export const LOCAL_STORAGE_KEY = "dx-sidebar-recent-searches";

export const LIMIT = 5;

export class RecentSearches {
    items: string[] = [];

    constructor() {
        this._init();
    }

    get() {
        return this.items;
    }

    add(item: string | undefined) {
        if (!item || typeof item !== "string") {
            return;
        }
        const normalized = item.trim();
        if (normalized === "") {
            return;
        }
        this._prepend(normalized);
        this._removeDuplicates(normalized);
        this._cutOffExcess();
        this._addToStorage();
    }

    // private
    _init() {
        this.items = JSON.parse(
            window.localStorage.getItem(LOCAL_STORAGE_KEY) || "[]"
        );
    }

    _prepend(item: string) {
        this.items.unshift(item);
    }

    _removeDuplicates(item: string) {
        while (this.items.lastIndexOf(item) > 0) {
            this.items.splice(this.items.lastIndexOf(item), 1);
        }
    }

    _cutOffExcess() {
        this.items = this.items.slice(0, LIMIT);
    }

    _addToStorage() {
        window.localStorage.setItem(
            LOCAL_STORAGE_KEY,
            JSON.stringify(this.items)
        );
    }
}