// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2018 Georgi Marinov
//
// 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 { Injectable, EventEmitter } from '@angular/core';

import { ModelModel } from '../../model/model/model.model';

import { SearchEngineService } from '../../services/search-engine/search-engine.service';
import { CountCacheService } from '../count-cache/count-cache.service';

import { ProfessionalExperience } from '../../interfaces/cv/professional-experience';
import { Education } from '../../interfaces/cv/education';

import { Accomplishment } from '../../classes/accomplishment/accomplishment';

import { Language } from '../../interfaces/cv/language';
import { Publication } from '../../interfaces/cv/publication';
import { Project } from '../../interfaces/project/project';

/**
 * A filter service.
 */
@Injectable({
  providedIn: 'root'
})
export class FilterService {
  /** Data getter. */
  public get data() {
    return {
      cv: this.model.cv,
      entities: this.model.entities,
      projects: this.model.projects,
      ui: this.model.ui
    };
  }

  /** Search query string expression changed event. */
  public readonly searchTokenChanged$ = new EventEmitter<string>();

  /** Search query string expression setter. */
  public searchTokenChangeHandler() {
    this.model.filtered.Projects = this.calcFilteredProjects();
    // this.model.filtered.Languages = this.data.cv.Languages;
    this.model.filtered.Languages = this.calcFilteredLanguages();
    this.model.filtered.Accomplishments = this.calcFilteredAccomplishments();
    this.model.filtered.Publications = this.calcFilteredPublications();
    this.model.filtered.ProfessionalExperience = this.calcFilteredProfessionalExperience();
    this.model.filtered.Education = this.calcFilteredEducation();
    this.countCacheService.calcCountCache([]);
    this.searchTokenChanged$.emit(this.model.searchToken);
  }

  /** Empty frequency getter delegate. */
  public get emptyFrequency() { return this.getEmptyFrequency(''); }

  /** Empty frequency. */
  public getEmptyFrequency(propertyNameKey: string) {
    return [
      propertyNameKey,
      {
        Count: 1,
        Percentage: 100,
        Lightness: 0,
        Size: 16,
        Weight: 400,
        get Label() { return ''; },
        get ShortLabel() { return ''; }
      }
    ];
  }

  /** Project frequency getter. */
  public projectFrequency(project: Project): any[] {
    const propertyNameKey = 'Project name';
    const propertyName = project[propertyNameKey];
    const frequencies: [string, Record<string, unknown>][] = this.model.frequenciesCache.Project;
    return frequencies?.find((_) => _[0] === propertyName) ?? this.emptyFrequency;
  }

  /**
   * Constructs the Filter service.
   * ~constructor
   *
   * @param dataService The data service injected dependency.
   * @param searchEngineService The search engine service injected dependency.
   * @param countCacheService The count cache service injected dependency.
   * @param model The model injected dependency.
   */
  constructor(
    private readonly searchEngineService: SearchEngineService,
    public readonly countCacheService: CountCacheService,
    private readonly model: ModelModel,
  ) {
  }

  /**
   * Calculates the filtered projects for the current search context.
   *
   * @returns The filtered projects for the current search context.
   */
  private calcFilteredProjects(): Project[] {
    if (typeof this.data.projects === 'undefined') { return []; }

    const retVal = this.calcFiltered<Project>(this.data.projects);

    return retVal;
  }

  /**
   * Calculates the filtered languages for the current search context.
   *
   * @returns The filtered languages for the current search context.
   */
  private calcFilteredLanguages(): Language[] {
    if (typeof this.data.cv === 'undefined') { return []; }
    if (typeof this.data.cv.Languages === 'undefined') { return []; }

    const retVal = this.calcFiltered<Language>(this.data.cv.Languages);

    return retVal;
  }

  /**
   * Calculates the filtered accomplishments for the current search context.
   *
   * @returns The filtered accomplishments for the current search context.
   */
  private calcFilteredAccomplishments(): Accomplishment[] {
    if (typeof this.data.cv === 'undefined') { return []; }
    if (typeof this.data.cv.Courses === 'undefined') { return []; }

    const retVal = this.calcFiltered<Accomplishment>(this.data.cv.Courses);

    return retVal;
  }

  /**
   * Calculates the filtered publications for the current search context.
   *
   * @returns The filtered publications for the current search context.
   */
  private calcFilteredPublications(): Publication[] {
    if (typeof this.data.cv === 'undefined') { return []; }
    if (typeof this.data.cv.Publications === 'undefined') { return []; }

    const retVal = this.calcFiltered<Publication>(this.data.cv.Publications);

    return retVal;
  }

  /**
   * Calculates the filtered professional experiences for the current search context.
   *
   * @returns The filtered professional experiences for the current search context.
   */
  private calcFilteredProfessionalExperience(): ProfessionalExperience[] {
    const retVal = this.calcFiltered<ProfessionalExperience>(this.data.cv['Professional experience']);

    // console.log('Debug: calcFilteredProfessionalExperience', retVal);
    return retVal;
  }

  /**
   * Calculates the filtered education entries for the current search context.
   *
   * @returns The filtered education entries for the current search context.
   */
  private calcFilteredEducation(): Education[] {
    const retVal = this.calcFiltered<Education>(this.data.cv.Education);

    // console.log('Debug: calcFilteredEducation', retVal);
    return retVal;
  }

  /**
   * Performs the search.
   *
   * @param array The assay to filter.
   *
   * @returns Filtered array according to the current search context.
   */
  private calcFiltered<T>(array: Array<T>): Array<T> {
    return this.searchEngineService.search<T>(array, this.model.searchToken);
  }
}