#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
    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/>.
    
    @author: RaNaN
"""
from os import remove
from os.path import exists
from time import sleep
from re import search

import pycurl

from HTTPRequest import HTTPRequest

class WrongFormat(Exception):
    pass

class ChunkInfo():
    def __init__(self, name):
        self.name = name
        self.size = 0
        self.resume = False
        self.chunks = []

    def setSize(self, size):
        self.size = int(size)

    def addChunk(self, name, range):
        self.chunks.append((name, range))

    def clear(self):
        self.chunks = []

    def createChunks(self, chunks):
        self.clear()
        chunk_size = self.size / chunks

        current = 0
        for i in range(chunks):
            end = self.size-1 if (i == chunks-1) else current+chunk_size
            self.addChunk("%s.chunk%s" % (self.name, i), (current, end))
            current += chunk_size + 1


    def save(self):
        fh = open("%s.chunks" % self.name, "w")
        fh.write("name:%s\n" % self.name)
        fh.write("size:%s\n" % self.size)
        for i, c in enumerate(self.chunks):
            fh.write("#%d:\n" % i)
            fh.write("\tname:%s\n" % c[0])
            fh.write("\trange:%i-%i\n" % c[1])
        fh.close()

    @staticmethod
    def load(name):
        if not exists("%s.chunks" % name):
            raise IOError()
        fh = open("%s.chunks" % name, "r")
        name = fh.readline()[:-1]
        size = fh.readline()[:-1]
        if name.startswith("name:") and size.startswith("size:"):
            name = name[5:]
            size = size[5:]
        else:
            fh.close()
            raise WrongFormat()
        ci = ChunkInfo(name)
        ci.loaded = True
        ci.setSize(size)
        while True:
            if not fh.readline(): #skip line
                break
            name = fh.readline()[1:-1]
            range = fh.readline()[1:-1]
            if name.startswith("name:") and range.startswith("range:"):
                name = name[5:]
                range = range[6:].split("-")
            else:
                raise WrongFormat()

            ci.addChunk(name, (long(range[0]), long(range[1])))
        fh.close()
        return ci

    def remove(self):
        if exists("%s.chunks" % self.name): remove("%s.chunks" % self.name)
                
    def getCount(self):
        return len(self.chunks)

    def getChunkName(self, index):
        return self.chunks[index][0]

    def getChunkRange(self, index):
        return self.chunks[index][1]

class HTTPChunk(HTTPRequest):
    def __init__(self, id, parent, range=None, resume=False):
        self.id = id
        self.p = parent # HTTPDownload instance
        self.range = range # tuple (start, end)
        self.resume = resume

        self.arrived = 0
        self.lastURL = self.p.referer

        self.c = pycurl.Curl()

        self.header = ""
        self.headerParsed = False #indicates if the header has been processed

        self.fp = None #file handle

        self.initHandle()
        self.setInterface(self.p.interface, self.p.proxies)

    @property
    def cj(self):
        return self.p.cj

    def getHandle(self):
        """ returns a Curl handle ready to use for perform/multiperform """

        self.setRequestContext(self.p.url, self.p.get, self.p.post, self.p.referer, self.p.cj)
        self.c.setopt(pycurl.WRITEFUNCTION, self.writeBody)
        self.c.setopt(pycurl.HEADERFUNCTION, self.writeHeader)

        if self.resume:
            self.fp = open(self.p.info.getChunkName(self.id), "ab")
            self.arrived = self.fp.tell()

            if self.range:
                print "Chunked resume with range %i-%i" % (self.arrived+self.range[0], self.range[1])
                self.c.setopt(pycurl.RANGE, "%i-%i" % (self.arrived+self.range[0], self.range[1]))
            else:
                print "Resume File from %i" % self.arrived
                self.c.setopt(pycurl.RESUME_FROM, self.arrived)

        else:
            if self.range:
                print "Chunked with range %i-%i" % self.range
                self.c.setopt(pycurl.RANGE, "%i-%i" % self.range)

            self.fp = open(self.p.info.getChunkName(self.id), "wb")

        return self.c

    def writeHeader(self, buf):
        self.header += buf
        #@TODO forward headers?, this is possibly unneeeded, when we just parse valid 200 headers
        # as first chunk, we will parse the headers
        if not self.range and self.header.endswith("\r\n\r\n"):
            self.parseHeader()
        elif not self.range and buf.startswith("150") and "data connection" in buf: #ftp file size parsing
            size = search(r"(\d+) bytes", buf)
            if size:
                self.p.size = int(size.group(1))
                self.p.chunkSupport = True

        self.headerParsed = True

    def writeBody(self, buf):
        size = len(buf)
        self.arrived += size

        self.fp.write(buf)

        if self.p.bucket:
            sleep(self.p.bucket.consumed(size))

        if self.range and self.arrived > (self.range[1]-self.range[0]):
            return 0 #close if we have enough data


    def parseHeader(self):
        """parse data from recieved header"""
        for line in self.header.splitlines():
            line = line.strip().lower()
            if line.startswith("accept-ranges") and "bytes" in line:
                self.p.chunkSupport = True

            if not self.resume and line.startswith("content-length"):
                self.p.size = int(line.split(":")[1])
                
        self.headerParsed = True

    def close(self):
        """ closes everything, unusable after this """
        if self.fp: self.fp.close()
        self.c.close()
        if hasattr(self, "p"): del self.p