"""
Template for PDF Receipt/Invoice Generation
"""
from PIL import Image
import logging
from reportlab.lib import colors
from django.conf import settings
from django.utils.translation import ugettext as _
from reportlab.pdfgen.canvas import Canvas
from reportlab.lib.pagesizes import letter
from reportlab.lib.units import mm
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.platypus import Paragraph
from reportlab.platypus.tables import Table, TableStyle
from microsite_configuration import microsite
from xmodule.modulestore.django import ModuleI18nService

log = logging.getLogger("PDF Generation")


class NumberedCanvas(Canvas):
    """
    Canvas child class with auto page-numbering.
    """
    def __init__(self, *args, **kwargs):
        """
            __init__
        """
        Canvas.__init__(self, *args, **kwargs)
        self._saved_page_states = []

    def insert_page_break(self):
        """
        Starts a new page.
        """
        self._saved_page_states.append(dict(self.__dict__))
        self._startPage()

    def current_page_count(self):
        """
        Returns the page count in the current pdf document.
        """
        return len(self._saved_page_states) + 1

    def save(self):
        """
            Adds page numbering to each page (page x of y)
        """
        num_pages = len(self._saved_page_states)
        for state in self._saved_page_states:
            self.__dict__.update(state)
            if num_pages > 1:
                self.draw_page_number(num_pages)
            Canvas.showPage(self)
        Canvas.save(self)

    def draw_page_number(self, page_count):
        """
        Draws the String "Page x of y" at the bottom right of the document.
        """
        self.setFontSize(7)
        self.drawRightString(
            200 * mm,
            12 * mm,
            _("Page {page_number} of {page_count}").format(page_number=self._pageNumber, page_count=page_count)
        )


class PDFInvoice(object):
    """
    PDF Generation Class
    """
    def __init__(self, items_data, item_id, date, is_invoice, total_cost, payment_received, balance):
        """
        Accepts the following positional arguments

        items_data - A list having the following items for each row.
            item_description - String
            quantity - Integer
            list_price - float
            discount - float
            item_total - float
        id - String
        date - datetime
        is_invoice - boolean - True (for invoice) or False (for Receipt)
        total_cost - float
        payment_received - float
        balance - float
        """

        # From settings
        self.currency = settings.PAID_COURSE_REGISTRATION_CURRENCY[1]
        self.logo_path = microsite.get_value("PDF_RECEIPT_LOGO_PATH", settings.PDF_RECEIPT_LOGO_PATH)
        self.cobrand_logo_path = microsite.get_value(
            "PDF_RECEIPT_COBRAND_LOGO_PATH", settings.PDF_RECEIPT_COBRAND_LOGO_PATH
        )
        self.tax_label = microsite.get_value("PDF_RECEIPT_TAX_ID_LABEL", settings.PDF_RECEIPT_TAX_ID_LABEL)
        self.tax_id = microsite.get_value("PDF_RECEIPT_TAX_ID", settings.PDF_RECEIPT_TAX_ID)
        self.footer_text = microsite.get_value("PDF_RECEIPT_FOOTER_TEXT", settings.PDF_RECEIPT_FOOTER_TEXT)
        self.disclaimer_text = microsite.get_value("PDF_RECEIPT_DISCLAIMER_TEXT", settings.PDF_RECEIPT_DISCLAIMER_TEXT)
        self.billing_address_text = microsite.get_value(
            "PDF_RECEIPT_BILLING_ADDRESS", settings.PDF_RECEIPT_BILLING_ADDRESS
        )
        self.terms_conditions_text = microsite.get_value(
            "PDF_RECEIPT_TERMS_AND_CONDITIONS", settings.PDF_RECEIPT_TERMS_AND_CONDITIONS
        )
        self.brand_logo_height = microsite.get_value(
            "PDF_RECEIPT_LOGO_HEIGHT_MM", settings.PDF_RECEIPT_LOGO_HEIGHT_MM
        ) * mm
        self.cobrand_logo_height = microsite.get_value(
            "PDF_RECEIPT_COBRAND_LOGO_HEIGHT_MM", settings.PDF_RECEIPT_COBRAND_LOGO_HEIGHT_MM
        ) * mm

        # From Context
        self.items_data = items_data
        self.item_id = item_id
        self.date = ModuleI18nService().strftime(date, 'SHORT_DATE')
        self.is_invoice = is_invoice
        self.total_cost = '{currency}{amount:.2f}'.format(currency=self.currency, amount=total_cost)
        self.payment_received = '{currency}{amount:.2f}'.format(currency=self.currency, amount=payment_received)
        self.balance = '{currency}{amount:.2f}'.format(currency=self.currency, amount=balance)

        # initialize the pdf variables
        self.margin = 15 * mm
        self.page_width = letter[0]
        self.page_height = letter[1]
        self.min_clearance = 3 * mm
        self.second_page_available_height = ''
        self.second_page_start_y_pos = ''
        self.first_page_available_height = ''
        self.pdf = None

    def is_on_first_page(self):
        """
        Returns True if it's the first page of the pdf, False otherwise.
        """
        return self.pdf.current_page_count() == 1

    def generate_pdf(self, file_buffer):
        """
        Takes in a buffer and puts the generated pdf into that buffer.
        """
        self.pdf = NumberedCanvas(file_buffer, pagesize=letter)

        self.draw_border()
        y_pos = self.draw_logos()
        self.second_page_available_height = y_pos - self.margin - self.min_clearance
        self.second_page_start_y_pos = y_pos

        y_pos = self.draw_title(y_pos)
        self.first_page_available_height = y_pos - self.margin - self.min_clearance

        y_pos = self.draw_course_info(y_pos)
        y_pos = self.draw_totals(y_pos)
        self.draw_footer(y_pos)

        self.pdf.insert_page_break()
        self.pdf.save()

    def draw_border(self):
        """
        Draws a big border around the page leaving a margin of 15 mm on each side.
        """
        self.pdf.setStrokeColorRGB(0.5, 0.5, 0.5)
        self.pdf.setLineWidth(0.353 * mm)

        self.pdf.rect(self.margin, self.margin,
                      self.page_width - (self.margin * 2), self.page_height - (self.margin * 2),
                      stroke=True, fill=False)

    @staticmethod
    def load_image(img_path):
        """
        Loads an image given a path. An absolute path is assumed.
        If the path points to an image file, it loads and returns the Image object, None otherwise.
        """
        try:
            img = Image.open(img_path)
        except IOError, ex:
            log.exception('Pdf unable to open the image file: %s', str(ex))
            img = None

        return img

    def draw_logos(self):
        """
        Draws logos.
        """
        horizontal_padding_from_border = self.margin + 9 * mm
        vertical_padding_from_border = 11 * mm
        img_y_pos = self.page_height - (
            self.margin + vertical_padding_from_border + max(self.cobrand_logo_height, self.brand_logo_height)
        )

        # Left-Aligned cobrand logo
        if self.cobrand_logo_path:
            cobrand_img = self.load_image(self.cobrand_logo_path)
            if cobrand_img:
                img_width = float(cobrand_img.size[0]) / (float(cobrand_img.size[1]) / self.cobrand_logo_height)
                self.pdf.drawImage(cobrand_img.filename, horizontal_padding_from_border, img_y_pos, img_width,
                                   self.cobrand_logo_height, mask='auto')

        # Right aligned brand logo
        if self.logo_path:
            logo_img = self.load_image(self.logo_path)
            if logo_img:
                img_width = float(logo_img.size[0]) / (float(logo_img.size[1]) / self.brand_logo_height)
                self.pdf.drawImage(
                    logo_img.filename,
                    self.page_width - (horizontal_padding_from_border + img_width),
                    img_y_pos,
                    img_width,
                    self.brand_logo_height,
                    mask='auto'
                )

        return img_y_pos - self.min_clearance

    def draw_title(self, y_pos):
        """
        Draws the title, order/receipt ID and the date.
        """
        if self.is_invoice:
            title = (_('Invoice'))
            id_label = (_('Invoice'))
        else:
            title = (_('Receipt'))
            id_label = (_('Order'))

        # Draw Title "RECEIPT" OR "INVOICE"
        vertical_padding = 5 * mm
        horizontal_padding_from_border = self.margin + 9 * mm
        font_size = 21
        self.pdf.setFontSize(font_size)
        self.pdf.drawString(horizontal_padding_from_border, y_pos - vertical_padding - font_size / 2, title)
        y_pos = y_pos - vertical_padding - font_size / 2 - self.min_clearance

        horizontal_padding_from_border = self.margin + 11 * mm
        font_size = 12
        self.pdf.setFontSize(font_size)
        y_pos = y_pos - font_size / 2 - vertical_padding
        # Draw Order/Invoice No.
        self.pdf.drawString(horizontal_padding_from_border, y_pos,
                            _(u'{id_label} # {item_id}').format(id_label=id_label, item_id=self.item_id))
        y_pos = y_pos - font_size / 2 - vertical_padding
        # Draw Date
        self.pdf.drawString(
            horizontal_padding_from_border, y_pos, _(u'Date: {date}').format(date=self.date)
        )

        return y_pos - self.min_clearance

    def draw_course_info(self, y_pos):
        """
        Draws the main table containing the data items.
        """
        course_items_data = [
            ['', (_('Description')), (_('Quantity')), (_('List Price\nper item')), (_('Discount\nper item')),
             (_('Amount')), '']
        ]
        for row_item in self.items_data:
            course_items_data.append([
                '',
                Paragraph(row_item['item_description'], getSampleStyleSheet()['Normal']),
                row_item['quantity'],
                '{currency}{list_price:.2f}'.format(list_price=row_item['list_price'], currency=self.currency),
                '{currency}{discount:.2f}'.format(discount=row_item['discount'], currency=self.currency),
                '{currency}{item_total:.2f}'.format(item_total=row_item['item_total'], currency=self.currency),
                ''
            ])

        padding_width = 7 * mm
        desc_col_width = 60 * mm
        qty_col_width = 26 * mm
        list_price_col_width = 21 * mm
        discount_col_width = 21 * mm
        amount_col_width = 40 * mm
        course_items_table = Table(
            course_items_data,
            [
                padding_width,
                desc_col_width,
                qty_col_width,
                list_price_col_width,
                discount_col_width,
                amount_col_width,
                padding_width
            ],
            splitByRow=1,
            repeatRows=1
        )

        course_items_table.setStyle(TableStyle([
            #List Price, Discount, Amount data items
            ('ALIGN', (3, 1), (5, -1), 'RIGHT'),

            # Amount header
            ('ALIGN', (5, 0), (5, 0), 'RIGHT'),

            # Amount column (header + data items)
            ('RIGHTPADDING', (5, 0), (5, -1), 7 * mm),

            # Quantity, List Price, Discount header
            ('ALIGN', (2, 0), (4, 0), 'CENTER'),

            # Description header
            ('ALIGN', (1, 0), (1, -1), 'LEFT'),

            # Quantity data items
            ('ALIGN', (2, 1), (2, -1), 'CENTER'),

            # Lines below the header and at the end of the table.
            ('LINEBELOW', (0, 0), (-1, 0), 1.00, '#cccccc'),
            ('LINEBELOW', (0, -1), (-1, -1), 1.00, '#cccccc'),

            # Innergrid around the data rows.
            ('INNERGRID', (1, 1), (-2, -1), 0.50, '#cccccc'),

            # Entire table
            ('VALIGN', (0, 0), (-1, -1), 'MIDDLE'),
            ('TOPPADDING', (0, 0), (-1, -1), 2 * mm),
            ('BOTTOMPADDING', (0, 0), (-1, -1), 2 * mm),
            ('TEXTCOLOR', (0, 0), (-1, -1), colors.black),
        ]))
        rendered_width, rendered_height = course_items_table.wrap(0, 0)
        table_left_padding = (self.page_width - rendered_width) / 2

        split_tables = course_items_table.split(0, self.first_page_available_height)
        if len(split_tables) > 1:
            # The entire Table won't fit in the available space and requires splitting.
            # Draw the part that can fit, start a new page
            # and repeat the process with the rest of the table.
            split_table = split_tables[0]
            __, rendered_height = split_table.wrap(0, 0)
            split_table.drawOn(self.pdf, table_left_padding, y_pos - rendered_height)

            self.prepare_new_page()
            split_tables = split_tables[1].split(0, self.second_page_available_height)
            while len(split_tables) > 1:
                split_table = split_tables[0]
                __, rendered_height = split_table.wrap(0, 0)
                split_table.drawOn(self.pdf, table_left_padding, self.second_page_start_y_pos - rendered_height)

                self.prepare_new_page()
                split_tables = split_tables[1].split(0, self.second_page_available_height)
            split_table = split_tables[0]
            __, rendered_height = split_table.wrap(0, 0)
            split_table.drawOn(self.pdf, table_left_padding, self.second_page_start_y_pos - rendered_height)
        else:
            # Table will fit without the need for splitting.
            course_items_table.drawOn(self.pdf, table_left_padding, y_pos - rendered_height)

        if not self.is_on_first_page():
            y_pos = self.second_page_start_y_pos

        return y_pos - rendered_height - self.min_clearance

    def prepare_new_page(self):
        """
        Inserts a new page and includes the border and the logos.
        """
        self.pdf.insert_page_break()
        self.draw_border()
        y_pos = self.draw_logos()
        return y_pos

    def draw_totals(self, y_pos):
        """
        Draws the boxes containing the totals and the tax id.
        """
        totals_data = [
            [(_('Total')), self.total_cost],
            [(_('Payment Received')), self.payment_received],
            [(_('Balance')), self.balance]
        ]

        if self.is_invoice:
            # only print TaxID if we are generating an Invoice
            totals_data.append(
                ['', '{tax_label}:  {tax_id}'.format(tax_label=self.tax_label, tax_id=self.tax_id)]
            )

        heights = 8 * mm
        totals_table = Table(totals_data, 40 * mm, heights)

        styles = [
            # Styling for the totals table.
            ('ALIGN', (0, 0), (-1, -1), 'RIGHT'),
            ('VALIGN', (0, 0), (-1, -1), 'MIDDLE'),
            ('TEXTCOLOR', (0, 0), (-1, -1), colors.black),

            # Styling for the Amounts cells
            # NOTE: since we are not printing the TaxID for Credit Card
            # based receipts, we need to change the cell range for
            # these formatting rules
            ('RIGHTPADDING', (-1, 0), (-1, 2), 7 * mm),
            ('GRID', (-1, 0), (-1, 2), 3.0, colors.white),
            ('BACKGROUND', (-1, 0), (-1, 2), '#EEEEEE'),
        ]

        totals_table.setStyle(TableStyle(styles))

        __, rendered_height = totals_table.wrap(0, 0)

        left_padding = 97 * mm
        if y_pos - (self.margin + self.min_clearance) <= rendered_height:
            # if space left on page is smaller than the rendered height, render the table on the next page.
            self.prepare_new_page()
            totals_table.drawOn(self.pdf, self.margin + left_padding, self.second_page_start_y_pos - rendered_height)
            return self.second_page_start_y_pos - rendered_height - self.min_clearance
        else:
            totals_table.drawOn(self.pdf, self.margin + left_padding, y_pos - rendered_height)
            return y_pos - rendered_height - self.min_clearance

    def draw_footer(self, y_pos):
        """
        Draws the footer.
        """

        para_style = getSampleStyleSheet()['Normal']
        para_style.fontSize = 8

        footer_para = Paragraph(self.footer_text.replace("\n", "<br/>"), para_style)
        disclaimer_para = Paragraph(self.disclaimer_text.replace("\n", "<br/>"), para_style)
        billing_address_para = Paragraph(self.billing_address_text.replace("\n", "<br/>"), para_style)

        footer_data = [
            ['', footer_para],
            [(_('Billing Address')), ''],
            ['', billing_address_para],
            [(_('Disclaimer')), ''],
            ['', disclaimer_para]
        ]

        footer_style = [
            # Styling for the entire footer table.
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('VALIGN', (0, 0), (-1, -1), 'MIDDLE'),
            ('TEXTCOLOR', (0, 0), (-1, -1), colors.black),
            ('FONTSIZE', (0, 0), (-1, -1), 9),
            ('TEXTCOLOR', (0, 0), (-1, -1), '#AAAAAA'),

            # Billing Address Header styling
            ('LEFTPADDING', (0, 1), (0, 1), 5 * mm),

            # Disclaimer Header styling
            ('LEFTPADDING', (0, 3), (0, 3), 5 * mm),
            ('TOPPADDING', (0, 3), (0, 3), 2 * mm),

            # Footer Body styling
            # ('BACKGROUND', (1, 0), (1, 0), '#EEEEEE'),

            # Billing Address Body styling
            ('BACKGROUND', (1, 2), (1, 2), '#EEEEEE'),

            # Disclaimer Body styling
            ('BACKGROUND', (1, 4), (1, 4), '#EEEEEE'),
        ]

        if self.is_invoice:
            terms_conditions_para = Paragraph(self.terms_conditions_text.replace("\n", "<br/>"), para_style)
            footer_data.append([(_('TERMS AND CONDITIONS')), ''])
            footer_data.append(['', terms_conditions_para])

            # TERMS AND CONDITIONS header styling
            footer_style.append(('LEFTPADDING', (0, 5), (0, 5), 5 * mm))
            footer_style.append(('TOPPADDING', (0, 5), (0, 5), 2 * mm))

            # TERMS AND CONDITIONS body styling
            footer_style.append(('BACKGROUND', (1, 6), (1, 6), '#EEEEEE'))

        footer_table = Table(footer_data, [5 * mm, 176 * mm])

        footer_table.setStyle(TableStyle(footer_style))
        __, rendered_height = footer_table.wrap(0, 0)

        if y_pos - (self.margin + self.min_clearance) <= rendered_height:
            self.prepare_new_page()

        footer_table.drawOn(self.pdf, self.margin, self.margin + 5 * mm)
