(function () {
  'use strict';

  function toPartialUrl(input, fallbackView) {
    const url = new URL(input, window.location.origin);
    if (!url.searchParams.has('view') && fallbackView) {
      url.searchParams.set('view', fallbackView);
    }
    url.searchParams.set('partial', '1');
    return url;
  }

  async function fetchHtml(url, options) {
    const response = await fetch(url.toString(), {
      credentials: 'same-origin',
      headers: {
        Accept: 'text/html',
        'X-Requested-With': 'XMLHttpRequest'
      },
      ...options
    });

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}`);
    }

    return response.text();
  }

  function enhanceHost(host, state) {
    host.querySelectorAll('a[href]').forEach((link) => {
      const href = link.getAttribute('href') || '';
      if (!href.startsWith('/apps/boersenchecker')) {
        return;
      }

      link.addEventListener('click', (event) => {
        event.preventDefault();
        state.load(href);
      });
    });

    host.querySelectorAll('form').forEach((form) => {
      form.addEventListener('submit', async (event) => {
        event.preventDefault();

        const method = String(form.getAttribute('method') || 'get').toUpperCase();
        const action = form.getAttribute('action') || state.currentUrl.toString();
        const formData = new FormData(form);
        const url = toPartialUrl(action, state.defaultView);

        try {
          if (method === 'GET') {
            const next = new URL(url.toString());
            next.search = '';
            next.searchParams.set('partial', '1');
            for (const [key, value] of formData.entries()) {
              next.searchParams.append(key, String(value));
            }
            await state.load(next.toString());
            return;
          }

          const html = await fetchHtml(url, {
            method,
            body: formData
          });
          state.render(html, url);
        } catch (error) {
          state.renderError(error);
        }
      });
    });
  }

  window.initBoersencheckerApp = function initBoersencheckerApp(host, options) {
    if (!(host instanceof HTMLElement)) {
      return;
    }

    const entryRoute = String(options?.entryRoute || '/apps/boersenchecker');
    const defaultView = String(options?.defaultView || 'overview');

    const state = {
      defaultView,
      currentUrl: toPartialUrl(entryRoute, defaultView),
      async load(targetUrl) {
        const url = toPartialUrl(targetUrl, defaultView);
        this.currentUrl = url;
        host.innerHTML = '<div class="window-app-loading"><p>Börsenchecker wird geladen...</p></div>';
        try {
          const html = await fetchHtml(url);
          this.render(html, url);
        } catch (error) {
          this.renderError(error);
        }
      },
      render(html, url) {
        this.currentUrl = url;
        host.innerHTML = html;
        enhanceHost(host, this);
        if (typeof window.initBoersencheckerCharts === 'function') {
          window.initBoersencheckerCharts(host);
        }
      },
      renderError(error) {
        const message = error instanceof Error ? error.message : 'Börsenchecker konnte nicht geladen werden.';
        host.innerHTML = `<div class="window-app-error-state"><p>${message}</p></div>`;
      }
    };

    state.load(entryRoute);
  };
})();