(() => {
  const elForm = document.querySelector("form.search-form");
  const elQ = document.querySelector("#q");
  const elSelDict = document.querySelector("form.search-form select");
  const defaultLang = elSelDict.value;


  // ===================================
  // Helper functions.

  function selectDict(dict) {
    // dict is in the format '$fromLang/$toLang'.
    const langs = dict.split("/");
    Object.assign(localStorage, { dict, from_lang: langs[0], to_lang: langs[1] });
    elSelDict.value = dict;
    elForm.setAttribute("action", `${_ROOT_URL}/dictionary/${dict}`);
  }

  // Capture the form submit and send it as a canonical URL instead
  // of the ?q query param. 
  function search(q) {
    let val = q.trim();

    const uri = elForm.getAttribute("action");
    document.location.href = `${uri}/${encodeURIComponent(val).replace(/%20/g, "-")}`;
  }

  // ===================================
  // Events

  // On ~ press, focus search input.
  document.onkeydown = (function (e) {
    if (e.key !== "`" && e.key !== "~") {
      return;
    }

    e.preventDefault();
    q.focus();
    q.select();
  });

  // Bind to language change.
  elSelDict.addEventListener("change", function (e) {
    selectDict(e.target.value);
  });

  // Bind to form submit.
  elForm.addEventListener("submit", function (e) {
    e.preventDefault();
    search(elQ.value);
  });

  // "More" link next to entries/defs that expands an entry.
  document.querySelectorAll(".more-toggle").forEach((el) => {
    el.onclick = (e) => {
      e.preventDefault();

      let state = "block";
      if (el.dataset.open) {
        delete (el.dataset.open);
        state = "none";
      } else {
        el.dataset.open = true;
        state = "block";
      }

      const container = document.getElementById(el.dataset.id);
      container.style.display = state;

      // fetch() content from the dataset data.guid from /api/entry/{guid}
      // and populate the div.more innerHTML with the content.
      if (state === "block" && !el.dataset.fetched) {
        container.innerHTML = `<div aria-busy="true"></div>`;

        fetch(`${window._ROOT_URL}/api/dictionary/entries/${el.dataset.entryGuid}`)
          .then((resp) => resp.json())
          .then((data) => {
            const d = data.data;
            container.innerHTML = "";

            // If there's data.data.meta.synonyms, add them to the synonyms div.
            if (d.meta.synonyms) {
              const syns = document.createElement("div");
              syns.classList.add("synonyms");
              syns.innerHTML = d.meta.synonyms.map((s) => `<a href="${window._ROOT_URL}/dictionary/${el.dataset.fromLang}/${el.dataset.toLang}/${s}">${s}</a>`).join("");
              container.appendChild(syns);
            }

            // Each data.content[] word, add to target.
            const more = document.createElement("div");
            more.classList.add("words");
            more.innerHTML = d.content.slice(window._MAX_CONTENT_ITEMS).map((c) => `<span class="word">${c}</span>`).join("");
            container.appendChild(more);

            el.dataset.fetched = true;
          })
          .catch((err) => {
            console.error("Error fetching entry content:", err);
          });
      }
    };
  });

  // ===================================

  // Select a language based on the page URL.
  let dict = localStorage.dict || defaultLang;
  const uri = /(dictionary)\/((.+?)\/(.+?))\//i.exec(document.location.href);
  if (uri && uri.length == 5) {
    dict = uri[2];
  }

  selectDict(dict);
  elQ.focus();
  elQ.select();
})();

// Submission form.
(() => {
  function filterTypes(e) {
    // Filter the types select field with elements that are supported by the language.
    const types = e.target.closest("[data-relation-controls]").querySelector("select[name=relation_type]");
    types.querySelectorAll("option").forEach((o) => o.style.display = "none");
    types.querySelectorAll(`option[data-lang=${e.target.value}]`).forEach((o) => o.style.display = "block");
    types.selectedIndex = 1;
  }


  if (document.querySelector(".form-submit")) {
    document.querySelectorAll("select[name=relation_lang]").forEach((e) => {
      e.onchange = filterTypes;
    });

    // +definition button.
    document.querySelector(".btn-add-relation").onclick = (e) => {
      e.preventDefault();

      if (document.querySelectorAll(".add-relations li").length >= 20) {
        return false;
      }

      // Clone and add a relation fieldset.
      const d = document.querySelector(".add-relations li").cloneNode(true);
      d.dataset.added = true
      d.querySelector("select[name=relation_lang]").onchange = filterTypes;
      document.querySelector(".add-relations").appendChild(d);

      // Remove definition link.
      d.querySelector(".btn-remove-relation").onclick = (e) => {
        e.preventDefault();
        d.remove();
      };
    };
  }
})();

// Edit form using ot-dropdown.
(() => {
  const tpl = document.querySelector("#tpl-form-comments");
  if (!tpl) return;

  let counter = 0;
  document.querySelectorAll("[data-edit-from]").forEach((btn) => {
    const parent = btn.parentNode;

    // Clone template content and give the popover a unique ID.
    const popoverId = `form-comments-${counter++}`;
    const form = tpl.content.firstElementChild.cloneNode(true);
    form.id = popoverId;

    // Wire the button as the popover trigger.
    btn.setAttribute("popovertarget", popoverId);

    // Build <ot-dropdown> with children fully assembled before inserting into DOM
    // so that init() finds [popovertarget] and [popover].
    const dropdown = document.createElement("ot-dropdown");
    dropdown.appendChild(btn);
    dropdown.appendChild(form);
    parent.appendChild(dropdown);

    const txt = form.querySelector("textarea");

    // Handle submission.
    form.querySelector("button.submit-comment").onclick = () => {
      fetch(`${window._ROOT_URL}/api/submissions/comments`, {
        method: "POST",
        headers: {
          "Content-Type": "application/json"
        },
        body: JSON.stringify({
          from_guid: btn.dataset.editFrom,
          to_guid: btn.dataset.editTo,
          comments: txt.value
        })
      }).catch((err) => {
        alert(`Error submitting: ${err}`);
      });

      alert(form.dataset.success);
      form.hidePopover();
    };

    form.querySelector("button.close").onclick = () => form.hidePopover();
  });
})();

// Autocomplete.
(() => {
  if (!autocomp) {
    return;
  }

  const elForm = document.querySelector("form.search-form");
  const elQ = document.querySelector("#q");
  let debounce;

  autocomp(elQ, {
    autoSelect: false,
    onQuery: async (val) => {
      const langCode = localStorage.from_lang;
      clearTimeout(debounce);
      return new Promise(resolve => {
        debounce = setTimeout(async () => {
          const response = await fetch(`${_ROOT_URL}/api/autocomplete/${langCode}/${val}`);
          const data = await response.json();

          const suggestions = data.data.map(item => item.content[0]);

          debounce = null;
          resolve(suggestions);
        }, 50);
      });
    },

    onSelect: (val) => {
      // autocomp search isn't complete. Use the user's input instead of autocomp selection.
      if (val) {
        elQ.value = val;
      }

      elForm.dispatchEvent(new Event("submit", { cancelable: true }));
      return elQ.value;
    }
  });
})();

// Audio playback.
document.querySelectorAll("[data-audio]").forEach((el) => {
  el.onclick = (e) => {
    e.preventDefault();
    const audio = new Audio(el.dataset.src);
    audio.play().catch((err) => {
      console.error("error playing audio:", err);
      alert("error playing audio");
    });
  };
});

// Scroll to hash on load.
window.setTimeout(() => {
  if (window.location.hash) {
    document.querySelector(window.location.hash)?.scrollIntoView();
  }
}, 100);

// Screenshot share.
document.querySelectorAll("[data-share-entry]").forEach((el) => {
  el.onclick = async (e) => {
    e.preventDefault();
    const entryEl = document.getElementById(el.dataset.shareEntry);
    if (!entryEl) return;
    try {
      await shareEntry(entryEl);
    } catch (err) {
      console.error("Error sharing entry:", err);
      alert(`Error sharing: ${err?.message || err}`);
    }
  };
});