kiss/contrib/kiss-link

#!/bin/sh -ef
# Link a repository file to another repository

[ "$1" ] || {
    printf 'usage: kiss-link file\n'
    exit 1
}

[ -f "${file:=$1}" ] || {
    printf 'file %s does not exist in the current directory\n' "$1"
    exit 1
}

oPWD=$PWD

# Check if the package exists in a repository and error out here
# if it does not. The error message from the package manager will
# be displayed.
kiss s "${PWD##*/}" >/dev/null

# Disable this warning as globbing is disabled and word splitting
# is intentional. This grabs the location of the package's files.
# shellcheck disable=2046
{
    # Generate a list of repositories in which the package
    # exists. Then 'cd' to the first found directory to do a
    # comparison.
    set -- $(kiss s "${PWD##*/}"); cd "$1"

    # Error if the package exists nowhere but the current
    # directory and this script would create a broken symlink.
    [ -z "$2" ] && [ "$PWD" = "$oPWD" ] && {
        printf 'error: cannot symlink file to itself\n'
        exit 1
    }

    # If the first repository in '$KISS_PATH' is the current
    # directory, use the second repository in the list.
    [ "$PWD" = "$oPWD" ] && shift

    # Finally, make the link to the file in whatever repository
    # it was found in.
    ln -sf "$1/$file" "$oPWD/$file"
}

printf 'linked %s to %s\n' "$file" "$1"