# -*- coding: utf-8 -*-
#:vim:et:ts=4:sts=4:sw=4:
import rrdtool
import os
import os.path
import sys
import glob
import hashlib
import tempfile
import time
import syslog
import sqlite3
import traceback
import datetime
import struct
import binascii
import json
import subprocess
from colorsys import hls_to_rgb

import config
import atomicfile
import settings

fridge_settings = settings.Settings()

def sensor_rrd_path(s):
    return '%s/sensor_%s.rrd' % (config.DATA_PATH, str(s))

# returns (path, sensor_name) tuples
def all_sensors():
    return [(r, os.path.basename(r[:-4])) 
        for r in glob.glob('%s/*.rrd' % config.DATA_PATH)]

def create_rrd(sensor_id):
    # start date of 10 seconds into 1970 is used so that we can
    # update with prior values straight away.
    if 'voltage' in sensor_id:
        args = [ 
                '--step', '3600',
                'DS:temp:GAUGE:7200:1:10',
                'RRA:AVERAGE:0.5:1:87600']
    elif 'fridge_on' in sensor_id:
        args = [
                '--step', '300',
                'DS:temp:GAUGE:600:-100:500',
                'RRA:LAST:0.5:1:1051200']
    else:
        args = [
                '--step', '300',
                'DS:temp:GAUGE:600:-100:500',
                'RRA:AVERAGE:0.5:1:1051200']

    rrdtool.create(sensor_rrd_path(sensor_id), 
                '--start', 'now-60d',
                *args)

# stolen from viewmtn, stolen from monotone-viz
def colour_from_string(str):
    def f(off):
        return hashval[off] / 256.0
    hashval = hashlib.sha1(str.encode()).digest()
    hue = f(5)
    li = f(1) * 0.15 + 0.55
    sat = f(2) * 0.5 + .5
    return ''.join(["%.2x" % int(x * 256) for x in hls_to_rgb(hue, li, sat)])

def graph_png(start, length):
    os.environ['MATT_PNG_BODGE_COMPRESS'] = '4'
    os.environ['MATT_PNG_BODGE_FILTER'] = 'paeth'
    rrds = all_sensors()

    graph_args = []
    have_volts = False

    ## volts = temp * volts_div + volts_shift
    #volts_div = 10
    #volts_shift = 2
    volts_div = 1
    volts_shift = 0

    volts_mult = 1.0/volts_div

    # (title, sensorline) pairs.
    sensor_lines = []

    wort_sensor = None
    fridge_sensor = None
    for n, (rrdfile, sensor) in enumerate(rrds):
        unit = None
        if 'avrtemp' in sensor:
            continue
        if 'voltage' in sensor:
            have_volts = True
            vname = 'scalevolts'
            graph_args.append('DEF:%(vname)s=%(rrdfile)s:temp:AVERAGE:step=3600' % locals())
            unit = 'V'
        elif 'fridge_on' in sensor:
            vname = 'fridge_on'
            graph_args.append('DEF:raw%(vname)s=%(rrdfile)s:temp:LAST' % locals())
            graph_args.append('CDEF:%(vname)s=raw%(vname)s,-0.2,*,3,+' % locals())
        else:
            vname = 'temp%d' % n
            graph_args.append('DEF:raw%(vname)s=%(rrdfile)s:temp:AVERAGE' % locals())
            # limit max temp to 50
            graph_args.append('CDEF:%(vname)s=raw%(vname)s,38,GT,UNKN,raw%(vname)s,%(volts_mult)f,*,%(volts_shift)f,+,IF' % locals())
            unit = '<span face="Liberation Serif">°</span>C'

        format_last_value = None
        if unit:
            try:
                last_value = float(rrdtool.info(rrdfile)['ds[temp].last_ds'])
                format_last_value = ('%f' % last_value).rstrip('0').rstrip('.') + unit
            except ValueError:
                pass
        width = config.LINE_WIDTH
        legend = config.SENSOR_NAMES.get(sensor, sensor)
        colour = config.SENSOR_COLOURS.get(legend, colour_from_string(sensor))
        print_legend = ''
        if legend in config.LEGEND_NAMES:
            if format_last_value:
                print_legend = ':%s (%s)' % (legend, format_last_value)
            else:
                print_legend = ":%s" % legend
        sensor_lines.append( (legend, 'LINE%(width)f:%(vname)s#%(colour)s%(print_legend)s' % locals()) )
        if legend == 'Wort':
            wort_sensor = vname
        elif legend == 'Fridge':
            fridge_sensor = vname

    # calculated bits
    colour = '000000'
    graph_args.append('CDEF:wortdel=%(wort_sensor)s,PREV(%(wort_sensor)s),-' % locals())
    graph_args.append('CDEF:tempdel=%(wort_sensor)s,%(fridge_sensor)s,-' % locals())
    graph_args.append('CDEF:fermheat=wortdel,80,*,tempdel,0.9,*,+' % locals())
    graph_args.append('CDEF:trendfermheat=fermheat,7200,TRENDNAN' % locals())
    graph_args.append('CDEF:limitfermheat=trendfermheat,5,+,11,MIN,2,MAX' % locals())
    graph_args.append('LINE0.5:limitfermheat#%(colour)s' % locals())

    # lines are done afterwards so they can be layered
    sensor_lines.sort(key = lambda legend_line: "Wort" in legend_line[0])
    graph_args += (line for (legend, line) in sensor_lines)

    #print>>sys.stderr, '\n'.join(graph_args)

    end = int(start+length)
    start = int(start)

    tempf = tempfile.NamedTemporaryFile()
    dateformat = '%H:%M:%S %Y-%m-%d'
    watermark = ("Now %s\t"
                "Start %s\t"
                "End %s" % (
                datetime.datetime.now().strftime(dateformat),
                datetime.datetime.fromtimestamp(start).strftime(dateformat),
                datetime.datetime.fromtimestamp(end).strftime(dateformat) ))

    args = [tempf.name, '-s', str(start),
        '-e', str(end),
        '-w', str(config.GRAPH_WIDTH),
        '-h', str(config.GRAPH_HEIGHT),
        '--slope-mode',
        '--border', '0',
#        '--vertical-label', 'Voltage',
        '--y-grid', '%(volts_mult)f:1' % locals(),
        '--dynamic-labels',
        '--grid-dash', '1:0',
        '--zoom', str(config.ZOOM),
        '--color', 'GRID#00000000',
        '--color', 'MGRID#aaaaaa',
        '--color', 'BACK#ffffff',
        '--disable-rrdtool-tag',
        '--pango-markup',
        '--watermark', watermark,
        '--imgformat', 'PNG'] \
        + graph_args
    args += ['--font', 'DEFAULT:12:%s' % config.GRAPH_FONT]
    args += ['--font', 'WATERMARK:10:%s' % config.GRAPH_FONT]
    if have_volts:
        volts_shift_div = volts_div * volts_shift
        args += ['--right-axis', '%(volts_div)f:-%(volts_shift_div)f' % locals(),
#            '--right-axis-format', '%.0lf',
#            '--right-axis-label', 'Temperature'
            ]

	#print>>sys.stderr, ' '.join("'%s'" % s for s in args)
    rrdtool.graph(*args)
    #return tempf
    return tempf.read()

def validate_value(m):
    if m == 85:
        return 'U'
    else:
        return '%f' % m

def sensor_update(sensor_id, measurements):
    try:
        open(sensor_rrd_path(sensor_id))
    except IOError as e:
        create_rrd(sensor_id)

    if measurements:
        values = ['%d:%s' % (t, validate_value(m)) for (t, m) in measurements]

        rrdfile = sensor_rrd_path(sensor_id)
        # XXX what to do here when it fails...
        for v in values:
            try:
                rrdtool.update(rrdfile, v)
            except rrdtool.error as e:
                print("Bad rrdtool update '%s': %s" % (v, str(e)), file=sys.stderr)
                traceback.print_exc(file=sys.stderr)

        # be paranoid
        #f = file(rrdfile)
        #os.fsync(f.fileno())

def debug_file(mode='r'):
    return open('%s/debug.log' % config.DATA_PATH, mode)

def record_debug(params):
    f = debug_file('a+')
    f.write('===== start %s =====\n' % time.strftime('%a, %d %b %Y %H:%M:%S'))
    json.dump(params, f, sort_keys=True, indent=4)
    f.write('===== end %s =====\n' % time.strftime('%a, %d %b %Y %H:%M:%S'))
    f.flush()
    return f

def tail_debug_log():
    f = debug_file()
    f.seek(0, 2)
    size = f.tell()
    f.seek(max(0, size-30000))
    return '\n'.join(l.strip() for l in f.readlines()[-400:])

def time_rem(name, entries):
    val_ticks = int(entries[name])
    val_rem = int(entries['%s_rem' % name])
    tick_wake = int(entries['tick_wake']) + 1
    tick_secs = int(entries['tick_secs'])
    return val_ticks + float(val_rem) * tick_secs / tick_wake

def write_current_params(current_params, current_epoch):
    fridge_settings.update(current_params, current_epoch)

def read_current_params():
    params, epochtag = fridge_settings.get()
    return params

def parse(params):

    start_time = time.time()
   
    debugf = record_debug(params)

    remote_now = params['now']

    time_diff = start_time - remote_now

    # readings is [ ({sensorname: value, ...}, time), ... ]
    readings = params['readings']

    # measurements is {sensorname: [(time, value), ...], ...}
    measurements = {}
    for rs, t in readings:
        real_t = t + time_diff
        for s, v in rs.items():
            measurements.setdefault(s, []).append((real_t, v))

    # one-off measurements here
    current_params = params['current_params']
    current_epoch = params['current_params_epoch']
    measurements['fridge_on'] = [ (time.time(), params['fridge_on']) ]
    measurements['fridge_setpoint'] = [ (time.time(), current_params['fridge_setpoint']) ]

    write_current_params(current_params, current_epoch)

    for s, vs in measurements.items():
        sensor_update(s, vs)

    timedelta = time.time() - start_time
    debugf.write("Updated sensors in %.2f secs\n" % timedelta)
    debugf.flush()

# types used here define the type of a field
_FIELD_DEFAULTS = {
    'fridge_setpoint': 16.0,
    'fridge_difference': 0.2,
    'overshoot_delay': 720, # 12 minutes
    'overshoot_factor': 1.0, # °C
    'disabled': False,
    'nowort': True,
    'fridge_range_lower': 3,
    'fridge_range_upper': 3,
    }

def fake_params():
    """ for quicker testing """
    r = []
    r.append({'name': 'going', 'value': 'true', 'kind': 'yesno', 'title': 'going'})
    r.append({'name': 'temperature', 'value': 12.5, 'kind': 'number', 'title': 'temperature', 'digits': 1, 'amount': 0.1, 'unit': '°'})
    return r

def get_params():
    """ Can return None if there aren't any parameters yet,
    otherwise returns the parameter list """

    r = []

    vals = read_current_params()
    if not vals:
        return None

    for k, v in _FIELD_DEFAULTS.items():
        n = {'name': k, 'value': type(v)(vals[k])}
        if type(v) is bool:
            kind = 'yesno'
        else:
            kind = 'number'
            if k == 'overshoot_delay':
                n['unit'] = ' sec'
                n['amount'] = 60
                n['digits'] = 0;
            else:
                n['unit'] = '°'
                n['amount'] = 0.1;
                n['digits'] = 1;
        n['kind'] = kind
        n['title'] = k
        r.append(n)

    return json.dumps(r, sort_keys=True, indent=4)

def same_type(a, b):
    ta = type(a)
    tb = type(b)

    if ta == int:
        ta = float
    if tb == int:
        tb = float

    return (ta == tb)

def update_params(p):
    params = {}
    for i in p:
        params[i['name']] = i['value']

    if params.keys() != _FIELD_DEFAULTS.keys():
        diff = params.keys() ^ _FIELD_DEFAULTS.keys()
        return "Key mismatch, difference %s" % str(diff)

    for k, v in params.items():
        if not same_type(v, _FIELD_DEFAULTS[k]):
            return "Bad type for %s, %s vs %s" % (k , type(v), type(_FIELD_DEFAULTS[k]))

    fridge_settings.update(params)
    return True