feat(api): add admin API client with auth, error handling, FormData, and abortable requests

src/lib/admin/api.ts

@@ -0,0 +1,93 @@
+import { goto } from '$app/navigation'
+
+export type HttpMethod = 'GET' | 'POST' | 'PUT' | 'PATCH' | 'DELETE'
+
+export interface RequestOptions<TBody = unknown> {
+  method?: HttpMethod
+  body?: TBody
+  signal?: AbortSignal
+  headers?: Record<string, string>
+}
+
+export interface ApiError extends Error {
+  status: number
+  details?: unknown
+}
+
+function getAuthHeader() {
+  if (typeof localStorage === 'undefined') return {}
+  const auth = localStorage.getItem('admin_auth')
+  return auth ? { Authorization: `Basic ${auth}` } : {}
+}
+
+async function handleResponse(res: Response) {
+  if (res.status === 401) {
+    // Redirect to login for unauthorized requests
+    try {
+      goto('/admin/login')
+    } catch {}
+  }
+
+  const contentType = res.headers.get('content-type') || ''
+  const isJson = contentType.includes('application/json')
+  const data = isJson ? await res.json().catch(() => undefined) : undefined
+
+  if (!res.ok) {
+    const err: ApiError = Object.assign(new Error('Request failed'), {
+      status: res.status,
+      details: data
+    })
+    throw err
+  }
+  return data
+}
+
+export async function request<TResponse = unknown, TBody = unknown>(
+  url: string,
+  opts: RequestOptions<TBody> = {}
+): Promise<TResponse> {
+  const { method = 'GET', body, signal, headers } = opts
+
+  const isFormData = typeof FormData !== 'undefined' && body instanceof FormData
+  const mergedHeaders: Record<string, string> = {
+    ...(isFormData ? {} : { 'Content-Type': 'application/json' }),
+    ...getAuthHeader(),
+    ...(headers || {})
+  }
+
+  const res = await fetch(url, {
+    method,
+    headers: mergedHeaders,
+    body: body ? (isFormData ? (body as any) : JSON.stringify(body)) : undefined,
+    signal
+  })
+
+  return handleResponse(res) as Promise<TResponse>
+}
+
+export const api = {
+  get: <T = unknown>(url: string, opts: Omit<RequestOptions, 'method' | 'body'> = {}) =>
+    request<T>(url, { ...opts, method: 'GET' }),
+  post: <T = unknown, B = unknown>(url: string, body: B, opts: Omit<RequestOptions<B>, 'method' | 'body'> = {}) =>
+    request<T, B>(url, { ...opts, method: 'POST', body }),
+  put: <T = unknown, B = unknown>(url: string, body: B, opts: Omit<RequestOptions<B>, 'method' | 'body'> = {}) =>
+    request<T, B>(url, { ...opts, method: 'PUT', body }),
+  patch: <T = unknown, B = unknown>(url: string, body: B, opts: Omit<RequestOptions<B>, 'method' | 'body'> = {}) =>
+    request<T, B>(url, { ...opts, method: 'PATCH', body }),
+  delete: <T = unknown>(url: string, opts: Omit<RequestOptions, 'method' | 'body'> = {}) =>
+    request<T>(url, { ...opts, method: 'DELETE' })
+}
+
+export function createAbortable() {
+  let controller: AbortController | null = null
+  return {
+    nextSignal() {
+      if (controller) controller.abort()
+      controller = new AbortController()
+      return controller.signal
+    },
+    abort() {
+      if (controller) controller.abort()
+    }
+  }
+}