#!/bin/bash
# This file is mainly used for bash shell prompt (PS1) configuration.
# Reference material for further reading - http://www.gnu.org/software/bash/manual/bashref.html#Controlling-the-Prompt

# Depends: https://github.com/lhunath/scripts/blob/master/bashlib/bashlib

# Non-UTF8 prompt. Use this when term does not support UTF8.
#PS1="\n\A \[$green\]\[$bold\]\u\[$reset\]@\[$blue\]\H\[$reset\]:\l: \[$bold\]\[$cyan\]\w\[$reset\] [\$?]\[$bold\]\$(__git_ps1)\[$reset\] \n\$ "

# PROMPT_COMMAND runs before the prompt starts.
# Here I specify the colors of the exit status indicator, based on the exit status. More info - http://mywiki.wooledge.org/BashGuide/TestsAndConditionals#Exit_Status
# 0 gets green, 1 gets red and everything else gets a mellow yellow.
PROMPT_COMMAND='case $? in 
0) exit_color=$green ;; 
1) exit_color=$red ;; 
*) exit_color=$yellow ;; 
esac'

# Here I specify an array of colors used to give a non-0 job indicator a color.
# So that means that when there are some jobs in the background, the job indicator will get colored.
job_colors=( [0]="$bold$yellow" )

# PS1 depending if the user has root privileges or not.
# Do `sudo bash` and then see the prompt change. (This however might not work on many Red Hat based systems, primarily because of SELinux isolation)
if (( UID > 0 ));
 then PS1='\n┌───| \[$bold$cyan\]\w\[$reset\] ](\[$bold$green\]\u\[$reset\]@\[$blue\]\H\[$reset\])[$SHELL]|[\[$white\]\A\[$reset\]][bn:\l]\[${job_colors[\j==0]}\][j:\j]\[$reset\]► [\[$exit_color\]$?\[$reset\]]\[$bold\]$(__git_ps1)\[$reset\] \n└─▪ ';
  else PS1='\n┌───| \[$bold$red\]\w\[$reset\] ](\[$bold$red\]\u\[$reset\]@\[$blue\]\H\[$reset\])[$SHELL]|[\[$white\]\A\[$reset\]][bn:\l]\[${job_colors[\j==0]}\][j:\j]\[$reset\]► [\[$exit_color\]$?\[$reset\]]\[$bold\]$(__git_ps1)\[$reset\] \n└─▪ ';
fi

# Also note the \[${job_colors[\j==0]}\][j:\j]\[$reset\] part.
# Let's break this down a bit. 
# You have the ${job_colors[\j==0]} array operation encased inside the non-printing character sequence indicators ( the things that start with \[ and end with \] )
# You can do arithmetic tests within bash arrays. In our case, this means that when the amount of background jobs equals 0 (\j==0), the outcome of the test will be equal to 'true'. 
# When outcome of the test is equal to true, it will choose the first item in the array (in this case the $bold$yellow we have specified in the job_colors array.
# To not color any further than we need, we reset the color by issuing \[$reset\].