#!/bin/bash

# This script will log into your OASIS account, download any new OCC ("official communication
# channel") messages and also instruct the server to forward them to your email address.

username="your-student-number"
password="your-OASIS-password"
email="email@address"
dir=~/oasis_occ

# Modify the following lines to execute suitable commands when login, download or forwarding errors
# occur.
alias login_error='kdialog --error "Could not log in to OASIS to retrieve OCC messages."'
alias download_error='kdialog --error "OCC message could not be downloaded."'
alias forward_error='kdialog --error "OCC message downloaded but could not be forwarded."'


# ======

# The URL associated with the login button, and also the main OASIS page.
main_url="https://portalb.curtin.edu.au/http://sm-portal.curtin.edu.au:8080/portal/dt?dt.isPortletRequest=true&dt.action=process&dt.provider=PortletWindowProcessChannel&dt.windowProvider.targetPortletChannel=portallogin_jsr168&dt.containerName=Welcome&dt.windowProvider.currentChannelMode=VIEW&dt.window.portletAction=ACTION"

# This must be prepended to the OCC message URLs found in the main page.
url_prefix="https://portalb.curtin.edu.au/redirect/"

# The URL of the page where the user enters their email address, for message forwarding.
forward_page_url="https://portalb.curtin.edu.au/http://sm-portal.curtin.edu.au:8903/oca/viewmessage.jsf"

# The URL loaded when the user clicks the Send button.
forward_button_url="https://portalb.curtin.edu.au/http://sm-portal.curtin.edu.au:8903/oca/forwardtoemail.jsf"


mkdir -p "$dir"

# Login and load the main OASIS page, and parse it to find the URLs of unread OCC messages.
urls=$( wget --save-cookies "$dir/cookies.txt" \
             --keep-session-cookies \
             --post-data "Login.Token1=${username}&Login.Token2=${password}" \
             --output-document - \
             "$main_url" | \
        sed -r "s/'(http[^']*)'/\n\1\n/" | \
        grep '^http.*occId=' | \
        uniq )


if [ $? -ne 0 ]; then
    login_error
    exit 1

elif [ -n $urls ]; then

    # Replace the @ in the email so that it can be embedded in POST data.
    email=${email/@/%40}

    for url in $urls; do

        # Pick a filename for the downloaded message. A more intelligent/useful technique might be
        # based on the sender and/or title of the message. This code just does it by date.
        filename=`date +%Y-%m-%d`
        i=1
        while [ -e "$dir/$filename.html" ]; do
            filename=`date +%Y-%m-%d_$i`
            i=$(( i + 1 ))
        done
        message_file="$dir/$filename.html"

        # Retrieve and parse the message itself, in order to:
        # (a) save a copy, and
        # (b) get the "ViewState" parameter that we need in order to use the forward-to-email function.
        wget --load-cookies "$dir/cookies.txt" \
             --save-cookies "$dir/cookies.txt" \
             --keep-session-cookies \
             --convert-links \
             --span-hosts \
             --output-document "$message_file" \
             "$url_prefix$url"

        if [ $? -ne 0 ]; then
            download_error

        else
            # To forward an OCC message, we first need to load two URLs:
            # 1) the page where the user would normally enter their email address, and
            # 2) the URL associated with the "Send" button.

            # Both URLs must be supplied with a "ViewState" POST parameter, which (AFAIK) is a
            # serialised Java object used by the server to keep track of state. The first URL
            # cannot be skipped because the ViewState parameter required for the second can only be
            # obtained by loading the first. The ViewState parameter for the first can be extracted
            # from the original message page.

            function get_view_state() {
                # This function extracts and formats the "javax.faces.ViewState" POST parameter
                # from HTML input.
                sed -r 's/<input [^>]*name="javax.faces.ViewState"[^>]*value="([^"]+)" *\/>/\nViewState \1\n/' | \
                    awk '/^ViewState/ { print gensub("=", "%3D", "g", $2); exit }'
            }

            # A note about the following two wget commands: they will appear to abort before
            # downloading is complete. This is because their output is piped into the commands sed,
            # awk and grep, which (in this case) will terminate when the necessary information
            # has been found.

            forward_page_view_state=$( cat "$message_file" | get_view_state )
            forward_page_post_data="viewMailboxForm%3A_id65=Forward+to+email&viewMailboxForm_SUBMIT=1&viewMailboxForm%3A_idcl=&viewMailboxForm%3A_link_hidden_=&javax.faces.ViewState=${forward_page_view_state}"

            forward_button_view_state=$( wget --load-cookies "$dir/cookies.txt" \
                                              --post-data "$forward_page_post_data" \
                                              --output-document - \
                                              "$forward_page_url" | \
                                         get_view_state )
            forward_button_post_data="forwardForm%3AforwardFormInit=true&forwardForm%3AemailAddress=${email}&forwardForm%3AformAction5=Send&forwardForm_SUBMIT=1&forwardForm%3A_link_hidden_=&forwardForm%3A_idcl=&javax.faces.ViewState=${forward_button_view_state}"

            wget --load-cookies "$dir/cookies.txt" \
                 --post-data "$forward_button_post_data" \
                 --output-document - \
                 "$forward_button_url" | \
                 grep -q "The Official Communication has been sent to the specified email address."

            if [ $? -ne 0 ]; then
                forward_error
            fi
        fi
    done
fi