#   This library is free software; you can redistribute it and/or
#   modify it under the terms of the GNU Lesser General Public
#   License as published by the Free Software Foundation; either
#   version 2.1 of the License, or (at your option) any later version.
#
#   This library is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   Lesser General Public License for more details.
#
#   You should have received a copy of the GNU Lesser General Public
#   License along with this library; if not, write to the 
#      Free Software Foundation, Inc., 
#      59 Temple Place, Suite 330, 
#      Boston, MA  02111-1307  USA

# This file is part of urlgrabber, a high-level cross-protocol url-grabber
# Copyright 2002-2004 Michael D. Stenner, Ryan Tomayko


# This code is all straight from python-urlgrabber, which we historically
# used the system installed version of. But since the project is in
# maintenance mode upstream, and eventually we want to switch to python3,
# we are just copying this for now.


import sys
import time
import math
import thread
import fcntl
import struct
import termios

# Code from http://mail.python.org/pipermail/python-list/2000-May/033365.html
def terminal_width(fd=1):
    """ Get the real terminal width """
    try:
        buf = 'abcdefgh'
        buf = fcntl.ioctl(fd, termios.TIOCGWINSZ, buf)
        ret = struct.unpack('hhhh', buf)[1]
        if ret == 0:
            return 80
        # Add minimum too?
        return ret
    except: # IOError
        return 80

_term_width_val  = None
_term_width_last = None
def terminal_width_cached(fd=1, cache_timeout=1.000):
    """ Get the real terminal width, but cache it for a bit. """
    global _term_width_val
    global _term_width_last

    now = time.time()
    if _term_width_val is None or (now - _term_width_last) > cache_timeout:
        _term_width_val  = terminal_width(fd)
        _term_width_last = now
    return _term_width_val

class TerminalLine:
    """ Help create dynamic progress bars, uses terminal_width_cached(). """

    def __init__(self, min_rest=0, beg_len=None, fd=1, cache_timeout=1.000):
        if beg_len is None:
            beg_len = min_rest
        self._min_len = min_rest
        self._llen    = terminal_width_cached(fd, cache_timeout)
        if self._llen < beg_len:
            self._llen = beg_len
        self._fin = False

    def __len__(self):
        """ Usable length for elements. """
        return self._llen - self._min_len

    def rest_split(self, fixed, elements=2):
        """ After a fixed length, split the rest of the line length among
            a number of different elements (default=2). """
        if self._llen < fixed:
            return 0
        return (self._llen - fixed) / elements

    def add(self, element, full_len=None):
        """ If there is room left in the line, above min_len, add element.
            Note that as soon as one add fails all the rest will fail too. """

        if full_len is None:
            full_len = len(element)
        if len(self) < full_len:
            self._fin = True
        if self._fin:
            return ''

        self._llen -= len(element)
        return element

    def rest(self):
        """ Current rest of line, same as .rest_split(fixed=0, elements=1). """
        return self._llen

class BaseMeter:
    def __init__(self):
        self.update_period = 0.3 # seconds

        self.filename   = None
        self.url        = None
        self.basename   = None
        self.text       = None
        self.size       = None
        self.start_time = None
        self.last_amount_read = 0
        self.last_update_time = None
        self.re = RateEstimator()
        
    def start(self, filename=None, url=None, basename=None,
              size=None, now=None, text=None):
        self.filename = filename
        self.url      = url
        self.basename = basename
        self.text     = text

        #size = None #########  TESTING
        self.size = size
        if not size is None: self.fsize = format_number(size) + 'B'

        if now is None: now = time.time()
        self.start_time = now
        self.re.start(size, now)
        self.last_amount_read = 0
        self.last_update_time = now
        self._do_start(now)
        
    def _do_start(self, now=None):
        pass

    def update(self, amount_read, now=None):
        # for a real gui, you probably want to override and put a call
        # to your mainloop iteration function here
        if now is None: now = time.time()
        if (not self.last_update_time or
            (now >= self.last_update_time + self.update_period)):
            self.re.update(amount_read, now)
            self.last_amount_read = amount_read
            self.last_update_time = now
            self._do_update(amount_read, now)

    def _do_update(self, amount_read, now=None):
        pass

    def end(self, amount_read, now=None):
        if now is None: now = time.time()
        self.re.update(amount_read, now)
        self.last_amount_read = amount_read
        self.last_update_time = now
        self._do_end(amount_read, now)

    def _do_end(self, amount_read, now=None):
        pass
        
#  This is kind of a hack, but progress is gotten from grabber which doesn't
# know about the total size to download. So we do this so we can get the data
# out of band here. This will be "fixed" one way or anther soon.
_text_meter_total_size = 0
_text_meter_sofar_size = 0
def text_meter_total_size(size, downloaded=0):
    global _text_meter_total_size
    global _text_meter_sofar_size
    _text_meter_total_size = size
    _text_meter_sofar_size = downloaded

#
#       update: No size (minimal: 17 chars)
#       -----------------------------------
# <text>                          <rate> | <current size> <elapsed time> 
#  8-48                          1    8  3             6 1            9 5
#
# Order: 1. <text>+<current size> (17)
#        2. +<elapsed time>       (10, total: 27)
#        3. +                     ( 5, total: 32)
#        4. +<rate>               ( 9, total: 41)
#
#       update: Size, Single file
#       -------------------------
# <text>            <pc>  <bar> <rate> | <current size> <eta time> ETA
#  8-25            1 3-4 1 6-16 1   8  3             6 1        9 1  3 1
#
# Order: 1. <text>+<current size> (17)
#        2. +<eta time>           (10, total: 27)
#        3. +ETA                  ( 5, total: 32)
#        4. +<pc>                 ( 4, total: 36)
#        5. +<rate>               ( 9, total: 45)
#        6. +<bar>                ( 7, total: 52)
#
#       update: Size, All files
#       -----------------------
# <text> <total pc> <pc>  <bar> <rate> | <current size> <eta time> ETA
#  8-22 1      5-7 1 3-4 1 6-12 1   8  3             6 1        9 1  3 1
#
# Order: 1. <text>+<current size> (17)
#        2. +<eta time>           (10, total: 27)
#        3. +ETA                  ( 5, total: 32)
#        4. +<total pc>           ( 5, total: 37)
#        4. +<pc>                 ( 4, total: 41)
#        5. +<rate>               ( 9, total: 50)
#        6. +<bar>                ( 7, total: 57)
#
#       end
#       ---
# <text>                                 | <current size> <elapsed time> 
#  8-56                                  3             6 1            9 5
#
# Order: 1. <text>                ( 8)
#        2. +<current size>       ( 9, total: 17)
#        3. +<elapsed time>       (10, total: 27)
#        4. +                     ( 5, total: 32)
#

def _term_add_bar(tl, bar_max_length, pc):
    blen = bar_max_length
    bar  = '='*int(blen * pc)
    if (blen * pc) - int(blen * pc) >= 0.5:
        bar += '-'
    return tl.add(' [%-*.*s]' % (blen, blen, bar))

def _term_add_end(tl, osize, size):
    if osize: # osize should be None or >0, but that's been broken.
        if size > osize: # Is ??? better? Really need something to say < vs >.
            return tl.add(' !!! '), True
        elif size != osize:
            return tl.add(' ... '), True
    return tl.add(' ' * 5), False

class TextMeter(BaseMeter):
    def __init__(self, fo=sys.stderr):
        BaseMeter.__init__(self)
        self.fo = fo

    def _do_update(self, amount_read, now=None):
        etime = self.re.elapsed_time()
        fread = format_number(amount_read)
        #self.size = None
        if self.text is not None:
            text = self.text
        else:
            text = self.basename

        ave_dl = format_number(self.re.average_rate())
        sofar_size = None
        if _text_meter_total_size:
            sofar_size = _text_meter_sofar_size + amount_read
            sofar_pc   = (sofar_size * 100) / _text_meter_total_size

        # Include text + ui_rate in minimal
        tl = TerminalLine(8, 8+1+8)
        if tl._llen > 80:
            use_hours = True # For big screens, make it more readable.
        else:
            use_hours = False
        ui_size = tl.add(' | %5sB' % fread)
        if self.size is None:
            ui_time = tl.add('  %s' % format_time(etime, use_hours))
            ui_end  = tl.add(' ' * 5)
            ui_rate = tl.add(' %5sB/s' % ave_dl)
            out = '%-*.*s%s%s%s%s\r' % (tl.rest(), tl.rest(), text,
                                        ui_rate, ui_size, ui_time, ui_end)
        else:
            rtime = self.re.remaining_time()
            frtime = format_time(rtime, use_hours)
            frac = self.re.fraction_read()

            ui_time = tl.add('  %s' % frtime)
            ui_end  = tl.add(' ETA ')

            if sofar_size is None:
                ui_sofar_pc = ''
            else:
                ui_sofar_pc = tl.add(' (%i%%)' % sofar_pc,
                                     full_len=len(" (100%)"))

            ui_pc   = tl.add(' %2i%%' % (frac*100))
            ui_rate = tl.add(' %5sB/s' % ave_dl)
            # Make text grow a bit before we start growing the bar too
            blen = 4 + tl.rest_split(8 + 8 + 4)
            ui_bar = _term_add_bar(tl, blen, frac)
            out = '\r%-*.*s%s%s%s%s%s%s%s\r' % (tl.rest(), tl.rest(), text,
                                                ui_sofar_pc, ui_pc, ui_bar,
                                                ui_rate,ui_size,ui_time, ui_end)

        self.fo.write(out)
        self.fo.flush()

    def _do_end(self, amount_read, now=None):
        global _text_meter_total_size
        global _text_meter_sofar_size

        total_size = format_number(amount_read)
        if self.text is not None:
            text = self.text
        else:
            text = self.basename

        tl = TerminalLine(8)
        if tl._llen > 80:
            use_hours = True # For big screens, make it more readable.
        else:
            use_hours = False
        ui_size = tl.add(' | %5sB' % total_size)
        ui_time = tl.add('  %s' % format_time(self.re.elapsed_time(), use_hours))
        ui_end, not_done = _term_add_end(tl, self.size, amount_read)
        out = '\r%-*.*s%s%s%s\n' % (tl.rest(), tl.rest(), text,
                                    ui_size, ui_time, ui_end)
        self.fo.write(out)
        self.fo.flush()

        # Don't add size to the sofar size until we have all of it.
        # If we don't have a size, then just pretend/hope we got all of it.
        if not_done:
            return

        if _text_meter_total_size:
            _text_meter_sofar_size += amount_read
        if _text_meter_total_size <= _text_meter_sofar_size:
            _text_meter_total_size = 0
            _text_meter_sofar_size = 0

text_progress_meter = TextMeter

######################################################################
# support classes and functions

class RateEstimator:
    def __init__(self, timescale=5.0):
        self.timescale = timescale

    def start(self, total=None, now=None):
        if now is None: now = time.time()
        self.total = total
        self.start_time = now
        self.last_update_time = now
        self.last_amount_read = 0
        self.ave_rate = None
        
    def update(self, amount_read, now=None):
        if now is None: now = time.time()
        # libcurl calls the progress callback when fetching headers
        # too, thus amount_read = 0 .. hdr_size .. 0 .. content_size.
        # Ocassionally we miss the 2nd zero and report avg speed < 0.
        # Handle read_diff < 0 here. BZ 1001767.
        if amount_read == 0 or amount_read < self.last_amount_read:
            # if we just started this file, all bets are off
            self.last_update_time = now
            self.last_amount_read = amount_read
            self.ave_rate = None
            return

        #print 'times', now, self.last_update_time
        time_diff = now         - self.last_update_time
        read_diff = amount_read - self.last_amount_read
        # First update, on reget is the file size
        if self.last_amount_read:
            self.last_update_time = now
            self.ave_rate = self._temporal_rolling_ave(\
                time_diff, read_diff, self.ave_rate, self.timescale)
        self.last_amount_read = amount_read
        #print 'results', time_diff, read_diff, self.ave_rate
        
    #####################################################################
    # result methods
    def average_rate(self):
        "get the average transfer rate (in bytes/second)"
        return self.ave_rate

    def elapsed_time(self):
        "the time between the start of the transfer and the most recent update"
        return self.last_update_time - self.start_time

    def remaining_time(self):
        "estimated time remaining"
        if not self.ave_rate or not self.total: return None
        return (self.total - self.last_amount_read) / self.ave_rate

    def fraction_read(self):
        """the fraction of the data that has been read
        (can be None for unknown transfer size)"""
        if self.total is None: return None
        elif self.total == 0: return 1.0
        else: return float(self.last_amount_read)/self.total

    #########################################################################
    # support methods
    def _temporal_rolling_ave(self, time_diff, read_diff, last_ave, timescale):
        """a temporal rolling average performs smooth averaging even when
        updates come at irregular intervals.  This is performed by scaling
        the "epsilon" according to the time since the last update.
        Specifically, epsilon = time_diff / timescale

        As a general rule, the average will take on a completely new value
        after 'timescale' seconds."""
        epsilon = time_diff / timescale
        if epsilon > 1: epsilon = 1.0
        return self._rolling_ave(time_diff, read_diff, last_ave, epsilon)
    
    def _rolling_ave(self, time_diff, read_diff, last_ave, epsilon):
        """perform a "rolling average" iteration
        a rolling average "folds" new data into an existing average with
        some weight, epsilon.  epsilon must be between 0.0 and 1.0 (inclusive)
        a value of 0.0 means only the old value (initial value) counts,
        and a value of 1.0 means only the newest value is considered."""
        
        try:
            recent_rate = read_diff / time_diff
        except ZeroDivisionError:
            recent_rate = None
        if last_ave is None: return recent_rate
        elif recent_rate is None: return last_ave

        # at this point, both last_ave and recent_rate are numbers
        return epsilon * recent_rate  +  (1 - epsilon) * last_ave

    def _round_remaining_time(self, rt, start_time=15.0):
        """round the remaining time, depending on its size
        If rt is between n*start_time and (n+1)*start_time round downward
        to the nearest multiple of n (for any counting number n).
        If rt < start_time, round down to the nearest 1.
        For example (for start_time = 15.0):
         2.7  -> 2.0
         25.2 -> 25.0
         26.4 -> 26.0
         35.3 -> 34.0
         63.6 -> 60.0
        """

        if rt < 0: return 0.0
        shift = int(math.log(rt/start_time)/math.log(2))
        rt = int(rt)
        if shift <= 0: return rt
        return float(int(rt) >> shift << shift)
        

def format_time(seconds, use_hours=0):
    if seconds is None or seconds < 0:
        if use_hours: return '--:--:--'
        else:         return '--:--'
    elif seconds == float('inf'):
        return 'Infinite'
    else:
        seconds = int(seconds)
        minutes = seconds / 60
        seconds = seconds % 60
        if use_hours:
            hours = minutes / 60
            minutes = minutes % 60
            return '%02i:%02i:%02i' % (hours, minutes, seconds)
        else:
            return '%02i:%02i' % (minutes, seconds)
            
def format_number(number, SI=0, space=' '):
    """Turn numbers into human-readable metric-like numbers"""
    symbols = ['',  # (none)
               'k', # kilo
               'M', # mega
               'G', # giga
               'T', # tera
               'P', # peta
               'E', # exa
               'Z', # zetta
               'Y'] # yotta
    
    if SI: step = 1000.0
    else: step = 1024.0

    thresh = 999
    depth = 0
    max_depth = len(symbols) - 1
    
    # we want numbers between 0 and thresh, but don't exceed the length
    # of our list.  In that event, the formatting will be screwed up,
    # but it'll still show the right number.
    while number > thresh and depth < max_depth:
        depth  = depth + 1
        number = number / step

    if type(number) == type(1) or type(number) == type(1L):
        # it's an int or a long, which means it didn't get divided,
        # which means it's already short enough
        format = '%i%s%s'
    elif number < 9.95:
        # must use 9.95 for proper sizing.  For example, 9.99 will be
        # rounded to 10.0 with the .1f format string (which is too long)
        format = '%.1f%s%s'
    else:
        format = '%.0f%s%s'
        
    return(format % (float(number or 0), space, symbols[depth]))
