#! /usr/bin/env python
# -*- coding: utf-8 -*-

#   eLyXer -- convert LyX source files to HTML output.
#
#   Copyright (C) 2009 Alex Fernández
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program 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 General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.

# --end--
# Alex 20090308
# File line management for eLyXer

import sys
import codecs
from util.trace import Trace


class LineReader(object):
  "Reads a file line by line"

  def __init__(self, filename, directory = ''):
    if isinstance(filename, file):
      self.file = directory + filename
    else:
      self.file = codecs.open(filename, 'rU', 'utf-8')
    if (directory != ''):
      #Make sure directory has a trailing GNU/Linux type slash
      assert(directory.endswith('/') == True)
    self.dir = directory
    self.linenumber = 1
    self.lastline = None
    self.current = None
    self.mustread = True
    self.depleted = False
    try:
      self.readline()
    except UnicodeDecodeError:
      # try compressed file
      import gzip
      self.file = gzip.open(filename, 'rb')
      self.readline()

  def setstart(self, firstline):
    "Set the first line to read."
    for i in range(firstline):
      self.file.readline()
    self.linenumber = firstline

  def setend(self, lastline):
    "Set the last line to read."
    self.lastline = lastline

  def currentline(self):
    "Get the current line"
    if self.mustread:
      self.readline()
    return self.current

  def nextline(self):
    "Go to next line"
    if self.depleted:
      Trace.fatal('Read beyond file end')
    self.mustread = True

  def readline(self):
    "Read a line from file"
    self.current = self.file.readline()
    if not isinstance(self.file, codecs.StreamReaderWriter):
      self.current = self.current.decode('utf-8')
    if len(self.current) == 0:
      self.depleted = True
    self.current = self.current.rstrip('\n\r')
    self.linenumber += 1
    self.mustread = False
    Trace.prefix = 'Line ' + unicode(self.linenumber) + ': '
    if self.linenumber % 1000 == 0:
      Trace.message('Parsing')

  def finished(self):
    "Find out if the file is finished"
    if self.lastline and self.linenumber == self.lastline:
      return True
    if self.mustread:
      self.readline()
    return self.depleted

  def close(self):
    self.file.close()

class LineWriter(object):
  "Writes a file as a series of lists"

  def __init__(self, filename):
    if isinstance(filename, file):
      self.file = filename
      self.filename = None
    else:
      self.file = codecs.open(filename, 'w', "utf-8")
      self.filename = filename

  def write(self, strings):
    "Write a list of strings"
    for string in strings:
      if not isinstance(string, basestring):
        Trace.error('Not a string: ' + unicode(string) + ' in ' + unicode(strings))
        return
      self.writestring(string)

  def writestring(self, string):
    "Write a string"
    if self.file == sys.stdout:
      string = string.encode('utf-8')
    self.file.write(string)

  def writeline(self, line):
    "Write a line to file"
    self.writestring(line + '\n')

  def close(self):
    self.file.close()

