import { Injectable, Logger } from '@nestjs/common';
import { Cron } from '@nestjs/schedule';
import { ConfigService } from '@nestjs/config';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { DocumentField } from '../database/entities/document-field.entity';
import { DocumentType } from '../database/entities/document-type.entity';
import { PaperlessService } from './paperless.service';
import { PostprocessingService } from '../postprocessing/postprocessing.service';

@Injectable()
export class PaperlessProcessorService {
  private readonly logger = new Logger(PaperlessProcessorService.name);

  constructor(
    private readonly configService: ConfigService,
    private readonly paperlessService: PaperlessService,
    private readonly postprocessingService: PostprocessingService,
    @InjectRepository(DocumentType)
    private readonly docTypeRepo: Repository<DocumentType>,
    @InjectRepository(DocumentField)
    private readonly docFieldRepo: Repository<DocumentField>,
  ) {}

  @Cron(process.env.PAPERLESS_PROCESSOR_CRON || '0 * * * * *')
  async processDocuments() {
    try {
      const response = await this.paperlessService.getDocuments({
        tags__id__all: 16,
        page_size: 9999,
      });
      const documents: any[] = Array.isArray(response)
        ? response
        : (response?.results ?? []);
      if (documents.length === 0) return;

      const customFields = await this.paperlessService.getCustomFields();
      const validFieldIds = new Set(customFields.map((f: any) => f.id));

      this.logger.log(
        `Verarbeite ${documents.length} Dokument(e) mit Tag "paperlessmanager" (ID: 16).`,
      );

      for (const doc of documents) {
        try {
          const updatedDoc = await this.processSingleDocument(
            doc,
            validFieldIds,
          );
          // Postprocessing nach dem Speichern evaluieren
          await this.postprocessingService.evaluate(updatedDoc || doc);
        } catch (innerErr: any) {
          this.logger.error(
            `Fehler bei Dokument ID ${doc.id}: ${innerErr.message}`,
          );
          if (innerErr.response?.data) {
            this.logger.error(
              `Paperless API Response: ${JSON.stringify(innerErr.response.data)}`,
            );
          }
        }
      }
    } catch (err) {
      this.logger.error('Fehler bei der Dokumentenverarbeitung:', err);
    }
  }

  private async processSingleDocument(
    doc: any,
    validFieldIds: Set<number>,
  ): Promise<any> {
    this.logger.log(`Verarbeite Dokument ID: ${doc.id}`);

    if (!doc.document_type) {
      this.logger.warn(
        `Dokument ${doc.id} hat keinen Dokumenten-Typen – setze Tag 17.`,
      );
      const tagsSet = new Set<number>(doc.tags || []);
      tagsSet.add(17);
      if (!tagsSet.has(1)) {
        tagsSet.add(6);
      }
      const updated = await this.paperlessService.updateDocument(doc.id, {
        tags: Array.from(tagsSet),
      });
      return updated;
    }

    const docTypeConfig = await this.docTypeRepo.findOne({
      where: { DocumentTypeId: doc.document_type },
    });

    if (!docTypeConfig) {
      this.logger.warn(
        `Konfiguration für DocumentType ${doc.document_type} nicht in der Datenbank gefunden.`,
      );
      return null;
    }

    const fieldsConfig = await this.docFieldRepo.find({
      where: { DocumentType: doc.document_type },
    });

    if (fieldsConfig.length === 0) {
      this.logger.log(
        `Dokument ${doc.id} (Typ ${doc.document_type}) hat keine Dokument-Felder in der DB konfiguriert.`,
      );
      const newTagsNoFields = Array.from(new Set([...(doc.tags || []), 17]));
      const updated = await this.paperlessService.updateDocument(doc.id, {
        tags: newTagsNoFields,
      });
      return updated;
    }

    const currentCustomFields = doc.custom_fields || [];
    const newCustomFields = [...currentCustomFields];
    let isAllRequiredFilled = true;

    for (const fieldConf of fieldsConfig) {
      if (fieldConf.Type === 4) {
        const customFieldId = fieldConf.TypeIndex;
        if (!customFieldId) continue;

        if (!validFieldIds.has(customFieldId)) {
          this.logger.warn(
            `Überspringe ungültiges Custom Field (TypeIndex: ${customFieldId}) für Dokument ${doc.id} - in Paperless nicht vorhanden.`,
          );
          continue;
        }

        const existingField = newCustomFields.find(
          (f) => f.field === customFieldId,
        );
        let isFilled = false;

        if (existingField) {
          isFilled = existingField.value !== null && existingField.value !== '';
        } else {
          newCustomFields.push({ field: customFieldId, value: null });
        }

        if (fieldConf.IsRequired && !isFilled) {
          isAllRequiredFilled = false;
        }
      } else {
        if (fieldConf.IsRequired) {
          let isFilled = false;
          switch (fieldConf.Type) {
            case 1:
              isFilled =
                doc.correspondent !== null && doc.correspondent !== undefined;
              break;
            case 2:
              isFilled = !!doc.created || !!doc.created_date;
              break;
            case 3:
              isFilled =
                doc.archive_serial_number !== null &&
                doc.archive_serial_number !== undefined;
              break;
            case 5:
              isFilled = !!doc.title;
              break;
            default:
              isFilled = true;
          }
          if (!isFilled) {
            isAllRequiredFilled = false;
          }
        }
      }
    }

    const tagsSet = new Set<number>(doc.tags || []);

    if (isAllRequiredFilled) {
      if (docTypeConfig.TagReady) tagsSet.add(docTypeConfig.TagReady);
      if (docTypeConfig.TagNotReady) tagsSet.delete(docTypeConfig.TagNotReady);
    } else {
      if (docTypeConfig.TagNotReady) tagsSet.add(docTypeConfig.TagNotReady);
      if (docTypeConfig.TagReady) tagsSet.delete(docTypeConfig.TagReady);
    }

    tagsSet.add(17);

    // Titel-Template auflösen
    const updatePayload: any = {
      custom_fields: newCustomFields,
      tags: Array.from(tagsSet),
    };

    if (docTypeConfig.TitelTemplate) {
      let title = docTypeConfig.TitelTemplate;

      // Prüfen ob alle im Template referenzierten Custom Fields ausgefüllt sind
      const placeholderRegex = /\{\{CUSTOM\[(\d+)\]\}\}/g;
      let allFilled = true;
      let match: RegExpExecArray | null;

      while ((match = placeholderRegex.exec(title)) !== null) {
        const fieldId = parseInt(match[1], 10);
        const cf = newCustomFields.find((f) => f.field === fieldId);
        if (!cf || cf.value == null || cf.value === '') {
          allFilled = false;
          break;
        }
      }

      if (allFilled) {
        for (const cf of newCustomFields) {
          const placeholder = `{{CUSTOM[${cf.field}]}}`;
          if (title.includes(placeholder)) {
            title = title.replaceAll(
              placeholder,
              cf.value != null ? String(cf.value) : '',
            );
          }
        }

        if (title.includes('{{DATE}}')) {
          const created = doc.created ? new Date(doc.created) : new Date();
          const dateStr = `${String(created.getDate()).padStart(2, '0')}.${String(created.getMonth() + 1).padStart(2, '0')}.${created.getFullYear()}`;
          title = title.replaceAll('{{DATE}}', dateStr);
        }

        if (title.includes('{{ZEITSTEMPEL}}')) {
          const now = new Date();
          const ts = `${String(now.getDate()).padStart(2, '0')}.${String(now.getMonth() + 1).padStart(2, '0')}.${now.getFullYear()} ${String(now.getHours()).padStart(2, '0')}:${String(now.getMinutes()).padStart(2, '0')}:${String(now.getSeconds()).padStart(2, '0')}`;
          title = title.replaceAll('{{ZEITSTEMPEL}}', ts);
        }

        updatePayload.title = title;
      } else {
        this.logger.log(
          `Dokument ${doc.id}: Titel-Template nicht angewendet – nicht alle referenzierten Custom Fields ausgefüllt.`,
        );
      }
    }

    const updated = await this.paperlessService.updateDocument(
      doc.id,
      updatePayload,
    );

    this.logger.log(
      `Dokument ${doc.id} erfolgreich aktualisiert (Alle Pflichtfelder vorhanden: ${isAllRequiredFilled}).`,
    );
    return updated;
  }
}