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

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

import {QueryMode, QUERY_MODES} from './query-mode';
import {QueryState} from './query-state';
import {QueryStep} from './query-step';

@Injectable()
export class QueryService {
        
    public neo4jBaseUrl = 'http://localhost:7474/db/data';
    public state: QueryState;
    public ismiObjectTypes: any;
    
    constructor(private _http: Http) {
        this.state = {
            'steps': [],
            'resultCypherQuery': '',
            'cypherQueryParams': {},
            'attributesCypherQuery': '',
            'relationsCypherQuery': '',
            'results': [],
            'resultTypes': '',
            'numResults': 0,
            'resultInfo': ''
        };
    }
    
    setup() {
        this.setupIsmiObjectTypes();
    }
    
    getState() {
        return this.state;
    }
    
    getQueryModes(): QueryMode[] {
        return QUERY_MODES;
    }
    
    getQueryOptions(queryMode: QueryMode) {
        var options = ['a1', 'b1', 'c1'];
        if (queryMode.id === 'type_is') {
            options = this.ismiObjectTypes;
        } else if (queryMode.id === 'relation_is') {
            options = this.state.nextQueryRelations;
        } else if (queryMode.id === 'att_contains') {
            options = this.state.nextQueryAttributes;
        } else if (queryMode.id === 'att_contains_norm') {
            options = this.state.nextQueryAttributes;
        }
        console.debug("getQueryOptions returns: ", options);
        return 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.results[0].data.map(elem => elem.row[0]).filter(elem => elem[0] != "_");
                console.debug("ismi types=", this.ismiObjectTypes);
                },
            err => console.error("neo4j error=", err),
            () => console.debug('neo4j query Complete')
        );
    }
    
    setQueryStep(index: number, step: QueryStep) {
        this.state.steps[index] = step;
        this.createCypherQuery();
    }
    
    createCypherQuery() {
        var queryMatch = '';
        var queryWhere = '';
        var queryReturn = '';
        var queryParams = {};
        var resultQuery = '';
        var attributesQuery = '';
        var relationsQuery = '';
        var returnType = '';
        var nIdx = 1;
        this.state.steps.forEach((step, stepIdx) => {
            // object type is
            if (step.mode.id === 'type_is') {
                queryMatch = `MATCH (n${nIdx}:${step.objectType})`;
                queryWhere = '';
                queryReturn =  `RETURN n${nIdx}`;
                returnType = 'node';
            }
            
            // relation type is
            if (step.mode.id === 'relation_is') {
                nIdx += 1;
                queryMatch += `-[:\`${step.relationType}\`]->(n${nIdx})`;
                queryReturn =  `RETURN n${nIdx}`;
                returnType = 'node';
            }
            
            // attribute contains
            if (step.mode.id === 'att_contains') {
                if (!queryWhere) {
                    queryWhere = 'WHERE ';
                } else {
                    queryWhere += ' AND ';
                }
                queryWhere += `lower(n${nIdx}.${step.attribute}) CONTAINS lower({att_val${stepIdx}})`;
                queryParams[`att_val${stepIdx}`] = step.value;
            }
            
            // attribute contains (normalized)
            if (step.mode.id === 'att_contains_norm') {
                if (!queryWhere) {
                    queryWhere = 'WHERE ';
                } else {
                    queryWhere += ' AND ';
                }
                queryWhere += `lower(n${nIdx}._n_${step.attribute}) CONTAINS lower('${step.value}')`;
            }
            
        });
        resultQuery = queryMatch + '\n' + queryWhere + '\n' + queryReturn;
        attributesQuery = queryMatch + ' ' + queryWhere + ` WITH DISTINCT keys(n${nIdx}) AS atts UNWIND atts AS att RETURN DISTINCT att ORDER BY att`;
        relationsQuery = queryMatch + '-[r]-() ' + queryWhere + ' RETURN DISTINCT type(r)';
        this.state.resultCypherQuery = resultQuery;
        this.state.cypherQueryParams = queryParams;
        this.state.attributesCypherQuery = attributesQuery;
        this.state.relationsCypherQuery = relationsQuery;
        this.state.resultTypes = returnType;
    }
    
    updateQuery() {
        this.createCypherQuery();
        // run query for result table
        var resQuery = this.state.resultCypherQuery;
        var queryParams = this.state.cypherQueryParams;
        var resRes = this.fetchCypherResult(resQuery, queryParams);
        resRes.subscribe(
            data => {
                console.debug("neo4j result data=", data);
                this.state.results = data.results[0].data.map(elem => elem.row[0]);
                this.state.numResults = this.state.results.length;
                // count all types
                var resTypes = {};
                this.state.results.forEach((r) => {
                    if (resTypes[r.type] == null) {
                        resTypes[r.type] = 1;
                    } else {
                        resTypes[r.type] += 1;
                    }
                });
                var info = '';
                for (var t in resTypes) {
                    info += t + '(' + resTypes[t] + ') ';   
                }
                this.state.resultInfo = info;
            },
            err => console.error("neo4j result error=", err),
            () => console.debug('neo4j result query Complete')
        );
        // run query for attribute list
        if (this.state.attributesCypherQuery) {
            var attRes = this.fetchCypherResult(this.state.attributesCypherQuery, queryParams);
            attRes.subscribe(
                data => {
                    console.debug("neo4j att data=", data);
                    this.state.nextQueryAttributes = data.results[0].data.map(elem => elem.row[0]).filter(elem => elem[0] != "_");;
                },
                err => console.error("neo4j att error=", err),
                () => console.debug('neo4j att query Complete')
            );
        }
        // run query for relations list
        if (this.state.relationsCypherQuery) {
            var attRes = this.fetchCypherResult(this.state.relationsCypherQuery, queryParams);
            attRes.subscribe(
                data => {
                    console.debug("neo4j rel data=", data);
                    this.state.nextQueryRelations = data.results[0].data.map(elem => elem.row[0]).filter(elem => elem[0] != "_");;
                },
                err => console.error("neo4j rel error=", err),
                () => console.debug('neo4j rel query Complete')
            );
        }
    }
    
    fetchCypherResult(query: string, params = {}) {
        console.debug("fetching cypher query: ", query);
        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({'statements': [
            {'statement': query, 'parameters': params}
            ]});
        // make post request asynchronously
        var resp = this._http.post(this.neo4jBaseUrl+'/transaction/commit', data, opts)
        // filter result as JSON
        .map(res => res.json());
        // return Observable
        return resp;
    }
}