import os

from io import BytesIO
from reportlab.graphics.barcode import code128
from reportlab.lib.pagesizes import mm
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak

from constants import APP_PATH


class PDFGenerator:
    def __init__(self):
        ASSETS_FOLDER = os.path.join(APP_PATH, 'assets')
        FONTS_FOLDER = os.path.join(ASSETS_FOLDER, 'fonts')
        FONT_FILE_PATH = os.path.join(FONTS_FOLDER, 'DejaVuSans.ttf')
        self.page_width = 58 * mm
        self.page_height = 40 * mm

        pdfmetrics.registerFont(TTFont('DejaVuSans', FONT_FILE_PATH))

        # Get standard styles and create a new style with a smaller font size
        styles = getSampleStyleSheet()
        self.small_style = ParagraphStyle(
            'Small',
            parent=styles['Normal'],
            fontName='DejaVuSans',  # Specify the new font
            fontSize=6,
            leading=7,
            spaceAfter=2,
            leftIndent=2,
            rightIndent=2
        )

    def generate(self, barcode_value, text, num_duplicates=1):
        buffer = BytesIO()

        # Create document with specified page size
        doc = SimpleDocTemplate(buffer,
                                pagesize=(self.page_width, self.page_height),
                                rightMargin=1 * mm,
                                leftMargin=1 * mm,
                                topMargin=1 * mm,
                                bottomMargin=1 * mm)

        # Create paragraph with new style
        paragraph = Paragraph(text, self.small_style)

        # Create barcode
        barcode = code128.Code128(barcode_value, humanReadable=True)

        # Function to draw barcode on canvas
        def add_barcode(canvas, doc):
            barcode_width = barcode.width
            barcode_x = (self.page_width - barcode_width) / 2  # Center the barcode
            barcode.drawOn(canvas, barcode_x, self.page_height - barcode.height - 5)

        # Create list of elements to add to the document
        elements = []
        for _ in range(num_duplicates):
            elements.append(Spacer(1, 8 * mm))
            elements.append(paragraph)
            elements.append(PageBreak())

        # Build document
        doc.build(elements[:-1], onFirstPage=add_barcode, onLaterPages=add_barcode)  # Remove the last PageBreak

        buffer.seek(0)
        return buffer