from __future__ import unicode_literals
from PIL import Image, ImageDraw
from hashlib import md5
import base64
import random
from six import StringIO

GRID_SIZE = 5
BORDER_SIZE = 20
SQUARE_SIZE = 40


class Identicon(object):
	def __init__(self, str_, background='#fafbfc'):
		"""
		`str_` is the string used to generate the identicon.
		`background` is the background of the identicon.
		"""
		w = h = BORDER_SIZE * 2 + SQUARE_SIZE * GRID_SIZE
		self.image = Image.new('RGB', (w, h), background)
		self.draw = ImageDraw.Draw(self.image)
		self.hash = self.digest(str_)

	def digest(self, str_):
		"""
		Returns a md5 numeric hash
		"""
		return int(md5(str_.encode('utf-8')).hexdigest(), 16)

	def calculate(self):
		"""
		Creates the identicon.
		First three bytes are used to generate the color,
		remaining bytes are used to create the drawing
		"""
		# color = (self.hash & 0xff, self.hash >> 8 & 0xff, self.hash >> 16 & 0xff)
		color = random.choice((
			(254, 196, 197),
			(253, 138, 139),
			(254, 231, 206),
			(254, 208, 159),
			(210, 211, 253),
			(163, 165, 252),
			(247, 213, 247),
			(242, 172, 238),
			(235, 247, 206),
			(217, 241, 157),
			(211, 248, 237),
			(167, 242, 221),
			(255, 249, 207),
			(254, 245, 161),
			(211, 241, 254),
			(168, 228, 254),
			(207, 245, 210),
			(159, 235, 164),
		))
		# print color
		# color = (254, 232, 206)

		self.hash >>= 24  # skip first three bytes
		square_x = square_y = 0  # init square position
		for x in range(GRID_SIZE * (GRID_SIZE + 1) // 2):
			if self.hash & 1:
				x = BORDER_SIZE + square_x * SQUARE_SIZE
				y = BORDER_SIZE + square_y * SQUARE_SIZE
				self.draw.rectangle(
					(x, y, x + SQUARE_SIZE, y + SQUARE_SIZE),
					fill=color,
					outline=color
				)
				# following is just for mirroring
				x = BORDER_SIZE + (GRID_SIZE - 1 - square_x) * SQUARE_SIZE
				self.draw.rectangle(
					(x, y, x + SQUARE_SIZE, y + SQUARE_SIZE),
					fill=color,
					outline=color
				)
			self.hash >>= 1  # shift to right
			square_y += 1
			if square_y == GRID_SIZE:  # done with first column
				square_y = 0
				square_x += 1

	def generate(self):
		"""
		Save and show calculated identicon
		"""
		self.calculate()
		with open('identicon.png', 'wb') as out:
			self.image.save(out, 'PNG')
		self.image.show()

	def base64(self, format='PNG'):
		'''
		usage:  i = Identicon('xx')
				print(i.base64())
		return: this image's base64 code
		created by: liuzheng712
		bug report: https://github.com/liuzheng712/identicons/issues
		'''
		self.calculate()
		fp = StringIO()
		self.image.encoderinfo = {}
		self.image.encoderconfig = ()

		if format.upper() not in Image.SAVE:
			Image.init()
		save_handler = Image.SAVE[format.upper()]
		try:
			save_handler(self.image, fp, '')
		finally:
			fp.seek(0)
			return "data:image/png;base64,{0}".format(base64.b64encode(fp.read()))
