import VBox from 'sap/m/VBox';
import MessageToast from 'sap/m/MessageToast';
import Log from 'sap/base/Log';
import WizardController from '../Wizard';
import Wizard from 'sap/m/Wizard';
import WizardStep from 'sap/m/WizardStep';
import HeaderSelectionStep from './HeaderSelectionStep';
import PreviewStep from './PreviewStep';
import MessagesStep from './MessagesStep';

/**
 * UploadStep – first wizard step where the user selects the spreadsheet file.
 *
 * This step handles file upload, processes the file, and manages wizard navigation.
 */
export default class UploadStep {
  public readonly stepName = 'uploadStep';

  private wizardController: WizardController;
  public wizard: Wizard;
  private util: any; // Util instance for i18n

  constructor(wizardController: WizardController, wizard?: Wizard, util?: any) {
    this.wizardController = wizardController;
    this.wizard = wizard;
    this.util = util;
  }

  /** Build method - The UI is already defined in the fragment */
  public build(container: VBox): void {
    // The UI is already defined in the fragment
    // This step only needs to handle the logic
    // The fragment will call onFileUpload and onFileDrop methods
  }

  public validate(): boolean {
    return true;
  }

  /**
   * Handle file upload from FileUploader
   */
  public async onFileUpload(event: any): Promise<void> {
    try {
      const files = event.getParameter('files');
      const file = files && (files[0] as File);
      if (file) {
        await this.processFileAndNavigate(file);
      } else {
        const noFileMessage = this.util?.geti18nText?.('spreadsheetimporter.noFileSelected') || 'No file selected';
        MessageToast.show(noFileMessage);
      }

      this.wizardController.getStep('uploadStep').setBusy(false);
    } catch (error) {
      Log.error('Error handling file upload', error as Error, 'UploadStep');
      const errorMessage = this.util?.geti18nText?.('spreadsheetimporter.errorProcessingFileToast') || 'Error processing file';
      MessageToast.show(errorMessage);
    }
  }

  /**
   * Reset the wizard progress to avoid circular references when uploading a new file
   */
  private resetWizardProgress(): void {
    try {
      if (this.wizard) {
        // Reset wizard progress back to the upload step (first step)
        const uploadStepControl = this.wizardController.getStep('uploadStep');
        if (uploadStepControl) {
          this.wizard.discardProgress(uploadStepControl, false);
          Log.debug('Wizard progress reset to upload step', undefined, 'UploadStep');
        }

        // Clear any previous step configurations
        const uploadStep = this.wizardController.getStep('uploadStep');
        const headerStep = this.wizardController.getStep('headerSelectionStep');
        const previewStep = this.wizardController.getStep('previewDataStep');

        // Reset step flow configurations
        if (uploadStep) {
          uploadStep.setSubsequentSteps([]);
          uploadStep.setNextStep(null);
        }
        if (headerStep) {
          headerStep.setValidated(false);
        }
        if (previewStep) {
          previewStep.setValidated(false);
        }
      }
    } catch (error) {
      Log.warning('Error resetting wizard progress', error as Error, 'UploadStep');
    }
  }

  /**
   * Process the file and handle wizard navigation
   */
  private async processFileAndNavigate(file: File): Promise<void> {
    try {
      this.wizardController.setUploadButtonEnabled(false);
      this.wizardController.resetCurrentCoordinates();

      // Process the file using enhanced pipeline with centralized coordinates
      // Use current coordinates from the model (defaults to A1 if not set)
      const processedData = await this.wizardController.processFile(file, this.wizardController.getCurrentCoordinates(), true, false);
      // Update Wizard with the file data
      this.wizardController.setFileData(file, processedData);

      // create steps controllers
      this.createStepsControllers();

      // Check for header validation issues
      const headerValidationResult = processedData.validationMessages.find((message: any) => message.type.title === 'EmptyHeaders');

      let navigateToStep: WizardStep;

      if (processedData.validationMessages.length > 0 && headerValidationResult) {
        // Wrong headers but other errors found - Navigate to MessagesStep
        const uploadStepControl = this.wizardController.getStep('uploadStep');
        const headerStepControl = this.wizardController.getStep('headerSelectionStep');
        const messagesStepControl = this.wizardController.getStep('messagesStep');
        if (uploadStepControl && messagesStepControl && uploadStepControl.getNextStep() !== messagesStepControl.getId()) {
          uploadStepControl.setNextStep(messagesStepControl);
        }
        if (headerStepControl && messagesStepControl && headerStepControl.getNextStep() !== messagesStepControl.getId()) {
          headerStepControl.setNextStep(messagesStepControl);
        }
        navigateToStep = headerStepControl;
        // if build already rebuild headerSelectionStep
        if (this.wizardController.stepsBuilt.has('headerSelectionStep')) {
          const headerSelectionController = this.wizardController.getStepControl('headerSelectionStep') as HeaderSelectionStep;
          headerSelectionController.build(this.wizardController.findStepContainer('headerSelectionStep'));
        } else {
          this.wizardController.activateStep('headerSelectionStep');
        }
      }
      if (headerValidationResult) {
        // Wrong header detected - Configure wizard flow
        const uploadStepControl = this.wizardController.getStep('uploadStep');
        const headerStepControl = this.wizardController.getStep('headerSelectionStep');
        if (uploadStepControl && headerStepControl && uploadStepControl.getNextStep() !== headerStepControl.getId()) {
          uploadStepControl.setNextStep(headerStepControl);
        }
        navigateToStep = headerStepControl;
        // if build already rebuild headerSelectionStep
        if (this.wizardController.stepsBuilt.has('headerSelectionStep')) {
          const headerSelectionController = this.wizardController.getStepControl('headerSelectionStep') as HeaderSelectionStep;
          headerSelectionController.build(this.wizardController.findStepContainer('headerSelectionStep'));
        } else {
          this.wizardController.activateStep('headerSelectionStep');
        }
      } else if (processedData.validationMessages.length > 0) {
        // Valid headers but other errors found - Navigate to MessagesStep
        const uploadStepControl = this.wizardController.getStep('uploadStep');
        const messagesStepControl = this.wizardController.getStep('messagesStep');
        if (uploadStepControl && messagesStepControl && uploadStepControl.getNextStep() !== messagesStepControl.getId()) {
          uploadStepControl.setNextStep(messagesStepControl);
        }

        // Store validation messages in the message handler for use in MessagesStep
        if (this.wizardController.getDialogController()?.messageHandler) {
          this.wizardController.getDialogController().messageHandler.setMessages(processedData.validationMessages);
        }

        navigateToStep = messagesStepControl;
        // Build or rebuild messagesStep
        if (this.wizardController.stepsBuilt.has('messagesStep')) {
          const messagesController = this.wizardController.getStepControl('messagesStep');
          messagesController.build(this.wizardController.findStepContainer('messagesStep'));
        } else {
          this.wizardController.activateStep('messagesStep');
        }
      } else {
        // Valid headers - Configure direct flow to preview
        const uploadStepControl = this.wizardController.getStep('uploadStep');
        const previewStepControl = this.wizardController.getStep('previewDataStep');
        if (uploadStepControl && previewStepControl && uploadStepControl.getNextStep() !== previewStepControl.getId()) {
          uploadStepControl.setNextStep(previewStepControl);
        }
        navigateToStep = previewStepControl;
        if (this.wizardController.stepsBuilt.has('previewDataStep')) {
          const previewStepController = this.wizardController.getStepControl('previewDataStep') as PreviewStep;
          previewStepController.build(this.wizardController.findStepContainer('previewDataStep'), this.wizardController.processedData);
        } else {
          this.wizardController.activateStep('previewDataStep');
        }

        this.wizardController.setUploadButtonEnabled(true);
      }

      this.wizard.goToStep(navigateToStep, true);
      this.wizard.nextStep();
    } catch (error) {
      Log.error('Error processing file', error as Error, 'UploadStep');
      this.wizardController.getWizardModel().setProperty('/fileUploaded', false);

      const errorMessage = this.util?.geti18nText?.('spreadsheetimporter.errorProcessingFile') || 'Error processing file';
      MessageToast.show(errorMessage);
    }
  }

  private createStepsControllers(): void {
    // init steps controllers creation and calling build method
    // both steps need the data from the upload step
    this.wizardController.activateStep('headerSelectionStep');
    // this.wizardController.activateStep("messagesStep");
    this.wizardController.activateStep('previewDataStep');
  }
}