#!/bin/bash

#
# arch2parabola - converts an Arch GNU/Linux system to Parabola GNU/Linux-libre
#
#  Copyright © 2010 Joshua Ismael Haase Hernández
#  Copyright © 2011 Joseph Graham
#        ^^^ Lies, it's a TaylanUB rewrite !
#  Copyright © 2011 Taylan Ulrich Bayırlı
#
#  ---------- GNU General Public License 3 ----------
#
#  This file is part of Parabola.
#
#  Parabola 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.
#
#  Parabola 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 Parabola.  If not, see <http://www.gnu.org/licenses/>.
#

blacklist='http://repo.parabolagnulinux.org/docs/blacklist.txt'

mirrorlist='http://repo.parabolagnulinux.org/files/mirrorlist'

kernel_pkgnames=('kernel26' 'kernel26-lts')

logfile="$(pwd)/arch2parabola-$$.log"

Usage ()
{
    echo >&2 'arch2parabola [-c|--check-nonfree]'
}

Log ()
{
    printf '%s\n' "$@"
    printf '%s\n' "$@" >> "$logfile"
}

# Sets $section
Section ()
{
    section=$1
    Log '' "--- $section ---"
}

Abort ()
{
    Log  >&2 "$@"
    Log  >&2 "Aborted in section: $section"
    echo >&2 "Log saved to: $logfile"
    exit 1
}

# Sets $ans
Ask ()
{
    unset ans
    while true
    do
        printf '%s' "$1" >&2
        read -r ans; ans=${ans,}
        [[ $ans == [yn] ]] && break
        echo '("y" for yes, "n" for no)' >&2
    done
}

CheckAns ()
{
    case $ans in
    y) ;;
    n) Abort 'Cancelled by user.' ;;
    *) echo >&2 'What the fuck?'
    esac
}

Download ()
{
    wget -nv -O- 2>> "$logfile"
}

# Sets $nonfree_pkgs and $replacements
CheckNonfree ()
    while IFS=: read -r pkg repl _
    do
        if pacman -Q "$pkg" > /dev/null 2>&1
        then
            nonfree_pkgs+=("$pkg")
            replacements+=("$repl")
            echo "$pkg, replacement: ${repl:-NONE!}"
        fi
    done <<< $(Download "$blacklist" | sort || Abort 'Download failed.')


case $# in
0) ;;
1)
    case $1 in
    -c|--check-nonfree) CheckNonfree; exit ;;
    *) Usage; exit 1
    esac
    ;;
*) Usage; exit 1
esac


Section 'Sanity check'

    if ! [[ -w / ]]
    then
        echo >&2 'This script must be run as root.'
        exit 1
    fi

    for name in ${kernel_pkgnames[@]}
    do
	if pacman -Q "${name}" > /dev/null 2>&1
	then
	    what_is_the_kernel="${name}"
	    break
	fi
    done

    if (( ! what_is_the_kernel ))
    then
        echo >&2 'The system is running a custom kernel.'
        echo >&2 'Please uninstall it before re-running this script.'
        echo >&2
        echo >&2 'You can find a PKGBUILD for a linux-libre kernel at'
        echo >&2
        echo >&2 'http://repo.parabolagnulinux.org/pkgbuilds/'

        exit 1
    fi

    if [[ -e $logfile ]]
    then
        Abort "The file '$logfile' already exists, not overwriting."
    else
        > "$logfile" || Abort "Can't touch '$logfile'!"
        echo "Logging to: $logfile"
    fi


Section 'Non-free packages revision'

    echo '* Downloading blacklist and searching for proprietary software on the system.'

    CheckNonfree | tee -a "$logfile"


Section 'Pacman mirrorlist replacement'

    echo '* Pacman will be synced. (pacman -S pacman)'
    echo '* /etc/pacman.d/mirrorlist will be replaced by the Parabola mirrorlist.'
    echo '* Package databases will be forced to sync, to make the mirrorlist take effect. (pacman -Syy)'
    echo
    Ask  'Do you wish to continue? [y/n] '
    CheckAns

    pacman -S --noconfirm pacman 2>&1 | tee -a "$logfile" || Abort 'Syncing pacman failed.'

    Ask 'Shall the mirrorlist be run through rankmirrors? [y/n] '
    case $ans in
    y) Download "$mirrorlist" | rankmirrors - > /etc/pacman.d/mirrorlist ;;
    n) Download "$mirrorlist" > /etc/pacman.d/mirrorlist ;;
    *) echo 'What the fuck?'
    esac

    pacman -Syy --noconfirm 2>&1 | tee -a "$logfile" || Abort 'Syncing databases failed.'


Section 'Package replacement and removal'

    echo '* Replacements will be installed when possible.'
    echo '* Non-free packages will be removed.'
    echo '  Packages rendered useless by this will be removed.'
    echo '  (pacman -Rnsc ...) (Will let pacman prompt you once more!)'
    echo '* Pacman cache will be cleared to purge the old non-free packages. (pacman -Sc)'
    echo
    Ask  'Do you wish to continue? [y/n] '
    CheckAns

    i=0
    while pkg=${nonfree_pkgs[$i]}; repl=${replacements[$i]}; (( ++i < ${#nonfree_pkgs[@]} ))
    do
        if [[ $repl ]]
        then
            if ! pacman -Q  "$repl" > /dev/null 2>&1 &&
                 pacman -Si "$repl" > /dev/null 2>&1
            then
                pacman -S --noconfirm "$pkg" 2>&1 | tee -a "$logfile" ||
                    Abort "Installation of '$repl' failed."
            else
                Log "The replacement '$repl' for '$pkg' was not found in the repos."
            fi
        else
            Log "There is no known replacement for '$pkg'."
        fi
        # The replacement might have caused removal already
        if pacman -Q "$pkg" > /dev/null 2>&1
        then
            pacman -Rnsc "$pkg" 2>&1 | tee -a "$logfile" || Abort "Removal of '$pkg' failed."
        fi
    done


Section 'You are now on Parabola GNU/Linux-libre !'

    echo 'Welcome to Freedom.'
    echo '* You have to manually remove any non-free packages you installed from the AUR.'
    echo
    Ask  'Do you wish to keep the log? [y/n] '

    case $ans in
    y) echo "The log is at: $logfile" ;;
    n) rm -f "$logfile" ;;
    *) echo >&2 'What the fuck?'
    esac