#!/bin/sh -e
#
# This is a simple package manager written in POSIX 'sh' for
# KISS Linux utlizing the core unix utilites where needed.
#
# The script runs with 'set -e' enabled. It will exit on any
# non-zero return code. This ensures that no function continues
# if it fails at any point.
#
# Keep in mind that this involves extra code in the case where
# an error is optional or required.
#
# The code below conforms to shellcheck's rules. However, some
# lint errors *are* disabled as they relate to unexpected
# behavior (which we do expect).
#
# KISS is available under the MIT license.
#
# - Dylan Araps.

die() {
    # Print a message and exit with '1' (error).
    printf '\033[31m!>\033[m %s\n' "$@" >&2
    exit 1
}

log() {
    # Print a message with a colorful arrow to distinguish
    # from other output.
    printf '\033[32m=>\033[m %s\n' "$@"
}

pkg_search() {
    # Figure out which repository a package belongs to by
    # searching for directories matching the package name
    # in $KISS_PATH/*.
    [ "$KISS_PATH" ] || \
        die "\$KISS_PATH needs to be set." \
            "Example: KISS_PATH=/packages/core:/packages/extra:/packages/xorg" \
            "Repositories will be searched in the configured order." \
            "The variable should work just like \$PATH."

    # Disable globbing with 'set -f' to ensure that the unquoted
    # variable doesn't expand into anything nasty.
    # shellcheck disable=2086,2046
    {
        set -f
        set -- "$1" $(IFS=:; find $KISS_PATH -maxdepth 1 -name "$1")
        set +f
    }

    # A package may also not be found due to a repository not being
    # readable by the current user. Either way, we need to die here.
    [ -z "$2" ] && die "Package '$1' not in any repository."

    printf '%s\n' "$2"
}

args() {
    # Parse script arguments manually. POSIX 'sh' has no 'getopts'
    # or equivalent built in.
    [ "$1" ] || {
        log "$kiss [b|c|i|l|r|u] [pkg]" \
            "build:     Build a package." \
            "checksum:  Generate checksums." \
            "install:   Install a package (Runs build if needed)." \
            "list:      List packages." \
            "remove:    Remove a package." \
            "update:    Check for updates."
        exit
    }

    action=$1
    shift

    while [ "$1" ]; do
        case $action in
            b*)
                pkg_search "$1"
                shift
            ;;
        esac
    done
}

main() {
    kiss=${0##*/}

    args "$@"
}

main "$@"