import { apiInitializer } from "discourse/lib/api";
import { ajax } from "discourse/lib/ajax";

const URL_REGEX = /^(https?:\/\/[^\s/$.?#][^\s]*)$/i;

const STRINGS = {
  bar_label: "URL detected — import as article?",
  fetch_button: "Import Article",
  onebox_button: "Use Onebox",
  dismiss: "Dismiss",
  fetching: "Fetching…",
  success: "Article imported!",
  error_generic: "Unknown error",
  error_prefix: "Error:",
  source_label: "Source",
  retry_button: "Retry",
};

export default apiInitializer("1.8.0", (api) => {
  if (!api.container.lookup("site-settings:main").url_to_article_enabled) {
    return;
  }

  api.modifyClass("component:composer-editor", {
    pluginId: "url-to-article",

    didInsertElement() {
      this._super(...arguments);
      this._attachTitlePasteListener();
    },

    willDestroyElement() {
      this._super(...arguments);
      if (this._titleInputEl && this._titlePasteHandler) {
        this._titleInputEl.removeEventListener(
          "paste",
          this._titlePasteHandler,
          true
        );
      }
    },

    // ---- Title paste interception -------------------------------------
    // capture:true so our handler runs before Discourse's, then
    // preventDefault + stopImmediatePropagation so Discourse never sees
    // the paste event — no title lookup, no onebox race.

    _attachTitlePasteListener(attempts = 0) {
      const input = document.querySelector("#reply-title");
      if (input) {
        this._titleInputEl = input;
        this._titlePasteHandler = (e) => {
          const text = (e.clipboardData || window.clipboardData)
            .getData("text/plain")
            .trim();
          if (!URL_REGEX.test(text)) return;

          e.preventDefault();
          e.stopImmediatePropagation();

          // Show URL in the field visually without going through Ember binding
          input.value = text;
          this._pendingUrl = text;
          this._showArticleBar(text);
        };
        input.addEventListener("paste", this._titlePasteHandler, true);
      } else if (attempts < 15) {
        setTimeout(() => this._attachTitlePasteListener(attempts + 1), 200);
      }
    },

    // ---- Bar UI -------------------------------------------------------

    _showArticleBar(url) {
      this._hideArticleBar();

      const bar = document.createElement("div");
      bar.className = "url-to-article-bar";
      bar.innerHTML = `
        <span class="url-to-article-icon">📄</span>
        <span class="url-to-article-label">${STRINGS.bar_label}</span>
        <button class="btn btn-small btn-primary url-to-article-btn">
          ${STRINGS.fetch_button}
        </button>
        <button class="btn btn-small btn-default url-to-article-onebox-btn">
          ${STRINGS.onebox_button}
        </button>
        <button class="btn btn-small btn-flat url-to-article-dismiss"
          aria-label="${STRINGS.dismiss}">✕</button>
      `;

      bar.querySelector(".url-to-article-btn").addEventListener("click", () => {
        this._fetchAndPopulate(url);
      });

      bar.querySelector(".url-to-article-onebox-btn").addEventListener("click", () => {
        this._hideArticleBar();
        this._commitUrlToModel();
      });

      bar.querySelector(".url-to-article-dismiss").addEventListener("click", () => {
        this._hideArticleBar();
        this._pendingUrl = null;
      });

      const container = this.element.querySelector(".d-editor-container");
      if (container) {
        container.insertAdjacentElement("afterbegin", bar);
      }
    },

    _hideArticleBar() {
      this.element
        ?.querySelectorAll(".url-to-article-bar")
        .forEach((el) => el.remove());
    },

    _setStatus(message, type = "info") {
      const bar = this.element?.querySelector(".url-to-article-bar");
      if (!bar) return;
      let status = bar.querySelector(".url-to-article-status");
      if (!status) {
        status = document.createElement("span");
        status.className = "url-to-article-status";
        bar.appendChild(status);
      }
      status.textContent = message;
      status.className = `url-to-article-status url-to-article-status--${type}`;
    },

    // Release the URL into Ember's data-binding so Discourse handles it normally
    _commitUrlToModel() {
      const input = this._titleInputEl;
      const url = this._pendingUrl;
      if (!input || !url) return;
      input.value = url;
      input.dispatchEvent(new Event("input", { bubbles: true }));
      this._pendingUrl = null;
    },

    // ---- Fetch & populate ---------------------------------------------

    async _fetchAndPopulate(url) {
      const bar = this.element?.querySelector(".url-to-article-bar");
      const btn = bar?.querySelector(".url-to-article-btn");

      if (btn) {
        btn.disabled = true;
        btn.textContent = STRINGS.fetching;
      }
      this._setStatus(STRINGS.fetching, "info");

      try {
        const data = await ajax("/url-to-article/extract", {
          type: "POST",
          data: { url },
        });

        if (data.error) throw new Error(data.error);

        this._populateComposer(data);
        this._setStatus(STRINGS.success, "success");
        setTimeout(() => this._hideArticleBar(), 3000);
      } catch (err) {
        const msg =
          err.jqXHR?.responseJSON?.error ||
          err.message ||
          STRINGS.error_generic;
        this._setStatus(`${STRINGS.error_prefix} ${msg}`, "error");
        if (btn) {
          btn.disabled = false;
          btn.textContent = STRINGS.retry_button;
        }
      }
    },

    _populateComposer(data) {
      const composerModel = this.get("composer.model");
      if (!composerModel) return;

      const lines = [];
      const siteName = data.site_name ? `**${data.site_name}**` : "";
      const byline = data.byline ? ` — *${data.byline}*` : "";
      if (siteName || byline) {
        lines.push(`> ${siteName}${byline}`);
        lines.push(`> ${STRINGS.source_label}: <${data.url}>`);
        lines.push("");
      } else {
        lines.push(`> ${STRINGS.source_label}: <${data.url}>`);
        lines.push("");
      }

      if (data.description) {
        lines.push(`*${data.description}*`);
        lines.push("");
        lines.push("---");
        lines.push("");
      }

      lines.push(data.markdown || "");

      composerModel.set("title", data.title || this._pendingUrl || "");
      composerModel.set("reply", lines.join("\n"));
      this._pendingUrl = null;

      if (this._titleInputEl) {
        this._titleInputEl.value = composerModel.get("title");
      }
    },
  });
});