from __future__ import print_function

import base64
import mimetypes
import os
from email.mime.audio import MIMEAudio
from email.mime.base import MIMEBase
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import httplib2
import oauth2client
from apiclient import errors, discovery
from oauth2client import client, tools

SCOPES = 'https://www.googleapis.com/auth/gmail.send'
CLIENT_SECRET_FILE = 'client_secret.json'
APPLICATION_NAME = 'Gmail API Python Send Email'


def get_credentials():
    home_dir = os.path.expanduser('~')
    credential_dir = os.path.join(home_dir, '.credentials')
    if not os.path.exists(credential_dir):
        os.makedirs(credential_dir)
    credential_path = os.path.join(credential_dir,
                                   'gmail-python-email-send.json')
    store = oauth2client.file.Storage(credential_path)
    credentials = store.get()
    if not credentials or credentials.invalid:
        flow = client.flow_from_clientsecrets(CLIENT_SECRET_FILE, SCOPES)
        flow.user_agent = APPLICATION_NAME
        credentials = tools.run_flow(flow, store)

        print('Storing credentials to ' + credential_path)

    return credentials


def SendMessage(sender, to, subject, msgHtml, msgPlain, attachmentFile=None):
    credentials = get_credentials()
    http = credentials.authorize(httplib2.Http())
    service = discovery.build('gmail', 'v1', http=http)
    if attachmentFile:
        message1 = createMessageWithAttachment(sender, to, subject, msgHtml, msgPlain, attachmentFile)
    else:
        message1 = CreateMessageHtml(sender, to, subject, msgHtml, msgPlain)
    result = SendMessageInternal(service, "me", message1)
    return result


def SendMessageInternal(service, user_id, message):
    try:
        message = (service.users().messages().send(userId=user_id, body=message).execute())

        print('Message Id: %s' % message['id'])

        return message
    except errors.HttpError as error:
        print('An error occurred: %s' % error)
        return "Error"
    return "OK"


def createMessageWithAttachment(
    sender, to, subject, msgHtml, msgPlain, attachmentFile):
    """Create a message for an email.

    Args:
        sender: Email address of the sender.
        to: Email address of the receiver.
        subject: The subject of the email message.
        msgHtml: Html message to be sent
        msgPlain: Alternative plain text message for older email clients
        attachmentFile: The path to the file to be attached.

    Returns:
        An object containing a base64url encoded email object.
    """
    message = MIMEMultipart('mixed')
    message['to'] = to
    message['from'] = sender
    message['subject'] = subject

    messageA = MIMEMultipart('alternative')
    messageR = MIMEMultipart('related')

    messageR.attach(MIMEText(msgHtml, 'html'))
    messageA.attach(MIMEText(msgPlain, 'plain'))
    messageA.attach(messageR)

    message.attach(messageA)

    print("create_message_with_attachment: file:", attachmentFile)
    content_type, encoding = mimetypes.guess_type(attachmentFile)

    if content_type is None or encoding is not None:
        content_type = 'application/octet-stream'
    main_type, sub_type = content_type.split('/', 1)
    if main_type == 'text':
        fp = open(attachmentFile, 'rb')
        msg = MIMEText(fp.read(), _subtype=sub_type)
        fp.close()
    elif main_type == 'image':
        fp = open(attachmentFile, 'rb')
        msg = MIMEImage(fp.read(), _subtype=sub_type)
        fp.close()
    elif main_type == 'audio':
        fp = open(attachmentFile, 'rb')
        msg = MIMEAudio(fp.read(), _subtype=sub_type)
        fp.close()
    else:
        fp = open(attachmentFile, 'rb')
        msg = MIMEBase(main_type, sub_type)
        msg.set_payload(fp.read())
        fp.close()
    filename = os.path.basename(attachmentFile)
    msg.add_header('Content-Disposition', 'attachment', filename=filename)
    message.attach(msg)

    return {'raw': base64.urlsafe_b64encode(message.as_string())}


def CreateMessageHtml(sender, to, subject, msgHtml, msgPlain):
    msg = MIMEMultipart('alternative')
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = to
    msg.attach(MIMEText(msgPlain, 'plain'))
    msg.attach(MIMEText(msgHtml, 'html'))
    return {'raw': base64.urlsafe_b64encode(msg.as_string())}


def main():
    to = input("Enter Email Address: ")
    sender = input("Your Mail ID: ")
    subject = input("Enter your Subject: ")
    msgHtml = input("Enter your Message: ")
    msgPlain = "Hi\nPlain Email"
    SendMessage(sender, to, subject, msgHtml, msgPlain)
    # Send message with attachment: 
    # SendMessage(sender, to, subject, msgHtml, msgPlain, '/path/to/file.pdf')


if __name__ == '__main__':
    main()