import { load } from "../lib/settings.js";
import { prepareAction } from "../lib/prepare-action.js";
import { openChat } from "./open-chat.js";
import { showActionDialog } from "./dialogs.js";
import { initializeMenus } from "./menus.js";

const COMMAND_ID = "ask-chatgpt";

// Reads the user's selection for the keyboard-shortcut path. The context menu
// does not need this — it receives info.selectionText directly.
//
// A commands invocation confers activeTab (ext-commands.js grants it before
// firing onCommand), so executeScript works with no host permission.
//
// Every frame keeps its own independent Selection, and a selection made in a
// non-focused frame is not cleared when the user selects elsewhere. Without a
// filter, a stale selection in an unfocused (possibly cross-origin) iframe
// could win over — or be pulled alongside — the selection the user actually
// made, with the winner among multiple non-empty results decided by an
// executeScript ordering that isn't specified. The injected snippet is
// therefore gated on document.hasFocus(), which is true for the focused
// document and all of its ancestors: the top frame wins when the user
// selected there, and an iframe's selection is only picked up when it is
// itself the focused frame. Exclude ancestors whose active element is a frame.
//
// Failure has three measured shapes, all handled here: a thrown
// "Missing host permission for the tab", a thrown variant naming frames, and a
// SILENT resolution to [null] on parent-process about: pages. Never index into
// a result without a null check.
async function readSelection() {
  let tabs;
  try {
    tabs = await browser.tabs.query({ active: true, currentWindow: true });
  } catch {
    return "";
  }

  // Only tab.id may be read. Reading tab.url or tab.title would require the
  // "tabs" permission, which does add an install-prompt warning line.
  const tabId = tabs?.[0]?.id;
  if (typeof tabId !== "number") {
    return "";
  }

  let results;
  try {
    results = await browser.tabs.executeScript(tabId, {
      code: "document.hasFocus() && !['IFRAME', 'FRAME'].includes(document.activeElement?.tagName) ? window.getSelection().toString() : ''",
      allFrames: true,
      matchAboutBlank: true,
    });
  } catch {
    return "";
  }

  if (!Array.isArray(results)) {
    return "";
  }
  for (const result of results) {
    if (typeof result === "string" && result.trim() !== "") {
      return result;
    }
  }
  return "";
}

async function runAction(request) {
  let preparation = prepareAction(request);
  if (preparation.kind === "ready") {
    try {
      await openChat(browser, preparation.url, request.settings.openIn);
      return;
    } catch {
      // Keep the ready payload so the dialog's Continue button retries it.
    }
  }
  try {
    await showActionDialog(browser, { request, preparation });
  } catch {
    console.error("Could not open the action dialog. Please try the action again.");
  }
}

void initializeMenus({ browser, load, onAction: runAction }).catch(console.error);
if (browser.commands) {
  browser.commands.onCommand.addListener(async command => {
    if (command !== COMMAND_ID) return;
    // Read the selection before another asynchronous API loses activeTab context.
    const source = await readSelection();
    await runAction({ actionId: "ask", source, settings: await load() });
  });
}