from django.shortcuts import render, redirect
from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.urls import reverse
from django.utils.text import slugify
import openpyxl
from .models import Category, Supplier
from .forms_import import ImportFileForm

@login_required
def import_categories(request):
    """
    Import categories from an Excel (.xlsx) file.
    Expected columns: Name (Eng), Name (Ar)
    """
    if request.method == 'POST':
        form = ImportFileForm(request.POST, request.FILES)
        if form.is_valid():
            excel_file = request.FILES['file']
            
            try:
                wb = openpyxl.load_workbook(excel_file)
                sheet = wb.active
                
                count = 0
                updated_count = 0
                errors = []
                
                # Skip header row (min_row=2)
                for i, row in enumerate(sheet.iter_rows(min_row=2, values_only=True), start=2):
                    if not any(row): continue # Skip empty rows
                    
                    # Unpack columns with fallbacks for safety
                    # Format: name_en, name_ar
                    name_en = str(row[0]).strip() if row[0] else None
                    name_ar = str(row[1]).strip() if len(row) > 1 and row[1] else name_en
                    
                    if not name_en:
                        errors.append(f"Row {i}: Missing English Name. Skipped.")
                        continue
                    
                    slug = slugify(name_en)
                    
                    category, created = Category.objects.update_or_create(
                        slug=slug,
                        defaults={
                            'name_en': name_en,
                            'name_ar': name_ar,
                        }
                    )
                    
                    if created:
                        count += 1
                    else:
                        updated_count += 1
                
                if count > 0 or updated_count > 0:
                    msg = f"Import completed: {count} new categories added"
                    if updated_count > 0:
                        msg += f", {updated_count} categories updated"
                    messages.success(request, msg)
                    
                if errors:
                    for error in errors:
                        messages.warning(request, error)
                        
            except Exception as e:
                messages.error(request, f"Error processing file: {str(e)}")
            
            return redirect(reverse('inventory') + '#categories-list')
    else:
        form = ImportFileForm()

    return render(request, 'core/import_categories.html', {'form': form})

@login_required
def import_suppliers(request):
    """
    Import suppliers from an Excel (.xlsx) file.
    Expected columns: Name, Contact Person, Phone
    """
    if request.method == 'POST':
        form = ImportFileForm(request.POST, request.FILES)
        if form.is_valid():
            excel_file = request.FILES['file']
            
            try:
                wb = openpyxl.load_workbook(excel_file)
                sheet = wb.active
                
                count = 0
                updated_count = 0
                errors = []
                
                # Skip header row (min_row=2)
                for i, row in enumerate(sheet.iter_rows(min_row=2, values_only=True), start=2):
                    if not any(row): continue # Skip empty rows
                    
                    # Unpack columns with fallbacks for safety
                    # Format: Name, Contact Person, Phone
                    name = str(row[0]).strip() if row[0] else None
                    contact_person = str(row[1]).strip() if len(row) > 1 and row[1] else ''
                    phone = str(row[2]).strip() if len(row) > 2 and row[2] else ''
                    
                    if not name:
                        errors.append(f"Row {i}: Missing Name. Skipped.")
                        continue
                    
                    supplier, created = Supplier.objects.update_or_create(
                        name=name,
                        defaults={
                            'contact_person': contact_person,
                            'phone': phone,
                        }
                    )
                    
                    if created:
                        count += 1
                    else:
                        updated_count += 1
                
                if count > 0 or updated_count > 0:
                    msg = f"Import completed: {count} new suppliers added"
                    if updated_count > 0:
                        msg += f", {updated_count} suppliers updated"
                    messages.success(request, msg)
                    
                if errors:
                    for error in errors:
                        messages.warning(request, error)
                        
            except Exception as e:
                messages.error(request, f"Error processing file: {str(e)}")
            
            return redirect('suppliers')
    else:
        form = ImportFileForm()

    return render(request, 'core/import_suppliers.html', {'form': form})