import os.path
import struct
import re

from hashlib import md5
from datetime import datetime, timedelta

from django.urls import reverse
from django.contrib.auth.models import User
from django.db import models

vertex_pattern = re.compile(r'vertex\s+([0-9.e+-]+)\s+([0-9.e+-]+)\s+([0-9.e+-]+)')




def model_path(instance, filename):
    ext = os.path.splitext(filename)[1]
    md5sum = md5()
    md5sum.update(instance.name.encode('utf-8') + 
    	str(datetime.now()).encode('utf-8') + 
    	filename.encode('utf-8'))
    randomname = md5sum.hexdigest()
    return os.path.join('models', '%s%s' % (randomname, ext))

def source_path(instance, filename):
    ext = os.path.splitext(filename)[1]
    md5sum = md5()
    md5sum.update(instance.name.encode('utf-8') + 
    	str(datetime.now()).encode('utf-8') + 
    	filename.encode('utf-8'))
    randomname = md5sum.hexdigest()
    return os.path.join('sources', '%s%s' % (randomname, ext))



class Geometry(models.Model):

    HOUR = 0
    DAY = 1
    WEEK = 2
    MONTH = 3
    FORERVER = 4

    EXPIRATION_CHOICES = ((HOUR, 'one hour'), (DAY, 'one day'), (WEEK, 'one week'),
                          (MONTH, 'one month'), (FORERVER, 'forever'))

    DELTAS = {
        HOUR: timedelta(hours=1),
        DAY: timedelta(days=1),
        WEEK: timedelta(weeks=1),
        MONTH: timedelta(weeks=4)
    }

    name = models.CharField(max_length=128)
    description = models.TextField(blank=True)
    user = models.ForeignKey(User, blank=True, null=True, on_delete=models.CASCADE)
    date = models.DateTimeField(auto_now_add=True)
    expiration = models.IntegerField(default=0, choices=EXPIRATION_CHOICES)
    public = models.BooleanField(default=True)
    polycount = models.IntegerField(blank=True, default=0)
    width = models.FloatField(blank=True, default=0)
    depth = models.FloatField(blank=True, default=0)
    height = models.FloatField(blank=True, default=0)
    file = models.FileField(upload_to=model_path)
    sourcefile = models.FileField(upload_to=source_path, blank=True)

    def get_absolute_url(self):
        return reverse('geometry_details', kwargs={'id': self.pk})

    @classmethod
    def get_latest(cls):
        return cls.objects.all().filter(public=True).order_by('-date')[:10]

    def get_expiration_date(self):
        for expiration in [self.HOUR, self.DAY, self.WEEK, self.MONTH]:
            if self.expiration == expiration:
                return self.date + self.DELTAS[expiration]

        return None

    def _generate_meta_infos(self):
        print("Generating metainfos %s" % self.name)

        self.file.open()

        count = 0
        min_coord = [None, None, None]
        max_coord = [None, None, None]

        if self.file.read(5) != "solid":
            print("binary")
            # Skip header
            self.file.seek(80)
            count = struct.unpack("i", self.file.read(4))[0]

            done = False
            for pos in range(0, count):
                # Skip normal (3 * 32bit)
                self.file.seek(self.file.tell() + 3 * 4)
                # Loop over each coordinate
                for vert in range(0, 3):
                    # Loop over each coordinate
                    for i in range(0, 3):
                        x = struct.unpack("<f", self.file.read(4))[0]

                        if min_coord[i] is not None:
                            min_coord[i] = min(min_coord[i], x)
                        else:
                            min_coord[i] = x

                        if max_coord[i] is not None:
                            max_coord[i] = max(max_coord[i], x)
                        else:
                            max_coord[i] = x
                # Skip attributes (16bit)
                self.file.seek(self.file.tell() + 2)

        else:
            print("ascii")

            line = self.file.readline()
            while line != "":
                line = line.strip()
                if line.startswith("facet"):
                    count = count + 1
                if line.startswith("vertex"):
                    coords = vertex_pattern.match(line).groups()
                    for i in range(0, 3):
                        x = float(coords[i])

                        if min_coord[i] is not None:
                            min_coord[i] = min(min_coord[i], x)
                        else:
                            min_coord[i] = x

                        if max_coord[i] is not None:
                            max_coord[i] = max(max_coord[i], x)
                        else:
                            max_coord[i] = x

                line = self.file.readline()

        self.file.close()

        self.width = max_coord[0] - min_coord[0]
        self.depth = max_coord[1] - min_coord[1]
        self.height = max_coord[2] - min_coord[2]
        self.polycount = count

        self.save()

    def get_polycount(self):
        if self.polycount == 0:
            self._generate_meta_infos()
        return self.polycount

    def get_width(self):
        if self.polycount == 0:
            self._generate_meta_infos()
        return self.width

    def get_depth(self):
        if self.polycount == 0:
            self._generate_meta_infos()
        return self.depth

    def get_height(self):
        if self.polycount == 0:
            self._generate_meta_infos()
        return self.height