import { useState, useEffect } from 'react';
import { connectionModeService } from '@app/services/connectionModeService';
import { endpointAvailabilityService } from '@app/services/endpointAvailabilityService';
import { tauriBackendService } from '@app/services/tauriBackendService';
import { selfHostedServerMonitor } from '@app/services/selfHostedServerMonitor';
import { EXTENSION_TO_ENDPOINT } from '@app/constants/convertConstants';
import { getEndpointName } from '@app/utils/convertUtils';

/**
 * Comprehensive conversion status data
 */
export interface ConversionStatus {
  availability: Record<string, boolean>;   // Available on local OR SaaS?
  cloudStatus: Record<string, boolean>;    // Will use cloud?
  localOnly: Record<string, boolean>;      // Available ONLY locally (not on SaaS)?
}

/**
 * Desktop hook to check conversion availability and cloud routing
 * Returns comprehensive data about each conversion
 * @returns Object with availability, cloudStatus, and localOnly maps
 */
export function useConversionCloudStatus(): ConversionStatus {
  const [status, setStatus] = useState<ConversionStatus>({
    availability: {},
    cloudStatus: {},
    localOnly: {},
  });

  useEffect(() => {
    const checkConversions = async () => {
      const mode = await connectionModeService.getCurrentMode();

      // Self-hosted offline path: server is down but local backend is available.
      // Check each conversion against the local backend only (no cloud routing).
      if (mode === 'selfhosted') {
        const { status } = selfHostedServerMonitor.getSnapshot();
        const localUrl = tauriBackendService.getBackendUrl();
        if (status === 'offline' && localUrl) {
          const pairs: [string, string, string][] = [];
          for (const fromExt of Object.keys(EXTENSION_TO_ENDPOINT)) {
            for (const toExt of Object.keys(EXTENSION_TO_ENDPOINT[fromExt] || {})) {
              const endpointName = getEndpointName(fromExt, toExt);
              if (endpointName) pairs.push([fromExt, toExt, endpointName]);
            }
          }
          const availability: Record<string, boolean> = {};
          const cloudStatus: Record<string, boolean> = {};
          const localOnly: Record<string, boolean> = {};
          const results = await Promise.all(
            pairs.map(async ([fromExt, toExt, endpointName]) => {
              const key = `${fromExt}-${toExt}`;
              try {
                const supported = await endpointAvailabilityService.isEndpointSupportedLocally(endpointName, localUrl);
                return { key, supported };
              } catch {
                return { key, supported: false };
              }
            })
          );
          for (const { key, supported } of results) {
            availability[key] = supported;
            cloudStatus[key] = false;
            localOnly[key] = supported;
          }
          setStatus({ availability, cloudStatus, localOnly });
          return;
        }
        // Server online or local not ready: let normal endpoint checking handle it
        setStatus({ availability: {}, cloudStatus: {}, localOnly: {} });
        return;
      }

      // Don't check until backend is healthy (SaaS startup guard)
      if (!tauriBackendService.isOnline) {
        setStatus({ availability: {}, cloudStatus: {}, localOnly: {} });
        return;
      }

      if (mode !== 'saas') {
        // Non-SaaS, non-self-hosted: local endpoint checking handles everything
        setStatus({ availability: {}, cloudStatus: {}, localOnly: {} });
        return;
      }

      const availability: Record<string, boolean> = {};
      const cloudStatus: Record<string, boolean> = {};
      const localOnly: Record<string, boolean> = {};

      // Collect all conversion pairs first, then check all in parallel
      const pairs: [string, string, string][] = [];
      for (const fromExt of Object.keys(EXTENSION_TO_ENDPOINT)) {
        for (const toExt of Object.keys(EXTENSION_TO_ENDPOINT[fromExt] || {})) {
          const endpointName = getEndpointName(fromExt, toExt);
          if (endpointName) pairs.push([fromExt, toExt, endpointName]);
        }
      }

      const results = await Promise.all(
        pairs.map(async ([fromExt, toExt, endpointName]) => {
          const key = `${fromExt}-${toExt}`;
          try {
            const combined = await endpointAvailabilityService.checkEndpointCombined(
              endpointName,
              tauriBackendService.getBackendUrl()
            );
            return { key, isAvailable: combined.isAvailable, willUseCloud: combined.willUseCloud, localOnly: combined.localOnly };
          } catch (error) {
            console.error(`[useConversionCloudStatus] Endpoint check failed for ${key}:`, error);
            return { key, isAvailable: false, willUseCloud: false, localOnly: false };
          }
        })
      );

      for (const { key, isAvailable, willUseCloud: wuc, localOnly: lo } of results) {
        availability[key] = isAvailable;
        cloudStatus[key] = wuc;
        localOnly[key] = lo;
      }

      setStatus({ availability, cloudStatus, localOnly });
    };

    // Initial check
    checkConversions();

    // Re-check when SaaS local backend becomes healthy
    const unsubLocal = tauriBackendService.subscribeToStatus((status) => {
      if (status === 'healthy') {
        checkConversions();
      }
    });

    // Re-check when self-hosted server goes offline or comes back online.
    // By the time the server is confirmed offline, the local port is already
    // discovered (waitForPort completes in ~500ms vs the 8s server poll timeout).
    // selfHostedServerMonitor.subscribe immediately invokes the listener with the
    // current state, which would cause a duplicate check alongside the one above.
    // Skip the first invocation since checkConversions() was already called above.
    let skipFirst = true;
    const unsubServer = selfHostedServerMonitor.subscribe(() => {
      if (skipFirst) { skipFirst = false; return; }
      void checkConversions();
    });

    return () => {
      unsubLocal();
      unsubServer();
    };
  }, []);

  return status;
}