import { useCallback, useEffect, useState } from 'react';

const createDefaultSettings = () => ({
  ntfy: { enabled: false, topic: '', serverUrl: '' },
  telegram: { enabled: false, chatId: '' }
});

const createDefaultCapabilities = () => ({
  ntfy: { enabled: false, serverUrl: '', topicPrefix: '' },
  telegram: { enabled: false }
});

const useNotificationSettings = ({ authorizedFetch, sessionToken }) => {
  const [settings, setSettings] = useState(createDefaultSettings);
  const [capabilities, setCapabilities] = useState(createDefaultCapabilities);
  const [dirty, setDirty] = useState(false);
  const [loading, setLoading] = useState(false);
  const [saving, setSaving] = useState(false);
  const [message, setMessage] = useState('');
  const [error, setError] = useState('');
  const [copyFeedback, setCopyFeedback] = useState('');

  const resetState = useCallback(() => {
    setSettings(createDefaultSettings());
    setCapabilities(createDefaultCapabilities());
    setDirty(false);
    setLoading(false);
    setSaving(false);
    setMessage('');
    setError('');
    setCopyFeedback('');
  }, []);

  const loadNotificationSettings = useCallback(async () => {
    if (!sessionToken) {
      return;
    }
    setLoading(true);
    setError('');
    try {
      const response = await authorizedFetch('/api/notifications/settings');
      if (!response.ok) {
        throw new Error(`HTTP ${response.status}`);
      }
      const data = await response.json();
      setSettings({
        ntfy: {
          enabled: Boolean(data?.settings?.ntfy?.enabled),
          topic: data?.settings?.ntfy?.topic || '',
          serverUrl: data?.settings?.ntfy?.serverUrl || ''
        },
        telegram: {
          enabled: Boolean(data?.settings?.telegram?.enabled),
          chatId: data?.settings?.telegram?.chatId || ''
        }
      });
      setCapabilities({
        ntfy: {
          enabled: Boolean(data?.capabilities?.ntfy?.enabled),
          serverUrl: data?.capabilities?.ntfy?.serverUrl || '',
          topicPrefix: data?.capabilities?.ntfy?.topicPrefix || ''
        },
        telegram: {
          enabled: Boolean(data?.capabilities?.telegram?.enabled)
        }
      });
      setDirty(false);
    } catch (err) {
      setError(`Benachrichtigungseinstellungen konnten nicht geladen werden: ${err.message}`);
    } finally {
      setLoading(false);
    }
  }, [authorizedFetch, sessionToken]);

  const handleFieldChange = useCallback((channel, field, value) => {
    if (channel === 'ntfy' && field === 'serverUrl') {
      return;
    }
    setSettings((prev) => {
      const nextChannel = {
        ...prev[channel],
        [field]: value
      };
      return {
        ...prev,
        [channel]: nextChannel
      };
    });
    setDirty(true);
  }, []);

  const saveNotificationSettings = useCallback(async () => {
    if (!sessionToken) {
      return;
    }
    setSaving(true);
    setError('');
    setMessage('');
    try {
      const response = await authorizedFetch('/api/notifications/settings', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ notifications: settings })
      });
      if (!response.ok) {
        throw new Error(`HTTP ${response.status}`);
      }
      const data = await response.json();
      setSettings({
        ntfy: {
          enabled: Boolean(data?.ntfy?.enabled),
          topic: data?.ntfy?.topic || settings.ntfy.topic,
          serverUrl: data?.ntfy?.serverUrl || settings.ntfy.serverUrl
        },
        telegram: {
          enabled: Boolean(data?.telegram?.enabled),
          chatId: data?.telegram?.chatId || settings.telegram.chatId
        }
      });
      setDirty(false);
      setMessage('Benachrichtigungseinstellungen gespeichert.');
      setTimeout(() => setMessage(''), 4000);
    } catch (err) {
      setError(`Speichern der Benachrichtigungen fehlgeschlagen: ${err.message}`);
    } finally {
      setSaving(false);
    }
  }, [authorizedFetch, sessionToken, settings]);

  const sendNotificationTest = useCallback(
    async (channel) => {
      if (!sessionToken) {
        return;
      }
      setError('');
      setMessage('');
      try {
        const response = await authorizedFetch('/api/notifications/test', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ channel })
        });
        if (!response.ok) {
          throw new Error(`HTTP ${response.status}`);
        }
        await response.json();
        setMessage('Testbenachrichtigung gesendet.');
        setTimeout(() => setMessage(''), 4000);
      } catch (err) {
        setError(`Testbenachrichtigung fehlgeschlagen: ${err.message}`);
      }
    },
    [authorizedFetch, sessionToken]
  );

  const copyToClipboard = useCallback(async (text) => {
    if (!text) {
      return;
    }
    setCopyFeedback('');
    try {
      if (navigator?.clipboard?.writeText) {
        await navigator.clipboard.writeText(text);
      } else {
        const tempInput = document.createElement('textarea');
        tempInput.value = text;
        tempInput.style.position = 'fixed';
        tempInput.style.top = '-9999px';
        document.body.appendChild(tempInput);
        tempInput.focus();
        tempInput.select();
        document.execCommand('copy');
        document.body.removeChild(tempInput);
      }
      setCopyFeedback('Link kopiert!');
      setTimeout(() => setCopyFeedback(''), 2000);
    } catch (err) {
      setCopyFeedback(`Kopieren fehlgeschlagen: ${err.message}`);
      setTimeout(() => setCopyFeedback(''), 3000);
    }
  }, []);

  useEffect(() => {
    if (!sessionToken) {
      resetState();
      return;
    }
    loadNotificationSettings();
  }, [sessionToken, loadNotificationSettings, resetState]);

  return {
    notificationSettings: settings,
    notificationCapabilities: capabilities,
    notificationDirty: dirty,
    notificationLoading: loading,
    notificationSaving: saving,
    notificationMessage: message,
    notificationError: error,
    copyFeedback,
    loadNotificationSettings,
    handleNotificationFieldChange: handleFieldChange,
    saveNotificationSettings,
    sendNotificationTest,
    copyToClipboard,
    resetNotificationState: resetState
  };
};

export default useNotificationSettings;