# Copyright (c) 2014 Adafruit Industries
# Author: Tony DiCola
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import logging
import unittest

from mock import Mock, patch

import Adafruit_GPIO.Platform as Platform


# Enable debug logging to stdout during tests.
logging.basicConfig()
logging.getLogger().setLevel(logging.DEBUG)


class MockSMBus(object):
	# Mock the smbus.SMBus class to record all data written to specific
	# addresses and registers in the _written member.
	def __init__(self):
		# _written will store a dictionary of address to register dictionary.
		# Each register dictionary will store a mapping of register value to
		# an array of all written values (in sequential write order).
		self._written = {}
		self._read = {}

	def _write_register(self, address, register, value):
		self._written.setdefault(address, {}).setdefault(register, []).append(value)

	def _read_register(self, address, register):
		return self._read.get(address).get(register).pop(0)

	def write_byte_data(self, address, register, value):
		self._write_register(address, register, value)

	def write_word_data(self, address, register, value):
		self._write_register(address, register, value >> 8 & 0xFF)
		self._write_register(address, register+1, value & 0xFF)

	def write_i2c_block_data(self, address, register, values):
		for i, value in enumerate(values):
			self._write_register(address, register+i, value & 0xFF)

	def read_byte_data(self, address, register):
		return self._read_register(address, register)

	def read_word_data(self, address, register):
		high = self._read_register(address, register)
		low = self._read_register(address, register+1)
		return (high << 8) | low

	def read_i2c_block_data(self, address, length):
		return [self._read_register(address+i) for i in range(length)]


def create_device(address, busnum):
	# Mock the smbus module and inject it into the global namespace so the
	# Adafruit_GPIO.I2C module can be imported.  Also inject a mock SMBus
	# instance to be returned by smbus.SMBus function calls.
	smbus = Mock()
	mockbus = MockSMBus()
	smbus.SMBus.return_value = mockbus
	with patch.dict('sys.modules', {'smbus': smbus}):
		import Adafruit_GPIO.I2C as I2C
		return (I2C.Device(address, busnum), smbus, mockbus)

def safe_import_i2c():
	# Mock the smbus module and inject it into the global namespace so the
	# Adafruit_GPIO.I2C module can be imported.  The imported I2C module is
	# returned so global functions can be called on it.
	with patch.dict('sys.modules', {'smbus': Mock() }):
		import Adafruit_GPIO.I2C as I2C
		return I2C


class TestI2CDevice(unittest.TestCase):

	def test_address_and_bus_set_correctly(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		self.assertEqual(device._bus, mockbus)
		smbus.SMBus.assert_called_with(1)
		self.assertEqual(device._address, 0x1F)

	def test_write8(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		device.write8(0xFE, 0xED)
		self.assertDictEqual(mockbus._written, { 0x1F: { 0xFE: [0xED] }})

	def test_write8_truncates_to_8bits(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		device.write8(0xFE, 0xBEEFED)
		self.assertDictEqual(mockbus._written, { 0x1F: { 0xFE: [0xED] }})

	def test_write16(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		device.write16(0xFE, 0xBEEF)
		self.assertDictEqual(mockbus._written, { 0x1F: { 0xFE: [0xBE], 
														 0xFF: [0xEF] }})

	def test_write16_truncates_to_8bits(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		device.write16(0xFE, 0xFEEDBEEF)
		self.assertDictEqual(mockbus._written, { 0x1F: { 0xFE: [0xBE], 
														 0xFF: [0xEF] }})

	def test_writeList(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		device.writeList(0x00, [0xFE, 0xED, 0xBE, 0xEF])
		self.assertDictEqual(mockbus._written, { 0x1F: { 0x00: [0xFE], 
														 0x01: [0xED],
														 0x02: [0xBE],
														 0x03: [0xEF] }})

	def test_readU8(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		mockbus._read[0x1F] = { 0xFE: [0xED] }
		value = device.readU8(0xFE)
		self.assertEqual(value, 0xED)

	def test_readS8(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		mockbus._read[0x1F] = { 0xFE: [0xED] }
		value = device.readS8(0xFE)
		self.assertEqual(value, -19)

	def test_readU16(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		mockbus._read[0x1F] = { 0xFE: [0xED], 0xFF: [0x01] }
		value = device.readU16(0xFE)
		self.assertEqual(value, 0xED01)

	def test_readS16(self):
		device, smbus, mockbus = create_device(0x1F, 1)
		mockbus._read[0x1F] = { 0xFE: [0xED], 0xFF: [0x01] }
		value = device.readS16(0xFE)
		self.assertEqual(value, -4863)


class TestGetDefaultBus(unittest.TestCase):
	@patch('Adafruit_GPIO.Platform.pi_revision', Mock(return_value=1))
	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.RASPBERRY_PI))
	def test_raspberry_pi_rev1(self):
		I2C = safe_import_i2c()
		bus = I2C.get_default_bus()
		self.assertEqual(bus, 0)

	@patch('Adafruit_GPIO.Platform.pi_revision', Mock(return_value=2))
	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.RASPBERRY_PI))
	def test_raspberry_pi_rev2(self):
		I2C = safe_import_i2c()
		bus = I2C.get_default_bus()
		self.assertEqual(bus, 1)

	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.BEAGLEBONE_BLACK))
	def test_beaglebone_black(self):
		I2C = safe_import_i2c()
		bus = I2C.get_default_bus()
		self.assertEqual(bus, 1)

	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.UNKNOWN))
	def test_unknown(self):
		I2C = safe_import_i2c()
		self.assertRaises(RuntimeError, I2C.get_default_bus)
