi/slack';
import { Relation, PermissionSettingsInterface } from '~/entities/relation';
import { RelationRepository } from '~/repositories/relation';

import loggerFactory from '~/utils/logger';

const logger = loggerFactory('slackbot-proxy:services:RelationsService');

type CheckPermissionForInteractionsResults = {
  allowedRelations:Relation[],
  disallowedGrowiUrls:Set<string>,
  commandName:string,
  rejectedResults:PromiseRejectedResult[]
}

type CheckEachRelationResult = {
  allowedRelation:Relation|null,
  disallowedGrowiUrl:string|null,
  eachRelationCommandName:string,
}

@Service()
export class RelationsService {

  @Inject()
  relationRepository: RelationRepository;

  async resetAllExpiredAtCommands(): Promise<void> {
    await this.relationRepository.update({}, { expiredAtCommands: new Date('2000-01-01') });
  }

  private async getSupportedGrowiCommands(relation:Relation):Promise<any> {
    // generate API URL
    const url = new URL('/_api/v3/slack-integration/supported-commands', relation.growiUri);
    return axios.get(url.toString(), {
      headers: {
        'x-growi-ptog-tokens': relation.tokenPtoG,
      },
      timeout: REQUEST_TIMEOUT_FOR_PTOG,
    });
  }

  private async syncSupportedGrowiCommands(relation:Relation): Promise<Relation> {
    const res = await this.getSupportedGrowiCommands(relation);
    const { permissionsForBroadcastUseCommands, permissionsForSingleUseCommands } = res.data.data;
    if (relation !== null) {
      relation.permissionsForBroadcastUseCommands = permissionsForBroadcastUseCommands;
      relation.permissionsForSingleUseCommands = permissionsForSingleUseCommands;
      relation.expiredAtCommands = addHours(new Date(), 48);
      return this.relationRepository.save(relation);
    }
    throw Error('No relation exists.');
  }

  private async syncRelation(relation: Relation): Promise<Relation> {
    // TODO use assert (relation != null)

    const isDataNull = relation.permissionsForBroadcastUseCommands == null || relation.permissionsForBroadcastUseCommands == null;
    const distanceMillisecondsToExpiredAt = relation.getDistanceInMillisecondsToExpiredAt(new Date());
    const isExpired = distanceMillisecondsToExpiredAt < 0;

    if (isDataNull || isExpired) {
      return this.syncSupportedGrowiCommands(relation);
    }

    // 24 hours
    const isLimitUnder24Hours = distanceMillisecondsToExpiredAt < 24 * 60 * 60 * 1000;
    if (isLimitUnder24Hours) {
      this.syncSupportedGrowiCommands(relation);
    }
    return relation;
  }

  private isPermitted(permissionSettings: PermissionSettingsInterface, growiCommandType: string, channelName: string): boolean {
    // TODO assert (permissionSettings != null)

    const permissionForCommand = permissionSettings[growiCommandType];

    if (permissionForCommand == null) {
      return false;
    }

    if (Array.isArray(permissionForCommand)) {
      return permissionForCommand.includes(channelName);
    }

    return permissionForCommand;
  }

  async isPermissionsForSingleUseCommands(relation: Relation, growiCommandType: string, channelName: string): Promise<boolean> {
    // TODO assert (relation != null)
    if (relation == null) {
      return false;
    }

    let relationToEval = relation;

    try {
      relationToEval = await this.syncRelation(relation);
    }
    catch (err) {
      logger.error('failed to sync', err);
      return false;
    }

    // TODO assert (relationToEval.permissionsForSingleUseCommands != null) because syncRelation success

    return this.isPermitted(relationToEval.permissionsForSingleUseCommands, growiCommandType, channelName);
  }

  async isPermissionsUseBroadcastCommands(relation: Relation, growiCommandType: string, channelName: string):Promise<boolean> {
    // TODO assert (relation != null)
    if (relation == null) {
      return false;
    }

    let relationToEval = relation;

    try {
      relationToEval = await this.syncRelation(relation);
    }
    catch (err) {
      logger.error('failed to sync', err);
      return false;
    }

    // TODO assert (relationToEval.permissionsForSingleUseCommands != null) because syncRelation success

    return this.isPermitted(relationToEval.permissionsForBroadcastUseCommands, growiCommandType, channelName);
  }

  async checkPermissionForInteractions(
      relations:Relation[], actionId:string, callbackId:string, channelName:string,
  ):Promise<CheckPermissionForInteractionsResults> {

    const allowedRelations:Relation[] = [];
    const disallowedGrowiUrls:Set<string> = new Set();
    let commandName = '';

    const results = await Promise.allSettled(relations.map((relation) => {
      const relationResult = this.checkEachRelation(relation, actionId, callbackId, channelName);
      const { allowedRelation, disallowedGrowiUrl, eachRelationCommandName } = relationResult;

      if (allowedRelation != null) {
        allowedRelations.push(allowedRelation);
      }
      if (disallowedGrowiUrl != null) {
        disallowedGrowiUrls.add(disallowedGrowiUrl);
      }
      commandName = eachRelationCommandName;
      return relationResult;
    }));

    // Pick up only a relation which status is "rejected" in results. Like bellow
    const rejectedResults: PromiseRejectedResult[] = results.filter((result): result is PromiseRejectedResult => result.status === 'rejected');

    return {
      allowedRelations, disallowedGrowiUrls, commandName, rejectedResults,
    };
  }

  checkEachRelation(relation:Relation, actionId:string, callbackId:string, channelName:string):CheckEachRelationResult {

    let allowedRelation:Relation|null = null;
    let disallowedGrowiUrl:string|null = null;
    let eachRelationCommandName = '';

    let permissionForInteractions:boolean|string[];
    const singleUse = Object.keys(relation.permissionsForSingleUseCommands);
    const broadCastUse = Object.keys(relation.permissionsForBroadcastUseCommands);

    [...singleUse, ...broadCastUse].forEach(async(tempCommandName) => {

      // ex. search OR search:handlerName
      const commandRegExp = getSupportedGrowiActionsRegExp(tempCommandName);
      // skip this forEach loop if the requested command is not in permissionsForBroadcastUseCommands and permissionsForSingleUseCommands
      if (!commandRegExp.test(actionId) && !commandRegExp.test(callbackId)) {
        return;
      }

      eachRelationCommandName = tempCommandName;

      // case: singleUse
      permissionForInteractions = relation.permissionsForSingleUseCommands[tempCommandName];
      // case: broadcastUse
      if (permissionForInteractions == null) {
        permissionForInteractions = relation.permissionsForBroadcastUseCommands[tempCommandName];
      }

      if (permissionForInteractions === true) {
        allowedRelation = relation;
        return;
      }

      // check permission at channel level
      if (Array.isArray(permissionForInteractions) && permissionForInteractions.includes(channelName)) {
        allowedRelation = relation;
        return;
      }

      disallowedGrowiUrl = relation.growiUri;
    });

    return { allowedRelation, disallowedGrowiUrl, eachRelationCommandName };
  }

}