from collections.abc import Iterator
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import mm, cm

# Usage:
#   label = AveryLabels.AveryLabel(5160)
#   label.open( "labels5160.pdf" )
#   label.render( RenderAddress, 30 )
#   label.close()
#
# 'render' can either pass a callable, which receives the canvas object
# (with X,Y=0,0 at the lower right) or a string "form" name of a form
# previously created with canv.beginForm().


# labels across
# labels down
# label size w/h
# label gutter across/down
# page margins left/top
# page size w/h or name from reportlab.lib.pagesizes

labelInfo = {
    # 24x 70mm x 37mm on A4 with 3x8
    6605: (3, 8, (70 * mm, 37 * mm), (0, 0), (0, 0), A4),
    # 22x 32mm x 10mm mini labels
    3044: (2, 11, (32, 10), (2, 2), (1, 1), (66.5 * mm, 120.5 * mm)),
    # 189x 25.4mm x 10mm mini labels
    4731: (7, 27, (25.4 * mm, 10 * mm), (2.5 * mm, 0), (9 * mm, 13.5 * mm), A4),
    # 2.6 x 1 address labels
    5160: (3, 10, (187, 72), (11, 0), (14, 36), A4),
    5161: (2, 10, (288, 72), (0, 0), (18, 36), A4),
    # 4 x 2 address labels
    5163: (2, 5, (288, 144), (0, 0), (18, 36), A4),
    # 1.75 x 0.5 return address labels
    5167: (4, 20, (126, 36), (0, 0), (54, 36), A4),
    # 3.5 x 2 business cards
    5371: (2, 5, (252, 144), (0, 0), (54, 36), A4),
    # 48x 45.7x21.2mm
    4778: (4, 12, (45.7 * mm, 21.2 * mm), (0.25 * cm, 0), (1.1 * cm, 2 * cm), A4),
    # APLI 100984 40x 52.5x29.7mm
    100984: (4, 10, (52.5 * mm, 29.7 * mm), (0, 0), (0, 0), A4),
}


class AveryLabel:

    def __init__(self, label, **kwargs):
        data = labelInfo[label]
        self.across = data[0]
        self.down = data[1]
        self.size = data[2]
        self.labelsep = self.size[0] + data[3][0], self.size[1] + data[3][1]
        self.margins = data[4]
        self.top_down = True
        self.debug = False
        self.pagesize = data[5]
        self.position = 0
        self.__dict__.update(kwargs)

    def open(self, filename):
        """open a canvas for the file"""
        self.canvas = canvas.Canvas(filename, pagesize=self.pagesize)
        if self.debug:
            self.canvas.setPageCompression(0)
        self.canvas.setLineJoin(1)
        self.canvas.setLineCap(1)

    def top_left(self, x=None, y=None):
        """ return top left"""
        if x is None:
            x = self.position
        if y is None:
            if self.top_down:
                x, y = divmod(x, self.down)
            else:
                y, x = divmod(x, self.across)

        return (
            self.margins[0] + x * self.labelsep[0],
            self.pagesize[1] - self.margins[1] - (y + 1) * self.labelsep[1],
        )

    def advance(self):
        """ move to next position"""
        self.position += 1
        if self.position == self.across * self.down:
            self.canvas.showPage()
            self.position = 0

    def close(self):
        """save and close canvas"""
        if self.position:
            self.canvas.showPage()
        self.canvas.save()
        self.canvas = None

    # To render, you can either create a template and tell me
    # "go draw N of these templates" or provide a callback.
    # Callback receives canvas, width, height.
    #
    # Or, pass a callable and an iterator.  We'll do one label
    # per iteration of the iterator.

    def render(self, thing, count, offset=0, *args):
        """ render loop"""
        assert callable(thing) or isinstance(thing, str)
        if isinstance(count, Iterator):
            self.render_iterator(thing, count)
            return

        canv = self.canvas
        for i in range(offset + count):
            if i >= offset:
                canv.saveState()
                canv.translate(*self.top_left())
                if self.debug:
                    canv.setLineWidth(0.25)
                    canv.rect(0, 0, self.size[0], self.size[1])
                if callable(thing):
                    thing(canv, self.size[0], self.size[1], *args)
                elif isinstance(thing, str):
                    canv.doForm(thing)
                canv.restoreState()
            self.advance()

    def render_iterator(self, func, iterator):
        """ render loop for iterator """
        canv = self.canvas
        for chunk in iterator:
            canv.saveState()
            canv.translate(*self.top_left())
            if self.debug:
                canv.setLineWidth(0.25)
                canv.rect(0, 0, self.size[0], self.size[1])
            func(canv, self.size[0], self.size[1], chunk)
            canv.restoreState()
            self.advance()