import {Injectable} from 'angular2/core';
import {Http, Headers} from 'angular2/http';

import 'rxjs/Rx'; // import all RxJS operators

import {QueryMode} from './query-mode';

@Injectable()
export class QueryService {
        
    public ismiObjectTypes;
    
    public QUERY_MODES: QueryMode[] = [
        {id: 'type_is', label:'Object type is'},
        {id: 'att_contains', label: 'Attribute contains'}];
        
    constructor(private _http: Http) {}
    
    getQueryModes(): QueryMode[] {
        return this.QUERY_MODES;
    }
    
    getQueryOptions(queryMode: QueryMode) {
        var options = ['a1', 'b1', 'c1'];
        if (queryMode.id === 'att_contains') {
            options = ['d', 'e', 'f'];
        } else if (queryMode.id === 'type_is') {
            options = this.ismiObjectTypes;
        }
        return Promise.resolve(options);
    }
    
    setupIsmiObjectTypes() {
        var query = `MATCH (n) WITH DISTINCT labels(n) AS labels
                UNWIND labels AS label 
                RETURN DISTINCT label ORDER BY label`;

        var res = this.fetchCypherResult(query);
        res.subscribe(
            data => {
                console.debug("neo4j data=", data);
                this.ismiObjectTypes = data.data.map(elem => elem[0]).filter(elem => elem[0] != "_");
                console.debug("ismi types=", this.ismiObjectTypes);
                },
            err => console.error("neo4j error=", err),
            () => console.debug('neo4j query Complete')
        );
    }
    
    fetchCypherResult(query: string, params = {}) {
        var headers = new Headers();
        headers.append('Authorization', 'Basic ' + btoa('neo4j' + ':' + 'neo5j'));
        headers.append('Content-Type', 'application/json');
        headers.append('Accept', 'application/json');
        // put headers in options
        var opts = {'headers': headers};
        // create POST data from query
        var data = JSON.stringify({'query': query, 'params': params});
        // make post request asynchronously
        var resp = this._http.post('http://localhost:7474/db/data/cypher/', data, opts)
        // filter result as JSON
        .map(res => res.json());
        // return Observable
        return resp;
    }
}