import { createTextVNode, defineComponent, h, inject, onServerPrefetch, ref, type VNode, watchEffect } from "vue";
import { RouterLink } from "vue-router";
import useAsyncState from "@/useAsyncState.ts";
import useHead from "@/useHead.ts";

export default defineComponent({
    name: "ge-deutsch-article",
    props: {
        articleName: {
            type: String,
            required: true,
        },
    },
    async setup(props) {
        const currentLang = ref<"en" | "de">("de");

        function clickBtn() {
            currentLang.value = currentLang.value === "en" ? "de" : "en";
        }

        const parseDom = inject(
            "dom-parse",
            (innerHTML: string) => Object.assign(document.createElement("div"), { innerHTML }),
        );

        const title = ref("");

        const { result: articleContent, stateIsReady } = useAsyncState(
            "ge-deutsch-article-data",
            async ({ hostUrl }) => {
                const articleResponse = await fetch(`${hostUrl}/generative-energy/content/${props.articleName}.html`);
                const result = await articleResponse.text();
                title.value = result.split('<h1 lang="de">')[1].split("</h1>")[0];
                return result;
            },
        );

        useHead({ title });

        onServerPrefetch(() =>
            new Promise<void>((res) => {
                watchEffect(() => {
                    if (title.value !== "") {
                        console.log("resolve", title.value);
                        res();
                    }
                });
            })
        );

        function transformArticleNode(node: Node): VNode | string {
            if (node.nodeType === node.ELEMENT_NODE) {
                const el = node as Element;
                const attrs: Record<string, string> = {};
                const children = [...node.childNodes].map((_) => transformArticleNode(_));

                if (el.tagName === "P") {
                    el.classList.add("text-slab");
                    children.unshift(h("button", {
                        class: "swap",
                        onClick: (e) => {
                            e.target.parentElement.classList.toggle("swap");
                        },
                    }, "↻"));
                }

                for (let i = 0; i < el.attributes.length; i++) {
                    const item = el.attributes.item(i);
                    if (item) {
                        attrs[item.name] = item.value;
                    }
                }

                return h((node as Element).tagName, attrs, children);
            } else {
                return createTextVNode(node.textContent ?? "");
            }
        }

        function ArticleContentTransformed() {
            if (articleContent.value) {
                const dom = parseDom(articleContent.value);
                return h("div", {}, [...dom.children].map((_) => transformArticleNode(_)));
            }
            return <div>Artikel lädt...</div>;
        }

        await stateIsReady;

        return () => (
            <div class="ge-article">
                <div class="header">
                    <RouterLink to={{ name: "GEDeutsch" }}>Zur Artikelübersicht</RouterLink>
                    <button onClick={clickBtn}>
                        Sprache auf <span>{currentLang.value === "en" ? "Deutsch" : "Englisch"}</span> umschalten
                    </button>
                </div>
                <article class={`lang-${currentLang.value}`}>
                    <ArticleContentTransformed />
                </article>
            </div>
        );
    },
});