#!/usr/bin/ruby
require 'time'

# This sucks, but I haven't figured out a better way of getting the namespaces right.
module FeedParserMixin
  # ISO-8601 date parsing routines written by Fazal Majid.
  # The ISO 8601 standard is very convoluted and irregular - a full ISO 8601
  # parser is beyond the scope of feedparser and the current Time.iso8601 
  # method does not work.  
  # A single regular expression cannot parse ISO 8601 date formats into groups
  # as the standard is highly irregular (for instance is 030104 2003-01-04 or
  # 0301-04-01), so we use templates instead.
  # Please note the order in templates is significant because we need a
  # greedy match.
  def _parse_date_iso8601(dateString)
    # Parse a variety of ISO-8601-compatible formats like 20040105

    # What I'm about to show you may be the ugliest code in all of 
    # rfeedparser.
    # FIXME The century regexp maybe not work ('\d\d$' says "two numbers at 
    # end of line" but we then attach more of a regexp.  
    iso8601_regexps = [ '^(\d{4})-?([01]\d)-([0123]\d)',
    '^(\d{4})-([01]\d)',
    '^(\d{4})-?([0123]\d\d)',
    '^(\d\d)-?([01]\d)-?([0123]\d)',
    '^(\d\d)-?([0123]\d\d)',
    '^(\d{4})',
    '-(\d\d)-?([01]\d)',
    '-([0123]\d\d)',
    '-(\d\d)',
    '--([01]\d)-?([0123]\d)',
    '--([01]\d)',
    '---([0123]\d)',
    '(\d\d$)',
    '' ]
    iso8601_values = { '^(\d{4})-?([01]\d)-([0123]\d)' => ['year', 'month', 'day'],
    '^(\d{4})-([01]\d)' => ['year','month'], 
    '^(\d{4})-?([0123]\d\d)' => ['year', 'ordinal'],
    '^(\d\d)-?([01]\d)-?([0123]\d)' => ['year','month','day'], 
    '^(\d\d)-?([0123]\d\d)' => ['year','ordinal'],
    '^(\d{4})' => ['year'],
    '-(\d\d)-?([01]\d)' => ['year','month'], 
    '-([0123]\d\d)' => ['ordinal'], 
    '-(\d\d)' => ['year'],
    '--([01]\d)-?([0123]\d)' => ['month','day'],
    '--([01]\d)' => ['month'],
    '---([0123]\d)' => ['day'],
    '(\d\d$)' => ['century'], 
    '' => [] }
    add_to_all = '(T?(\d\d):(\d\d)(?::(\d\d))?([+-](\d\d)(?::(\d\d))?|Z)?)?'
    add_to_all_fields = ['hour', 'minute', 'second', 'tz', 'tzhour', 'tzmin'] 
    # NOTE We use '(?:' to prevent grouping of optional matches (ones trailed
    # by '?'). The second ':' *are* matched.
    m = nil
    param_keys = []
    iso8601_regexps.each do |s|
      $stderr << "Trying iso8601 regexp: #{s+add_to_all}\n" if $debug
      param_keys = iso8601_values[s] + add_to_all_fields
      m = dateString.match(Regexp.new(s+add_to_all))
      break if m
    end
    return if m.nil? or (m.begin(0).zero? and m.end(0).zero?) 

    param_values = m.to_a
    param_values = param_values[1..-1] 
    params = {}
    param_keys.each_with_index do |key,i|
      params[key] = param_values[i]
    end

    ordinal = params['ordinal'].to_i unless params['ordinal'].nil?
    year = params['year'] || '--'
    if year.nil? or year.empty? or year == '--' # FIXME When could the regexp ever return a year equal to '--'?
      year = Time.now.utc.year
    elsif year.length == 2
      # ISO 8601 assumes current century, i.e. 93 -> 2093, NOT 1993
      year = 100 * (Time.now.utc.year / 100) + year.to_i
    else
      year = year.to_i
    end

    month = params['month'] || '-'
    if month.nil? or month.empty? or month == '-'
      # ordinals are NOT normalized by mktime, we simulate them
      # by setting month=1, day=ordinal
      if ordinal
        month = DateTime.ordinal(year,ordinal).month
      else
        month = Time.now.utc.month
      end
    end
    month = month.to_i unless month.nil?
    day = params['day']
    if day.nil? or day.empty?
      # see above
      if ordinal
        day = DateTime.ordinal(year,ordinal).day
      elsif params['century'] or params['year'] or params['month']
        day = 1
      else
        day = Time.now.utc.day
      end
    else
      day = day.to_i
    end
    # special case of the century - is the first year of the 21st century
    # 2000 or 2001 ? The debate goes on...
    if params.has_key? 'century'
      year = (params['century'].to_i - 1) * 100 + 1
    end
    # in ISO 8601 most fields are optional
    hour = params['hour'].to_i 
    minute = params['minute'].to_i 
    second = params['second'].to_i 
    weekday = nil
    # daylight savings is complex, but not needed for feedparser's purposes
    # as time zones, if specified, include mention of whether it is active
    # (e.g. PST vs. PDT, CET). Using -1 is implementation-dependent and
    # and most implementations have DST bugs
    tm = [second, minute, hour, day, month, year, nil, ordinal, false, nil]
    tz = params['tz']
    if tz and not tz.empty? and tz != 'Z'
      # FIXME does this cross over days?
      if tz[0] == '-'
        tm[3] += params['tzhour'].to_i
        tm[4] += params['tzmin'].to_i
      elsif tz[0] == '+'
        tm[3] -= params['tzhour'].to_i
        tm[4] -= params['tzmin'].to_i
      else
        return nil
      end
    end
    return Time.utc(*tm) # Magic!

  end

  def _parse_date_onblog(dateString)
    # Parse a string according to the OnBlog 8-bit date format
    # 8-bit date handling routes written by ytrewq1
    korean_year  = u("년") # b3e2 in euc-kr
    korean_month = u("월") # bff9 in euc-kr
    korean_day   = u("일") # c0cf in euc-kr


    korean_onblog_date_re = /(\d{4})#{korean_year}\s+(\d{2})#{korean_month}\s+(\d{2})#{korean_day}\s+(\d{2}):(\d{2}):(\d{2})/


    m = korean_onblog_date_re.match(dateString)
    return unless m
    w3dtfdate = "#{m[1]}-#{m[2]}-#{m[3]}T#{m[4]}:#{m[5]}:#{m[6]}+09:00"

    $stderr << "OnBlog date parsed as: %s\n" % w3dtfdate if $debug
    return _parse_date_w3dtf(w3dtfdate)
  end

  def _parse_date_nate(dateString)
    # Parse a string according to the Nate 8-bit date format
    # 8-bit date handling routes written by ytrewq1
    korean_am    = u("오전") # bfc0 c0fc in euc-kr
    korean_pm    = u("오후") # bfc0 c8c4 in euc-kr

    korean_nate_date_re = /(\d{4})-(\d{2})-(\d{2})\s+(#{korean_am}|#{korean_pm})\s+(\d{0,2}):(\d{0,2}):(\d{0,2})/
    m = korean_nate_date_re.match(dateString)
    return unless m
    hour = m[5].to_i
    ampm = m[4]
    if ampm == korean_pm
      hour += 12
    end
    hour = hour.to_s.rjust(2,'0') 
    w3dtfdate = "#{m[1]}-#{m[2]}-#{m[3]}T#{hour}:#{m[6]}:#{m[7]}+09:00"
    $stderr << "Nate date parsed as: %s\n" % w3dtfdate if $debug
    return _parse_date_w3dtf(w3dtfdate)
  end

  def _parse_date_mssql(dateString)
    mssql_date_re = /(\d{4})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2}):(\d{2})(\.\d+)?/

    m = mssql_date_re.match(dateString)
    return unless m
    w3dtfdate =  "#{m[1]}-#{m[2]}-#{m[3]}T#{m[4]}:#{m[5]}:#{m[6]}+09:00"
    $stderr << "MS SQL date parsed as: %s\n" % w3dtfdate if $debug
    return _parse_date_w3dtf(w3dtfdate)
  end

  def _parse_date_greek(dateString)
    # Parse a string according to a Greek 8-bit date format
    # Unicode strings for Greek date strings
    greek_months = { 
      u("Ιαν") => u("Jan"),       # c9e1ed in iso-8859-7
      u("Φεβ") => u("Feb"),       # d6e5e2 in iso-8859-7
      u("Μάώ") => u("Mar"),       # ccdcfe in iso-8859-7
      u("Μαώ") => u("Mar"),       # cce1fe in iso-8859-7
      u("Απρ") => u("Apr"),       # c1f0f1 in iso-8859-7
      u("Μάι") => u("May"),       # ccdce9 in iso-8859-7
      u("Μαϊ") => u("May"),       # cce1fa in iso-8859-7
      u("Μαι") => u("May"),       # cce1e9 in iso-8859-7
      u("Ιούν") => u("Jun"), # c9effded in iso-8859-7
      u("Ιον") => u("Jun"),       # c9efed in iso-8859-7
      u("Ιούλ") => u("Jul"), # c9effdeb in iso-8859-7
      u("Ιολ") => u("Jul"),       # c9f9eb in iso-8859-7
      u("Αύγ") => u("Aug"),       # c1fde3 in iso-8859-7
      u("Αυγ") => u("Aug"),       # c1f5e3 in iso-8859-7
      u("Σεπ") => u("Sep"),       # d3e5f0 in iso-8859-7
      u("Οκτ") => u("Oct"),       # cfeaf4 in iso-8859-7
      u("Νοέ") => u("Nov"),       # cdefdd in iso-8859-7
      u("Νοε") => u("Nov"),       # cdefe5 in iso-8859-7
      u("Δεκ") => u("Dec"),       # c4e5ea in iso-8859-7
    }

    greek_wdays =   { 
      u("Κυρ") => u("Sun"), # caf5f1 in iso-8859-7
      u("Δευ") => u("Mon"), # c4e5f5 in iso-8859-7
      u("Τρι") => u("Tue"), # d4f1e9 in iso-8859-7
      u("Τετ") => u("Wed"), # d4e5f4 in iso-8859-7
      u("Πεμ") => u("Thu"), # d0e5ec in iso-8859-7
      u("Παρ") => u("Fri"), # d0e1f1 in iso-8859-7
      u("Σαβ") => u("Sat"), # d3e1e2 in iso-8859-7   
    }

    greek_date_format = /([^,]+),\s+(\d{2})\s+([^\s]+)\s+(\d{4})\s+(\d{2}):(\d{2}):(\d{2})\s+([^\s]+)/

    m = greek_date_format.match(dateString)
    return unless m
    begin
      wday = greek_wdays[m[1]]
      month = greek_months[m[3]]
    rescue
      return nil
    end
    rfc822date = "#{wday}, #{m[2]} #{month} #{m[4]} #{m[5]}:#{m[6]}:#{m[7]} #{m[8]}" 
    $stderr << "Greek date parsed as: #{rfc822date}\n" if $debug
    return _parse_date_rfc822(rfc822date) 
  end

  def _parse_date_hungarian(dateString)
    # Parse a string according to a Hungarian 8-bit date format.
    hungarian_date_format_re = /(\d{4})-([^-]+)-(\d{0,2})T(\d{0,2}):(\d{2})((\+|-)(\d{0,2}:\d{2}))/
    m = hungarian_date_format_re.match(dateString)
    return unless m

    # Unicode strings for Hungarian date strings
    hungarian_months = { 
      u("január") =>   u("01"),  # e1 in iso-8859-2
      u("februári") => u("02"),  # e1 in iso-8859-2
      u("március") =>  u("03"),  # e1 in iso-8859-2
      u("április") =>  u("04"),  # e1 in iso-8859-2
      u("máujus") =>   u("05"),  # e1 in iso-8859-2
      u("június") =>   u("06"),  # fa in iso-8859-2
      u("július") =>   u("07"),  # fa in iso-8859-2
      u("augusztus") =>     u("08"),
      u("szeptember") =>    u("09"),
      u("október") =>  u("10"),  # f3 in iso-8859-2
      u("november") =>      u("11"),
      u("december") =>      u("12"),
    }
    begin
      month = hungarian_months[m[2]]
      day = m[3].rjust(2,'0')
      hour = m[4].rjust(2,'0')
    rescue
      return
    end

    w3dtfdate = "#{m[1]}-#{month}-#{day}T#{hour}:#{m[5]}:00#{m[6]}"
    $stderr << "Hungarian date parsed as: #{w3dtfdate}\n" if $debug
    return _parse_date_w3dtf(w3dtfdate)
  end

  def rollover(num, modulus)
    return num % modulus, num / modulus
  end

  def set_self(num, modulus)
    r = num / modulus
    if r == 0
      return num
    end
    return r
  end
  # W3DTF-style date parsing
  # FIXME shouldn't it be "W3CDTF"?
  def _parse_date_w3dtf(dateString)
    # Ruby's Time docs claim w3cdtf is an alias for iso8601 which is an alias for xmlschema
    # Whatever it is, it doesn't work.  This has been fixed in Ruby 1.9 and 
    # in Ruby on Rails, but not really. They don't fix the 25 hour or 61 minute or 61 second rollover and fail in other ways.

    m = dateString.match(/^(\d{4})-?(?:(?:([01]\d)-?(?:([0123]\d)(?:T(\d\d):(\d\d):(\d\d)([+-]\d\d:\d\d|Z))?)?)?)?/)

    w3 = m[1..3].map{|s| s=s.to_i; s += 1 if s == 0;s}  # Map the year, month and day to integers and, if they were nil, set them to 1
    w3 += m[4..6].map{|s| s.to_i}			  # Map the hour, minute and second to integers
    w3 << m[-1]					  # Leave the timezone as a String

    # FIXME this next bit needs some serious refactoring
    # Rollover times. 0 minutes and 61 seconds -> 1 minute and 1 second
    w3[5],r = rollover(w3[5], 60)     # rollover seconds
    w3[4] += r
    w3[4],r = rollover(w3[4], 60)      # rollover minutes
    w3[3] += r
    w3[3],r = rollover(w3[3], 24)      # rollover hours

    w3[2] = w3[2] + r
    if w3[1] > 12
      w3[1],r = rollover(w3[1],12)
      w3[1] = 12 if w3[1] == 0
      w3[0] += r
    end

    num_days = Time.days_in_month(w3[1], w3[0])
    while w3[2] > num_days
      w3[2] -= num_days
      w3[1] += 1
      if w3[1] > 12
        w3[0] += 1
        w3[1] = set_self(w3[1], 12)
      end
      num_days = Time.days_in_month(w3[1], w3[0])
    end


    unless w3[6].class != String
      if /^-/ =~ w3[6] # Zone offset goes backwards
        w3[6][0] = '+'
      elsif /^\+/ =~ w3[6]
        w3[6][0] = '-'
      end
    end
    return Time.utc(w3[0], w3[1], w3[2] , w3[3], w3[4], w3[5])+Time.zone_offset(w3[6] || "UTC")
  end

  def _parse_date_rfc822(dateString)
    # Parse an RFC822, RFC1123, RFC2822 or asctime-style date 
    # These first few lines are to fix up the stupid proprietary format from Disney
    unknown_timezones = { 'AT' => 'EDT', 'ET' => 'EST', 
      'CT' => 'CST', 'MT' => 'MST', 
      'PT' => 'PST' 
    }

    mon = dateString.split[2]
    if mon.length > 3 and Time::RFC2822_MONTH_NAME.include?mon[0..2]
      dateString.sub!(mon,mon[0..2])
    end
    if dateString[-3..-1] != "GMT" and unknown_timezones[dateString[-2..-1]]
      dateString[-2..-1] = unknown_timezones[dateString[-2..-1]]
    end
    # Okay, the Disney date format should be fixed up now.
    rfc = dateString.match(/([A-Za-z]{3}), ([0123]\d) ([A-Za-z]{3}) (\d{4})( (\d\d):(\d\d)(?::(\d\d))? ([A-Za-z]{3}))?/)
    if rfc.to_a.length > 1 and rfc.to_a.include? nil
      dow, day, mon, year, hour, min, sec, tz = rfc[1..-1]
      hour,min,sec = [hour,min,sec].map{|e| e.to_s.rjust(2,'0') }
      tz ||= "GMT"
    end
    asctime_match = dateString.match(/([A-Za-z]{3}) ([A-Za-z]{3})  (\d?\d) (\d\d):(\d\d):(\d\d) ([A-Za-z]{3}) (\d\d\d\d)/).to_a
    if asctime_match.to_a.length > 1
      # Month-abbr dayofmonth hour:minute:second year
      dow, mon, day, hour, min, sec, tz, year = asctime_match[1..-1]
      day.to_s.rjust(2,'0')
    end
    if (rfc.to_a.length > 1 and rfc.to_a.include? nil) or asctime_match.to_a.length > 1
      ds = "#{dow}, #{day} #{mon} #{year} #{hour}:#{min}:#{sec} #{tz}"
    else
      ds = dateString
    end
    t = Time.rfc2822(ds).utc
    return t
  end

  def _parse_date_perforce(aDateString) # FIXME not in 4.1?
    # Parse a date in yyyy/mm/dd hh:mm:ss TTT format
    # Note that there is a day of the week at the beginning 
    # Ex. Fri, 2006/09/15 08:19:53 EDT
    return Time.parse(aDateString).utc
  end

  def extract_tuple(atime)
    # NOTE leave the error handling to parse_date
    t = [atime.year, atime.month, atime.mday, atime.hour,
      atime.min, atime.sec, (atime.wday-1) % 7, atime.yday,
      atime.isdst
    ]
    # yay for modulus! yaaaaaay!  its 530 am and i should be sleeping! yaay!
    t[0..-2].map!{|s| s.to_i}
    t[-1] = t[-1] ? 1 : 0
    return t
  end

  def parse_date(dateString)
    @date_handlers.each do |handler|
      begin 
        $stderr << "Trying date_handler #{handler}\n" if $debug
        datething = extract_tuple(send(handler,dateString))
        return datething
      rescue Exception => e
        $stderr << "#{handler} raised #{e}\n" if $debug
      end
    end
    return nil
  end
end

module FeedParserUtilities
  def py2rtime(pytuple)
    return Time.utc(*pytuple[0..5]) unless pytuple.blank? 
  end
end