import { LightningElement, api } from "lwc";

// Extracts filename and extension from a file URL
const FILENAME_FROM_URL_REGEX = /(?=\w+\.\w{3,4}$).+/;
const EXTENSION_FROM_URL_REGEX = /\.([^.]*)$/;

export default class InteractiveImage extends LightningElement {
    @api header!: string;
    @api featuredSrc!: string;

    @api
    set downloadUrls(values: any) {
        // Normalize input values
        let urls;
        if (typeof values === "string") {
            if (values.startsWith("[")) {
                urls = JSON.parse(values);
            } else {
                urls = [values];
            }
        } else {
            urls = values;
        }
        // Ensure that we have some URLs
        if (!urls || urls.length === 0) {
            throw new Error(
                `No download url found for interactive image with title "${this.header}"`
            );
        }
        // Prepare download options with labels
        this.urls = urls.map((url: string) => {
            return {
                label: this.getDownloadLabelFromUrl(url),
                id: url
            };
        });
    }
    get downloadUrls() {
        return this.urls;
    }

    private urls: { label: string; id: string }[] = [];

    private get isSingleDownload() {
        return this.urls.length === 1;
    }

    private get singleDownloadHref() {
        return this.urls[0].id;
    }

    private get singleDownloadFilename() {
        const pathParts = this.urls[0].id.match(FILENAME_FROM_URL_REGEX);
        return pathParts ? pathParts[0] : "";
    }

    private get downloadButtonLabel() {
        return this.isSingleDownload ? this.urls[0].label : "Download as...";
    }

    private handleDownloadOptionChange(event: CustomEvent) {
        window.open(event.detail, "_blank");
    }

    private getDownloadLabelFromUrl(url: string): string {
        const urlParts = url.match(EXTENSION_FROM_URL_REGEX);
        return urlParts
            ? `Download as ${urlParts[1].toUpperCase()}`
            : "Download";
    }
}