/// Typed-item add/edit form. Slice 6 ships full Login parity; other
/// types show a coming-soon placeholder (use the CLI for now).
///
/// Carry-forward from Slice 5 review M3: on edit, trashed_at is
/// explicitly reset to undefined so stale trash state cannot survive an
/// edit. (The capture path already uses spread + fetched item; this
/// popup flow uses state.selectedItem.)

import { getState, setState, sendMessage, navigate, escapeHtml } from '../popup';
import type {
  Item, ItemId, ItemType, ManifestEntry, LoginCore, TotpConfig,
} from '../../shared/types';
import { DEFAULT_PASSWORD_REQUEST } from '../../shared/types';
import { base32Decode, base32Encode } from '../../shared/base32';

// Which types support add/edit in Slice 6.
function isEditableType(t: ItemType): boolean {
  return t === 'login';
}

export function renderItemForm(app: HTMLElement, mode: 'add' | 'edit'): void {
  const state = getState();
  const existing = mode === 'edit' ? state.selectedItem : null;

  // Determine the type we're editing/creating. Add defaults to login.
  const type: ItemType = existing?.type ?? 'login';

  if (!isEditableType(type)) {
    renderComingSoon(app, type);
    return;
  }

  renderLoginForm(app, mode, existing);
}

// --- Coming-soon -------------------------------------------------------

function renderComingSoon(app: HTMLElement, type: ItemType): void {
  app.innerHTML = `
    <div class="pad">
      <div class="detail-title" style="margin-bottom:16px;">${escapeHtml(type.replace('_', ' '))}</div>
      <p class="muted">editing ${escapeHtml(type)} items is coming in a later slice.</p>
      <p class="muted" style="margin-top:8px;">use the CLI for now.</p>
      <div class="form-actions">
        <button class="btn" id="back-btn">back</button>
      </div>
    </div>
  `;
  document.getElementById('back-btn')?.addEventListener('click', () => navigate('list'));
  const handler = (e: KeyboardEvent) => {
    if (e.key === 'Escape') {
      document.removeEventListener('keydown', handler);
      navigate('list');
    }
  };
  document.addEventListener('keydown', handler);
}

// --- Login add/edit ----------------------------------------------------

/// Encode TotpConfig secret bytes back to a base32 display string.
function totpSecretToBase32(totp: TotpConfig | undefined): string {
  if (!totp) return '';
  return base32Encode(new Uint8Array(totp.secret));
}

function renderLoginForm(app: HTMLElement, mode: 'add' | 'edit', existing: Item | null): void {
  const state = getState();
  const existingCore = (existing?.core.type === 'login')
    ? (existing.core as LoginCore & { type: 'login' })
    : null;

  const title = existing?.title ?? '';
  const url = existingCore?.url ?? '';
  const username = existingCore?.username ?? '';
  const password = existingCore?.password ?? '';
  const totpStr = totpSecretToBase32(existingCore?.totp);
  const group = existing?.group ?? '';
  const notes = existing?.notes ?? '';

  app.innerHTML = `
    <div class="pad">
      <div class="detail-title" style="margin-bottom:16px;">${mode === 'add' ? 'new login' : 'edit login'}</div>
      ${state.error ? `<div class="error">${escapeHtml(state.error)}</div>` : ''}
      <div class="form-group">
        <label class="label" for="f-title">title *</label>
        <input id="f-title" type="text" value="${escapeHtml(title)}" placeholder="GitHub">
      </div>
      <div class="form-group">
        <label class="label" for="f-url">url</label>
        <input id="f-url" type="text" value="${escapeHtml(url)}" placeholder="https://github.com/login">
      </div>
      <div class="form-group">
        <label class="label" for="f-username">username</label>
        <input id="f-username" type="text" value="${escapeHtml(username)}" placeholder="alice@example.com">
      </div>
      <div class="form-group">
        <label class="label" for="f-password">password</label>
        <div class="inline-row">
          <input id="f-password" type="password" value="${escapeHtml(password)}">
          <button class="btn" id="gen-btn" title="generate">gen</button>
        </div>
      </div>
      <div class="form-group">
        <label class="label" for="f-totp">totp secret (base32)</label>
        <input id="f-totp" type="text" value="${escapeHtml(totpStr)}" placeholder="JBSWY3DPEHPK3PXP">
      </div>
      <div class="form-group">
        <label class="label" for="f-group">group</label>
        <input id="f-group" type="text" value="${escapeHtml(group)}" placeholder="work">
      </div>
      <div class="form-group">
        <label class="label" for="f-notes">notes</label>
        <textarea id="f-notes" placeholder="recovery codes, security questions...">${escapeHtml(notes)}</textarea>
      </div>
      <div class="form-actions">
        <button class="btn" id="cancel-btn">cancel</button>
        <button class="btn btn-primary" id="save-btn">${state.loading ? '<span class="spinner"></span>' : 'save'}</button>
      </div>
    </div>
  `;

  // --- Generate password ---
  document.getElementById('gen-btn')?.addEventListener('click', async () => {
    const resp = await sendMessage({ type: 'generate_password', request: DEFAULT_PASSWORD_REQUEST });
    if (resp.ok) {
      const data = resp.data as { password: string };
      const pwInput = document.getElementById('f-password') as HTMLInputElement;
      pwInput.value = data.password;
      pwInput.type = 'text'; // Show generated password.
    } else {
      setState({ error: resp.error });
    }
  });

  // --- Cancel ---
  document.getElementById('cancel-btn')?.addEventListener('click', () => goBack(mode));

  // --- Save ---
  document.getElementById('save-btn')?.addEventListener('click', async () => {
    await saveLogin(mode, existing);
  });

  // --- Escape to cancel ---
  const escHandler = (e: KeyboardEvent) => {
    if (e.key === 'Escape') {
      document.removeEventListener('keydown', escHandler);
      goBack(mode);
    }
  };
  document.addEventListener('keydown', escHandler);

  // Focus the title field.
  (document.getElementById('f-title') as HTMLInputElement | null)?.focus();
}

function goBack(mode: 'add' | 'edit'): void {
  const s = getState();
  if (mode === 'edit' && s.selectedId && s.selectedItem) {
    navigate('detail');
  } else {
    navigate('list');
  }
}

/// Normalize a URL input so the Rust-side `url::Url::parse` accepts it.
///
/// Prepends `https://` when the input looks like a bare host (no scheme),
/// then validates via the JS URL constructor. Returns { ok, value, error }.
function normalizeUrl(raw: string): { ok: true; value: string } | { ok: false; error: string } {
  if (!raw) return { ok: true, value: '' };
  const trimmed = raw.trim();
  // If it already has a scheme, pass through. Otherwise assume https://.
  const candidate = /^[a-zA-Z][a-zA-Z0-9+.-]*:\/\//.test(trimmed)
    ? trimmed
    : `https://${trimmed}`;
  try {
    const u = new URL(candidate);
    // url::Url rejects schemes without an authority (host). Require a host.
    if (!u.host) return { ok: false, error: 'URL must include a host (e.g. https://example.com)' };
    return { ok: true, value: u.toString() };
  } catch {
    return { ok: false, error: 'URL is not valid — try something like https://example.com' };
  }
}

async function saveLogin(mode: 'add' | 'edit', existing: Item | null): Promise<void> {
  const state = getState();

  const title = (document.getElementById('f-title') as HTMLInputElement).value.trim();
  const rawUrl = (document.getElementById('f-url') as HTMLInputElement).value;
  const username = (document.getElementById('f-username') as HTMLInputElement).value.trim();
  const password = (document.getElementById('f-password') as HTMLInputElement).value;
  const totpStr = (document.getElementById('f-totp') as HTMLInputElement).value.trim();
  const group = (document.getElementById('f-group') as HTMLInputElement).value.trim();
  const notes = (document.getElementById('f-notes') as HTMLTextAreaElement).value;

  if (!title) {
    setState({ error: 'Title is required' });
    return;
  }

  const urlResult = normalizeUrl(rawUrl);
  if (!urlResult.ok) {
    setState({ error: urlResult.error });
    return;
  }
  const url = urlResult.value;

  let totp: TotpConfig | undefined;
  if (totpStr) {
    try {
      const bytes = base32Decode(totpStr);
      totp = {
        secret: Array.from(bytes),
        algorithm: 'sha1',
        digits: 6,
        period_seconds: 30,
        kind: 'totp',
      };
    } catch (err) {
      setState({ error: `Invalid TOTP secret: ${err instanceof Error ? err.message : String(err)}` });
      return;
    }
  }

  const now = Math.floor(Date.now() / 1000);
  const core: LoginCore & { type: 'login' } = {
    type: 'login',
    username: username || undefined,
    password: password || undefined,
    url: url || undefined,
    totp,
  };

  // Build the Item. On edit we preserve id/created/tags/favorite/sections/
  // attachments/field_history from the existing item, but we EXPLICITLY
  // set trashed_at: undefined — never preserve stale trash state through
  // an edit (carry-forward from Slice 5 review M3).
  const item: Item = {
    id: existing?.id ?? '', // SW fills in for add_item.
    title,
    type: 'login',
    tags: existing?.tags ?? [],
    favorite: existing?.favorite ?? false,
    group: group || undefined,
    notes: notes || undefined,
    created: existing?.created ?? now,
    modified: now,
    trashed_at: undefined,
    core,
    sections: existing?.sections ?? [],
    attachments: existing?.attachments ?? [],
    field_history: existing?.field_history ?? {},
  };

  setState({ loading: true, error: null });

  let resp;
  if (mode === 'add') {
    resp = await sendMessage({ type: 'add_item', item });
  } else {
    if (!state.selectedId) {
      setState({ loading: false, error: 'Missing item id' });
      return;
    }
    resp = await sendMessage({ type: 'update_item', id: state.selectedId, item });
  }

  if (resp.ok) {
    const listResp = await sendMessage({ type: 'list_items' });
    if (listResp.ok) {
      const data = listResp.data as { items: Array<[ItemId, ManifestEntry]> };
      navigate('list', { entries: data.items, selectedId: null, selectedItem: null });
    } else {
      navigate('list');
    }
  } else {
    setState({ loading: false, error: resp.error });
  }
}