#!/bin/bash

user_id=`id -u`

if [ $user_id -ne 0 ]; then
    echo "Need to run with sudo privilege"
    exit 1
fi

# Determine OS type 
# Debian based OS (Debian, Ubuntu, Linux Mint) has /etc/debian_version
# Fedora based OS (Fedora, Red Hat Enterprise Linux, CentOS, Oracle Linux 7) has /etc/redhat-release
# SUSE based OS (OpenSUSE, SUSE Enterprise) has ID_LIKE=suse in /etc/os-release

function print_errormessage() 
{
    echo "Can't install dotnet 5 dependencies."
    echo "You can manually install all required dependencies based on following documentation"
    echo "https://docs.microsoft.com/en-us/dotnet/core/linux-prerequisites?tabs=netcore2x"
}

function print_rhel6message() 
{
    echo "We did our best effort to install dotnet 5 dependencies"
    echo "However, there are some dependencies which require manual installation" 
    echo "You can install all remaining required dependencies based on the following documentation"
    echo "https://github.com/dotnet/core/blob/master/Documentation/build-and-install-rhel6-prerequisites.md"
}

function print_rhel6errormessage() 
{
    echo "We couldn't install dotnet 5 dependencies"
    echo "You can manually install all required dependencies based on following documentation"
    echo "https://docs.microsoft.com/en-us/dotnet/core/linux-prerequisites?tabs=netcore2x"
    echo "In addition, there are some dependencies which require manual installation. Please follow this documentation" 
    echo "https://github.com/dotnet/core/blob/master/Documentation/build-and-install-rhel6-prerequisites.md"
}

if [ -e /etc/os-release ]
then
    echo "--------OS Information--------"
    cat /etc/os-release
    echo "------------------------------"

    if [ -e /etc/debian_version ]
    then
        echo "The current OS is Debian based"
        echo "--------Debian Version--------"
        cat /etc/debian_version
        echo "------------------------------"
        
        # prefer apt-get over apt
        command -v apt-get
        if [ $? -eq 0 ]
        then
            apt_get=apt-get
        else
            command -v apt
            if [ $? -eq 0 ]
            then
                apt_get=apt
            else
                echo "Found neither 'apt-get' nor 'apt'"
                print_errormessage
                exit 1
            fi
        fi

        $apt_get update && $apt_get install -y liblttng-ust0 libkrb5-3 zlib1g
        if [ $? -ne 0 ]
        then
            echo "'$apt_get' failed with exit code '$?'"
            print_errormessage
            exit 1
        fi

        apt_get_with_fallbacks() {
            $apt_get install -y $1
            fail=$?
            if [ $fail -eq 0 ]
            then
                if [ "${1#"${1%?}"}" = '$' ]; then
                    dpkg -l "${1%?}" > /dev/null 2> /dev/null
                    fail=$?
                fi
            fi
            if [ $fail -ne 0 ]
            then
                shift
                if [ -n "$1" ]
                then
                    apt_get_with_fallbacks "$@"
                fi
            fi
        }

        # libssl version prefer: libssl1.1 -> libssl1.0.2 -> libssl1.0.0
        apt_get_with_fallbacks libssl1.1$ libssl1.0.2$ libssl1.0.0$
        if [ $? -ne 0 ]
        then
            echo "'$apt_get' failed with exit code '$?'"
            print_errormessage
            exit 1
        fi

        # libicu version prefer: libicu66 -> libicu63 -> libicu60 -> libicu57 -> libicu55 -> libicu52
        apt_get_with_fallbacks libicu66 libicu63 libicu60 libicu57 libicu55 libicu52
        if [ $? -ne 0 ]
        then
            echo "'$apt_get' failed with exit code '$?'"
            print_errormessage
            exit 1
        fi
    elif [ -e /etc/redhat-release ]
    then
        echo "The current OS is Fedora based"
        echo "--Fedora/RHEL/CentOS Version--"
        cat /etc/redhat-release
        echo "------------------------------"

        # use dnf on fedora
        # use yum on centos and rhel
        if [ -e /etc/fedora-release ]
        then
            command -v dnf
            if [ $? -eq 0 ]
            then
                dnf install -y lttng-ust openssl-libs krb5-libs zlib libicu
                if [ $? -ne 0 ]
                then
                    echo "'dnf' failed with exit code '$?'"
                    print_errormessage
                    exit 1
                fi         
            else
                echo "Can not find 'dnf'"
                print_errormessage
                exit 1
            fi
        else
            command -v yum
            if [ $? -eq 0 ]
            then
                yum install -y lttng-ust openssl-libs krb5-libs zlib libicu
                if [ $? -ne 0 ]
                then                    
                    echo "'yum' failed with exit code '$?'"
                    print_errormessage
                    exit 1
                fi
            else
                echo "Can not find 'yum'"
                print_errormessage
                exit 1
            fi
        fi
    else
        # we might on OpenSUSE
        OSTYPE=$(grep ID_LIKE /etc/os-release | cut -f2 -d=)
        echo $OSTYPE
        echo $OSTYPE | grep "suse"
        if [ $? -eq 0 ]
        then
            echo "The current OS is SUSE based"
            command -v zypper
            if [ $? -eq 0 ]
            then
                zypper -n install lttng-ust libopenssl1_1 krb5 zlib libicu60_2
                if [ $? -ne 0 ]
                then
                    echo "'zypper' failed with exit code '$?'"
                    print_errormessage
                    exit 1
                fi
            else
                echo "Can not find 'zypper'"
                print_errormessage
                exit 1
            fi
        else
            echo "Can't detect current OS type based on /etc/os-release."
            print_errormessage
            exit 1
        fi
    fi
elif [ -e /etc/redhat-release ]
# RHEL6 doesn't have an os-release file defined, read redhat-release instead
then
    redhatRelease=$(</etc/redhat-release)
    if [[ $redhatRelease == "CentOS release 6."* || $redhatRelease == "Red Hat Enterprise Linux Server release 6."* ]]
    then
        echo "The current OS is Red Hat Enterprise Linux 6 or CentOS 6"

        # Install known dependencies, as a best effort.
        # The remaining dependencies are covered by the GitHub doc that will be shown by `print_rhel6message`
        command -v yum
        if [ $? -eq 0 ]
        then
            yum install -y openssl krb5-libs zlib
            if [ $? -ne 0 ]
            then                    
                echo "'yum' failed with exit code '$?'"
                print_rhel6errormessage
                exit 1
            fi
        else
            echo "Can not find 'yum'"
            print_rhel6errormessage
            exit 1
        fi

        print_rhel6message
        exit 1
    else
        echo "Unknown RHEL OS version"
        print_errormessage
        exit 1
    fi
else
    echo "Unknown OS version"
    print_errormessage
    exit 1
fi

echo "-----------------------------"
echo " Finish Install Dependencies"
echo "-----------------------------"