import { createMemo, createResource, createSignal, For, Show } from 'solid-js';
import AdminShell from '~/components/AdminShell';

const API = '/api/gateway';

type ModuleRecord = {
  id: string;
  name: string;
  key: string;
  description?: string;
  isActive: boolean;
};

type ModuleForm = {
  name: string;
  key: string;
  description: string;
  isActive: boolean;
};

const EMPTY_FORM: ModuleForm = { name: '', key: '', description: '', isActive: true };

async function fetchModules(): Promise<ModuleRecord[]> {
  const res = await fetch(`${API}/api/modules`);
  if (!res.ok) return [];
  const data = await res.json();
  return Array.isArray(data) ? data : data?.modules || [];
}

export default function ModulesPage() {
  const [refreshToken, setRefreshToken] = createSignal(0);
  const [isModalOpen, setIsModalOpen] = createSignal(false);
  const [editing, setEditing] = createSignal<ModuleRecord | null>(null);
  const [form, setForm] = createSignal<ModuleForm>({ ...EMPTY_FORM });
  const [error, setError] = createSignal('');
  const [submitting, setSubmitting] = createSignal(false);

  const [modules] = createResource(refreshToken, fetchModules);
  const modalTitle = createMemo(() => editing() ? 'Edit Module' : 'Create Module');

  function openModal(item?: ModuleRecord) {
    if (item) {
      setEditing(item);
      setForm({
        name: item.name || '',
        key: item.key || '',
        description: item.description || '',
        isActive: Boolean(item.isActive),
      });
    } else {
      setEditing(null);
      setForm({ ...EMPTY_FORM });
    }
    setError('');
    setIsModalOpen(true);
  }

  function closeModal() {
    setIsModalOpen(false);
    setEditing(null);
    setForm({ ...EMPTY_FORM });
    setError('');
  }

  async function submitForm(event: Event) {
    event.preventDefault();
    const current = form();
    if (!current.name.trim() || !current.key.trim()) {
      setError('Name and key are required.');
      return;
    }

    setSubmitting(true);
    setError('');
    try {
      const target = editing();
      const method = target ? 'PATCH' : 'POST';
      const url = target ? `${API}/api/modules/${target.id}` : `${API}/api/modules`;
      const res = await fetch(url, {
        method,
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(current),
      });
      if (!res.ok) {
        const message = await res.text();
        throw new Error(message || 'Failed to save module');
      }
      closeModal();
      setRefreshToken((value) => value + 1);
    } catch (nextError: any) {
      setError(nextError?.message || 'Failed to save module');
    } finally {
      setSubmitting(false);
    }
  }

  async function removeModule(id: string) {
    if (!confirm('Are you sure you want to delete this module?')) return;
    try {
      const res = await fetch(`${API}/api/modules/${id}`, { method: 'DELETE' });
      if (!res.ok) throw new Error('Delete failed');
      setRefreshToken((value) => value + 1);
    } catch {
      setError('Failed to delete module.');
    }
  }

  return (
    <AdminShell>
      <div class="page-hero-card page-actions">
        <div>
          <h1 class="page-title">Module Registry</h1>
          <p class="page-subtitle">Manage internal module definitions and activation state.</p>
        </div>
        <button class="btn primary" onClick={() => openModal()}>Add Module</button>
      </div>

      <Show when={error() && !isModalOpen()}>
        <div class="card"><p class="error-note">{error()}</p></div>
      </Show>

      <Show when={modules.loading}>
        <div class="card"><p class="notice">Loading modules...</p></div>
      </Show>

      <div class="card">
        <div class="table-wrap">
          <table class="list-table">
            <thead>
              <tr>
                <th>Name</th>
                <th>Key</th>
                <th>Description</th>
                <th>Status</th>
                <th class="align-right">Actions</th>
              </tr>
            </thead>
            <tbody>
              <Show when={(modules() || []).length > 0} fallback={
                <tr><td colspan="5" class="notice" style="padding:16px">No modules found.</td></tr>
              }>
                <For each={modules() || []}>
                  {(item) => (
                    <tr>
                      <td>{item.name}</td>
                      <td><code>{item.key}</code></td>
                      <td>{item.description || '—'}</td>
                      <td>
                        <span class={`status-pill ${item.isActive ? 'status-approved' : 'status-rejected'}`}>
                          {item.isActive ? 'Active' : 'Inactive'}
                        </span>
                      </td>
                      <td class="align-right">
                        <div class="table-actions">
                          <button class="btn" onClick={() => openModal(item)}>Edit</button>
                          <button class="btn danger" onClick={() => removeModule(item.id)}>Delete</button>
                        </div>
                      </td>
                    </tr>
                  )}
                </For>
              </Show>
            </tbody>
          </table>
        </div>
      </div>

      <Show when={isModalOpen()}>
        <div class="modal-backdrop">
          <div class="modal">
            <h2 style="margin-top:0">{modalTitle()}</h2>
            <form onSubmit={submitForm}>
              <div class="field">
                <label>Name</label>
                <input
                  value={form().name}
                  onInput={(event) => setForm((prev) => ({ ...prev, name: event.currentTarget.value }))}
                  placeholder="e.g. Job Board"
                  required
                />
              </div>
              <div class="field">
                <label>Key</label>
                <input
                  value={form().key}
                  onInput={(event) => setForm((prev) => ({ ...prev, key: event.currentTarget.value }))}
                  placeholder="e.g. manage_jobs"
                  required
                />
              </div>
              <div class="field">
                <label>Description</label>
                <textarea
                  rows="3"
                  value={form().description}
                  onInput={(event) => setForm((prev) => ({ ...prev, description: event.currentTarget.value }))}
                  placeholder="Short description..."
                />
              </div>
              <label style="display:flex;gap:8px;align-items:center;font-size:13px">
                <input
                  type="checkbox"
                  checked={form().isActive}
                  onChange={(event) => setForm((prev) => ({ ...prev, isActive: event.currentTarget.checked }))}
                />
                Active
              </label>

              <Show when={error()}>
                <p class="error-note">{error()}</p>
              </Show>

              <div class="actions" style="justify-content:flex-end">
                <button type="button" class="btn" onClick={closeModal}>Cancel</button>
                <button type="submit" class="btn primary" disabled={submitting()}>
                  {editing() ? 'Save Changes' : 'Create'}
                </button>
              </div>
            </form>
          </div>
        </div>
      </Show>
    </AdminShell>
  );
}