#!/usr/bin/python3

import getopt
import paho.mqtt.client as mqtt
import sys
import time

debug_mode = False
indent = 0

def debug(msg):
    if debug_mode:
        print(("\t" * indent) + msg)

class State:
    def __init__(self):
            self.attrs = {}

    def update(self):
        self.now = time.time()
        tm = time.localtime(self.now)
        self.year = tm.tm_year
        self.month = tm.tm_mon
        self.day = tm.tm_mday
        self.hour = tm.tm_hour
        self.min = tm.tm_min
        self.wday = tm.tm_wday
        self.hyst_state = {}
        debug("[{}-{:02d}-{:02d} {:02d}:{:02d}:{:02d} wday={}]".format(
            self.year, self.month, self.day,
            self.hour, self.min, tm.tm_sec,
            self.wday
            ))

    def get_sensor(self, key):
        topic = "burrow/" + key
        if topic in self.attrs:
            s = self.attrs[topic].split(" ")
            if len(s) >= 2 and int(s[1]) < self.now - 120:
                debug("< {} EXPIRED".format(key))
                return None
            else:
                debug("< {} = {}".format(key, s[0]))
                return float(s[0])
        else:
            debug("< {} UNDEFINED".format(key))
            return None

    def set(self, key, val):
        global mq
        topic = "burrow/" + key
        debug("> {} = {}".format(topic, val))
        mq.publish(topic, val, qos=1, retain=True)

    def auto_enabled(self, key):
        topic = "burrow/auto/" + key
        if topic in self.attrs:
            return self.attrs[topic] != '0'
        else:
            return True

    def hysteresis(self, key, value, low, high):
        if key in self.hyst_state:
            old_state = self.hyst_state[key]
        else:
            old_state = 0
        if value is None:
            new_state = 0
        elif old_state <= 0:
            if value >= high:
                new_state = 1
            else:
                new_state = -1
        else:
            if value <= low:
                new_state = -1
            else:
                new_state = 1
        self.hyst_state[key] = new_state
        return new_state

st = State()

def on_connect(mq, userdata, flags, rc):
    mq.subscribe("burrow/#")

def on_message(mq, userdata, msg):
    global st
    # debug("Message {}: {}".format(msg.topic, msg.payload))
    st.attrs[msg.topic] = msg.payload.decode('utf-8')

def auto_loft_fan():
    global st
    lt = st.get_sensor("temp/loft")
    lt_high = st.hysteresis('lt_high', lt, 29, 30)
    lt_mid = st.hysteresis('lt_mid', lt, 24, 25)
    if lt_high > 0:
            fs = 3
    elif lt_mid > 0:
        if st.hour in range(10, 20):
                fs = 3
        else:
            fs = 1
    else:
        if st.hour in range(8, 22):
            if st.min % 30 in range(0, 5):
                fs = 3
            else:
                fs = 0
        else:
            fs = 0
    # FIXME: Disabled for now
    fs = 0
    st.set("loft/fan", fs)

def auto_circ():
    global st
    if st.hour in range(20, 22):
        c = 1
    else:
        c = 0;
    st.set("loft/circulation", c)

def auto_air():
    global st
    tii = st.get_sensor('air/inside-intake')
    tie = st.get_sensor('air/inside-exhaust')
    toi = st.get_sensor('air/outside-intake')
    tmix = st.get_sensor('air/mixed')
    house_warm = st.hysteresis('house_warm', tii, 23.5, 24.5)
    house_hot = st.hysteresis('house_hot', tii, 24.5, 25)

    # Is AC currently on (mixed air is significantly colder than inside exhaust)?
    if tie is None or tmix is None:
            ac_off = 1
    else:
        ac_off = st.hysteresis('ac_off', tmix, tie - 5, tie - 4)

    # Do we want to bypass the heat exchanger?
    if toi is None or tie is None:
        st.set('air/bypass', 0)
    else:
        outside_warmer = (st.hysteresis('bypass', toi, tii - 0.5, tii + 0.5) >= 0)
        if (house_warm >= 0) == outside_warmer:
            st.set('air/bypass', 0)
        else:
            st.set('air/bypass', 1)

    # Is mixed air colder than air from the inside?
    if tii is None or tmix is None:
        mixed_warmer = 0
    else:
        mixed_warmer = st.hysteresis('mixed_warmer', tmix, tii - 1, tii)

    # Do we want to boost heat exchanger fan?
    if ac_off < 0 or (house_hot > 0 and mixed_warmer < 0):
        st.set('air/exchanger-fan', 255)
    else:
        st.set('air/exchanger-fan', 0)

    debug("Air: house_warm={} house_hot={} ac_off={} outside_warmer={} mixed_warmer={}".format(house_warm, house_hot, ac_off, outside_warmer, mixed_warmer))

opts, args = getopt.gnu_getopt(sys.argv[1:], "", ["debug"])
for opt in opts:
    o, arg = opt
    if o == "--debug":
        debug_mode = True

mq = mqtt.Client()
mq.on_connect = on_connect
mq.on_message = on_message
mq.will_set("status/auto", "dead", retain=True)
mq.connect("127.0.0.1")
mq.publish("status/auto", "ok", retain=True)
mq.loop_start()

# Heuristic delay to get all attributes from MQTT
time.sleep(3)

checks = [
    ('loft-fan', auto_loft_fan),
    ('circ', auto_circ),
    ('air', auto_air)
]

while True:
    st.update()
    for name, func in checks:
        if st.auto_enabled(name):
            debug(name)
            indent += 1
            func()
            indent -= 1
        else:
            debug("{} DISABLED".format(name))
    debug("=" * 80)
    time.sleep(10)