/* Helper to manage the visibility and icon of a pageAction button.
 * Each callback is evaluated whenever the tab has changed.
 * Callbacks may be async (i.e. return a Promise).
 *
 * Arguments:
 *   - options.visible: Tab => boolean; whether to show the pageAction button
 *   - options.icon: Tab => either a string (the icon path), or null (to get the
 *     default icon from the manifest), or an object (with path or imageData, see
 *     docs of browser.pageAction.setIcon).
 *   - options.title: Tab => string (to use as button tooltip), or null (to use
 *     default title from the manifest)
 *   - options.onClicked: Tab => void; executed on click, after which the button
 *     state is automatically updated on all tabs.
 *
 * Returns an object with the following methods:
 *   - update(tab?): update visibility, icons, etcetera of a given tab, or of
 *     all tabs if the tab argument is omitted.
 *
 * Example usage:
 *   const pageActionButton = PageActionButton({
 *     visible: tab => tab.url.startsWith('https'),
 *     icon: tab => isEnabled(tab.url) ? '/icon_enabled.svg' : '/icon_disabled.svg',
 *     title: tab => isEnabled(tab.url) ? 'Disable' : 'Enable',
 *     onClicked: tab => toggleEnabled(tab.url),
 *   })
 *   // Manually trigger an update of a tab.
 *   pageActionButton.update(tab)
 */

import browser from 'webextension-polyfill'


export default function PageActionButton({
  visible = tab => true,
  icon = tab => null,
  title = tab => null,
  onClicked = tab => {},
}) {
  async function setIcon(tab) {
    let iconSetting = await icon(tab)
    if (typeof iconSetting === 'string' || iconSetting === null) {
      iconSetting = { path: iconSetting }
    }
    browser.pageAction.setIcon({
      ...iconSetting,
      tabId: tab.id,
    })
  }

  async function setTitle(tab) {
    browser.pageAction.setTitle({
      title: await title(tab),
      tabId: tab.id,
    })
  }

  async function checkTab(tab) {
    if (await visible(tab)) {
      setIcon(tab)
      setTitle(tab)
      browser.pageAction.show(tab.id)
    } else {
      browser.pageAction.hide(tab.id)
    }
  }

  async function checkAllTabs() {
    const tabs = await browser.tabs.query({})
    for (const tab of tabs) {
      await checkTab(tab)
    }
  }

  // Show/hide the button on current tabs (XXX not awaiting it's completion)
  checkAllTabs()

  // Show/hide the button whenever a tab changes.
  browser.tabs.onUpdated.addListener((id, changeInfo, tab) => {
    checkTab(tab)
  });

  // Handle button clicks
  browser.pageAction.onClicked.addListener(async tab => {
    await onClicked(tab)
    await checkAllTabs(tab)
  })

  return {
    update: tab => tab ? checkTab(tab) : checkAllTabs()
  }
}