import { Injectable } from '@angular/core';

/**
 * A wrapper around localStorage and sessionStorage
 * to improve ease of use and maintainability.
 * Works with JSON out of the box.
 */
@Injectable()
export class StorageService{

    store: Storage;
    id: string;

    local(){
        this.store = localStorage;
        return this;
    }

    session(){
        this.store = sessionStorage;
        return this;
    }

    init(initialValues: Object, storeType: 'local' | 'session' = 'local'){
        //set store type
        this[storeType]();
        this.id = Math.floor(Math.random()*10000).toString();
        this.store.setItem(this.id, JSON.stringify(initialValues));
    }

    get(key?: string): any{
        return (key.length > 0) ? JSON.parse(this.store.getItem(this.id))[key] : JSON.parse(this.store.getItem(this.id));
    }
    
    set(key: string, value: any): StorageService;
    set(keyValue: Object): StorageService;
    set(keyOrKeyValue: string | Object, value?: any): StorageService{
        if(typeof keyOrKeyValue == 'string'){
            this.store.setItem(this.id, JSON.stringify(Object.assign({}, this.get(), {
                keyOrKeyValue: value
            })));
        }
        else if(typeof keyOrKeyValue == 'object'){
            this.store.setItem(this.id, JSON.stringify(Object.assign({}, this.get(), keyOrKeyValue)));
        }
        return this;
    }

    remove(key: string): void;
    remove(keys: string[]): void;
    remove(keyOrKeys: string | string[]): void{
        let s = this.get();
        if(typeof keyOrKeys == 'string'){
            delete s[keyOrKeys];
        }
        else{
            keyOrKeys.forEach((k) => {
                delete s[k];
            })
        }
        this.set(s);
    }
    
    clear(): void{
        return this.store.clear();
    }
}