import xml.etree.ElementTree as ET
import urllib.parse
import pystache
import ntpath
import os
from shutil import copy
from xml.dom import minidom


class SheetBuilder:
    def __init__(self):
        self.data_dir = None
        self.scale = "NTS"

    def create(self, name, titleblock_name):
        sheet_path = "{}sheets/{}.svg".format(self.data_dir, name)
        root = ET.Element("svg")
        root.attrib["xmlns"] = "http://www.w3.org/2000/svg"
        root.attrib["xmlns:xlink"] = "http://www.w3.org/1999/xlink"
        root.attrib["id"] = "root"
        root.attrib["version"] = "1.1"

        view_root = ET.parse(
            os.path.join(self.data_dir, "templates", "titleblocks", titleblock_name + ".svg")
        ).getroot()
        view_width = self.convert_to_mm(view_root.attrib.get("width"))
        view_height = self.convert_to_mm(view_root.attrib.get("height"))
        view = ET.SubElement(root, "g")
        view.attrib["data-type"] = "titleblock"
        titleblock = ET.SubElement(view, "image")
        titleblock.attrib["xlink:href"] = "../templates/titleblocks/" + titleblock_name + ".svg"
        titleblock.attrib["x"] = "0"
        titleblock.attrib["y"] = "0"
        titleblock.attrib["width"] = str(view_width)
        titleblock.attrib["height"] = str(view_height)

        root.attrib["width"] = "{}mm".format(view_width)
        root.attrib["height"] = "{}mm".format(view_height)
        root.attrib["viewBox"] = "0 0 {} {}".format(view_width, view_height)

        with open(sheet_path, "w") as f:
            f.write(minidom.parseString(ET.tostring(root)).toprettyxml(indent="    "))

    def add_drawing(self, view_name, sheet_name):
        sheet_path = os.path.join(self.data_dir, "sheets", sheet_name + ".svg")
        view_path = os.path.join(self.data_dir, "diagrams", view_name + ".svg")

        if not os.path.isfile(view_path):
            raise FileNotFoundError

        ET.register_namespace("", "http://www.w3.org/2000/svg")
        ET.register_namespace("xlink", "http://www.w3.org/1999/xlink")

        sheet_tree = ET.parse(sheet_path)
        sheet_root = sheet_tree.getroot()

        view_tree = ET.parse(view_path)
        view_root = view_tree.getroot()

        # The view is placed into a group with a background image element.
        # Although the foreground SVG already has a background, it is duplicated
        # here to accommodate browsers which do not nest images.
        view = ET.SubElement(sheet_root, "g")
        view.attrib["data-type"] = "drawing"
        view_width = self.convert_to_mm(view_root.attrib.get("width"))
        view_height = self.convert_to_mm(view_root.attrib.get("height"))

        background = ET.SubElement(view, "image")
        background.attrib["xlink:href"] = "../diagrams/{}.png".format(view_name)
        background.attrib["x"] = "30"
        background.attrib["y"] = "30"
        background.attrib["width"] = str(view_width)
        background.attrib["height"] = str(view_height)

        foreground = ET.SubElement(view, "image")
        foreground.attrib["xlink:href"] = "../diagrams/{}.svg".format(view_name)
        foreground.attrib["x"] = "30"
        foreground.attrib["y"] = "30"
        foreground.attrib["width"] = str(view_width)
        foreground.attrib["height"] = str(view_height)

        self.add_view_title(30, view_height + 35, view)
        sheet_tree.write(sheet_path)

    def add_schedule(self, schedule_name, sheet_name):
        sheet_path = os.path.join(self.data_dir, "sheets", sheet_name + ".svg")
        view_path = os.path.join(self.data_dir, "schedules", schedule_name + ".svg")

        ET.register_namespace("", "http://www.w3.org/2000/svg")
        ET.register_namespace("xlink", "http://www.w3.org/1999/xlink")

        sheet_tree = ET.parse(sheet_path)
        sheet_root = sheet_tree.getroot()

        view_tree = ET.parse(view_path)
        view_root = view_tree.getroot()
        view_width = self.convert_to_mm(view_root.attrib.get("width"))
        view_height = self.convert_to_mm(view_root.attrib.get("height"))

        group = ET.SubElement(sheet_root, "g")
        group.attrib["data-type"] = "schedule"

        foreground = ET.SubElement(group, "image")
        foreground.attrib["xlink:href"] = "../schedules/{}.svg".format(schedule_name)
        foreground.attrib["x"] = "30"
        foreground.attrib["y"] = "30"
        foreground.attrib["width"] = str(view_width)
        foreground.attrib["height"] = str(view_height)

        self.add_view_title(30, view_height + 35, group)
        sheet_tree.write(sheet_path)

    def add_view_title(self, x, y, parent):
        title_tree = ET.parse(os.path.join(self.data_dir, "templates", "view-title.svg"))
        title_root = title_tree.getroot()
        title = ET.SubElement(parent, "image")
        title.attrib["xlink:href"] = "../templates/view-title.svg"
        title.attrib["x"] = str(x)
        title.attrib["y"] = str(y)
        title.attrib["width"] = str(self.convert_to_mm(title_root.attrib.get("width")))
        title.attrib["height"] = str(self.convert_to_mm(title_root.attrib.get("height")))

    def build(self, sheet_name):
        os.makedirs("{}build/{}/".format(self.data_dir, sheet_name), exist_ok=True)

        sheet_path = "{}sheets/{}.svg".format(self.data_dir, sheet_name)

        ET.register_namespace("", "http://www.w3.org/2000/svg")
        ET.register_namespace("xlink", "http://www.w3.org/1999/xlink")

        tree = ET.parse(sheet_path)
        root = tree.getroot()

        titleblock = root.findall('{http://www.w3.org/2000/svg}g[@data-type="titleblock"]')[0]
        image = titleblock.findall("{http://www.w3.org/2000/svg}image")[0]
        titleblock.append(self.parse_embedded_svg(image, {"number": sheet_name, "revision": "A"}))
        titleblock.remove(image)

        self.group_number = 1
        self.build_drawings(root.findall('{http://www.w3.org/2000/svg}g[@data-type="drawing"]'), sheet_name)
        self.build_schedules(root.findall('{http://www.w3.org/2000/svg}g[@data-type="schedule"]'))

        with open("{}build/{}/{}.svg".format(self.data_dir, sheet_name, sheet_name), "wb") as output:
            tree.write(output)

    def build_drawings(self, drawings, sheet_name):
        for view in drawings:
            images = view.findall("{http://www.w3.org/2000/svg}image")
            background = images[0]
            foreground = images[1]
            view_title = images[2]
            self.scale = "NTS"

            # Add foreground
            view.append(self.parse_embedded_svg(foreground, {}))

            # Add background
            background_path = "{}sheets/{}".format(self.data_dir, self.get_href(background))
            copy(background_path, "{}build/{}/".format(self.data_dir, sheet_name))

            # Add view title
            foreground_path = self.get_href(foreground)
            view.append(
                self.parse_embedded_svg(
                    view_title,
                    {"no": self.group_number, "name": ntpath.basename(foreground_path)[0:-4], "scale": self.scale},
                )
            )

            for image in images:
                view.remove(image)

            self.group_number += 1

    def build_schedules(self, schedules):
        for group in schedules:
            images = group.findall("{http://www.w3.org/2000/svg}image")
            schedule = images[0]
            group_title = images[1]
            self.scale = "NTS"

            group.append(self.parse_embedded_svg(schedule, {}))

            path = self.get_href(schedule)
            group.append(
                self.parse_embedded_svg(
                    group_title, {"no": self.group_number, "name": ntpath.basename(path)[0:-4], "scale": self.scale}
                )
            )

            for image in images:
                group.remove(image)

            self.group_number += 1

    def get_href(self, element):
        return urllib.parse.unquote(element.attrib.get("{http://www.w3.org/1999/xlink}href"))

    def parse_embedded_svg(self, image, data):
        group = ET.Element("g")
        group.attrib["transform"] = "translate({},{})".format(
            self.convert_to_mm(image.attrib.get("x")), self.convert_to_mm(image.attrib.get("y"))
        )
        svg_path = self.get_href(image)
        with open("{}sheets/{}".format(self.data_dir, svg_path), "r") as template:
            embedded = ET.fromstring(pystache.render(template.read(), data))
            # viewBox should not be nested
            embedded.attrib["viewBox"] = ""
            # TODO: This should not be in this function
            self.scale = embedded.attrib.get("data-scale")
            images = embedded.findall("{http://www.w3.org/2000/svg}image")
            for image in images:
                new_href = ntpath.basename(image.attrib.get("{http://www.w3.org/1999/xlink}href"))
                image.attrib["{http://www.w3.org/1999/xlink}href"] = new_href
        group.append(embedded)
        return group

    def convert_to_mm(self, value):
        # CSS is what defines these possibilities
        # https://www.w3.org/TR/SVG/refs.html#ref-css-values-3
        # https://www.w3.org/TR/css-values-3/#absolute-lengths
        # The relative units are not implemented. Go fish.
        if "cm" in value:
            return float(value[0:-2]) * 10
        elif "mm" in value:
            return float(value[0:-2])
        elif "Q" in value:
            return float(value[0:-1]) * (1 / 40) * 10
        elif "in" in value:
            return float(value[0:-2]) * 2.54 * 10
        elif "pc" in value:
            return float(value[0:-2]) * (1 / 6) * 2.54 * 10
        elif "pt" in value:
            return float(value[0:-2]) * (1 / 72) * 2.54 * 10
        elif "px" in value:
            return float(value[0:-2]) * (1 / 96) * 2.54 * 10
        return float(value)

    def mm_to_px(self, value):
        return (value / 25.4) * 96