import {Injectable} from "@angular/core";
import {HttpClient} from "@angular/common/http";
import {Observable} from "rxjs";
import {EnvProperties} from "../../utils/properties/env-properties";
import {map} from "rxjs/operators";

export interface Annotation {
    text: string;
    type: 'semantic' | 'keyword' | 'comment';
    urls?: string[];
    urlSize?: number;
}

@Injectable({
    providedIn: "root"
})
export class AnnotationService {

    api = 'api/';

    constructor(private http: HttpClient) {
    }

    getAllAnnotations(properties: EnvProperties, source: string): Observable<Annotation[]> {
        let url = properties.b2noteAPIURL + this.api + 'annotations?type[]=semantic&type[]=keyword&type[]=comment&format=json-ld&download=false&target-source=' + encodeURIComponent(source);
        return this.http.get<Annotation[]>(url).pipe(map((response: any[]) => {
            return this.parseAnnotations(response);
        }));
    }
    
    private parseAnnotations(response: any[]): Annotation[] {
        let annotations: Annotation[] = [];
        if(response && response.length > 0) {
            response.forEach(value => {
                let body = value.body;
                if(body.type === 'TextualBody') {
                    if(body.purpose === 'tagging') {
                        annotations.push({
                            text: body.value,
                            type: "keyword"
                        });
                    } else {
                        annotations.push({
                            text: body.value,
                            type: "comment"
                        });
                    }
                } else {
                    let items = body.items;
                    let urls: string[] = [];
                    let text: string = null;
                    items.forEach(item => {
                        if(item.type === 'SpecificResource') {
                            urls.push(item.source);
                        } else if(item.type === 'TextualBody') {
                            text = item.value;
                        }
                    });
                    annotations.push({
                        text: text,
                        type: "semantic",
                        urls: urls
                    });
                }
            });
        }
        return annotations.sort((a, b) => {
            if(a.type === b.type) {
                return 0;
            } else if (a.type === 'semantic') {
                return -1;
            } else if(b.type === 'semantic') {
                return 1;
            } else if(a.type === 'keyword') {
                return  -1;
            } else if(b.type === 'keyword') {
                return  1;
            }
        });
    }
}