import { Subject } from "rxjs/Subject";

import { CompleterItem } from "../components/completer-item";
import { CompleterData } from "./completer-data";
import { isNil } from "../globals";

export abstract class CompleterBaseData extends Subject<CompleterItem[] | null> implements CompleterData {


    protected _searchFields: string;
    protected _titleField: string;
    protected _descriptionField: string;
    protected _imageField: string;

    constructor() {
        super();
    }

    public abstract search(term: string): void;

    public cancel() { }

    public searchFields(searchFields: string) {
        this._searchFields = searchFields;
        return this;
    }

    public titleField(titleField: string) {
        this._titleField = titleField;
        return this;
    }

    public descriptionField(descriptionField: string) {
        this._descriptionField = descriptionField;
        return this;
    }

    public imageField(imageField: string) {
        this._imageField = imageField;
        return this;
    }

    public convertToItem(data: any) {
        let image: string | null = null;
        let formattedText: string;
        let formattedDesc: string | null = null;

        if (this._titleField) {
            formattedText = this.extractTitle(data);
        } else {
            formattedText = data;
        }

        if (typeof formattedText !== "string") {
            formattedText = JSON.stringify(formattedText);
        }

        if (this._descriptionField) {
            formattedDesc = this.extractValue(data, this._descriptionField);
        }

        if (this._imageField) {
            image = this.extractValue(data, this._imageField);
        }

        if (isNil(formattedText)) {
            return null;
        }

        return {
            title: formattedText,
            description: formattedDesc,
            image: image,
            originalObject: data
        } as CompleterItem;

    }

    protected extractMatches(data: any[], term: string) {
        let matches: any[] = [];
        const searchFields = this._searchFields ? this._searchFields.split(",") : null;
        if (this._searchFields !== null && this._searchFields !== undefined && term != "") {
            matches = data.filter(item => {
                const values: any[] = searchFields ? searchFields.map(searchField => this.extractValue(item, searchField)).filter(value => !!value) : [item];
                return values.some(value => value.toString().toLowerCase().indexOf(term.toString().toLowerCase()) >= 0);
            });
        } else {
            matches = data;
        }


        return matches;
    }

    protected extractTitle(item: any) {
        // split title fields and run extractValue for each and join with ' '
        return this._titleField.split(",")
            .map((field) => {
                return this.extractValue(item, field);
            })
            .reduce((acc, titlePart) => acc ? `${acc} ${titlePart}` : titlePart);
    }

    protected extractValue(obj: any, key: string | null) {
        let keys: string[];
        let result: any;
        if (key) {
            keys = key.split(".");
            result = obj;
            for (let i = 0; i < keys.length; i++) {
                if (result) {
                    result = result[keys[i]];
                }
            }
        }
        else {
            result = obj;
        }
        return result;
    }

    protected processResults(matches: string[]): CompleterItem[] {
        let i: number;
        let results: CompleterItem[] = [];

        if (matches && matches.length > 0) {
            for (i = 0; i < matches.length; i++) {
                const item = this.convertToItem(matches[i]);
                if (item) {
                    results.push(item);
                }
            }
        }
        return results;
    }
}