Aam-Digital/ndb-core

import { Injectable } from "@angular/core";
import { EntityMapperService } from "../../core/entity/entity-mapper/entity-mapper.service";
import { Note } from "../notes/model/note";
import { ChildSchoolRelation } from "./model/childSchoolRelation";
import moment, { Moment } from "moment";
import { DatabaseIndexingService } from "../../core/entity/database-indexing/database-indexing.service";
import { Entity } from "../../core/entity/model/entity";
import { groupBy } from "../../utils/utils";

@Injectable({ providedIn: "root" })
export class ChildrenService {
  constructor(
    private entityMapper: EntityMapperService,
    private dbIndexing: DatabaseIndexingService,
  ) {
    this.createDatabaseIndices();
  }

  private createDatabaseIndices() {
    this.createNotesIndex();
    this.createChildSchoolRelationIndex();
  }

  /**
   * returns a list of children with additional school info
   */
  async getChildren(): Promise<Entity[]> {
    const children = await this.entityMapper.loadType("Child");
    const relations = await this.entityMapper.loadType(ChildSchoolRelation);
    groupBy(relations, "childId").forEach(([id, rels]) => {
      const child = children.find((c) => c.getId() === id);
      if (child) {
        this.extendChildWithSchoolInfo(child, rels);
      }
    });
    return children;
  }

  /**
   * returns a child with additional school info
   * @param id id of child
   */
  async getChild(id: string): Promise<Entity> {
    const child = await this.entityMapper.load("Child", id);
    const relations = await this.queryRelations(id);
    this.extendChildWithSchoolInfo(child, relations);
    return child;
  }

  private extendChildWithSchoolInfo(
    child: Entity,
    relations: ChildSchoolRelation[],
  ) {
    const active = relations.filter((r) => r.isActive);
    child["schoolId"] = active.map((r) => r.schoolId);
    if (active.length > 0) {
      child["schoolClass"] = active[0]["schoolClass"];
    }
  }

  private createChildSchoolRelationIndex(): Promise<any> {
    const designDoc = {
      _id: "_design/childSchoolRelations_index",
      views: {
        by_child_school: {
          map: `(doc) => {
            if (!doc._id.startsWith("${ChildSchoolRelation.ENTITY_TYPE}:")) {
              return;
            };
            const start = new Date(doc.start || '3000-01-01').getTime();
            emit([doc.childId, start]);
            emit([doc.schoolId, start]);
            return;
          }`,
        },
      },
    };
    return this.dbIndexing.createIndex(designDoc);
  }

  queryRelations(prefix: string) {
    const startkey = prefix.endsWith(":") ? [prefix + "\uffff"] : [prefix, {}];
    return this.dbIndexing.queryIndexDocs(
      ChildSchoolRelation,
      "childSchoolRelations_index/by_child_school",
      {
        startkey,
        endkey: [prefix],
        descending: true,
      },
    );
  }

  queryActiveRelationsOf(
    id: string,
    date = new Date(),
  ): Promise<ChildSchoolRelation[]> {
    return this.queryRelations(id).then((relations) =>
      relations.filter((rel) => rel.isActiveAt(date)),
    );
  }

  /**
   * Query all notes that have been linked to the given other entity.
   * @param entityId ID (with prefix!) of the related record
   */
  async getNotesRelatedTo(entityId: string): Promise<Note[]> {
    let legacyLinkedNotes = [];
    if (this.inferNoteLinkPropertyFromEntityType(entityId)) {
      legacyLinkedNotes = await this.dbIndexing.queryIndexDocs(
        Note,
        `notes_index/by_${this.inferNoteLinkPropertyFromEntityType(entityId)}`,
        entityId,
      );
    }

    const explicitlyLinkedNotes = await this.dbIndexing.queryIndexDocsRange(
      Note,
      `notes_related_index/note_by_relatedEntities`,
      [entityId],
      [entityId],
    );

    return [...legacyLinkedNotes, ...explicitlyLinkedNotes].filter(
      // remove duplicates
      (element, index, array) =>
        array.findIndex((e) => e._id === element._id) === index,
    );
  }

  private inferNoteLinkPropertyFromEntityType(entityId: string): string {
    // TODO: rework this to check the entity schema and find the relevant field?
    const entityType = Entity.extractTypeFromId(entityId);
    switch (entityType) {
      case "Child":
        return "children";
      case "School":
        return "schools";
      case "User":
        return "authors";
    }
  }

  /**
   * Query how many days ago the last note for each child was added.
   *
   * Warning: Children without any notes will be missing from this map.
   *
   * @param entityType (Optional) entity for which days since last note are calculated. Default "Child".
   * @param forLastNDays (Optional) cut-off boundary how many days into the past the analysis will be done.
   * @return A map of childIds as key and days since last note as value;
   *         For performance reasons the days since last note are set to infinity when larger then the forLastNDays parameter
   */
  public async getDaysSinceLastNoteOfEachEntity(
    entityType = "Child",
    forLastNDays: number = 30,
  ): Promise<Map<string, number>> {
    const startDay = moment().subtract(forLastNDays, "days");

    const notes = await this.getNotesInTimespan(startDay);

    const results = new Map();
    const entities = await this.entityMapper.loadType(entityType);
    entities
      .filter((c) => c.isActive)
      .forEach((c) => results.set(c.getId(), Number.POSITIVE_INFINITY));

    const noteProperty = Note.getPropertyFor(entityType);
    for (const note of notes) {
      // TODO: filter notes to only include them if the given child is marked "present"

      for (const entityId of note[noteProperty]) {
        const daysSinceNote = moment().diff(note.date, "days");
        const previousValue = results.get(entityId);
        if (previousValue > daysSinceNote) {
          results.set(entityId, daysSinceNote);
        }
      }
    }

    return results;
  }

  /**
   * Returns all notes in the timespan.
   * It is only checked if the notes are on the same day als start and end day. The time is not checked.
   * @param startDay the first day where notes should be included
   * @param endDay the last day where notes should be included
   */
  public async getNotesInTimespan(
    startDay: Date | Moment,
    endDay: Date | Moment = moment(),
  ): Promise<Note[]> {
    return this.dbIndexing.queryIndexDocsRange(
      Note,
      "notes_index/note_child_by_date",
      moment(startDay).format("YYYY-MM-DD"),
      moment(endDay).format("YYYY-MM-DD"),
    );
  }

  private async createNotesIndex(): Promise<any> {
    const designDoc = {
      _id: "_design/notes_index",
      views: {
        note_child_by_date: {
          map: `(doc) => {
            if (!doc._id.startsWith("${Note.ENTITY_TYPE}")) return;
            if (!Array.isArray(doc.children) || !doc.date) return;
            if (doc.date.length === 10) {
              emit(doc.date);
            } else {
              var d = new Date(doc.date || null);
              emit(d.getFullYear() + "-" + String(d.getMonth()+1).padStart(2, "0") + "-" + String(d.getDate()).padStart(2, "0"));
            }
          }`,
        },
      },
    };

    // TODO: remove these and use general note_by_relatedEntities instead --> to be decided later #1501
    // creating a by_... view for each of the following properties
    ["children", "schools", "authors"].forEach(
      (prop) =>
        (designDoc.views[`by_${prop}`] = this.createNotesByFunction(prop)),
    );

    await this.dbIndexing.createIndex(designDoc);

    const newDesignDoc = {
      _id: "_design/notes_related_index",
      views: {
        note_by_relatedEntities: {
          map: `(doc) => {
            if (!doc._id.startsWith("${Note.ENTITY_TYPE}")) return;
            if (!Array.isArray(doc.relatedEntities)) return;
            var dString;
            if (doc.date && doc.date.length === 10) {
              dString = doc.date;
            } else {
              var d = new Date(doc.date || null);
              dString = d.getFullYear() + "-" + String(d.getMonth()+1).padStart(2, "0") + "-" + String(d.getDate()).padStart(2, "0");
            }
            doc.relatedEntities.forEach((relatedEntity) => {
              emit([relatedEntity, dString]);
            });
          }`,
        },
      },
    };
    await this.dbIndexing.createIndex(newDesignDoc);
  }

  private createNotesByFunction(property: string) {
    return {
      map: `(doc) => {
        if (!doc._id.startsWith("${Note.ENTITY_TYPE}")) return;
        if (!Array.isArray(doc.${property})) return;
        doc.${property}.forEach(val => emit(val));
      }`,
    };
  }
}