#!/bin/sh

dotnetDir="/opt/dotnet"
dotnetVersion="10.0"
dotnetRuntime="Microsoft.AspNetCore.App 10.0."
dotnetUrl="https://dot.net/v1/dotnet-install.sh"

if [ -d "/etc/dns/config" ]
then
    dnsDir="/etc/dns"
else
    dnsDir="/opt/technitium/dns"
fi

dnsConfig="/etc/dns"
dnsLog="/var/log/technitium/dns"
dnsTar="$dnsDir/DnsServerPortable.tar.gz"
dnsUrl="https://download.technitium.com/dns/DnsServerPortable.tar.gz"

serviceUser="dns-server"
installLog="$dnsDir/install.log"

echo ""
echo "==============================="
echo "Technitium DNS Server Installer"
echo "==============================="
echo ""

mkdir -p $dnsDir
mkdir -p $dnsConfig

echo "" > $installLog

if dotnet --list-runtimes 2> /dev/null | grep -q "$dotnetRuntime";
then
    dotnetFound="yes"
else
    dotnetFound="no"
fi

if [ ! -d $dotnetDir ] && [ "$dotnetFound" = "yes" ]
then
    echo "ASP.NET Core Runtime is already installed."
else
    if [ -d $dotnetDir ] && [ "$dotnetFound" = "yes" ]
    then
        dotnetUpdate="yes"
        echo "Updating ASP.NET Core Runtime..."
    else
        dotnetUpdate="no"
        echo "Installing ASP.NET Core Runtime..."
    fi

    curl -sSL $dotnetUrl | bash /dev/stdin -c $dotnetVersion --runtime aspnetcore --no-path --install-dir $dotnetDir --verbose >> $installLog 2>&1

    # On Alpine Linux dotnet requires libstdc++
    if command -v apk >/dev/null 2>&1
    then
        echo "Installing ASP.NET Core Runtime dependencies..."
        apk add --no-cache libstdc++ >> $installLog 2>&1
    fi

    if [ ! -f "/usr/bin/dotnet" ]
    then
        ln -s $dotnetDir/dotnet /usr/bin >> $installLog 2>&1
    fi

    if dotnet --list-runtimes 2> /dev/null | grep -q "$dotnetRuntime";
    then
        if [ "$dotnetUpdate" = "yes" ]
        then
            echo "ASP.NET Core Runtime was updated successfully!"
        else
            echo "ASP.NET Core Runtime was installed successfully!"
        fi
    else
        echo "Failed to install ASP.NET Core Runtime. Please check '$installLog' for details."
        exit 1
    fi
fi

echo ""
echo "Downloading Technitium DNS Server..."

if ! curl -o $dnsTar --fail $dnsUrl >> $installLog 2>&1
then
    echo "Failed to download Technitium DNS Server from: $dnsUrl"
    echo "Please check '$installLog' for details."
    exit 1
fi

if [ -d $dnsConfig ]
then
    echo "Updating Technitium DNS Server..."
else
    echo "Installing Technitium DNS Server..."
fi

tar -zxf $dnsTar -C $dnsDir >> $installLog 2>&1

echo ""

if $( dotnet $dnsDir/DnsServerApp.dll --icu-test >> $installLog 2>&1 ) >/dev/null 2>&1;
then
    echo "ICU package is already installed."
else
    echo "Checking for required ICU package..."

    if command -v apt-get >/dev/null 2>&1; then
        # Debian/Ubuntu based
        if ! dpkg -l | grep -q "libicu"; then
            echo "Installing required ICU package..."
            apt-get update >> $installLog 2>&1

            # Try to install the most common package name
            if apt-cache show libicu74 >/dev/null 2>&1; then
                echo "Installing libicu74 package..."
                apt-get install -y libicu74 >> $installLog 2>&1
            elif apt-cache show libicu72 >/dev/null 2>&1; then
                echo "Installing libicu72 package..."
                apt-get install -y libicu72 >> $installLog 2>&1
            elif apt-cache show libicu70 >/dev/null 2>&1; then
                echo "Installing libicu70 package..."
                apt-get install -y libicu70 >> $installLog 2>&1
            else
                # Fallback to a generic approach
                echo "No specific libicu package was found, trying generic installation..."
                apt-get install -y libicu* >> $installLog 2>&1
            fi
        fi
    elif command -v dnf >/dev/null 2>&1; then
        # Fedora/RHEL based
        if ! rpm -qa | grep -q "libicu"; then
            echo "Installing required ICU package..."
            dnf install -y libicu >> $installLog 2>&1
        fi
    elif command -v yum >/dev/null 2>&1; then
        # Older RHEL/CentOS systems
        if ! rpm -qa | grep -q "libicu"; then
            echo "Installing required ICU package..."
            yum install -y libicu >> $installLog 2>&1
        fi
    elif command -v zypper >/dev/null 2>&1; then
        # openSUSE based
        if ! rpm -qa | grep -q "libicu"; then
            echo "Installing required ICU package..."
            zypper install -y libicu >> $installLog 2>&1
        fi
    elif command -v pacman >/dev/null 2>&1; then
        # Arch based
        if ! pacman -Q | grep -q "icu"; then
            echo "Installing required ICU package..."
            pacman -S --noconfirm icu >> $installLog 2>&1
        fi
    elif command -v apk >/dev/null 2>&1; then
        # Alpine Linux
        if ! apk list --installed | grep -q "icu"; then
            echo "Installing required ICU package..."
            apk add --no-cache icu >> $installLog 2>&1
        fi
    else
        echo "Failed to install Technitium DNS Server: could not determine package manager to install ICU package. Please install ICU package manually and try again."
        echo "Please read the 'Missing ICU Package' section in this blog post to understand how to manually install the ICU package for your distro: https://blog.technitium.com/2017/11/running-dns-server-on-ubuntu-linux.html"
        exit 1
    fi

    #test again to confirm
    if $( dotnet $dnsDir/DnsServerApp.dll --icu-test >> $installLog 2>&1 ) >/dev/null 2>&1;
    then
        echo "ICU package was installed successfully!"
    else
        echo "Failed to install Technitium DNS Server: failed to install ICU package. Please install ICU package manually and try again."
        echo "Please read the 'Missing ICU Package' section in this blog post to understand how to manually install the ICU package for your distro: https://blog.technitium.com/2017/11/running-dns-server-on-ubuntu-linux.html"
        exit 1
    fi
fi

echo ""

if [ "$(ps --no-headers -o comm 1 | tr -d '\n')" = "systemd" ]
then
    if [ -f "/etc/systemd/system/dns.service" ]
    then
        echo "Configuring permissions..."
        chown -R $serviceUser:$serviceUser $dnsDir $dnsConfig $dnsLog >> $installLog 2>&1

        echo "Restarting systemd service..."
        systemctl restart dns.service >> $installLog 2>&1
    else
        mkdir -p $dnsLog

        echo "Configuring user and permissions..."
        useradd --system -M --shell /usr/sbin/nologin --user-group $serviceUser >> $installLog 2>&1
        chown -R $serviceUser:$serviceUser $dnsDir $dnsConfig $dnsLog >> $installLog 2>&1

        echo "Configuring systemd service..."
        cp $dnsDir/systemd.service /etc/systemd/system/dns.service
        systemctl enable dns.service >> $installLog 2>&1

        systemctl stop systemd-resolved >> $installLog 2>&1
        systemctl disable systemd-resolved >> $installLog 2>&1

        systemctl start dns.service >> $installLog 2>&1

        if [ -f "/etc/NetworkManager/NetworkManager.conf" ]
        then
            currentVal=$(grep -F "dns=" /etc/NetworkManager/NetworkManager.conf)

            if [ "$currentVal" = "" ]
            then
                printf "\n[main]\ndns=none\n" >> /etc/NetworkManager/NetworkManager.conf 2>> $installLog
            elif [ "$currentVal" != "dns=none" ]
            then
                sed -i "s/$currentVal/dns=none/g" /etc/NetworkManager/NetworkManager.conf 2>> $installLog
            fi
        fi
    fi
elif [ -x "/sbin/rc-service" ]
then
    if [ -f "/etc/init.d/dns" ]
    then
        echo "Configuring permissions..."
        chown -R $serviceUser:$serviceUser $dnsDir $dnsConfig $dnsLog >> $installLog 2>&1

        echo "Restarting OpenRC service..."
        rc-service dns stop >> $installLog 2>&1
        rc-service dns start >> $installLog 2>&1
    else
        mkdir -p $dnsLog

        echo "Configuring user and permissions..."
        addgroup -S $serviceUser >> $installLog 2>&1
        adduser -H -S -D -s /bin/false -G $serviceUser $serviceUser >> $installLog 2>&1
        chown -R $serviceUser:$serviceUser $dnsDir $dnsConfig $dnsLog >> $installLog 2>&1

        echo "Configuring OpenRC service..."
        cp $dnsDir/openrc.service /etc/init.d/dns
        chmod +x /etc/init.d/dns
        rc-update add dns >> $installLog 2>&1
        rc-service dns start >> $installLog 2>&1
    fi
else
    echo "Failed to install Technitium DNS Server: systemd/openrc was not detected."
    echo "Please read the 'Installing DNS Server Manually' section in this blog post to understand how to manually install the DNS server on your distro: https://blog.technitium.com/2017/11/running-dns-server-on-ubuntu-linux.html"
    exit 1
fi 2>/dev/null

cp -a /etc/resolv.conf $dnsDir/resolv.conf.bak >> $installLog 2>&1    
rm /etc/resolv.conf >> $installLog 2>&1    
printf "# Generated by Technitium DNS Server Installer\n\nnameserver 127.0.0.1\n" > /etc/resolv.conf 2>> $installLog

echo ""
echo "Technitium DNS Server was installed successfully!"
echo "Open http://$(cat /proc/sys/kernel/hostname):5380/ to access the web console."
echo ""
echo "Donate! Make a contribution by becoming a Patron: https://www.patreon.com/technitium"
echo ""