#!/bin/bash
# Script that setups LFS installer

set -e

# Helper function to pach the packages.ent
# Parameters are in this order: major, minor, patch, md5 and full path to packages.ent
patchKernelVersion()
{
    if [ ! -f "$5" ] ; then
        echo "The packages.ent file is not exist or not defined." >&2
        echo "File: $5"
        return 4
    fi

    sed -i -E "s@(<\!ENTITY linux-major-version \"+)(.+\">)@\1$1\">@" "$5"
    sed -i -E "s@(<\!ENTITY linux-minor-version \"+)(.+\">)@\1$2\">@" "$5"    
    sed -i -E "s@(<\!ENTITY linux-md5 \"+)(.+\">)@\1$4\">@" "$5"

    if [ "-" == "$3" ] ; then
        sed -i -E '/<!--/ n; /<\!ENTITY linux-patch-version "/{s/<!E/<!--<!E/g;s/">/">-->/g;}' "$5"
        sed -i -E '/linux-minor-version;">-->/{s/<!--//g;s/-->//g;}' "$5"
        sed -i -E '/<!--/ n; /linux-patch-version;">/{s/<!E/<!--<!E/g;s/;">/;">-->/g;}' "$5"
    else
        sed -i -E '/<!ENTITY linux-patch-version "/{s/<!--//g;s/-->//g;}' "$5"
        sed -i -E "s@(<\!ENTITY linux-patch-version \"+)(.+\">)@\1$3\">@" "$5"
        sed -i -E '/linux-patch-version;">-->/{s/<!--//g;s/-->//g;}' "$5"
        sed -i -E '/<!--/ n; /linux-minor-version;">/{s/<!E/<!--<!E/g;s/;">/;">-->/g;}' "$5"
    fi
}

# Check if the lfs mount point folder is specified as the first argument
if [ -z "$1" ]
then
    echo "Please specify the lfs mount point folder as the first argument!" >&2
    exit 1
fi

# Check if the lfs folder is exists
if [ ! -d "$1" ]
then
    echo "LFS mount point folder does not exist!" >&2
    exit 2
fi

# Check if jhalfs folder is already exist and delete it if yes
DIR_JHALFS="$1/jhalfs"
if [ -d "$DIR_JHALFS" ]
then
    echo Deleting old jhalfs folder: "$DIR_JHALFS"
    sudo rm -rf "$DIR_JHALFS"
    echo Done!
fi

# Now create the jhalfs folder and book-source sub-folder owned by the current user
DIR_BOOK="$DIR_JHALFS/book-source"
U="$(id -un)" # current user
G="$(id -gn)" # current group
echo Creating jhalfs folder...
sudo install -v -o "$U" -g root -m 1777 -d "$DIR_JHALFS"
sudo install -v -o "$U" -g "$G" -m 1777 -d "$DIR_BOOK"

# Clone the LFS book repository to book-source folder
echo Cloning lfs book sources...
git clone https://git.linuxfromscratch.org/lfs.git "$DIR_BOOK"

# Get the latest kernel version and download link from kernel.org
echo Getting latest kernel from kernel.org...
LATEST_KERNEL_URL="$(curl -v --silent https://www.kernel.org/ 2>&1 | sed -n '/<td id="latest_link">/{n; p}' | cut -d '"' -f 2)"
LATEST_KERNEL_VER="$(cut -d '-' -f 2 <<< "$LATEST_KERNEL_URL" | rev | cut -c8- | rev)"
echo Latest kernel version: "$LATEST_KERNEL_VER"
echo Download URL: "$LATEST_KERNEL_URL"

# Check sources folder existence and create if needed
DIR_SOURCES="$1/sources"
if [ ! -d "$DIR_SOURCES" ] ; then
    sudo install -v -o "$U" -g "$G" -m 1777 -d "$DIR_SOURCES"
else
    sudo chmod -v 1777 "$DIR_SOURCES"
fi

# Download latest kernel if not done yet
KERNEL_FILE_NAME="$(rev <<< "$LATEST_KERNEL_URL" | cut -d '/' -f1 | rev)"
if [ ! -f "$DIR_SOURCES/$KERNEL_FILE_NAME" ] ; then
    echo Downloading kernel tar ball...
    wget -T 30 -t 5 --directory-prefix="$DIR_SOURCES" "$LATEST_KERNEL_URL"
    echo Done!
fi

# Patch packages.ent with latest kernel
MD5_SUM="$(md5sum "$DIR_SOURCES/$KERNEL_FILE_NAME" | cut -d ' ' -f 1)"
NUM_VER_DOTS="$(awk -F. '{print NF-1}' <<< "$LATEST_KERNEL_VER")"
if [ "2" == "$NUM_VER_DOTS" ] ; then
    MAIN_VER="$(awk -F. '{print $(NF-2)}' <<< "$LATEST_KERNEL_VER")"
    MINOR_VER="$(awk -F. '{print $(NF-1)}' <<< "$LATEST_KERNEL_VER")"
    PATCH_VER="$(awk -F. '{print $(NF)}' <<< "$LATEST_KERNEL_VER")"
elif [ "1" == "$NUM_VER_DOTS" ] ; then
    MAIN_VER="$(awk -F. '{print $(NF-1)}' <<< "$LATEST_KERNEL_VER")"
    MINOR_VER="$(awk -F. '{print $(NF)}' <<< "$LATEST_KERNEL_VER")"
    PATCH_VER="-"
else
    echo Invalid count of version dots: "$NUM_VER_DOTS" >&2
    echo Where version number is: "$LATEST_KERNEL_VER" >&2
    exit 3
fi
patchKernelVersion "$MAIN_VER" "$MINOR_VER" "$PATCH_VER" "$MD5_SUM" "$DIR_BOOK/packages.ent"

# Check if setup folder is already exist and delete it if yes
DIR_SETUP="$1/setup"
if [ -d "$DIR_SETUP" ]
then
    echo Deleting old setup folder: "$DIR_SETUP"
    sudo rm -rf "$DIR_SETUP"
    echo Done!
fi

# Now create the setup folder owned by the current user
echo Creating setup folder...
sudo install -v -o "$U" -g "$G" -m 755 -d "$DIR_SETUP"

# Clone the jhalfs repository to setup folder
echo Cloning jhalfs sources...
git clone https://git.linuxfromscratch.org/jhalfs.git "$DIR_SETUP"

# Patch opt_config to use -O3 -pipe -march=native
echo Patching optimization config file...
sed -i -E '/DEF_OPT_MODE=/s/noOpt/O3pipe_march/g' "$DIR_SETUP/optimize/opt_config"

# Copy jhalfs config file and adjust some settings in it
cp -iv lfs_configs/configuration "$DIR_SETUP/"
echo Patching setup configuration file...
FILE_CFG="$DIR_SETUP/configuration"
sed -i -E "\@BUILDDIR=\"xxx\"@s@xxx@$1@g" "$FILE_CFG"
sed -i -E "\@FSTAB=\"xxx\"@s@xxx@/home/$U/fstab@g" "$FILE_CFG"
sed -i -E "\@CONFIG=\"xxx\"@s@xxx@/home/$U/config-$LATEST_KERNEL_VER@g" "$FILE_CFG"
sed -i -E "\@KEYMAP=\"xxx\"@s@xxx@$(localectl | grep Keymap | awk -F' ' '{printf $NF}')@g" "$FILE_CFG"

# Enter to setup folder and start installer
cd "$DIR_SETUP"
yes "yes" | ./jhalfs run