import type { ItemFilters } from './filters';
import { filtersToSearchParams } from './filters';

export interface ItemTag {
  id: number;
  name: string;
  color: string;
}

export interface Item {
  id: number;
  name: string;
  description: string | null;
  price_cents: number;
  images: { id: number; image_path: string; sort_order: number }[];
  status: 'pending' | 'available' | 'reserved' | 'sold';
  category_id: number | null;
  category_name: string | null;
  tags: ItemTag[];
}

export interface Category {
  id: number;
  name: string;
  parent_id: number | null;
  sort_order: number;
  item_count: number;
}

export interface Tag {
  id: number;
  name: string;
  color: string;
  item_count: number;
}

export interface FilterOptions {
  categories: Category[];
  tags: Tag[];
  priceRange: { min_cents: number; max_cents: number };
}

export interface SiteConfig {
  paypalClientId: string | null;
  demoMode: boolean;
  currency: string;
}

export async function fetchConfig(): Promise<SiteConfig> {
  const res = await fetch('/api/config');
  return res.json();
}

export async function fetchItems(filters?: ItemFilters): Promise<Item[]> {
  const query = filters ? filtersToSearchParams(filters).toString() : '';
  const res = await fetch(query ? `/api/items?${query}` : '/api/items');
  // An error response still parses as JSON — as `{ error: ... }`, not an array.
  // Returning that unchecked would set it as the item list and crash the grid
  // on `.map`, so a failure has to surface as a rejection the caller can show.
  if (!res.ok) throw new Error('failed to load items');
  return res.json();
}

export async function fetchFilterOptions(): Promise<FilterOptions> {
  const res = await fetch('/api/filters');
  if (!res.ok) throw new Error('failed to load filters');
  return res.json();
}

// Every admin call goes through this. Without the res.ok check a 4xx/5xx still
// resolves — the caller then reports success for a write that never happened,
// which is worse than failing outright because nothing prompts the user to look
// for the missing row.
async function expectOk(res: Response, action: string): Promise<Response> {
  if (res.ok) return res;
  const detail = await res.json().catch(() => null);
  throw new Error(detail?.error ? `${action}: ${detail.error}` : action);
}

export async function fetchAdminItems(filters?: ItemFilters): Promise<Item[]> {
  const query = filters ? filtersToSearchParams(filters).toString() : '';
  const res = await expectOk(
    await fetch(query ? `/api/admin/items?${query}` : '/api/admin/items'),
    'failed to load items'
  );
  return res.json();
}

export async function saveItem(id: number | null, formData: FormData): Promise<Item> {
  const url = id ? `/api/admin/items/${id}` : '/api/admin/items';
  const res = await expectOk(
    await fetch(url, { method: id ? 'PUT' : 'POST', body: formData }),
    'failed to save item'
  );
  return res.json();
}

export async function deleteItem(id: number): Promise<void> {
  await expectOk(await fetch(`/api/admin/items/${id}`, { method: 'DELETE' }), 'failed to delete item');
}

export async function deleteItemImage(itemId: number, imageId: number): Promise<void> {
  await expectOk(
    await fetch(`/api/admin/items/${itemId}/images/${imageId}`, { method: 'DELETE' }),
    'failed to remove image'
  );
}

export async function markSold(id: number): Promise<Item> {
  const res = await expectOk(
    await fetch(`/api/admin/items/${id}/mark-sold`, { method: 'POST' }),
    'failed to mark sold'
  );
  return res.json();
}

// Publishing a pending item is mark-available: it is the same transition and
// the same UPDATE, so the admin UI simply labels the button "Publish" when the
// item is pending rather than calling a second endpoint that does the same
// thing.
export async function markAvailable(id: number): Promise<Item> {
  const res = await expectOk(
    await fetch(`/api/admin/items/${id}/mark-available`, { method: 'POST' }),
    'failed to mark available'
  );
  return res.json();
}

// Not symmetrical with the above: the server refuses to unpublish a reserved or
// sold item and says which, so the message it returns is worth surfacing rather
// than replacing with a generic one.
export async function unpublishItem(id: number): Promise<Item> {
  const res = await expectOk(
    await fetch(`/api/admin/items/${id}/unpublish`, { method: 'POST' }),
    'failed to unpublish'
  );
  return res.json();
}

// The admin endpoints return a JSON error body on 4xx; surfacing its message
// lets the UI say "that name is already used here" instead of a generic
// failure.
async function sendJson<T>(url: string, method: string, body?: unknown): Promise<T> {
  const res = await fetch(url, {
    method,
    headers: { 'Content-Type': 'application/json' },
    body: body === undefined ? undefined : JSON.stringify(body)
  });
  if (!res.ok) {
    const detail = await res.json().catch(() => ({ error: 'request failed' }));
    throw new Error(detail.error || 'request failed');
  }
  return res.status === 204 ? (undefined as T) : res.json();
}

export async function fetchAdminCategories(): Promise<Category[]> {
  const res = await fetch('/api/admin/categories');
  return res.json();
}

export function createCategory(name: string, parentId: number | null): Promise<Category> {
  return sendJson('/api/admin/categories', 'POST', { name, parent_id: parentId });
}

export function updateCategory(
  id: number,
  changes: { name?: string; parent_id?: number | null }
): Promise<Category> {
  return sendJson(`/api/admin/categories/${id}`, 'PUT', changes);
}

export function deleteCategory(
  id: number
): Promise<{ deleted_categories: number; uncategorized_items: number }> {
  return sendJson(`/api/admin/categories/${id}`, 'DELETE');
}

export async function fetchAdminTags(): Promise<Tag[]> {
  const res = await fetch('/api/admin/tags');
  return res.json();
}

export function createTag(name: string): Promise<Tag> {
  return sendJson('/api/admin/tags', 'POST', { name });
}

export function updateTag(id: number, changes: { name?: string; color?: string }): Promise<Tag> {
  return sendJson(`/api/admin/tags/${id}`, 'PUT', changes);
}

export function deleteTag(id: number): Promise<void> {
  return sendJson(`/api/admin/tags/${id}`, 'DELETE');
}