#!/usr/bin/env python
# Last modified:  Time-stamp: <2008-05-08 16:11:36 haines>
"""Utilities to help data processing 

   Mostly time functions right now

   TO DO:
   check_configs()
   unit conversions (udunits?)
"""

__version__ = "v0.1"
__author__ = "Sara Haines <sara_haines@unc.edu>"

from datetime import datetime, timedelta, tzinfo
from dateutil.tz import tzlocal, tzutc
import time
import math

def check_configs():
    """Test config files for comformnity

    check either one or all for a platform
    
    id in filename == platform.id
    datetime in filename <= platform.config_start_date
       (close in time usually the same day
    also platform.config_start_date < platform.config_end_date
       (there needs to be some time that the platform was operational)
    test existence of specific structural elements (platform info and sensor info)
    and specific fields for both platform and sensor
    verify that for each platform_info['packages'] there is sensor_info and same id
      for pi['packages'][0] in si.keys()
      pi['packages'][0] == si['adcp']['id']
    bounds on data in fields
    show difference between two consecutive configs?
    pretty print to screen of dictionary info for platform and sensor info
    
        cn = os.path.splitext(os.path.basename(config))[0]
        cndt = filt_datetime(os.path.basename(config))[0]
        pi = get_config(cn+'.platform_info')
        if pi['config_start_date']:
            config_start_dt = filt_datetime(pi['config_start_date'])[0]
        elif pi['config_start_date'] == None:
            config_start_dt = now_dt
        if pi['config_end_date']:
            config_end_dt = filt_datetime(pi['config_end_date'])[0]
        elif pi['config_end_date'] == None:
            config_end_dt = now_dt

        print cn + ' -----------------'
        print cndt
        print config_start_dt
        print config_end_dt 
        print now_dt
        print 'file date ok? ' + str(cndt <= config_start_dt)
        print 'operation date ok? ' + str(config_start_dt < config_end_dt)
    """

def dt2es(dt):
    """Convert datetime object to epoch seconds (es) as seconds since Jan-01-1970 """
    # microseconds of timedelta object not used
    delta = dt - datetime(1970,1,1,0,0,0)
    es = delta.days*24*60*60 + delta.seconds
    return es 

def es2dt(es):
    """ Convert epoch seconds (es) to datetime object"""
    dt = datetime(*time.gmtime(es)[0:6])
    return dt

def find_months(year, month=1):
    """Find which months to process

    Since data are in subdirectories based on months determine
    previous, current, and next month to look in directories for data
    of the current month or month to process.

    :Parameters:
        year : int value or str 'yyyy_mm'
        month : int value

    :Returns:
        which_months : tuple of 3 datetime objects
             (prev_month, current_month, next_month)

    Examples
    --------
    >>> find_months(2007, 2)
    >>> find_months('2007_02')
    
    """
    if type(year) == int and type(month) == int :
        dt = datetime(year, month, day=1)
        this_month = dt
    elif type(year) == str :
        dt = filt_datetime(year)[0]
        this_month = dt
    #
    if dt.month == 1: # if January
        prev_month = datetime(dt.year-1, month=12, day=1) # Dec
        next_month = datetime(dt.year, dt.month+1, day=1) # Feb
    elif dt.month == 12: # if December
        prev_month = datetime(dt.year, dt.month-1, day=1) # Nov
        next_month = datetime(dt.year+1, month=1, day=1)  # Jan
    else:
        prev_month = datetime(dt.year, dt.month-1, day=1)
        next_month = datetime(dt.year, dt.month+1, day=1)
    #
    return (prev_month, this_month, next_month)

def this_month():
    """Return this month (GMT) as formatted string (yyyy_mm) """
    this_month_str = "%4d_%02d" % time.gmtime()[0:2]
    return this_month_str

def scanf_datetime(ts, fmt='%Y-%m-%dT%H:%M:%S'):
    """Convert string representing date and time to datetime object"""
    # default string format follows convention YYYY-MM-DDThh:mm:ss
    
    t = time.strptime(ts, fmt)
    # the '*' operator unpacks the tuple, producing the argument list.
    dt = datetime(*t[0:6])
    return dt

def filt_datetime(input_string, remove_ext=True):
    """
    Following the template, (YY)YYMMDDhhmmss
    and versions with of this with decreasing time precision,
    find the most precise, reasonable string match and
    return its datetime object.
    """

    # remove any trailing filename extension
    from os.path import splitext
    import re
    if remove_ext:
        (s, e) = splitext(input_string)
        input_string = s
    
    # YYYYMMDDhhmmss and should handle most cases of the stamp
    # other forms this should pass
    # YY_MM_DD_hh:mm:ss
    # YYYY_MM_DD_hh:mm:ss
    # YYYY,MM,DD,hh,mm,ss
    # YY,MM,DD,hh,mm,ss

    case1_regex = r"""
    # case 1: (YY)YYMMDDhhmmss 
    (\d{4}|\d{2})     # 2- or 4-digit YEAR (e.g. '07' or '2007')
    \D?               # optional 1 character non-digit separator (e.g. ' ' or '-')
    (\d{2})           # 2-digit MONTH (e.g. '12')
    \D?               # optional 1 character non-digit separator
    (\d{2})           # 2-digit DAY of month (e.g. '10')
    \D?               # optional 1 character non-digit separator (e.g. ' ' or 'T')
    (\d{2})           # 2-digit HOUR (e.g. '10')
    \D?               # optional 1 character non-digit separator (e.g. ' ' or ':')
    (\d{2})           # 2-digit MINUTE (e.g. '10')
    \D?               # optional 1 character non-digit separator (e.g. ' ' or ':')
    (\d{2})           # 2-digit SECOND (e.g. '10')
    """

    case2_regex = r"""
    # case 2: (YY)YYMMDDhhmm (no seconds) 
    (\d{4}|\d{2})     # 2- or 4-digit YEAR 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or '-')
    (\d{2})           # 2-digit MONTH 
    \D?               # optional 1 character non-digit separator
    (\d{2})           # 2-digit DAY 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or 'T')
    (\d{2})           # 2-digit HOUR 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or ':')
    (\d{2})           # 2-digit MINUTE 
    """

    case3_regex = r"""
    # case 3: (YY)YYMMDDhh (no seconds, no minutes)
    (\d{4}|\d{2})     # 2- or 4-digit YEAR 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or '-')
    (\d{2})           # 2-digit MONTH 
    \D?               # optional 1 character non-digit separator
    (\d{2})           # 2-digit DAY 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or 'T')
    (\d{2})           # 2-digit HOUR 
    """

    case4_regex = r"""
    # case 4: (YY)YYMMDD (no time values, just date)
    (\d{4}|\d{2})     # 2- or 4-digit YEAR 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or '-')
    (\d{2})           # 2-digit MONTH 
    \D?               # optional 1 character non-digit separator
    (\d{2})           # 2-digit DAY 
    """

    case5_regex = r"""
    # case 5: (YY)YYMM (no time values, just month year)
    (\d{4}|\d{2})     # 2- or 4-digit YEAR 
    \D?               # optional 1 character non-digit separator (e.g. ' ' or '-')
    (\d{2})           # 2-digit MONTH 
    """

    ##  Verbose regular expressions require use of re.VERBOSE flag.
    ##  so we can use multiline regexp

    # cases are ordered from precise to more coarse resolution of time
    cases = [case1_regex, case2_regex, case3_regex, case4_regex, case5_regex]
    patterns = [re.compile(c, re.VERBOSE) for c in cases]
    matches = [p.search(input_string) for p in patterns]

    # for testing, try to computer datetime objects
    # just because there is a match does not mean it makes sense
    for ind in range(len(matches)):
        if bool(matches[ind]):
            # print matches[ind].groups()
            bits = matches[ind].groups()
            values = [int(yi) for yi in bits]
            # check for 2-digit year 
            if values[0] < 50:
                values[0] += 2000
            elif values[0]>=50 and values[0]<100:
                values[0] += 1900
            #
            # we must have at least 3 arg input to datetime
            if len(values)==1:
                values.extend([1,1]) # add First of January
            elif len(values)==2:
                values.extend([1]) # add first day of month

            #
            # compute dt
            try:
                dt = datetime(*values)
            except ValueError, e:
                # value error if something not valid for datetime
                # e.g. month 1...12, something parsed wrong
                dt = None
            else:
                # absolute difference in days from now (UTC)
                z = dt - datetime.utcnow()
                daysdiff = abs(z.days)
                # if this date unreasonable (>10 years*365), throw it out
                # something parsed wrong
                if daysdiff > 3650:
                    dt = None                
        else:
            dt = None

        # place datetime object or None within sequence of matches
        matches[ind] = dt

    # find the first (most precise) date match since there might be more than
    # as we searched more coarse templates, but now we have thrown out 
    
    b = [bool(x) for x in matches]
    try:
        ind = b.index(True)
    except ValueError, e:
        print 'filt_datetime: No date found in ', input_string
        dt = None
    else:
       dt = matches[ind]
       return dt,ind 

def display_time_diff(diff):
    """Display time difference in HH:MM:DD using number weeks (W)
    and days (D) if necessary"""
    # weeks, days = divmod(diff.days, 7)
    days = diff.days
    minutes, seconds = divmod(diff.seconds, 60)
    hours, minutes = divmod(minutes, 60)    
    # if (weeks>2 and days>0):
    #    str = "%d Weeks, %d Days %02d:%02d" % (days, hours, minutes)
    if (days==1):
        str = "%02d:%02d" % (24+hours, minutes)
    elif (days>1):
        str = "%d Days %02d:%02d" % (days, hours, minutes)
    else:
        str = "%02d:%02d" % (hours, minutes)
    return str

def copy_loop_sequence(src, dst, fn_glob, numFiles=24):
    """ """
    # src = '/seacoos/data/nccoos/level3/bogue/adcpwaves/dspec/'+this_month.strftime("%Y_%m")
    # dst = '/home/haines/rayleigh/loop/'
    # fn_glob = 'bogue_dspec_plot*'

# unit conversions 
def meters2feet(meters):
    """Convert meters to feet: <feet> = <meters>*3.28084 """
    return meters*3.28084

        
def millibar2inches_Hg(millibar):
    """Convert millibars to inches Hg: <inches_Hg> = <millibar>*0.0295301 """
    return millibar*0.0295301


def celsius2fahrenheit(celsius):
    """Convert deg Celsius to deg Fahrenheit: <fahrenheit> = ((1.8*<celsius>)+32) """
    return (1.8*celsius)+32


def millimeters2inches(millimeters):
    """ Convert millimeter to inches: <inches> = <millimeters>*0.0393700787) """
    return millimeters*0.0393700787


def meters_sec2knots(meters_sec):
    """ Convert m/s to knots: <knots> = <meters_sec>*1.94384449) """
    return meters_sec*1.94384449


def wind_vector2u(wind_speed, wind_from_direction):
    """ Convert wind vector to U (east) component: <u> = <wind_speed>*sine(<wind_from_direction>*pi/180) """
    return wind_speed*math.sin(wind_from_direction*math.pi/180)


def wind_vector2v(wind_speed, wind_from_direction):
    """ Convert wind vector to V (north) component: <v> = <wind_speed>*cosine(<wind_from_direction>*pi/180) """
    return wind_speed*math.cos(wind_from_direction*math.pi/180)