import pandas as pd
from io import BytesIO
from django.http import HttpResponse
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter, A4
from reportlab.lib import colors
from reportlab.platypus import SimpleDocTemplate, Table, TableStyle, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet
from openpyxl import Workbook
from openpyxl.styles import Font, Border, Side, Alignment, PatternFill
from decimal import Decimal
import locale


def format_currency(amount):
    """Format amount as Indonesian Rupiah"""
    if amount is None:
        return "Rp 0,00"

    try:
        # Convert to Decimal for precise handling
        if not isinstance(amount, Decimal):
            amount = Decimal(str(amount))

        # Format with Indonesian decimal separator (comma)
        formatted = f"{amount:,.2f}"

        # Convert to Indonesian format: comma to dot, dot to comma
        formatted = formatted.replace(',', 'temp_comma').replace('.', ',').replace('temp_comma', '.')

        return f"Rp {formatted}"
    except (ValueError, TypeError):
        return "Rp 0,00"


def export_inventory_to_excel(inventory_items, total_inventory_value):
    """Export inventory data to Excel"""
    wb = Workbook()
    ws = wb.active
    ws.title = "Inventory Report"

    # Header
    ws['A1'] = "INVENTORY REPORT"
    ws['A1'].font = Font(bold=True, size=14)
    ws.merge_cells('A1:I1')

    # Column headers
    headers = [
        'Product Code', 'Product Name', 'Category', 'Warehouse',
        'Quantity', 'Unit', 'Unit Cost', 'Total Value', 'Status'
    ]

    for col_num, header in enumerate(headers, 1):
        cell = ws.cell(row=3, column=col_num)
        cell.value = header
        cell.font = Font(bold=True)
        cell.fill = PatternFill(start_color="CCCCCC", end_color="CCCCCC", fill_type="solid")
        cell.border = Border(
            left=Side(style='thin'),
            right=Side(style='thin'),
            top=Side(style='thin'),
            bottom=Side(style='thin')
        )
        cell.alignment = Alignment(horizontal='center')

    # Data rows
    for row_num, item in enumerate(inventory_items, 4):
        ws.cell(row=row_num, column=1).value = item.product.code
        ws.cell(row=row_num, column=2).value = item.product.name
        ws.cell(row=row_num, column=3).value = item.product.category.name
        ws.cell(row=row_num, column=4).value = item.warehouse.name
        ws.cell(row=row_num, column=5).value = float(item.quantity)
        ws.cell(row=row_num, column=6).value = item.product.unit_of_measure.abbreviation
        ws.cell(row=row_num, column=7).value = float(item.product.cost_price)
        ws.cell(row=row_num, column=8).value = float(item.total_value)
        ws.cell(row=row_num, column=9).value = 'In Stock' if item.quantity > item.product.reorder_level else 'Low Stock' if item.quantity > 0 else 'Out of Stock'

        # Add borders to data cells
        for col_num in range(1, 10):
            cell = ws.cell(row=row_num, column=col_num)
            cell.border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )

    # Total row
    total_row = len(inventory_items) + 5
    ws.cell(row=total_row, column=7).value = "TOTAL VALUE:"
    ws.cell(row=total_row, column=7).font = Font(bold=True)
    ws.cell(row=total_row, column=8).value = float(total_inventory_value)
    ws.cell(row=total_row, column=8).font = Font(bold=True)

    # Auto-adjust column widths
    for column in ws.columns:
        max_length = 0
        column_cells = [cell for cell in column]
        for cell in column_cells:
            if len(str(cell.value)) > max_length:
                max_length = len(str(cell.value))
        adjusted_width = (max_length + 2)
        # Get the column letter from the first cell that is not a merged cell
        column_letter = None
        for cell in column_cells:
            if hasattr(cell, 'column_letter'):
                column_letter = cell.column_letter
                break
        if column_letter:
            ws.column_dimensions[column_letter].width = min(adjusted_width, 50)

    # Create response
    response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
    response['Content-Disposition'] = 'attachment; filename=inventory_report.xlsx'

    wb.save(response)
    return response


def export_inventory_to_pdf(inventory_items, total_inventory_value):
    """Export inventory data to PDF"""
    buffer = BytesIO()
    doc = SimpleDocTemplate(buffer, pagesize=A4)
    elements = []

    styles = getSampleStyleSheet()

    # Title
    title_style = styles['Heading1']
    title = Paragraph("INVENTORY REPORT", title_style)
    elements.append(title)
    elements.append(Spacer(1, 20))

    # Table data
    data = [['Product Code', 'Product Name', 'Category', 'Warehouse',
             'Quantity', 'Unit', 'Unit Cost', 'Total Value', 'Status']]

    for item in inventory_items:
        data.append([
            item.product.code,
            item.product.name,
            item.product.category.name,
            item.warehouse.name,
            str(item.quantity),
            item.product.unit_of_measure.abbreviation,
            format_currency(item.product.cost_price),
            format_currency(item.total_value),
            'In Stock' if item.quantity > item.product.reorder_level else 'Low Stock' if item.quantity > 0 else 'Out of Stock'
        ])

    # Add total row
    data.append(['', '', '', '', '', '', 'TOTAL VALUE:', format_currency(total_inventory_value), ''])

    # Create table
    table = Table(data)
    table.setStyle(TableStyle([
        ('BACKGROUND', (0, 0), (-1, 0), colors.grey),
        ('TEXTCOLOR', (0, 0), (-1, 0), colors.whitesmoke),
        ('ALIGN', (0, 0), (-1, -1), 'CENTER'),
        ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
        ('FONTSIZE', (0, 0), (-1, 0), 12),
        ('BOTTOMPADDING', (0, 0), (-1, 0), 12),
        ('BACKGROUND', (0, -1), (-1, -1), colors.lightgrey),
        ('FONTNAME', (0, -1), (-1, -1), 'Helvetica-Bold'),
        ('GRID', (0, 0), (-1, -1), 1, colors.black)
    ]))

    elements.append(table)

    doc.build(elements)

    buffer.seek(0)
    response = HttpResponse(content_type='application/pdf')
    response['Content-Disposition'] = 'attachment; filename=inventory_report.pdf'
    response.write(buffer.getvalue())
    buffer.close()

    return response


def export_sales_to_excel(sales_orders, total_revenue, avg_order_value, total_orders):
    """Export sales data to Excel"""
    wb = Workbook()
    ws = wb.active
    ws.title = "Sales Report"

    # Header
    ws['A1'] = "SALES REPORT"
    ws['A1'].font = Font(bold=True, size=14)
    ws.merge_cells('A1:H1')

    # Column headers
    headers = [
        'Order Number', 'Customer', 'Order Date', 'Expected Delivery',
        'Status', 'Items', 'Total Amount'
    ]

    for col_num, header in enumerate(headers, 1):
        cell = ws.cell(row=3, column=col_num)
        cell.value = header
        cell.font = Font(bold=True)
        cell.fill = PatternFill(start_color="CCCCCC", end_color="CCCCCC", fill_type="solid")
        cell.border = Border(
            left=Side(style='thin'),
            right=Side(style='thin'),
            top=Side(style='thin'),
            bottom=Side(style='thin')
        )
        cell.alignment = Alignment(horizontal='center')

    # Data rows
    for row_num, order in enumerate(sales_orders, 4):
        ws.cell(row=row_num, column=1).value = order.so_number
        ws.cell(row=row_num, column=2).value = order.customer.name
        ws.cell(row=row_num, column=3).value = str(order.order_date)
        ws.cell(row=row_num, column=4).value = str(order.expected_delivery_date) if order.expected_delivery_date else "Not set"
        ws.cell(row=row_num, column=5).value = order.get_status_display()
        ws.cell(row=row_num, column=6).value = order.items.count()
        ws.cell(row=row_num, column=7).value = float(order.total_amount)

        # Add borders to data cells
        for col_num in range(1, 8):
            cell = ws.cell(row=row_num, column=col_num)
            cell.border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )

    # Summary section
    summary_row = len(sales_orders) + 6
    ws.cell(row=summary_row, column=5).value = "TOTAL ORDERS:"
    ws.cell(row=summary_row, column=5).font = Font(bold=True)
    ws.cell(row=summary_row, column=6).value = total_orders

    summary_row += 1
    ws.cell(row=summary_row, column=5).value = "TOTAL REVENUE:"
    ws.cell(row=summary_row, column=5).font = Font(bold=True)
    ws.cell(row=summary_row, column=6).value = float(total_revenue)

    summary_row += 1
    ws.cell(row=summary_row, column=5).value = "AVG ORDER VALUE:"
    ws.cell(row=summary_row, column=5).font = Font(bold=True)
    ws.cell(row=summary_row, column=6).value = float(avg_order_value)

    # Auto-adjust column widths
    for column in ws.columns:
        max_length = 0
        column_cells = [cell for cell in column]
        for cell in column_cells:
            if len(str(cell.value)) > max_length:
                max_length = len(str(cell.value))
        adjusted_width = (max_length + 2)
        # Get the column letter from the first cell that is not a merged cell
        column_letter = None
        for cell in column_cells:
            if hasattr(cell, 'column_letter'):
                column_letter = cell.column_letter
                break
        if column_letter:
            ws.column_dimensions[column_letter].width = min(adjusted_width, 50)

    response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
    response['Content-Disposition'] = 'attachment; filename=sales_report.xlsx'

    wb.save(response)
    return response


def export_manufacturing_to_excel(manufacturing_orders, total_orders, completed_orders, total_boms):
    """Export manufacturing data to Excel"""
    wb = Workbook()
    ws = wb.active
    ws.title = "Manufacturing Report"

    # Header
    ws['A1'] = "MANUFACTURING REPORT"
    ws['A1'].font = Font(bold=True, size=14)
    ws.merge_cells('A1:H1')

    # Column headers
    headers = [
        'MO Number', 'BOM', 'Product', 'Quantity', 'Status',
        'Start Date', 'End Date', 'Total Cost'
    ]

    for col_num, header in enumerate(headers, 1):
        cell = ws.cell(row=3, column=col_num)
        cell.value = header
        cell.font = Font(bold=True)
        cell.fill = PatternFill(start_color="CCCCCC", end_color="CCCCCC", fill_type="solid")
        cell.border = Border(
            left=Side(style='thin'),
            right=Side(style='thin'),
            top=Side(style='thin'),
            bottom=Side(style='thin')
        )
        cell.alignment = Alignment(horizontal='center')

    # Data rows
    for row_num, order in enumerate(manufacturing_orders, 4):
        ws.cell(row=row_num, column=1).value = order.mo_number
        ws.cell(row=row_num, column=2).value = order.bom.bom_code
        ws.cell(row=row_num, column=3).value = order.bom.product.name
        ws.cell(row=row_num, column=4).value = float(order.quantity_to_produce)
        ws.cell(row=row_num, column=5).value = order.get_status_display()
        ws.cell(row=row_num, column=6).value = str(order.actual_start_date) if order.actual_start_date else "Not started"
        ws.cell(row=row_num, column=7).value = str(order.actual_end_date) if order.actual_end_date else "Not completed"
        ws.cell(row=row_num, column=8).value = float(order.total_cost) if order.total_cost else 0

        # Add borders to data cells
        for col_num in range(1, 9):
            cell = ws.cell(row=row_num, column=col_num)
            cell.border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )

    # Summary section
    summary_row = len(manufacturing_orders) + 6
    ws.cell(row=summary_row, column=6).value = "TOTAL ORDERS:"
    ws.cell(row=summary_row, column=6).font = Font(bold=True)
    ws.cell(row=summary_row, column=7).value = total_orders

    summary_row += 1
    ws.cell(row=summary_row, column=6).value = "COMPLETED:"
    ws.cell(row=summary_row, column=6).font = Font(bold=True)
    ws.cell(row=summary_row, column=7).value = completed_orders

    summary_row += 1
    ws.cell(row=summary_row, column=6).value = "TOTAL BOMS:"
    ws.cell(row=summary_row, column=6).font = Font(bold=True)
    ws.cell(row=summary_row, column=7).value = total_boms

    # Auto-adjust column widths
    for column in ws.columns:
        max_length = 0
        column_cells = [cell for cell in column]
        for cell in column_cells:
            if len(str(cell.value)) > max_length:
                max_length = len(str(cell.value))
        adjusted_width = (max_length + 2)
        # Get the column letter from the first cell that is not a merged cell
        column_letter = None
        for cell in column_cells:
            if hasattr(cell, 'column_letter'):
                column_letter = cell.column_letter
                break
        if column_letter:
            ws.column_dimensions[column_letter].width = min(adjusted_width, 50)

    response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
    response['Content-Disposition'] = 'attachment; filename=manufacturing_report.xlsx'

    wb.save(response)
    return response


def export_purchasing_to_excel(purchase_orders, total_cost, avg_order_value, total_orders):
    """Export purchasing data to Excel"""
    wb = Workbook()
    ws = wb.active
    ws.title = "Purchasing Report"

    # Header
    ws['A1'] = "PURCHASING REPORT"
    ws['A1'].font = Font(bold=True, size=14)
    ws.merge_cells('A1:H1')

    # Column headers
    headers = [
        'PO Number', 'Supplier', 'Order Date', 'Expected Delivery',
        'Status', 'Items', 'Total Amount'
    ]

    for col_num, header in enumerate(headers, 1):
        cell = ws.cell(row=3, column=col_num)
        cell.value = header
        cell.font = Font(bold=True)
        cell.fill = PatternFill(start_color="CCCCCC", end_color="CCCCCC", fill_type="solid")
        cell.border = Border(
            left=Side(style='thin'),
            right=Side(style='thin'),
            top=Side(style='thin'),
            bottom=Side(style='thin')
        )
        cell.alignment = Alignment(horizontal='center')

    # Data rows
    for row_num, order in enumerate(purchase_orders, 4):
        ws.cell(row=row_num, column=1).value = order.po_number
        ws.cell(row=row_num, column=2).value = order.supplier.name
        ws.cell(row=row_num, column=3).value = str(order.order_date)
        ws.cell(row=row_num, column=4).value = str(order.expected_delivery_date) if order.expected_delivery_date else "Not set"
        ws.cell(row=row_num, column=5).value = order.get_status_display()
        ws.cell(row=row_num, column=6).value = order.items.count()
        ws.cell(row=row_num, column=7).value = float(order.total_amount)

        # Add borders to data cells
        for col_num in range(1, 8):
            cell = ws.cell(row=row_num, column=col_num)
            cell.border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )

    # Summary section
    summary_row = len(purchase_orders) + 6
    ws.cell(row=summary_row, column=5).value = "TOTAL ORDERS:"
    ws.cell(row=summary_row, column=5).font = Font(bold=True)
    ws.cell(row=summary_row, column=6).value = total_orders

    summary_row += 1
    ws.cell(row=summary_row, column=5).value = "TOTAL COST:"
    ws.cell(row=summary_row, column=5).font = Font(bold=True)
    ws.cell(row=summary_row, column=6).value = float(total_cost)

    summary_row += 1
    ws.cell(row=summary_row, column=5).value = "AVG ORDER VALUE:"
    ws.cell(row=summary_row, column=5).font = Font(bold=True)
    ws.cell(row=summary_row, column=6).value = float(avg_order_value)

    # Auto-adjust column widths
    for column in ws.columns:
        max_length = 0
        column_cells = [cell for cell in column]
        for cell in column_cells:
            if len(str(cell.value)) > max_length:
                max_length = len(str(cell.value))
        adjusted_width = (max_length + 2)
        # Get the column letter from the first cell that is not a merged cell
        column_letter = None
        for cell in column_cells:
            if hasattr(cell, 'column_letter'):
                column_letter = cell.column_letter
                break
        if column_letter:
            ws.column_dimensions[column_letter].width = min(adjusted_width, 50)

    response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
    response['Content-Disposition'] = 'attachment; filename=purchasing_report.xlsx'

    wb.save(response)
    return response


def export_financial_to_excel(total_revenue, total_purchase_cost, total_manufacturing_cost, total_inventory_value, gross_profit, profit_margin, monthly_trends):
    """Export financial data to Excel"""
    wb = Workbook()
    ws = wb.active
    ws.title = "Financial Report"

    # Header
    ws['A1'] = "FINANCIAL REPORT"
    ws['A1'].font = Font(bold=True, size=14)
    ws.merge_cells('A1:F1')

    # Financial Overview
    ws['A3'] = "Financial Overview"
    ws['A3'].font = Font(bold=True, size=12)
    
    # Overview data
    overview_data = [
        ['Metric', 'Value'],
        ['Total Revenue', total_revenue],
        ['Total Purchase Cost', total_purchase_cost],
        ['Total Manufacturing Cost', total_manufacturing_cost],
        ['Total Inventory Value', total_inventory_value],
        ['Gross Profit', gross_profit],
        ['Profit Margin (%)', profit_margin]
    ]
    
    for row_num, row_data in enumerate(overview_data, 3):
        for col_num, cell_data in enumerate(row_data, 1):
            cell = ws.cell(row=row_num, column=col_num)
            cell.value = cell_data
            if row_num == 3 or col_num == 1:  # Header or first column
                cell.font = Font(bold=True)
            cell.border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )

    # Monthly Trends Header
    trend_start_row = len(overview_data) + 5
    ws.cell(row=trend_start_row, column=1).value = "Monthly Trends"
    ws.cell(row=trend_start_row, column=1).font = Font(bold=True, size=12)
    
    # Monthly Trends data
    trend_headers = ['Period', 'Revenue', 'Costs', 'Profit']
    for col_num, header in enumerate(trend_headers, 1):
        cell = ws.cell(row=trend_start_row + 1, column=col_num)
        cell.value = header
        cell.font = Font(bold=True)
        cell.fill = PatternFill(start_color="CCCCCC", end_color="CCCCCC", fill_type="solid")
        cell.border = Border(
            left=Side(style='thin'),
            right=Side(style='thin'),
            top=Side(style='thin'),
            bottom=Side(style='thin')
        )
        cell.alignment = Alignment(horizontal='center')
    
    # Monthly trends data rows
    for row_num, trend in enumerate(monthly_trends, trend_start_row + 2):
        ws.cell(row=row_num, column=1).value = trend['period']
        ws.cell(row=row_num, column=2).value = float(trend['revenue'])
        ws.cell(row=row_num, column=3).value = float(trend['costs'])
        ws.cell(row=row_num, column=4).value = float(trend['profit'])
        
        # Add borders to data cells
        for col_num in range(1, 5):
            cell = ws.cell(row=row_num, column=col_num)
            cell.border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )

    # Auto-adjust column widths
    for column in ws.columns:
        max_length = 0
        column_cells = [cell for cell in column]
        for cell in column_cells:
            if len(str(cell.value)) > max_length:
                max_length = len(str(cell.value))
        adjusted_width = (max_length + 2)
        # Get the column letter from the first cell that is not a merged cell
        column_letter = None
        for cell in column_cells:
            if hasattr(cell, 'column_letter'):
                column_letter = cell.column_letter
                break
        if column_letter:
            ws.column_dimensions[column_letter].width = min(adjusted_width, 50)

    response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
    response['Content-Disposition'] = 'attachment; filename=financial_report.xlsx'

    wb.save(response)
    return response