import { useState, useEffect } from "react";
import { isAxiosError } from "axios";
import apiClient from "@app/services/apiClient";
import type { EndpointAvailabilityDetails } from "@app/types/endpointAvailability";

// Track globally fetched endpoint sets to prevent duplicate fetches across components
const globalFetchedSets = new Set<string>();
const globalEndpointCache: Record<string, EndpointAvailabilityDetails> = {};
/**
 * Hook to check if a specific endpoint is enabled
 * This wraps the context for single endpoint checks
 */
export function useEndpointEnabled(endpoint: string): {
  enabled: boolean | null;
  loading: boolean;
  error: string | null;
  refetch: () => Promise<void>;
} {
  const [enabled, setEnabled] = useState<boolean | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const fetchEndpointStatus = async () => {
    if (!endpoint) {
      setEnabled(null);
      setLoading(false);
      return;
    }

    try {
      setLoading(true);
      setError(null);

      const response = await apiClient.get<boolean>(
        `/api/v1/config/endpoint-enabled?endpoint=${encodeURIComponent(endpoint)}`,
      );

      const isEnabled = response.data;
      setEnabled(isEnabled);
    } catch (err) {
      const errorMessage =
        err instanceof Error ? err.message : "Unknown error occurred";
      setError(errorMessage);
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    fetchEndpointStatus();
  }, [endpoint]);

  return {
    enabled,
    loading,
    error,
    refetch: fetchEndpointStatus,
  };
}

/**
 * Hook to check multiple endpoints at once using batch API
 * Returns a map of endpoint -> enabled status
 */
export function useMultipleEndpointsEnabled(endpoints: string[]): {
  endpointStatus: Record<string, boolean>;
  endpointDetails: Record<string, EndpointAvailabilityDetails>;
  loading: boolean;
  error: string | null;
  refetch: () => Promise<void>;
} {
  const [endpointStatus, setEndpointStatus] = useState<Record<string, boolean>>(
    {},
  );
  const [endpointDetails, setEndpointDetails] = useState<
    Record<string, EndpointAvailabilityDetails>
  >({});
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const fetchAllEndpointStatuses = async (force = false) => {
    const endpointsKey = [...endpoints].sort().join(",");

    // Skip if we already fetched these exact endpoints globally
    if (!force && globalFetchedSets.has(endpointsKey)) {
      console.debug(
        "[useEndpointConfig] Already fetched these endpoints globally, using cache",
      );
      const cached = endpoints.reduce(
        (acc, endpoint) => {
          const cachedDetails = globalEndpointCache[endpoint];
          if (cachedDetails) {
            acc.status[endpoint] = cachedDetails.enabled;
            acc.details[endpoint] = cachedDetails;
          }
          return acc;
        },
        {
          status: {} as Record<string, boolean>,
          details: {} as Record<string, EndpointAvailabilityDetails>,
        },
      );
      setEndpointStatus(cached.status);
      setEndpointDetails((prev) => ({ ...prev, ...cached.details }));
      setLoading(false);
      return;
    }
    if (!endpoints || endpoints.length === 0) {
      setEndpointStatus({});
      setEndpointDetails({});
      setLoading(false);
      return;
    }

    try {
      setLoading(true);
      setError(null);

      // Check which endpoints we haven't fetched yet
      const newEndpoints = endpoints.filter(
        (ep) => !(ep in globalEndpointCache),
      );
      if (newEndpoints.length === 0) {
        console.debug(
          "[useEndpointConfig] All endpoints already in global cache",
        );
        const cached = endpoints.reduce(
          (acc, endpoint) => {
            const cachedDetails = globalEndpointCache[endpoint];
            if (cachedDetails) {
              acc.status[endpoint] = cachedDetails.enabled;
              acc.details[endpoint] = cachedDetails;
            }
            return acc;
          },
          {
            status: {} as Record<string, boolean>,
            details: {} as Record<string, EndpointAvailabilityDetails>,
          },
        );
        setEndpointStatus(cached.status);
        setEndpointDetails((prev) => ({ ...prev, ...cached.details }));
        globalFetchedSets.add(endpointsKey);
        setLoading(false);
        return;
      }
      // Use batch API for efficiency - only fetch new endpoints
      const endpointsParam = newEndpoints.join(",");

      const response = await apiClient.get<
        Record<string, EndpointAvailabilityDetails>
      >(
        `/api/v1/config/endpoints-availability?endpoints=${encodeURIComponent(endpointsParam)}`,
      );
      const statusMap = response.data;

      // Update global cache with new results
      Object.entries(statusMap).forEach(([endpoint, details]) => {
        globalEndpointCache[endpoint] = {
          enabled: details?.enabled ?? true,
          reason: details?.reason ?? null,
        };
      });
      // Get all requested endpoints from cache (including previously cached ones)
      const fullStatus = endpoints.reduce(
        (acc, endpoint) => {
          const cachedDetails = globalEndpointCache[endpoint];
          if (cachedDetails) {
            acc.status[endpoint] = cachedDetails.enabled;
            acc.details[endpoint] = cachedDetails;
          } else {
            acc.status[endpoint] = true;
          }
          return acc;
        },
        {
          status: {} as Record<string, boolean>,
          details: {} as Record<string, EndpointAvailabilityDetails>,
        },
      );
      setEndpointStatus(fullStatus.status);
      setEndpointDetails((prev) => ({ ...prev, ...fullStatus.details }));
      globalFetchedSets.add(endpointsKey);
    } catch (err: unknown) {
      // On 401 (auth error), use optimistic fallback instead of disabling
      if (isAxiosError(err) && err.response?.status === 401) {
        console.warn(
          "[useEndpointConfig] 401 error - using optimistic fallback",
        );
        const optimisticStatus = endpoints.reduce(
          (acc, endpoint) => {
            const optimisticDetails: EndpointAvailabilityDetails = {
              enabled: true,
              reason: null,
            };
            acc.status[endpoint] = true;
            acc.details[endpoint] = optimisticDetails;
            globalEndpointCache[endpoint] = optimisticDetails;
            return acc;
          },
          {
            status: {} as Record<string, boolean>,
            details: {} as Record<string, EndpointAvailabilityDetails>,
          },
        );
        setEndpointStatus(optimisticStatus.status);
        setEndpointDetails((prev) => ({
          ...prev,
          ...optimisticStatus.details,
        }));
        setLoading(false);
        return;
      }
      const errorMessage =
        err instanceof Error ? err.message : "Unknown error occurred";
      setError(errorMessage);
      console.error(
        "[EndpointConfig] Failed to check multiple endpoints:",
        err,
      );

      // Fallback: assume all endpoints are enabled on error (optimistic)
      const optimisticStatus = endpoints.reduce(
        (acc, endpoint) => {
          const optimisticDetails: EndpointAvailabilityDetails = {
            enabled: true,
            reason: null,
          };
          acc.status[endpoint] = true;
          acc.details[endpoint] = optimisticDetails;
          return acc;
        },
        {
          status: {} as Record<string, boolean>,
          details: {} as Record<string, EndpointAvailabilityDetails>,
        },
      );
      setEndpointStatus(optimisticStatus.status);
      setEndpointDetails((prev) => ({ ...prev, ...optimisticStatus.details }));
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    fetchAllEndpointStatuses();
  }, [endpoints.join(",")]); // Re-run when endpoints array changes

  return {
    endpointStatus,
    endpointDetails,
    loading,
    error,
    refetch: () => fetchAllEndpointStatuses(true),
  };
}