#!/bin/bash

# (C) Joshua Ismael Haase Hernández 2010
# Copyright © 2011 Joseph Graham

# This script is free software! You can do what you want with it, as long as
# you don't convert it into proprietary software and if you redistribute it
# either vertabim or modified you must do so under the same licence.

# Set this to the URL of the blacklist.
blacklist_url="http://repo.parabolagnulinux.org/docs/blacklist.txt"

# Set this to the url of the index page which will be parsed to find out the
# url of the mirrorlist.
repo_index_page="http://repo.parabolagnulinux.org/core/os/any/"

# Set this to the package name of Parabola's mirrorlist (excluding the version
# number).
parabola_mirrorlist_package_name="pacman-mirrorlist-libre"

# Set this to the package name of Arch's default kernel (excluding the version
# number).
arch_default_kernel_package_name="kernel26"

# Make a temporary directory.
tempdir=$(mktemp -d)

# This will be the name of the log file.
logname="$(pwd)/arch2parabola$(date +%Y%m%d).log"

# These are the dependencies of the script.
dependancies=(which date pacman wget seq sed wget test)

# ---------- Function Declarations ----------

# Define the abort procedure.
function abort
{
    cat << EOF
Something failed in ${section}.

A debug log has been saved to ${logname}.

Please fix the error and re-run the script to finnish converting your system to
Parabola Gnu/Linux.
EOF
    rm -rf ${tempdir}
    exit 1
}

# Ask yes or no (y/n), if given, stop, otherwise keep asking.
# uses variable "q"
function askyn
{
    case "$1" in 
	y | n ) ;;
	*) echo Answer "y" or "n"
	   read q
	   askyn ${q}
	   ;;
    esac
}

# This function logs, and echos the section.
function log_section
{
    cat >> ${logname} << EOF

${section}

EOF
    echo
    echo ${section}
}

# This function checks if the `askyn' function was cancelled, and if so, logs
# it and aborts.
function if_cancelled
{
    if [[ ${q} == "n" ]]
    then
	    echo "The user canceled the procedure" >> ${logname}
	    abort
    else
	    unset q
    fi
}

# This is an SGML parser function. It reads tags in the same way that `read'
# reads lines. The element is assigned to var `element' and the content is
# assigned to var `content'.
function rdom
{
    local IFS=\>
    read -d \< element content
}

section=" ---------- Sanity Check ----------"

declare issues=0

# If the user is not root then error and exit.
(( EUID )) && { echo "This script should be run as root user." ; exit 1 ; }

# Check if the dependencies are available. This won't be needed if this
# script is packaged.
for dep in ${dependancies[@]}
do
    if ! which ${dep} > /dev/null 2> /dev/null
    then
	issues="1"
	"${dep} is missing, please install it." >> ${logname}
    fi
done

# Check if the system is running a custom kernel.
if ! pacman -Q ${arch_default_kernel_package_name} >/dev/null 2>/dev/null
then
    issues="1"
    cat >> ${logname} << EOF
The system is running a custom kernel.
Please uninstall it before running this script.

You can find a PKGBUILD for a linux-libre kernel at

http://repo.parabolagnulinux.org/pkgbuilds/

EOF
fi

# If anything went wrong then abort.
(( issues )) && abort

unset issues

section="---------- Non free packages revision ----------"
log_section

cd ${tempdir}

echo "Downloading the blacklist of proprietary software packages."

if ! wget ${blacklist_url} >> ${logname} \
    2>> ${logname}
then
    echo "Download failed, exiting" >> ${logname}
    abort
fi

declare -a exists

echo "Searching for proprietary software on the system."
echo
exists[0]="These proprietary software packages have been found on the system:"

for package in $(cut -d: -f1 blacklist.txt)
do
    # Check if the package is in pacman's database.
    if pacman -Q ${package} >/dev/null 2>/dev/null
    then
        # Add this package to the array of blacklited packages that have been
	# found in the system.
	exists[${#exists[@]}]=${package}

	# Echo and log the package.
	echo ${package} | tee -a ${logname}
    fi
done

unset exists[0]

section="---------- Pacman mirrorlist replacement ----------"
log_section
cat << EOF
* Pacman will be synced to avoid any errors.
* Pacman mirror list will be replaced for parabola mirror list.

Do you wish to continue? [y/n]
EOF
askyn
if_cancelled

# Update pacman.
if ! pacman -S --noconfirm pacman
then
    echo "Syncing pacman failed." >> ${logname}
    abort
fi

# This piece of code automatically detects the url of the mirrorlist and puts
# it in the var `mirror'.
while rdom
do
    if [[ ${element%%[[:space:]]*} == "a" ]]
    then mirror="$(echo ${element##*[[:space:]]} | cut -d\" -f 2 | grep \
	"${parabola_mirrorlist_package_name}-")"
    fi
done <<< "$(curl "${repo_index_page}")"

# Install the mirrorlist.
if ! pacman -U --noconfirm ${mirror} >> ${logname} 2>> ${logname}
then
    cat >> ${logname} << EOF 
Installing the libre mirror list failed.
Maybe there's a new mirrorlist and we need to update the script.

If that's the case send a mail to dev@list.parabolagnulinux.org

Otherwise, try again.
EOF
    abort
fi

# Rename `mirrorlist.pacnew' to `mirrorlist'.
mv /etc/pacman.d/mirrorlist.pacnew /etc/pacman.d/mirrorlist

section="---------- Package Replacement ----------"
log_section
cat << EOF

* Pacman cache will be erased
* Pacman database will be updated for parabola
* Non free packages that have free replacement will be Synced

Do you wish to continue? [y/n] 
EOF
askyn
if_cancelled

pacman -Scc --noconfirm >> ${logname} 2>> ${logname} || abort
pacman -Syy --noconfirm >> ${logname} 2>> ${logname} || abort

declare replacement

# We search the blacklist to find packages that have libre replacements and
# install them.
for package in ${exists[@]}
do
    if [[ ${package} ]]
    then
	replacement=$(grep -e ${package}[:space:] blacklist.txt | cut -d: f2)
	if [[ ${replacement} ]]
	then
	    pacman -S --noconfirm ${replacement} >> ${logname} 2>> ${logname} ||
	    abort
	fi
    fi
done

unset replacement

section="---------- Non-free packages removal ----------"
log_section
cat <<EOF

* Non free packages that don't have free replacements will be Removed

Do you wish to continue? [y/n] 
EOF
askyn
if_cancelled

# Remove the packages that don't have free replacements.
for package in ${exists[@]}
do
    pacman -Rc --noconfirm ${package} >> ${logname} 2>> ${logname} || abort
done

rm -rf ${tempdir}

section="---------- You are now on Parabola GNU/Linux ----------"
log_section
cat << EOF
Welcome to Freedom.

* You have to manually remove any non-free packages you installed from the AUR.

Do you wish to keep the log? [y/n] 
EOF

askyn

# Ask the user if they want to keep the log and if not then delete it.
if [[ ${q} == "y" ]]
then
    echo "The log has been saved in ${logname}"
else
    rm -f ${logname}
fi

exit 0