import { useState, useEffect, useCallback } from "react";
import type { DashboardData, JobUpdate, DashboardMetrics } from "../types/index.ts";

interface UseDashboardDataResult {
  data: DashboardData | null;
  loading: boolean;
  error: string | null;
  refetch: () => void;
}

const API_BASE = "/api";

async function fetchJson<T>(url: string): Promise<T> {
  const token = localStorage.getItem("access_token");
  const headers: Record<string, string> = {
    "Content-Type": "application/json",
  };
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }
  const response = await fetch(url, { headers });
  if (!response.ok) {
    const body = await response.json().catch(() => ({}));
    throw new Error(
      (body as { error?: string }).error ||
        `HTTP ${response.status}: ${response.statusText}`
    );
  }
  return response.json() as Promise<T>;
}

export function useDashboardData(): UseDashboardDataResult {
  const [data, setData] = useState<DashboardData | null>(null);
  const [loading, setLoading] = useState<boolean>(true);
  const [error, setError] = useState<string | null>(null);

  const fetchData = useCallback(async () => {
    setLoading(true);
    setError(null);

    try {
      const [updates, metrics] = await Promise.all([
        fetchJson<JobUpdate[]>(`${API_BASE}/updates/latest/`),
        fetchJson<DashboardMetrics>(`${API_BASE}/updates/metrics/`),
      ]);
      setData({ updates, metrics });
    } catch (err: unknown) {
      const message =
        err instanceof Error ? err.message : "An unknown error occurred";
      setError(message);
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    fetchData();
  }, [fetchData]);

  return { data, loading, error, refetch: fetchData };
}