/*
 * Copyright (C) 2026 Mateusz Gruszczynski @linuxiarz.pl
 * Source-Available Code / Dual-Licensed.
 */

import { api } from "@rustpad/api";
import { getAvailableLanguages, getLanguage, setLanguage, t } from "@rustpad/i18n";
import { applyTheme, getTheme } from "@rustpad/theme";
import { toast } from "@rustpad/toast";

const AUTH_STATE_KEY = "rustpad:auth-state";
const THEMES = ["dark", "light"];
let initialized = false;
let saveChain = Promise.resolve();

function hasAccountSession() {
  try { return localStorage.getItem(AUTH_STATE_KEY) === "1"; } catch { return false; }
}

function icon(name) {
  if (name === "language") {
    return '<svg viewBox="0 0 24 24" aria-hidden="true"><circle cx="12" cy="12" r="9"></circle><path d="M3 12h18M12 3a15 15 0 0 1 0 18M12 3a15 15 0 0 0 0 18"></path></svg>';
  }
  if (name === "light") {
    return '<svg viewBox="0 0 24 24" aria-hidden="true"><circle cx="12" cy="12" r="4"></circle><path d="M12 2v2M12 20v2M4.93 4.93l1.42 1.42M17.65 17.65l1.42 1.42M2 12h2M20 12h2M4.93 19.07l1.42-1.42M17.65 6.35l1.42-1.42"></path></svg>';
  }
  return '<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M20.2 15.3A8.5 8.5 0 0 1 8.7 3.8 8.5 8.5 0 1 0 20.2 15.3Z"></path></svg>';
}

function closeOtherPickers(except = null) {
  document.querySelectorAll(".header-preference-picker[open]").forEach(details => {
    if (details !== except) details.open = false;
  });
}

function preferenceButton({ value, label, selected, languageCode }) {
  const button = document.createElement("button");
  button.type = "button";
  button.className = "header-preference-option";
  button.dataset.value = value;
  button.setAttribute("role", "option");
  button.setAttribute("aria-selected", selected ? "true" : "false");
  if (languageCode) button.lang = languageCode;

  const check = document.createElement("span");
  check.className = "header-preference-option__check";
  check.setAttribute("aria-hidden", "true");
  check.textContent = selected ? "✓" : "";

  const copy = document.createElement("span");
  copy.className = "header-preference-option__copy";
  copy.textContent = label;

  button.append(check, copy);
  return button;
}

function createPicker(kind) {
  const details = document.createElement("details");
  details.className = `header-preference-picker header-preference-picker--${kind}`;
  details.dataset.preferenceKind = kind;

  const summary = document.createElement("summary");
  summary.className = "header-preference-trigger";

  const iconWrap = document.createElement("span");
  iconWrap.className = "header-preference-trigger__icon";
  iconWrap.innerHTML = icon(kind === "theme" ? getTheme() : "language");

  const compactValue = document.createElement("span");
  compactValue.className = "header-preference-trigger__value";
  compactValue.setAttribute("aria-hidden", "true");

  const chevron = document.createElement("span");
  chevron.className = "header-preference-trigger__chevron";
  chevron.setAttribute("aria-hidden", "true");
  chevron.textContent = "▾";

  summary.append(iconWrap, compactValue, chevron);

  const menu = document.createElement("div");
  menu.className = "header-preference-menu";
  menu.setAttribute("role", "listbox");

  details.append(summary, menu);
  details.addEventListener("toggle", () => {
    if (details.open) closeOtherPickers(details);
  });
  return details;
}

async function persistAccountPreference(patch) {
  if (!hasAccountSession()) return;
  saveChain = saveChain.catch(() => undefined).then(() => api("/api/auth/profile", {
    method: "POST",
    body: JSON.stringify(patch),
  }));
  return saveChain;
}

function renderLanguagePicker(details) {
  const languages = getAvailableLanguages();
  const current = getLanguage();
  const selected = languages.find(language => language.code === current) || languages[0];
  const summary = details.querySelector(".header-preference-trigger");
  const value = details.querySelector(".header-preference-trigger__value");
  const menu = details.querySelector(".header-preference-menu");
  const label = t("common.language", {}, "Language");

  summary.setAttribute("aria-label", label);
  summary.title = label;
  menu.setAttribute("aria-label", label);
  value.textContent = String(selected?.code || current || "en").toUpperCase();
  menu.replaceChildren(...languages.map(language => preferenceButton({
    value: language.code,
    label: language.native_name || language.name || language.code,
    selected: language.code === current,
    languageCode: language.code,
  })));
}

function renderThemePicker(details) {
  const current = getTheme();
  const summary = details.querySelector(".header-preference-trigger");
  const iconWrap = details.querySelector(".header-preference-trigger__icon");
  const value = details.querySelector(".header-preference-trigger__value");
  const menu = details.querySelector(".header-preference-menu");
  const label = t("profile.theme", {}, "Interface theme");

  summary.setAttribute("aria-label", label);
  summary.title = label;
  menu.setAttribute("aria-label", label);
  iconWrap.innerHTML = icon(current);
  value.textContent = t(`theme.${current}`, {}, current === "light" ? "Light" : "Dark");
  menu.replaceChildren(...THEMES.map(theme => preferenceButton({
    value: theme,
    label: t(`theme.${theme}`, {}, theme === "light" ? "Light" : "Dark"),
    selected: theme === current,
  })));
}

function renderPicker(details) {
  if (details.dataset.preferenceKind === "language") renderLanguagePicker(details);
  else renderThemePicker(details);
}

function renderAll() {
  document.querySelectorAll(".header-preference-picker").forEach(renderPicker);
}

function bindPicker(details) {
  details.querySelector(".header-preference-menu")?.addEventListener("click", async event => {
    const button = event.target.closest(".header-preference-option");
    if (!(button instanceof HTMLButtonElement)) return;
    const next = button.dataset.value || "";
    const kind = details.dataset.preferenceKind;
    details.open = false;

    if (kind === "language") {
      const previous = getLanguage();
      if (!next || next === previous) return;
      await setLanguage(next);
      renderAll();
      try {
        await persistAccountPreference({ language: next });
      } catch (error) {
        if (error?.status !== 401) {
          await setLanguage(previous);
          renderAll();
          toast.danger(error.message, { title: t("profile.language.failed", {}, "Could not change language") });
        }
      }
      return;
    }

    const previous = getTheme();
    if (!THEMES.includes(next) || next === previous) return;
    applyTheme(next);
    renderAll();
    try {
      await persistAccountPreference({ theme: next });
    } catch (error) {
      if (error?.status !== 401) {
        applyTheme(previous);
        renderAll();
        toast.danger(error.message, { title: t("profile.updateFailed", {}, "Could not update profile") });
      }
    }
  });
}

function mount(container) {
  if (!(container instanceof HTMLElement) || container.dataset.headerPreferencesMounted === "true") return;
  container.dataset.headerPreferencesMounted = "true";
  container.setAttribute("data-i18n-ignore", "");
  const language = createPicker("language");
  const theme = createPicker("theme");
  container.replaceChildren(language, theme);
  bindPicker(language);
  bindPicker(theme);
  renderPicker(language);
  renderPicker(theme);
}

export function initHeaderPreferences() {
  document.querySelectorAll("[data-header-preferences]").forEach(mount);
  if (initialized) return;
  initialized = true;

  document.addEventListener("pointerdown", event => {
    const target = event.target instanceof Element ? event.target : null;
    if (!target?.closest(".header-preference-picker")) closeOtherPickers();
  }, { passive: true });
  document.addEventListener("keydown", event => {
    if (event.key === "Escape") closeOtherPickers();
  });
  document.addEventListener("rustpad:languagechange", renderAll);
  window.addEventListener("rustpad:theme-change", renderAll);
  window.addEventListener("rustpad:session-change", renderAll);
  window.addEventListener("rustpad:session-expired", renderAll);
}