import base64
import io
import logging

try:
    import xlsxwriter
except ImportError:
    xlsxwriter = None

from odoo import models, _
from odoo.exceptions import UserError

_logger = logging.getLogger(__name__)

class PurchaseOrder(models.Model):
    _inherit = 'purchase.order'

    def action_export_bc(self):
        self.ensure_one()
        if not xlsxwriter:
            raise UserError(_("The Python library 'xlsxwriter' is required. Please install it."))
        
        output = io.BytesIO()
        workbook = xlsxwriter.Workbook(output, {'in_memory': True})
        
        header_format = workbook.add_format({
            'bold': True, 'align': 'center', 'valign': 'vcenter', 'border': 1
        })
        
        headers = ["Type", "Item No.", "Description", "Qty", "Satuan"]
        
        lines_by_category = {}
        for line in self.order_line:
            # Handle display_type like line_section or line_note which shouldn't be exported as items
            if line.display_type in ('line_section', 'line_note'):
                continue

            categ_name = line.product_id.categ_id.name or 'Uncategorized'
            # Sheet names in Excel cannot exceed 31 characters
            categ_name = str(categ_name)[:31]
            
            # Excel sheet names cannot contain certain characters like :, \\, /, ?, *, [, ]
            invalid_chars = [':', '\\', '/', '?', '*', '[', ']']
            for char in invalid_chars:
                categ_name = categ_name.replace(char, ' ')
                
            if categ_name not in lines_by_category:
                lines_by_category[categ_name] = []
            lines_by_category[categ_name].append(line)
            
        if not lines_by_category:
            raise UserError(_("There are no order lines to export."))

        for categ_name, lines in lines_by_category.items():
            sheet = workbook.add_worksheet(categ_name)
            for col_num, header in enumerate(headers):
                sheet.write(0, col_num, header, header_format)
                
            row_num = 1
            for line in lines:
                item_type = "Item"
                
                # Check custom field x_studio_bc_item_id on product
                if 'x_studio_bc_item_id' in line.product_id._fields and line.product_id.x_studio_bc_item_id:
                    item_no = line.product_id.x_studio_bc_item_id
                else:
                    item_no = ''
                    
                description = line.product_id.name or line.name or ''
                qty = line.product_qty
                
                # Determine packaging or unit
                if 'product_packaging_id' in line._fields and line.product_packaging_id:
                    satuan = line.product_packaging_id.name
                else:
                    satuan = line.product_uom_id.name or ''
                    
                sheet.write(row_num, 0, item_type)
                sheet.write(row_num, 1, item_no)
                sheet.write(row_num, 2, description)
                sheet.write(row_num, 3, qty)
                sheet.write(row_num, 4, satuan)
                
                row_num += 1
                
        workbook.close()
        output.seek(0)
        
        attachment_name = f"PO_Export_BC_{self.name.replace('/', '_')}.xlsx"
        
        attachment = self.env['ir.attachment'].create({
            'name': attachment_name,
            'type': 'binary',
            'datas': base64.b64encode(output.read()),
            'mimetype': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
        })

        return {
            'type': 'ir.actions.act_url',
            'url': f'/web/content/{attachment.id}?download=true',
            'target': 'self',
        }