import ImageProvider, {ProvidedImage} from "./ImageProvider";
import BaseUIElement from "../../UI/BaseUIElement";
import Svg from "../../Svg";
import Link from "../../UI/Base/Link";
import {Utils} from "../../Utils";
import {LicenseInfo} from "./LicenseInfo";
import Wikimedia from "../Web/Wikimedia";

/**
 * This module provides endpoints for wikimedia and others
 */
export class WikimediaImageProvider extends ImageProvider {


    private readonly commons_key = "wikimedia_commons"
    public readonly defaultKeyPrefixes = [this.commons_key,"image"]
    public static readonly singleton = new WikimediaImageProvider();
    public static readonly commonsPrefixes = ["https://commons.wikimedia.org/wiki/", "https://upload.wikimedia.org", "File:"]

    private constructor() {
        super();
    }

    private static ExtractFileName(url: string) {
        if (!url.startsWith("http")) {
            return url;
        }
        const path = new URL(url).pathname
        return path.substring(path.lastIndexOf("/") + 1);

    }

    SourceIcon(backlink: string): BaseUIElement {
        const img = Svg.wikimedia_commons_white_svg()
            .SetStyle("width:2em;height: 2em");
        if (backlink === undefined) {
            return img
        }


        return new Link(Svg.wikimedia_commons_white_img,
            `https://commons.wikimedia.org/wiki/${backlink}`, true)


    }

    private static PrepareUrl(value: string): string {

        if (value.toLowerCase().startsWith("https://commons.wikimedia.org/wiki/")) {
            return value;
        }
        return (`https://commons.wikimedia.org/wiki/Special:FilePath/${encodeURIComponent(value)}?width=500&height=400`)
    }

    protected async DownloadAttribution(filename: string): Promise<LicenseInfo> {
        filename = WikimediaImageProvider.ExtractFileName(filename)

        if (filename === "") {
            return undefined;
        }

        const url = "https://en.wikipedia.org/w/" +
            "api.php?action=query&prop=imageinfo&iiprop=extmetadata&" +
            "titles=" + filename +
            "&format=json&origin=*";
        const data = await Utils.downloadJson(url)
        const licenseInfo = new LicenseInfo();
        const pageInfo = data.query.pages[-1]
        if(pageInfo === undefined){
            return undefined;
        }
        
        const license = (pageInfo.imageinfo ?? [])[0]?.extmetadata;
        if (license === undefined) {
            console.warn("The file", filename ,"has no usable metedata or license attached... Please fix the license info file yourself!")
            return undefined;
        }

        let title = pageInfo.title
        if(title.startsWith("File:")){
            title=  title.substr("File:".length)
        }
        if(title.endsWith(".jpg") || title.endsWith(".png")){
            title = title.substring(0, title.length - 4)
        }
        
        licenseInfo.title = title
        licenseInfo.artist = license.Artist?.value;
        licenseInfo.license = license.License?.value;
        licenseInfo.copyrighted = license.Copyrighted?.value;
        licenseInfo.attributionRequired = license.AttributionRequired?.value;
        licenseInfo.usageTerms = license.UsageTerms?.value;
        licenseInfo.licenseShortName = license.LicenseShortName?.value;
        licenseInfo.credit = license.Credit?.value;
        licenseInfo.description = license.ImageDescription?.value;
        return licenseInfo;

    }

    private UrlForImage(image: string): ProvidedImage {
        if (!image.startsWith("File:")) {
            image = "File:" + image
        }
        return {url: WikimediaImageProvider.PrepareUrl(image), key: undefined, provider: this}
    }
    
    private static startsWithCommonsPrefix(value: string): boolean{
        return  WikimediaImageProvider.commonsPrefixes.some(prefix => value.startsWith(prefix))
    }
    
    private static removeCommonsPrefix(value: string): string{
        if(value.startsWith("https://upload.wikimedia.org/")){
            value = value.substring(value.lastIndexOf("/") + 1)
            value = decodeURIComponent(value)
            if(!value.startsWith("File:")){
                value = "File:"+value
            }
            return value;
        }
        
        for (const prefix of WikimediaImageProvider.commonsPrefixes) {
            if(value.startsWith(prefix)){
                let part = value.substr(prefix.length)
                if(prefix.startsWith("http")){
                    part = decodeURIComponent(part)
                }
                return part
            }
        }
        return value;
    }

    public PrepUrl(value: string): ProvidedImage {
        const hasCommonsPrefix = WikimediaImageProvider.startsWithCommonsPrefix(value)
        value = WikimediaImageProvider.removeCommonsPrefix(value)

        if (value.startsWith("File:")) {
            return this.UrlForImage(value)
        }

        // We do a last effort and assume this is a file
        return this.UrlForImage("File:" + value)
    }

    public async ExtractUrls(key: string, value: string): Promise<Promise<ProvidedImage>[]> {
        const hasCommonsPrefix = WikimediaImageProvider.startsWithCommonsPrefix(value)
        if(key !== undefined && key !== this.commons_key && !hasCommonsPrefix){
            return []
        }
        
        value = WikimediaImageProvider.removeCommonsPrefix(value)
        if (value.startsWith("Category:")) {
            const urls = await Wikimedia.GetCategoryContents(value)
            return urls.filter(url => url.startsWith("File:")).map(image => Promise.resolve(this.UrlForImage(image)))
        }
        if (value.startsWith("File:")) {
            return [Promise.resolve(this.UrlForImage(value))]
        }
        if (value.startsWith("http")) {
            // PRobably an error
            return []
        }
        // We do a last effort and assume this is a file
        return [Promise.resolve(this.UrlForImage("File:" + value))]
    }


}