/* PRABA accessibility text scaling — STAGING v2.4.0 */
(() => {
  'use strict';

  const STORAGE_KEY = 'prabaTextSizePreferenceV1';
  const LEVELS = {
    standard: { label: '標準', factor: 1 },
    large: { label: '大きめ', factor: 1.15 },
    xlarge: { label: '特大', factor: 1.3 }
  };

  let systemRootSizePx = 16;

  function readSavedLevel() {
    try {
      const saved = window.localStorage.getItem(STORAGE_KEY);
      return Object.prototype.hasOwnProperty.call(LEVELS, saved) ? saved : 'standard';
    } catch (error) {
      return 'standard';
    }
  }

  function saveLevel(level) {
    try {
      window.localStorage.setItem(STORAGE_KEY, level);
    } catch (error) {
      // Storage can be unavailable in restrictive WebView/private modes.
    }
  }

  function updateButtons(level) {
    document.querySelectorAll('[data-praba-text-size-level]').forEach((button) => {
      const active = button.dataset.prabaTextSizeLevel === level;
      button.setAttribute('aria-pressed', active ? 'true' : 'false');
    });
  }

  function applyLevel(level, persist = true) {
    const safeLevel = Object.prototype.hasOwnProperty.call(LEVELS, level) ? level : 'standard';
    const factor = LEVELS[safeLevel].factor;
    const root = document.documentElement;

    root.dataset.prabaTextSize = safeLevel;
    root.style.fontSize = `${systemRootSizePx * factor}px`;
    updateButtons(safeLevel);

    if (persist) saveLevel(safeLevel);

    window.dispatchEvent(new CustomEvent('praba:textsizechange', {
      detail: { level: safeLevel, factor }
    }));
  }

  function createControl() {
    if (document.querySelector('.praba-text-size-control')) return;

    const control = document.createElement('div');
    control.className = 'praba-text-size-control';
    control.setAttribute('role', 'group');
    control.setAttribute('aria-label', '文字サイズ');

    const label = document.createElement('span');
    label.className = 'praba-text-size-label';
    label.textContent = '文字サイズ';
    control.appendChild(label);

    Object.entries(LEVELS).forEach(([level, config]) => {
      const button = document.createElement('button');
      button.type = 'button';
      button.className = 'praba-text-size-button';
      button.dataset.prabaTextSizeLevel = level;
      button.textContent = config.label;
      button.setAttribute('aria-pressed', 'false');
      button.addEventListener('click', () => applyLevel(level));
      control.appendChild(button);
    });

    const anchor = document.querySelector('.header') || document.querySelector('.top-bar');
    if (anchor && anchor.parentNode) {
      anchor.insertAdjacentElement('afterend', control);
    } else {
      document.body.insertAdjacentElement('afterbegin', control);
    }
  }

  function init() {
    const computedRootSize = Number.parseFloat(window.getComputedStyle(document.documentElement).fontSize);
    systemRootSizePx = Number.isFinite(computedRootSize) && computedRootSize > 0 ? computedRootSize : 16;

    createControl();
    applyLevel(readSavedLevel(), false);
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init, { once: true });
  } else {
    init();
  }
})();