import { parseXml, XmlDocument, XmlElement, XmlText } from "@rgrove/parse-xml";

export type versionNotes = {
    title: string;
    date: Date | string;
    link: string;
    html: string;
}

export default class Updater {
        public archiveURL: string;
        public feedType: string;
        constructor(archiveURL: string = "/", feedType: string = "atom") {
                this.archiveURL = archiveURL;
                this.feedType = feedType;
        }
        
        private async getRawArchive(): Promise<string> {
                const res = await fetch(`http://cors.emaker.limited/?url=${this.archiveURL}.${this.feedType}`, {
                        // "mode": "cors"
                });
                const text = await res.text();
                return text;
        }

        // atom feeds 
        private atomGetVersionDetails(entry: XmlElement): versionNotes {
                let outEntry: versionNotes = {title: "", date: new Date, link: "", html: ""};
                entry.children.forEach((elm) => {
                        let element = elm as XmlElement;
                        if (element.name == "title") {
                                outEntry.title = (element.children[0] as XmlText).text;
                        }
                        else if (element.name == "date") {
                                outEntry.date = new Date((element.children[0] as XmlText).text);
                        }
                        else if (element.name == "link") {
                                outEntry.link = element.attributes["href"];
                        } else if (element.name == "content") {
                                outEntry.html = (element.children[0] as XmlText).text; 
                        }
                })

                return outEntry;
        }

        private async atomGetArchive(): Promise<versionNotes[]> {
                const rawArchive: string = await this.getRawArchive();
                const releaseNotes: XmlDocument = parseXml(rawArchive);

                const output: versionNotes[] = [];
                // console.dir(releaseNotes) 
                (releaseNotes.children[0] as XmlElement).children.forEach((elm) => {
                        if (elm.type == "element") {
                                const element = elm as XmlElement;
                                if (element.name == "entry") {
                                        output.push(this.atomGetVersionDetails(element))
                                }
                        }
                });
                return output;
        }

        // rss feeds
        private rssGetVersionDetails(entry: XmlElement): versionNotes {
                let outEntry: versionNotes = {title: "", date: new Date, link: "", html: ""};
                entry.children.forEach((elm) => {
                        let element = elm as XmlElement;
                        if (element.name == "title") {
                                outEntry.title = (element.children[0] as XmlText).text;
                        }
                        else if (element.name == "pubDate") {
                                outEntry.date = (element.children[0] as XmlText).text;
                        }
                        else if (element.name == "link") {
                                outEntry.link = (element.children[0] as XmlText).text;
                        } else if (element.name == "content") {
                                outEntry.html = (element.children[0] as XmlText).text; 
                        }
                })

                return outEntry;
        }

        private async rssGetArchive(): Promise<versionNotes[]> {
                const rawArchive: string = await this.getRawArchive();
                const releaseNotes: XmlDocument = parseXml(rawArchive);

                const output: versionNotes[] = [];
                ((releaseNotes.children[0] as XmlElement).children[1] as XmlElement).children.forEach((elm) => {
                        if (elm.type == "element") {
                                const element = elm as XmlElement;
                                if (element.name == "item") {
                                        output.push(this.atomGetVersionDetails(element))
                                }
                        }
                })
                return output;
        }
        
        public async getArchive(): Promise<versionNotes[]> {
                if (this.feedType == "atom") {
                        return this.atomGetArchive()
                } else if (this.feedType == "rss"){
                        return this.rssGetArchive()
                }
        }
}