#!/bin/bash

# Copyright (C) 2015  Beniamine, David <David.Beniamine@tetras-libre.fr>
# Author: Beniamine, David <David.Beniamine@tetras-libre.fr>
#
# This program 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.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

timeout=10
DEBUG=true
interaction=true
echo "" > /var/log/vp.log
log(){
    if $DEBUG
    then
        echo "$@" | tee -a /var/log/vp.log
    fi
}
log  "starting VP $(date)"
# Get rights to access display
user=$(who | grep -v "root" | head -n 1 | cut -d ' ' -f 1)
if [ ! -z "$user" ]
then
	export DISPLAY=:0
    export LC_ALL="fr_FR.utf8"
	export XAUTHORITY="/home/$user/.Xauthority"
fi

DIR=$(realpath $(dirname $0))

# show max between two res
max_res(){
    [ -z "$2" ] && echo $1 && return
    first=$(echo $1 | sed 's/x/*/' | bc)
    second=$(echo $2 | sed 's/x/*/' | bc)
    [ $first -ge $second ] && echo $1 || echo $2
}

# Default main screens (external VGA or internal screen)
MAIN_SCREENS="DP-3 VGA-1 LVDS-1 eDP1"

# auto detect main screen
for m in $MAIN_SCREENS
do
	if [ ! -z "$(xrandr | grep " connected" | grep $m)" ]
	then
		MAIN_SCREEN=$m
		break
	fi
done

if [ -z "$MAIN_SCREEN" ]
then
	# No main screen : use the first connected
	MAIN_SCREEN=$(xrandr | grep " connected" | head -n 1 | cut -d ' ' -f 1)
fi
log  "MAIN_SCREEN '$MAIN_SCREEN'"

screens=$(xrandr | grep " connected" | cut -f 1 -d ' ' \
    | sed -e 's/ /\n/g' | grep -v "\<$MAIN_SCREEN\>")

log  "SCREENS '$screens'"
log  "all '$screens$MAIN_SCREEN'"
log  "cat '$(cat /tmp/vp-screens)'"
if [ -z "$screens$MAIN_SCREEN" ]
then
    log  "noscreens exiting on $(date)"
    exit
elif [ "$screens$MAIN_SCREEN" == "$(cat /tmp/vp-screens)" ]
then
    log "no changes exiting on $(date)"
    exit
fi
echo "$screens$MAIN_SCREEN" > /tmp/vp-screens

clone(){
    # Auto detect best resolution
    for m in $(xrandr | awk -v pattern="^$MAIN_SCREEN" '/^.* connected/{IN=0} $0 ~ pattern {IN=1} /^ /{if(IN==1){print $1}}')
    do
        # echo "testing mode $m"
        OTHERS=$(xrandr | awk -v pattern="^$MAIN_SCREEN" '/^.* connected/{IN=1} $0 ~ pattern {IN=0} {if(IN==1){print $1}}')
        if [ -z "$OTHERS" ]
        then
            # one screen look for best common resolution
            mode=$(max_res $m $mode)
        else
            # Several screen look for best common resolution
            for line in $OTHERS
            do
                # echo "line $line"
                if [[ $line =~ [0-9]* ]]
                then
                    # New mode
                    if [ "$line" == "$m" ]
                    then
                        found=1
                    fi
                else
                    # New screen
                    if [ "$found" == 0 ]
                    then
                        break
                    fi
                    found=0
                fi
                # echo "Found ? $found"
            done
            if [ "$found" == 1 ]
            then
                mode="$m"
                break
            fi
        fi
    done
    # echo "mode $mode"
    
    # Primary screen
    cmd="xrandr --output $MAIN_SCREEN --auto --mode $mode --rotate normal --primary"
    log  "command $cmd"
    
    # Add all connected as copy
    prev_s=$MAIN_SCREEN
    for s in $(echo -e $screens)
    do
        cmd="$cmd --output $s --auto --mode $mode --same-as $prev_s --rotate normal"
        prev_s="$s"
    done
    log  "command after all outputs $cmd"
    
    # Disable all disconnected screens
    screens=$(xrandr | grep " disconnected" | cut -f 1 -d ' ' )
    for s in $(echo -e $screens)
    do
    	cmd="$cmd --output $s --off"
    done
    log  "command after all offs $cmd"
    
    run_xrandr_cmd $cmd
}

extend(){
    log "I should extend screens on $1"
    case $1 in
        "gauche")
            placement="--left-of"
            ;;
        "droite")
            placement="--right-of"
            ;;
        "haut")
            placement="--above"
            ;;
        "bas")
            placement="--below"
            ;;
    esac
    cmd="xrandr --output $MAIN_SCREEN --primary --auto"
    log $cmd
    for s in $screens
    do
        cmd="$cmd --output $s $placement $MAIN_SCREEN --auto" 
        log $cmd
    done
    run_xrandr_cmd $cmd
}

run_xrandr_cmd(){
    # Actually do stuff
    old_cmd=$(cat /tmp/vp)
    new_cmd="$@"
    timeout
    echo $new_cmd > /tmp/vp
    $new_cmd
    log  "Runned $new_cmd"
    if $interaction
    then
        zenity --question --title "Configuration des écrans" \
            --text "La configuration des écrans vous convient-elle ?" \
            --timeout=$timeout
        code=$?
    else
        code=1
    fi
    if [ $code != 0 ]
    then
        log "Restoring old command : $old_cmd"
        $old_cmd
    fi
    log "exiting on $(date)"
}

if [ -z "$screens" ]
then
    interaction=false
fi

if $interaction
then
    choice=$(zenity --entry --title "Écran connecté" \
        --text "Selection du mode d'affichage" \
        --entry-text "Clone" 'Écrans étendus à droite' 'Écrans étendus à gauche' \
        'Écrans étendus en haut' 'Écrans étendus en bas' \
        --timeout $timeout)
    code=$?
else
    code=5
fi

log "Choice '$choice' / code $code"

if [ -z "$choice" ]
then
    if [ "$code" -eq 1 ]
    then
        # give up
        exit
    else
        # timeout
        log "timeout"
        clone
    fi
elif [ "$choice" == "Clone" ]
then
    clone
else
    extend $(echo $choice | cut -d ' ' -f 4)
fi