#!/usr/bin/env python

from __future__ import print_function
from __future__ import division

from subprocess import Popen, PIPE


def ioreg_battery_info():
    output = Popen(["ioreg", "-r", "-k", "LegacyBatteryInfo", "-w", "0"],
                   stdout=PIPE).communicate()[0]
    try:  # python3
        return str(output, encoding='utf-8')
    except TypeError:  # python2
        return output


def parse_ioreg_dict(output):
    return dict(
        [(kw.strip().strip('"'), vw.strip())
            for kw, vw
            in [line.split("=", 1)
                for line
                in output.split('\n') if line.find('=') > 0
                ]
         ]
        )


def is_two_complement_negative(value):
    return value > (2**63-1)


def two_complement(value):
    return 2**64 - value


def fix_negative(value):
    if is_two_complement_negative(value):
        return -two_complement(value)
    else:
        return value


def ioreg_battery_dict():
    output = ioreg_battery_info()
    return parse_ioreg_dict(output)


def fix_integer(string):
    return fix_negative(int(string))


def format_time(string):
    minutes = int(string)
    if minutes == 65535:
        return None
    else:
        return "%s:%s" % (minutes // 60, minutes % 60)


def percentage(ratio):
    return "%s%%" % (int(ratio * 100))

humanize_index = {
    "TimeRemaining": format_time,
    "AvgTimeToEmpty": format_time,
    "AvgTimeToFull": format_time,
    "InstantTimeToEmpty": format_time,
    "FullToEmptyTime": format_time,
    "WearRatio": percentage,
    "ChargeRatio": percentage,
    }


def humanize_data(k, v):
    if k in humanize_index:
        return humanize_index[k](v)
    else:
        return v


def wear_ratio(info):
    return int(info["MaxCapacity"]) / int(info["DesignCapacity"])


def charge_ratio(info):
    return int(info["CurrentCapacity"]) / int(info["MaxCapacity"])


def full_to_empty_time(info):
    if get_data(info, "Amperage") < 0:
        return -int(info["MaxCapacity"])*60 / get_data(info, "Amperage")
    else:
        return 65535

synthetize_index = {
    "Amperage": lambda i: fix_integer(i["Amperage"]),
    "InstantAmperage": lambda i: fix_integer(i["InstantAmperage"]),
    "WearRatio": wear_ratio,
    "ChargeRatio": charge_ratio,
    "FullToEmptyTime": full_to_empty_time,
    }


def synthetize_data(battery_info, k):
    if k in synthetize_index:
        return synthetize_index[k](battery_info)


def get_data(battery_info, k):
    if k in synthetize_index:
        return synthetize_data(battery_info, k)
    elif k in battery_info:
        return battery_info[k]
    else:
        raise KeyError("%s" % k)


keys_to_show = [
    "Temperature",
    "CycleCount",
    #"DesignCycleCount9C",
    "DesignCapacity",
    "MaxCapacity",
    "WearRatio",
    "CurrentCapacity",
    "ChargeRatio",
    "Voltage",
    "Amperage",
    "InstantAmperage",
    "InstantTimeToEmpty",
    "TimeRemaining",
    "AvgTimeToEmpty",
    "AvgTimeToFull",
    "FullToEmptyTime",
    ]


def print_key_value(k, v):
    if v is not None:
        print("%s = %s" % (k, v))


battery_info = ioreg_battery_dict()

for k in keys_to_show:
    print_key_value(k, humanize_data(k, get_data(battery_info, k)))