# Copyright (c) 2006,2007 Mitch Garnaat http://garnaat.org/
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish, dis-
# tribute, sublicense, and/or sell copies of the Software, and to permit
# persons to whom the Software is furnished to do so, subject to the fol-
# lowing conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
# ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
# SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.

import urllib
import socket
import mimetypes
import md5
import os
import rfc822
import StringIO
import time
import base64
import boto
import boto.utils
from boto.exception import S3ResponseError, S3DataError, BotoClientError
from boto.s3.user import User
from boto import UserAgent, config

class Key:

    DefaultContentType = 'application/octet-stream'

    BufferSize = 8192

    def __init__(self, bucket=None, name=None):
        self.bucket = bucket
        self.name = name
        self.metadata = {}
        self.content_type = self.DefaultContentType
        self.filename = None
        self.etag = None
        self.last_modified = None
        self.owner = None
        self.storage_class = None
        self.md5 = None
        self.base64md5 = None
        self.path = None
        self.resp = None
        self.mode = None

    def __repr__(self):
        if self.bucket:
            return '<Key: %s,%s>' % (self.bucket.name, self.name)
        else:
            return '<Key: None,%s>' % self.name

    def __getattr__(self, name):
        if name == 'key':
            return self.name
        else:
            raise AttributeError

    def __setattr__(self, name, value):
        if name == 'key':
            self.__dict__['name'] = value
        else:
            self.__dict__[name] = value

    def __iter__(self):
        return self

    def open_read(self, headers=None):
        if self.resp == None:
            self.mode = 'r'
            self.resp = self.bucket.connection.make_request('GET', self.bucket.name, self.name, headers)
            if self.resp.status < 199 or self.resp.status > 299:
                raise S3ResponseError(self.resp.status, self.resp.reason)
            response_headers = self.resp.msg
            self.metadata = boto.utils.get_aws_metadata(response_headers)
            for name,value in response_headers.items():
                if name.lower() == 'content-length':
                    self.size = int(value)
                elif name.lower() == 'etag':
                    self.etag = value
                elif name.lower() == 'content-type':
                    self.content_type = value
                elif name.lower() == 'last-modified':
                    self.last_modified = value

    def close_read(self):
        self.resp.read()
        self.resp = None
        self.mode = None

    def open_write(self, headers=None):
        raise BotoClientError('Not Implemented')

    def close_write(self):
        raise BotoClientError('Not Implemented')

    def open(self, mode='r', headers=None):
        if mode == 'r':
            self.open_read()
        elif mode == 'w':
            self.open_write()
        else:
            raise BotoClientError('Invalid mode: %s' % mode)

    def close(self):
        if mode == 'r':
            self.close_read()
        elif mode == 'w':
            self.close_write()
        else:
            raise BotoClientError('Invalid mode: %s' % mode)
    
    def next(self):
        """
        By providing a next method, the key object supports use as an iterator.
        For example, you can now say:

        for bytes in key:
            write bytes to a file or whatever

        All of the HTTP connection stuff is handled for you.
        """
        self.open_read()
        data = self.resp.read(self.BufferSize)
        if not data:
            self.close_read()
            raise StopIteration
        return data

    def read(self, size=0):
        if size == 0:
            size = self.BufferSize
        self.open_read()
        data = self.resp.read(size)
        if not data:
            self.close_read()
        return data

    def startElement(self, name, attrs, connection):
        if name == 'Owner':
            self.owner = User(self)
            return self.owner
        else:
            return None

    def endElement(self, name, value, connection):
        if name == 'Key':
            self.name = value
        elif name == 'ETag':
            self.etag = value
        elif name == 'LastModified':
            self.last_modified = value
        elif name == 'Size':
            self.size = int(value)
        elif name == 'StorageClass':
            self.storage_class = value
        elif name == 'Owner':
            pass
        else:
            setattr(self, name, value)

    def exists(self):
        return bool(self.bucket.lookup(self.name.encode('utf-8')))

    def delete(self):
        return self.bucket.delete_key(self.name.encode('utf-8'))

    def get_metadata(self, name):
        return self.metadata.get(name)

    def set_metadata(self, name, value):
        self.metadata[name] = value

    def update_metadata(self, d):
        self.metadata.update(d)
    
    # convenience methods for setting/getting ACL
    def set_acl(self, acl_str):
        if self.bucket != None:
            self.bucket.set_acl(acl_str, self.name)

    def get_acl(self):
        if self.bucket != None:
            return self.bucket.get_acl(self.name)

    def generate_url(self, expires_in, method='GET',
                     headers=None, query_auth=True):
        return self.bucket.connection.generate_url(expires_in, method,
                                                   self.bucket.name, self.name,
                                                   headers, query_auth)

    def send_file(self, fp, headers=None, cb=None, num_cb=10):
        def sender(http_conn, method, path, data, headers):
            http_conn.putrequest('PUT', path)
            for key in headers:
                http_conn.putheader(key, headers[key])
            http_conn.endheaders()
            fp.seek(0)
            save_debug = self.bucket.connection.debug
            self.bucket.connection.debug = 0
            if cb:
                if num_cb > 2:
                    cb_count = self.size / self.BufferSize / (num_cb-2)
                else:
                    cb_count = 0
                i = total_bytes = 0
                cb(total_bytes, self.size)
            l = fp.read(self.BufferSize)
            while len(l) > 0:
                http_conn.send(l)
                if cb:
                    total_bytes += len(l)
                    i += 1
                    if i == cb_count:
                        cb(total_bytes, self.size)
                        i = 0
                l = fp.read(self.BufferSize)
            if cb:
                cb(total_bytes, self.size)
            response = http_conn.getresponse()
            body = response.read()
            fp.seek(0)
            self.bucket.connection.debug = save_debug
            if response.status == 500 or response.status == 503 or \
                    response.getheader('location'):
                boto.log.info('key.py: received %d response, retrying in %d seconds' % (response.status, 2**i))
                # we'll try again
                return response
            elif response.status >= 200 and response.status <= 299:
                self.etag = response.getheader('etag')
                if self.etag != '"%s"'  % self.md5:
                    raise S3DataError('ETag from S3 did not match computed MD5')
                return response
            else:
                raise S3ResponseError(response.status, response.reason, body)

        if not headers:
            headers = {}
        else:
            headers = headers.copy()
        headers['User-Agent'] = UserAgent
        headers['Content-MD5'] = self.base64md5
        if headers.has_key('Content-Type'):
            self.content_type = headers['Content-Type']
        elif self.path:
            self.content_type = mimetypes.guess_type(self.path)[0]
            if self.content_type == None:
                self.content_type = self.DefaultContentType
            headers['Content-Type'] = self.content_type
        else:
            headers['Content-Type'] = self.content_type
        headers['Content-Length'] = self.size
        headers['Expect'] = '100-Continue'
        headers = boto.utils.merge_meta(headers, self.metadata)
        return self.bucket.connection.make_request('PUT', self.bucket.name,
                self.name, headers, sender=sender)

    def _compute_md5(self, fp):
        m = md5.new()
        s = fp.read(self.BufferSize)
        while s:
            m.update(s)
            s = fp.read(self.BufferSize)
        self.md5 = m.hexdigest()
        self.base64md5 = base64.encodestring(m.digest())
        if self.base64md5[-1] == '\n':
            self.base64md5 = self.base64md5[0:-1]
        self.size = fp.tell()
        fp.seek(0)

    def set_contents_from_file(self, fp, headers=None, replace=True,
                               cb=None, num_cb=10):
        """
        Store an object in S3 using the name of the Key object as the
        key in S3 and the contents of the file pointed to by 'fp' as the
        contents.
        
        Parameters:
        
        fp - a File-like object.
        headers - (optional) additional HTTP headers that will be
                  sent with the PUT request.
        replace - (optional) If this parameter is False, the method
                  will first check to see if an object exists in the
                  bucket with the same key.  If it does, it won't
                  overwrite it.  The default value is True which will
                  overwrite the object.
        cb - (optional) a callback function that will be called to report
             progress on the upload.  The callback should accept two integer
             parameters, the first representing the number of bytes that have
             been successfully transmitted to S3 and the second representing
             the total number of bytes that need to be transmitted.
        """
        if hasattr(fp, 'name'):
            self.path = fp.name
        if self.bucket != None:
            self._compute_md5(fp)
            if self.name == None:
                self.name = self.md5
            if not replace:
                k = self.bucket.lookup(self.name)
                if k:
                    return
            self.send_file(fp, headers, cb, num_cb)

    def set_contents_from_filename(self, filename, headers=None,
                                   replace=True, cb=None, num_cb=10):
        """
        Store an object in S3 using the name of the Key object as the
        key in S3 and the contents of the file named by 'filename'.
        See set_contents_from_file method for details about the
        parameters.
        """
        fp = open(filename, 'rb')
        self.set_contents_from_file(fp, headers, replace, cb, num_cb)
        fp.close()

    def set_contents_from_string(self, s, headers=None,
                                 replace=True, cb=None, num_cb=10):
        """
        Store an object in S3 using the name of the Key object as the
        key in S3 and the string 's' as the contents.
        See set_contents_from_file method for details about the
        parameters.
        """
        fp = StringIO.StringIO(s)
        self.set_contents_from_file(fp, headers, replace, cb, num_cb)
        fp.close()

    def get_file(self, fp, headers=None, cb=None, num_cb=10):
        if cb:
            if num_cb > 2:
                cb_count = self.size / self.BufferSize / (num_cb-2)
            else:
                cb_count = 0
            i = total_bytes = 0
            cb(total_bytes, self.size)
        save_debug = self.bucket.connection.debug
        if self.bucket.connection.debug == 1:
            self.bucket.connection.debug = 0
        self.open('r', headers)
        for bytes in self:
            fp.write(bytes)
            if cb:
                total_bytes += len(bytes)
                i += 1
                if i == cb_count:
                    cb(total_bytes, self.size)
                    i = 0
        if cb:
            cb(total_bytes, self.size)
        self.close()
        self.bucket.connection.debug = save_debug

    def get_contents_to_file(self, fp, headers=None, cb=None, num_cb=10):
        """
        Retrieve an object from S3 using the name of the Key object as the
        key in S3.  Write the contents of the object to the file pointed
        to by 'fp'.
        
        Parameters:
        
        fp - a File-like object.
        headers - (optional) additional HTTP headers that will be
                  sent with the GET request.
        cb - (optional) a callback function that will be called to report
             progress on the download.  The callback should accept two integer
             parameters, the first representing the number of bytes that have
             been successfully transmitted from S3 and the second representing
             the total number of bytes that need to be transmitted.
        """
        if self.bucket != None:
            self.get_file(fp, headers, cb, num_cb)

    def get_contents_to_filename(self, filename, headers=None,
                                 cb=None, num_cb=10):
        """
        Retrieve an object from S3 using the name of the Key object as the
        key in S3.  Store contents of the object to a file named by 'filename'.
        See get_contents_to_file method for details about the
        parameters.
        """
        fp = open(filename, 'wb')
        self.get_contents_to_file(fp, headers, cb, num_cb)
        fp.close()
        # if last_modified date was sent from s3, try to set file's timestamp
        if self.last_modified != None:
            try:
                modified_tuple = rfc822.parsedate_tz(self.last_modified)
                modified_stamp = int(rfc822.mktime_tz(modified_tuple))
                os.utime(fp.name, (modified_stamp, modified_stamp))
            except Exception, e: pass

    def get_contents_as_string(self, headers=None, cb=None, num_cb=10):
        """
        Retrieve an object from S3 using the name of the Key object as the
        key in S3.  Return the contents of the object as a string.
        See get_contents_to_file method for details about the
        parameters.
        """
        fp = StringIO.StringIO()
        self.get_contents_to_file(fp, headers, cb, num_cb)
        return fp.getvalue()

    def add_email_grant(self, permission, email_address):
        """
        Convenience method that provides a quick way to add an email grant to a key.
        This method retrieves the current ACL, creates a new grant based on the parameters
        passed in, adds that grant to the ACL and then PUT's the new ACL back to S3.
        Inputs:
            permission - The permission being granted.  Should be one of:
                         READ|WRITE|READ_ACP|WRITE_ACP|FULL_CONTROL
                         See http://docs.amazonwebservices.com/AmazonS3/2006-03-01/UsingAuthAccess.html
                         for more details on permissions.
            email_address - The email address associated with the AWS account your are granting
                            the permission to.
        Returns:
            Nothing
        """
        policy = self.get_acl()
        policy.acl.add_email_grant(permission, email_address)
        self.set_acl(policy)

    def add_user_grant(self, permission, user_id):
        """
        Convenience method that provides a quick way to add a canonical user grant to a key.
        This method retrieves the current ACL, creates a new grant based on the parameters
        passed in, adds that grant to the ACL and then PUT's the new ACL back to S3.
        Inputs:
            permission - The permission being granted.  Should be one of:
                         READ|WRITE|READ_ACP|WRITE_ACP|FULL_CONTROL
                         See http://docs.amazonwebservices.com/AmazonS3/2006-03-01/UsingAuthAccess.html
                         for more details on permissions.
            user_id - The canonical user id associated with the AWS account your are granting
                      the permission to.
        Returns:
            Nothing
        """
        policy = self.get_acl()
        policy.acl.add_user_grant(permission, user_id)
        self.set_acl(policy)
