import Foundation

enum RedditLoginBridgeStyle {
    static let messageHandlerName = "reddoraLogin"

    /// Intercepts Log In and blocks Reddit's embedded auth modal, which cannot complete
    /// credential sign-in reliably in WKWebView ("Server error. Try again later.").
    static let injectionScript = """
    (function() {
      if (window.__reddoraLoginBridgeInstalled) return;
      window.__reddoraLoginBridgeInstalled = true;

      const LOGIN_PATTERN = /log\\s*in/i;
      const HEADER_SELECTORS = 'header, [role="banner"], #header, faceplate-header, nav';
      const AUTH_MODAL_SELECTORS = [
        'auth-flow-modal',
        '[data-testid="login-modal"]',
        '#credentials-login-popup',
        'faceplate-modal[slot="login"]',
        'faceplate-modal[open]'
      ].join(', ');

      function nodeLabel(node) {
        if (!(node instanceof Element)) return '';
        return (
          (node.textContent || '') + ' ' +
          (node.getAttribute('aria-label') || '') + ' ' +
          (node.getAttribute('title') || '')
        ).trim();
      }

      function isHeaderLoginTrigger(node) {
        if (!(node instanceof Element)) return false;

        const clickable = node.matches('button, a, [role="button"], faceplate-tracker, faceplate-button')
          ? node
          : node.closest('button, a, [role="button"], faceplate-tracker, faceplate-button');
        if (!clickable) return false;

        if (clickable.id === 'login-button') return true;
        if (clickable.getAttribute('data-testid') === 'login-button') return true;

        const label = nodeLabel(clickable);
        if (!LOGIN_PATTERN.test(label)) return false;

        return !!clickable.closest(HEADER_SELECTORS);
      }

      function isLoginPage() {
        const host = window.location.hostname.toLowerCase();
        return (host === 'www.reddit.com' || host === 'reddit.com' || host === 'new.reddit.com')
          && /^\\/login\\/?$/i.test(window.location.pathname);
      }

      function requestInAppLogin() {
        if (isLoginPage()) return;
        if (window.__reddoraLoginPanelRequested) return;
        window.__reddoraLoginPanelRequested = true;
        setTimeout(function() {
          window.__reddoraLoginPanelRequested = false;
        }, 1000);

        if (
          window.webkit &&
          window.webkit.messageHandlers &&
          window.webkit.messageHandlers.reddoraLogin
        ) {
          window.webkit.messageHandlers.reddoraLogin.postMessage('open');
        }
      }

      function isAuthModal(element) {
        if (!(element instanceof Element)) return false;
        if (element.matches('auth-flow-modal, [data-testid="login-modal"], #credentials-login-popup')) {
          return true;
        }
        if (element.matches('faceplate-modal')) {
          const label = nodeLabel(element);
          return LOGIN_PATTERN.test(label) || !!element.querySelector('input[type="password"]');
        }
        return false;
      }

      window.__reddoraCloseRedditAuthModal = function() {
        document.querySelectorAll(AUTH_MODAL_SELECTORS).forEach(function(element) {
          if (!isAuthModal(element)) return;
          const closeButton = element.querySelector(
            '[aria-label="Close"], [aria-label="close"], button[close]'
          );
          if (closeButton) {
            closeButton.click();
          } else {
            element.remove();
          }
        });
      };

      function installAuthModalBlocker() {
        if (isLoginPage()) return;

        const STYLE_ID = 'reddora-auth-block-style';
        if (!document.getElementById(STYLE_ID)) {
          const style = document.createElement('style');
          style.id = STYLE_ID;
          style.textContent = [
            'auth-flow-modal,',
            '[data-testid="login-modal"],',
            '#credentials-login-popup {',
            '  display: none !important;',
            '  pointer-events: none !important;',
            '}'
          ].join('\\n');
          (document.head || document.documentElement).appendChild(style);
        }

        const observer = new MutationObserver(function() {
          if (isLoginPage()) return;
          let foundAuthModal = false;
          document.querySelectorAll(AUTH_MODAL_SELECTORS).forEach(function(element) {
            if (!isAuthModal(element)) return;
            foundAuthModal = true;
            element.remove();
          });
          if (foundAuthModal) {
            requestInAppLogin();
          }
        });

        observer.observe(document.documentElement, { childList: true, subtree: true });
      }

      document.addEventListener('click', function(event) {
        if (isLoginPage()) return;
        const path = event.composedPath();
        for (let i = 0; i < path.length; i++) {
          if (!isHeaderLoginTrigger(path[i])) continue;

          event.preventDefault();
          event.stopImmediatePropagation();
          window.__reddoraCloseRedditAuthModal();
          requestInAppLogin();
          return;
        }
      }, true);

      installAuthModalBlocker();
    })();
    """

    static let closeAuthModalScript = "window.__reddoraCloseRedditAuthModal && window.__reddoraCloseRedditAuthModal();"
}