Init commit

lib/data-source.tsx

@@ -0,0 +1,76 @@
+"use client"
+
+import { createContext, useContext, useEffect, useState, useCallback } from "react"
+
+// ── types ─────────────────────────────────────────────────────────────────────
+
+export type DataSourceMode = "mock" | "live"
+
+interface DataSourceContextValue {
+  mode:          DataSourceMode
+  setMode:       (m: DataSourceMode) => void
+  backendUrl:    string
+  setBackendUrl: (url: string) => void
+  /** undefined = не проверялось, true = OK, false = недоступен */
+  backendStatus: boolean | undefined
+  checkBackend:  () => Promise<void>
+}
+
+// ── context ───────────────────────────────────────────────────────────────────
+
+const DataSourceContext = createContext<DataSourceContextValue | null>(null)
+
+const LS_MODE    = "routerlists:data-source"
+const LS_BACKEND = "routerlists:backend-url"
+const DEFAULT_URL = "http://localhost:8000"
+
+export function DataSourceProvider({ children }: { children: React.ReactNode }) {
+  const [mode, setModeState] = useState<DataSourceMode>("mock")
+  const [backendUrl, setBackendUrlState] = useState(DEFAULT_URL)
+  const [backendStatus, setBackendStatus] = useState<boolean | undefined>(undefined)
+
+  // Restore from localStorage on mount
+  useEffect(() => {
+    const storedMode = localStorage.getItem(LS_MODE) as DataSourceMode | null
+    const storedUrl  = localStorage.getItem(LS_BACKEND)
+    if (storedMode === "mock" || storedMode === "live") setModeState(storedMode)
+    if (storedUrl) setBackendUrlState(storedUrl)
+  }, [])
+
+  const setMode = useCallback((m: DataSourceMode) => {
+    setModeState(m)
+    localStorage.setItem(LS_MODE, m)
+  }, [])
+
+  const setBackendUrl = useCallback((url: string) => {
+    setBackendUrlState(url)
+    localStorage.setItem(LS_BACKEND, url)
+  }, [])
+
+  const checkBackend = useCallback(async () => {
+    const url = (localStorage.getItem(LS_BACKEND) ?? DEFAULT_URL).replace(/\/$/, "")
+    try {
+      const res = await fetch(`${url}/health`, { signal: AbortSignal.timeout(3000) })
+      setBackendStatus(res.ok)
+    } catch {
+      setBackendStatus(false)
+    }
+  }, [])
+
+  // Auto-check when mode switches to live
+  useEffect(() => {
+    if (mode === "live") checkBackend()
+  }, [mode, checkBackend])
+
+  return (
+    <DataSourceContext.Provider value={{ mode, setMode, backendUrl, setBackendUrl, backendStatus, checkBackend }}>
+      {children}
+    </DataSourceContext.Provider>
+  )
+}
+
+export function useDataSource(): DataSourceContextValue {
+  const ctx = useContext(DataSourceContext)
+  if (!ctx) throw new Error("useDataSource must be used inside <DataSourceProvider>")
+  return ctx
+}