# -*- coding: utf-8 -*-

__authors__ = ["Sylvain Hellegouarch (sh _at_ defuze _dot_ org)"]
__copyright__ = """
Copyright (c) 2006, Sylvain Hellegouarch
All rights reserved.
"""
__license__ = """
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

     * Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.
     * Neither the name of Sylvain Hellegouarch nor the names of his contributors
       may be used to endorse or promote products derived from this software
       without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""
import sys
from StringIO import StringIO

import System
from System import Array
from System.IO import File, Stream, MemoryStream, FileStream, FileMode, SeekOrigin

import clr
clr.AddReference("ICSharpCode.SharpZipLib")
from ICSharpCode.SharpZipLib.GZip import GZipInputStream, GZipOutputStream

from System.Text import Encoding
raw = Encoding.GetEncoding('iso-8859-1')

__all__ = ["GzipFile", "open"]

def open(filename=None, mode='rb', compresslevel=9):
    return GzipFile(filename, mode, compresslevel)

class GzipFile:
    def __init__(self, filename=None, mode='rb', compresslevel=9, fileobj=None):
        if mode not in ['r', 'rb', 'w', 'wb']:
            raise IOError, "Mode %s not supported" % mode
        
        if mode in ['r', 'rb']:
            GZStreamHandler = GZipInputStream
            self.min_readsize = 100
            self.extrabuf = ""
            self.extrasize = 0
            self.offset = 0
        elif mode in ['w', 'wb']:
            GZStreamHandler = GZipOutputStream

        if not fileobj and not filename:
            raise ValueError, "You must provide either a filename or a fileobj"
        
        if fileobj is None:
            self.fileobj = FileStream(filename, FileMode.Open)
        elif isinstance(fileobj, StringIO):
            if mode in ['r', 'rb']:
                self.fileobj = MemoryStream(raw.GetBytes(fileobj.read()))
            elif mode in ['w', 'wb']:
                self.fileobj = MemoryStream()
        elif isinstance(fileobj, Stream):
            self.fileobj = fileobj
            
        if filename is None:
            if hasattr(self.fileobj, 'Name'): filename = self.fileobj.Name
            else: filename = ''

        self.gzstream = GZStreamHandler(self.fileobj)
            
    def __repr__(self):
        s = repr(self.fileobj)
        return '<gzip ' + s[1:-1] + ' ' + hex(id(self)) + '>'

    def close(self):
        self.gzstream.Close()
        self.fileobj.Close()
        self.gzstream = None
        self.fileobj = None
    
    def read(self, size=-1):
        if size < 0:
            result = []
            readsize = 1
            buf = Array.CreateInstance(System.Byte, 2048)
            while readsize > 0:
                readsize = self.gzstream.Read(buf, 0, 2048)
                if readsize > 0 and readsize < 2048:
                    tmp = Array.CreateInstance(System.Byte, readsize)
                    Array.Copy(buf, 0, tmp, 0, readsize)
                    result.append(raw.GetString(tmp))
                elif readsize > 0:
                    result.append(raw.GetString(buf))

            return ''.join([chunk for chunk in result])
        else:
            buf = Array.CreateInstance(System.Byte, size)
            readsize = self.gzstream.Read(buf, 0, size)
            if readsize > 0 and readsize < 2048:
                tmp = Array.CreateInstance(System.Byte, readsize)
                Array.Copy(buf, 0, tmp, 0, readsize)
                return raw.GetString(tmp)
            else:
                return raw.GetString(buf)

    def write(self, data):
        if self.fileobj is None:
            raise ValueError, "write() on closed GzipFile object"
        
        if len(data) > 0:
            bytes = raw.GetBytes(data)
            self.gzstream.Write(bytes, 0, bytes.Length)
            
    def fileno(self):
        return self.fileobj.Handle.ToInt32()

    def isatty(self):
        return False

    def flush(self):
        if self.fileobj.CanWrite:
            self.fileobj.Flush()

    def tell(self):
        return self.fileobj.Position

    def rewind(self):
        if not self.fileobj.CanRead:
            raise IOError("Can't rewind in write mode")
        self.fileobj.Seek(0, SeekOrigin.Begin)
        
    def seek(self, offset):
        if not self.fileobj.CanSeek:
            raise IOError('Cannot seek')
        
        if self.fileobj.CanWrite:
            if offset < self.fileobj.Position:
                raise IOError('Negative seek in write mode')
            self.fileobj.Seek(offset, SeekOrigin.Current)
        elif self.fileobj.CanRead:
            if offset < self.fileobj.Position:
                self.rewind()
            self.fileobj.Seek(offset, SeekOrigin.Current)

    def _unread(self, buf):
        self.extrabuf = buf + self.extrabuf
        self.extrasize = len(buf) + self.extrasize
        self.offset -= len(buf)
        
    def readline(self, size=-1):
        if size < 0:
            size = sys.maxint
            readsize = self.min_readsize
        else:
            readsize = size
        bufs = []
        while size != 0:
            c = self.read(readsize)
            i = c.find('\n')

            # We set i=size to break out of the loop under two
            # conditions: 1) there's no newline, and the chunk is
            # larger than size, or 2) there is a newline, but the
            # resulting line would be longer than 'size'.
            if (size <= i) or (i == -1 and len(c) > size):
                i = size - 1

            if i >= 0 or c == '':
                bufs.append(c[:i + 1])    # Add portion of last chunk
                self._unread(c[i + 1:])   # Push back rest of chunk
                break

            # Append chunk to list, decrease 'size',
            bufs.append(c)
            size = size - len(c)
            readsize = min(size, readsize * 2)
        if readsize > self.min_readsize:
            self.min_readsize = min(readsize, self.min_readsize * 2, 512)
        return ''.join(bufs) # Return resulting line

    def readlines(self, sizehint=0):
        # Negative numbers result in reading all the lines
        if sizehint <= 0:
            sizehint = sys.maxint
        L = []
        while sizehint > 0:
            line = self.readline()
            if line == "":
                break
            L.append(line)
            sizehint = sizehint - len(line)

        return L


    def __iter__(self):
        return self

    def next(self):
        line = self.readline()
        if line:
            return line
        else:
            raise StopIteration
    
    def __del__(self):
        try:
            if (self.gzstream is None and
                self.fileobj is None):
                return
        except AttributeError:
            return
        self.close()