slideshare/src/hooks/useSlideOperations.ts

import { useState } from 'react';
import { useNavigate } from 'react-router-dom';
import type { Presentation, Slide } from '../types/presentation.ts';
import { updatePresentation } from '../utils/presentationStorage.ts';
import { loggers } from '../utils/logger.ts';

interface UseSlideOperationsProps {
  presentation: Presentation | null;
  presentationId: string;
  onPresentationUpdate: (presentation: Presentation) => void;
  onError: (error: string) => void;
  confirmDelete: (message: string) => Promise<boolean>;
}

export const useSlideOperations = ({
  presentation,
  presentationId,
  onPresentationUpdate,
  onError,
  confirmDelete
}: UseSlideOperationsProps) => {
  const navigate = useNavigate();
  const [saving, setSaving] = useState(false);

  const duplicateSlide = async (slideIndex: number) => {
    if (!presentation) return;
    
    const slideToDuplicate = presentation.slides[slideIndex];
    if (!slideToDuplicate) return;
    
    try {
      setSaving(true);
      onError('');
      
      // Create a duplicate slide with new ID
      const duplicatedSlide: Slide = {
        ...slideToDuplicate,
        id: `slide_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
        order: slideIndex + 1 // Insert right after the original
      };
      
      // Create updated presentation with the duplicated slide
      const updatedPresentation = { ...presentation };
      const newSlides = [...presentation.slides];
      
      // Insert the duplicated slide after the original
      newSlides.splice(slideIndex + 1, 0, duplicatedSlide);
      
      // Update slide order for all slides after the insertion point
      newSlides.forEach((slide, index) => {
        slide.order = index;
      });
      
      updatedPresentation.slides = newSlides;
      
      // Save the updated presentation
      await updatePresentation(updatedPresentation);
      
      // Update local state
      onPresentationUpdate(updatedPresentation);
      
      // Navigate to the duplicated slide
      const newSlideNumber = slideIndex + 2; // +2 because we inserted after and slide numbers are 1-based
      navigate(`/presentations/${presentationId}/edit/slides/${newSlideNumber}`);
      
    } catch (err) {
      loggers.presentation.error('Failed to duplicate slide', err instanceof Error ? err : new Error(String(err)));
      onError(err instanceof Error ? err.message : 'Failed to duplicate slide');
    } finally {
      setSaving(false);
    }
  };

  const deleteSlide = async (slideIndex: number) => {
    if (!presentation) return;
    
    const slideToDelete = presentation.slides[slideIndex];
    if (!slideToDelete) return;
    
    const slideNumber = slideIndex + 1;
    const totalSlides = presentation.slides.length;
    let confirmMessage = `Are you sure you want to delete slide ${slideNumber}?`;
    
    if (totalSlides === 1) {
      confirmMessage = `Are you sure you want to delete the only slide in this presentation? The presentation will be empty after deletion.`;
    } else {
      confirmMessage += ` This will remove the slide and renumber all subsequent slides. This action cannot be undone.`;
    }
    
    const confirmed = await confirmDelete(confirmMessage);
    if (!confirmed) {
      return;
    }
    
    try {
      setSaving(true);
      onError('');
      
      // Create updated presentation with the slide removed
      const updatedPresentation = { ...presentation };
      updatedPresentation.slides = presentation.slides.filter((_, index) => index !== slideIndex);
      
      // Update slide order for remaining slides
      updatedPresentation.slides.forEach((slide, index) => {
        slide.order = index;
      });
      
      // Save the updated presentation
      await updatePresentation(updatedPresentation);
      
      // Update local state
      onPresentationUpdate(updatedPresentation);
      
      // Handle navigation after deletion
      const totalSlides = updatedPresentation.slides.length;
      if (totalSlides === 0) {
        // No slides left, stay on editor main view
        navigate(`/presentations/${presentationId}/edit`);
      } else {
        // Navigate to appropriate slide
        let newSlideIndex = slideIndex;
        if (slideIndex >= totalSlides) {
          // If we deleted the last slide, go to the new last slide
          newSlideIndex = totalSlides - 1;
        }
        // Navigate to the adjusted slide number
        const slideNumber = newSlideIndex + 1;
        navigate(`/presentations/${presentationId}/edit/slides/${slideNumber}`);
      }
      
    } catch (err) {
      loggers.presentation.error('Failed to delete slide', err instanceof Error ? err : new Error(String(err)));
      onError(err instanceof Error ? err.message : 'Failed to delete slide');
    } finally {
      setSaving(false);
    }
  };

  const reorderSlides = async (fromIndex: number, toIndex: number) => {
    if (!presentation || fromIndex === toIndex) return;

    try {
      setSaving(true);
      onError('');

      // Create updated presentation with reordered slides
      const updatedPresentation = { ...presentation };
      const newSlides = [...presentation.slides];

      // Remove the slide from its current position
      const [movedSlide] = newSlides.splice(fromIndex, 1);

      // Insert it at the new position
      newSlides.splice(toIndex, 0, movedSlide);

      // Update slide order for all slides
      newSlides.forEach((slide, index) => {
        slide.order = index;
      });

      updatedPresentation.slides = newSlides;

      // Save the updated presentation
      await updatePresentation(updatedPresentation);

      // Update local state
      onPresentationUpdate(updatedPresentation);

    } catch (err) {
      loggers.presentation.error('Failed to reorder slides', err instanceof Error ? err : new Error(String(err)));
      onError(err instanceof Error ? err.message : 'Failed to reorder slides');
    } finally {
      setSaving(false);
    }
  };

  return {
    duplicateSlide,
    deleteSlide,
    reorderSlides,
    saving
  };
};