#!/usr/bin/env python2

from __future__ import print_function
import subprocess
import os
import sys

SUPPORTED_SYSTEM_PRODUCT_NAMES = ["W230SS"]
SUPPORTED_I2C_BUS_NAMES = ["SMBus I801 adapter at f040"]
I2C_CLASS_PATH = "/sys/class/i2c-dev"
CMDLINE_PATH = "/proc/cmdline"
KERNEL_PARAMETER = "acpi_enforce_resources=lax"
MODULES_PATH = "/proc/modules"
DEVICE_ADDRESS = 0x73
DATA = [
#    CMD   Data0
    [0x0A, 0x41],
    [0x04, 0xEE],
    [0x09, 0xFF],
    [0x00, 0x86],
    [0x04, 0xEE],
    [0x05, 0x03],
    [0x07, 0x40],
    [0x08, 0x84],
    [0x09, 0xFF],
    [0x00, 0x82],
]

def get_system_product_name():
    try:
        return subprocess.check_output(["dmidecode", "-s", "system-product-name"]
                                       ).strip()
    except OSError:
        print("Error: dmidecode is not installed", file=sys.stderr)
        return False
    except subprocess.CalledProcessError:
        print("Error: dmidecode returned non-zero exit status", file=sys.stderr)
        return False

def get_i2c_busses():
    busses = []
    try:
        i2c_directories = os.listdir(I2C_CLASS_PATH)
    except OSError:
        print("Error: Can't list directory I2C_CLASS_PATH (%s)" % I2C_CLASS_PATH,
              file=sys.stderr)
        return False
    for i2c_dev in i2c_directories:
        with open(os.path.join(I2C_CLASS_PATH, i2c_dev, "name")) as name_file:
            i2c_dev_name = name_file.read().strip()
        with open(os.path.join(I2C_CLASS_PATH, i2c_dev, "dev")) as dev_file:
            i2c_dev_major, i2c_dev_minor = dev_file.read().strip().split(":")
            i2c_dev_major = int(i2c_dev_major)
            i2c_dev_minor = int(i2c_dev_minor)
        busses.append((i2c_dev_name, i2c_dev_minor))
    return busses

def check_root():
    if os.geteuid() != 0:
        print("Warning: This program needs root privileges", file=sys.stderr)
    return True

def check_cmdline():
    try:
        cmdline_file = open(CMDLINE_PATH, "r")
    except IOError:
        print("Warning: Can't open file CMDLINE_PATH (%s)" % CMDLINE_PATH,
              file=sys.stderr)
        return True
    cmdline_parameters = cmdline_file.read().split()
    cmdline_file.close()
    if KERNEL_PARAMETER not in cmdline_parameters:
        print("Warning: Kernel parameter %s is missing" % KERNEL_PARAMETER,
              file=sys.stderr)
    return True

def check_modules():
    try:
        modules_file = open(MODULES_PATH, "r")
    except IOError:
        print("Warning: Can't open file MODULES_PATH (%s)" % MODULES_PATH,
              file=sys.stderr)
        return True
    module_i2c_dev_found = False
    module_i2c_i801_found = False
    for line in modules_file.readlines():
        if "i2c_dev" == line.split()[0]:
            module_i2c_dev_found = True
        if "i2c_i801" == line.split()[0]:
            module_i2c_i801_found = True
    if not module_i2c_dev_found:
        print("Warning: Module i2c_dev is not loaded", file=sys.stderr)
    if not module_i2c_i801_found:
        print("Warning: Module i2c_i801 is not loaded", file=sys.stderr)
    return True

def init_headphone():
    try:
        import smbus
    except ImportError:
        print("Error: Python module smbus not installed", file=sys.stderr)
        return False
    if  check_root() == False:
        return False
    system_product_name = get_system_product_name()
    if system_product_name == False:
        return False
    if system_product_name not in SUPPORTED_SYSTEM_PRODUCT_NAMES:
        print("Error: Unsupported system: %s" % system_product_name,
              file=sys.stderr)
        print("Supported systems:\n%s" % "".join(map(lambda e: "    %s\n" % e,
                                                     SUPPORTED_SYSTEM_PRODUCT_NAMES)),
              end="")
        return False
    if check_cmdline() == False:
        return False
    if check_modules() == False:
        return False
    i2c_busses = get_i2c_busses()
    if i2c_busses == False:
        return False
    selected_i2c_bus_minor = None
    selected_i2c_bus_name = None
    for i2c_bus_name, i2c_bus_minor in i2c_busses:
        if i2c_bus_name in SUPPORTED_I2C_BUS_NAMES:
            selected_i2c_bus_minor = i2c_bus_minor
            selected_i2c_bus_name = i2c_bus_name
    if selected_i2c_bus_minor == None:
        print("Error: Can't find i2c bus", file=sys.stderr)
        print("Found:\n%s" % "".join(map(lambda e: "    %s\n" % e[0],
                                         i2c_busses)), end="")
        print("Looked for:\n%s" % "".join(map(lambda e: "    %s\n" % e,
                                              SUPPORTED_I2C_BUS_NAMES)), end="")
        return False

    try:
        i2c_bus = smbus.SMBus(selected_i2c_bus_minor)
    except IOError:
        print("Error: Can't access i2c bus (%s)" % selected_i2c_bus_name,
              file=sys.stderr)
        return False
    for device_cmd, device_data in DATA:
        i2c_bus.write_byte_data(DEVICE_ADDRESS, device_cmd, device_data)
    i2c_bus.close()
    return True

if __name__ == "__main__":
    success = init_headphone()
    exit(0 if success else 1)