'use client';
import React, { useEffect, useMemo, useState } from 'react';
import { useSearchParams, useRouter } from 'next/navigation';
import { ArrowLeft } from 'lucide-react';
import FormTemplateBuilder from '@/components/Form/FormTemplateBuilder';
import { useEstablishment } from '@/context/EstablishmentContext';
import { useCsrfToken } from '@/context/CsrfContext';
import {
  fetchRegistrationFileGroups,
  fetchRegistrationSchoolFileMasterById,
  createRegistrationSchoolFileMaster,
  editRegistrationSchoolFileMaster,
} from '@/app/actions/registerFileGroupAction';
import { getSecureFileUrl } from '@/utils/fileUrl';
import logger from '@/utils/logger';
import { useNotification } from '@/context/NotificationContext';
import { FE_ADMIN_STRUCTURE_URL } from '@/utils/Url';

export default function FormBuilderPage() {
  const searchParams = useSearchParams();
  const router = useRouter();
  const { selectedEstablishmentId } = useEstablishment();
  const csrfToken = useCsrfToken();
  const { showNotification } = useNotification();

  const formId = searchParams.get('id');
  const preGroupId = searchParams.get('groupId');
  const isEditing = !!formId;

  const [groups, setGroups] = useState([]);
  const [initialData, setInitialData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [uploadedFile, setUploadedFile] = useState(null);
  const [existingFileUrl, setExistingFileUrl] = useState(null);

  const normalizeBackendFile = (rawFile, rawFileUrl) => {
    if (typeof rawFileUrl === 'string' && rawFileUrl.trim()) {
      return rawFileUrl;
    }

    if (typeof rawFile === 'string' && rawFile.trim()) {
      return rawFile;
    }

    if (rawFile && typeof rawFile === 'object') {
      if (typeof rawFile.url === 'string' && rawFile.url.trim()) {
        return rawFile.url;
      }
      if (typeof rawFile.path === 'string' && rawFile.path.trim()) {
        return rawFile.path;
      }
      if (typeof rawFile.name === 'string' && rawFile.name.trim()) {
        return rawFile.name;
      }
    }

    return null;
  };

  const previewFileUrl = useMemo(() => {
    if (uploadedFile instanceof File) {
      return URL.createObjectURL(uploadedFile);
    }
    return existingFileUrl || null;
  }, [uploadedFile, existingFileUrl]);

  useEffect(() => {
    return () => {
      if (previewFileUrl && previewFileUrl.startsWith('blob:')) {
        URL.revokeObjectURL(previewFileUrl);
      }
    };
  }, [previewFileUrl]);

  useEffect(() => {
    if (!selectedEstablishmentId) return;

    Promise.all([
      fetchRegistrationFileGroups(selectedEstablishmentId),
      formId ? fetchRegistrationSchoolFileMasterById(formId) : Promise.resolve(null),
    ])
      .then(([groupsData, formData]) => {
        setGroups(groupsData || []);
        if (formData) {
          setInitialData(formData);
          const resolvedFile = normalizeBackendFile(
            formData.file,
            formData.file_url
          );
          if (resolvedFile) {
            setExistingFileUrl(resolvedFile);
          }
        } else if (preGroupId) {
          setInitialData({ groups: [{ id: Number(preGroupId) }] });
        }
      })
      .catch((err) => {
        logger.error('Error loading FormBuilder data:', err);
      })
      .finally(() => {
        setLoading(false);
      });
  }, [selectedEstablishmentId, formId, preGroupId]);

  const buildFormData = async (name, group_ids, formMasterData) => {
    const dataToSend = new FormData();
    dataToSend.append(
      'data',
      JSON.stringify({
        name,
        groups: group_ids,
        formMasterData,
        establishment: selectedEstablishmentId,
      })
    );

    if (uploadedFile instanceof File) {
      const ext =
        uploadedFile.name.lastIndexOf('.') !== -1
          ? uploadedFile.name.substring(uploadedFile.name.lastIndexOf('.'))
          : '';
      const cleanName = (name || 'document')
        .replace(/[^a-zA-Z0-9_\-]/g, '_')
        .replace(/_+/g, '_')
        .replace(/^_+|_+$/g, '');
      dataToSend.append('file', uploadedFile, `${cleanName}${ext}`);
    } else if (existingFileUrl && isEditing) {
      const lastDot = existingFileUrl.lastIndexOf('.');
      const ext = lastDot !== -1 ? existingFileUrl.substring(lastDot) : '';
      const cleanName = (name || 'document')
        .replace(/[^a-zA-Z0-9_\-]/g, '_')
        .replace(/_+/g, '_')
        .replace(/^_+|_+$/g, '');
      try {
        const resp = await fetch(getSecureFileUrl(existingFileUrl));
        if (resp.ok) {
          const blob = await resp.blob();
          dataToSend.append('file', blob, `${cleanName}${ext}`);
        }
      } catch (e) {
        logger.error('Could not re-fetch existing file:', e);
      }
    }

    return dataToSend;
  };

  const handleSave = async ({ name, group_ids, formMasterData, id }) => {
    const hasFileField = (formMasterData?.fields || []).some(
      (field) => field.type === 'file'
    );
    const hasUploadedDocument =
      uploadedFile instanceof File || Boolean(existingFileUrl);

    if (hasFileField && !hasUploadedDocument) {
      showNotification(
        'Un document PDF doit être uploadé si le formulaire contient un champ fichier.',
        'error',
        'Erreur'
      );
      return;
    }

    try {
      const dataToSend = await buildFormData(name, group_ids, formMasterData);
      if (isEditing) {
        await editRegistrationSchoolFileMaster(id || formId, dataToSend, csrfToken);
        showNotification(
          `Le formulaire "${name}" a été modifié avec succès.`,
          'success',
          'Succès'
        );
      } else {
        await createRegistrationSchoolFileMaster(dataToSend, csrfToken);
        showNotification(
          `Le formulaire "${name}" a été créé avec succès.`,
          'success',
          'Succès'
        );
      }
      router.push(FE_ADMIN_STRUCTURE_URL);
    } catch (err) {
      logger.error('Error saving form:', err);
      showNotification('Erreur lors de la sauvegarde du formulaire', 'error', 'Erreur');
    }
  };

  if (loading) {
    return (
      <div className="flex items-center justify-center min-h-screen">
        <p className="text-gray-500">Chargement...</p>
      </div>
    );
  }

  return (
    <div className="w-full min-h-screen bg-neutral">
      {/* Header sticky */}
      <div className="sticky top-0 z-10 bg-white border-b border-gray-200 px-4 py-3 flex items-center gap-4">
        <button
          onClick={() => router.push(FE_ADMIN_STRUCTURE_URL)}
          className="flex items-center gap-2 text-primary hover:text-secondary font-label font-medium transition-colors"
        >
          <ArrowLeft size={20} />
          Retour
        </button>
        <h1 className="text-lg font-headline font-semibold text-gray-800">
          {isEditing ? 'Modifier le formulaire' : 'Créer un formulaire personnalisé'}
        </h1>
      </div>

      <div className="max-w-5xl mx-auto px-4 py-6 space-y-4">
        {/* FormTemplateBuilder */}
        <FormTemplateBuilder
          onSave={handleSave}
          initialData={initialData}
          groups={groups}
          isEditing={isEditing}
          masterFile={previewFileUrl}
          onMasterFileUpload={(file) => setUploadedFile(file)}
        />
      </div>
    </div>
  );
}