#!/bin/sh -e

# Copyright (c) 2025 Alexander Hill

# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.

# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
# OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.

####################
# Global Variables #
####################

[ -z "$TREETAP_DIR" ] && TREETAP_DIR="$(pwd)/.treetap"
[ -z "$TREETAP_PKGDIR" ] && TREETAP_PKGDIR="$TREETAP_DIR/packages"
[ -z "$TREETAP_SYSROOT" ] && TREETAP_SYSROOT=/
TREETAP_VERSION="1.0.0"

#####################
# Utility Functions #
#####################

# Displays the usage information for treetap
help_message() {
    echo "treetap $TREETAP_VERSION"
    echo
    echo "Package Commands:"
    echo "    $0 install <package> [sysroot]"
    echo "    $0 uninstall <package> [sysroot]"
    echo
    echo "Source Commands:"
    echo "    $0 build <spec>"
    echo "    $0 clean <spec>"
    echo "    $0 fetch <spec>"
    echo "    $0 package <spec>"
    echo "    $0 purge <spec>"
    exit 1
}

# Confirms that the given strings are valid package and sysroot paths
package_check() {
    [ -z "$1" ] && (echo "package_check: Missing package file"; exit 1)
    [ -z "$2" ] && (echo "package_check: Missing sysroot"; exit 1)
    [ ! -f "$1" ] && (echo "package_check: Package file \"$1\" not found"; exit 1)
    [ ! -d "$2" ] && (echo "package_check: Sysroot \"$2\" not found"; exit 1)
    true
}

# Reads the source specification and ensures it includes the required data
source_spec() {
    # Sanity Check
    [ -z "$1" ] && (echo "source_spec: Missing specification file"; exit 1)
    [ ! -f "$1" ] && (echo "source_spec: Specification file \"$1\" not found"; exit 1)

    # Zhu Li, do the thing!
    source $1

    # Required Fields
    [ -z "$SRC_HASH" ] && (echo "source_spec: SRC_HASH is required but not defined"; exit 1)
    [ -z "$SRC_NAME" ] && (echo "source_spec: SRC_NAME is required but not defined"; exit 1)
    [ -z "$SRC_URL" ] && (echo "source_spec: SRC_URL is required but not defined"; exit 1)
    [ -z "$SRC_VERSION" ] && (echo "source_spec: SRC_VERSION is required but not defined"; exit 1)

    # Optional Fields
    [ -z "$SRC_FILENAME" ] && SRC_FILENAME=$(basename $SRC_URL)

    # Environmental Variables
    [ -z "$TREETAP_BINDIR" ] && TREETAP_BINDIR=/bin
    TREETAP_BUILD=$(clang -dumpmachine)
    [ -z "$TREETAP_TARGET" ] && TREETAP_TARGET=$TREETAP_BUILD
    TREETAP_BUILDDIR="$TREETAP_DIR/sources/$SRC_NAME/$SRC_VERSION/$TREETAP_TARGET"
    [ -z "$TREETAP_INCLUDEDIR" ] && TREETAP_INCLUDEDIR=/usr/include
    TREETAP_INSTALLDIR="$TREETAP_BUILDDIR/install"
    [ -z "$TREETAP_LIBDIR" ] && TREETAP_LIBDIR=/lib
    [ -z "$TREETAP_PREFIX" ] && TREETAP_PREFIX=/
    [ -z "$TREETAP_PROCS" ] && TREETAP_PROCS=$(nproc)

    true
}

###############
# Subcommands #
###############

# Installs a package to the sysroot
package_install() {
    [ ! -z "$2" ] && TREETAP_SYSROOT=$2
    package_check $1 $TREETAP_SYSROOT
    echo "Installing $(basename $1)"
    FULLPATH=$(pwd)/$1
    pushd $TREETAP_SYSROOT > /dev/null
    xz -cd $FULLPATH | cpio -idmu --quiet
    popd > /dev/null
    exit 0
}

# Uninstalls a package from the sysroot
package_uninstall() {
    [ ! -z "$2" ] && TREETAP_SYSROOT=$2
    package_check $1 $TREETAP_SYSROOT
    echo "Uninstalling $(basename $1)"
    FULLPATH=$(pwd)/$1
    pushd $TREETAP_SYSROOT > /dev/null
    xz -cd $FULLPATH | cpio -it --quiet | tail -n +2 | sort -r | while read path; do
        if [ -d $path ]; then
            rmdir --ignore-fail-on-non-empty $path
        else
            rm -f $path
        fi
    done
    popd > /dev/null
    exit 0
}

# Builds the source from the previously fetched tarball
source_build() {
    source_spec $1
    mkdir -p $TREETAP_BUILDDIR
    pushd $TREETAP_BUILDDIR > /dev/null
    echo "Building $SRC_NAME $SRC_VERSION"
    build > build-$(date +%Y%m%d%H%M%S).log 2>&1
    popd > /dev/null
    exit 0
}

# Cleans the source from the previous build
source_clean() {
    source_spec $1
    mkdir -p $TREETAP_BUILDDIR
    pushd $TREETAP_BUILDDIR > /dev/null
    echo "Cleaning $SRC_NAME $SRC_VERSION"
    clean
    rm -rf $TREETAP_INSTALLDIR
    popd > /dev/null
    exit 0
}

# Fetches and verifies the integrity of the source tarball
source_fetch() {
    source_spec $1
    mkdir -p $TREETAP_BUILDDIR
    pushd $TREETAP_BUILDDIR/.. > /dev/null
    echo "Fetching $SRC_FILENAME"
    curl -L -sS $SRC_URL -o $SRC_FILENAME
    echo "Verifying $SRC_FILENAME"
    echo "$SRC_HASH  $SRC_FILENAME" | sha256sum -c - > /dev/null
    popd > /dev/null
    exit 0
}

# Packages the built artifacts for distribution
source_package() {
    source_spec $1
    mkdir -p $TREETAP_BUILDDIR
    mkdir -p $TREETAP_INSTALLDIR
    mkdir -p $TREETAP_PKGDIR
    pushd $TREETAP_BUILDDIR > /dev/null
    echo "Moving artifacts for $SRC_NAME $SRC_VERSION"
    package > package-$(date +%Y%m%d%H%M%S).log
    echo "Archiving $SRC_NAME $SRC_VERSION"
    cd $TREETAP_INSTALLDIR
    find | cpio -o --quiet | xz -cz > "$TREETAP_PKGDIR/$SRC_NAME-$SRC_VERSION.cpio.xz"
    rm -rf $TREETAP_INSTALLDIR
    popd > /dev/null
    exit 0
}

# Purges the entire build directory for a source
source_purge() {
    source_spec $1
    rm -rf $TREETAP_BUILDDIR
    exit 0
}

###############
# Entry Point #
###############

case "$1" in
"build") source_build $2 ;;
"clean") source_clean $2 ;;
"fetch") source_fetch $2 ;;
"install") package_install $2 $3 ;;
"package") source_package $2 ;;
"purge") source_purge $2 ;;
"uninstall") package_uninstall $2 $3 ;;
*) help_message ;;
esac