#!/bin/sh
run_cmd() {
    CMD="$1"
    shift

    unset LD_LIBRARY_PATH
    export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
    export HOME="${SNAP_REAL_HOME}"
    export USER="${USERNAME}"
    IGNORERCFILES=""
    if [ "${HOME}" != "/root" ] && [ "${CMD}" = "nano" ]; then
        export XDG_DATA_HOME="${HOME}/.local/share"
        if [ ! -d "/var/lib/snapd/hostfs/${XDG_DATA_HOME}" ]; then
            echo "Instructing nano to ignore RC files due to missing directory: \"${XDG_DATA_HOME}\""
           IGNORERCFILES="--ignorercfiles"
        fi
    fi

    # shellcheck disable=SC2145
    exec unshare --kill-child -U -m -p -r -f --root="/var/lib/snapd/hostfs/" "/bin/sh" -c "mount -t proc proc /proc 2>/dev/null || true; exec \"${CMD}\" ${IGNORERCFILES} \"$@\""
}

# Detect base name
SNAP_BASE="$(sed -n '/^name:/ s/^name:\s*\(core[0-9]\{2\}\)/\1/p' /meta/snap.yaml)"

USERNS=1
[ -e /proc/sys/kernel/unprivileged_userns_clone ] && grep -qxF 0 /proc/sys/kernel/unprivileged_userns_clone && USERNS=0

find_and_spawn() {
    for path in / /usr/ /usr/local/; do
        if [ -e "/var/lib/snapd/hostfs/${path}bin/${1}" ] || [ -L "/var/lib/snapd/hostfs/${path}bin/${1}" ]; then
            run_cmd "$@"
        fi
    done
}

EDIT_CMD="${1}"
EDIT_PATH="${2}"
if [ -z "${EDIT_PATH}" ] || [ "$#" -ge "3" ]; then
    EDIT_CMD=""
    for arg in "${@}"; do
        EDIT_PATH="${arg}"
    done
fi

# Default to trying nano if no editor is provided
if [ -z "${EDIT_CMD}" ]; then
    EDIT_CMD="nano"
fi

# Try running the editor through the host.
if [ -n "${EDIT_CMD}" ] && [ "${USERNS}" = 1 ]; then
    exec 9< /tmp/
    # Replace "/tmp/" prefix by exec'ed FD 9.
    EDIT_PATH_HOST="/proc/self/fd/9/${EDIT_PATH##*/}"
    find_and_spawn "${EDIT_CMD}" "${EDIT_PATH_HOST}"
fi

# Fallback to using vim.tiny from base snap

# Search for a vimrc
for vimrc in "${SNAP_USER_COMMON}/.vimrc" "/snap/${SNAP_BASE}/current/etc/vim/vimrc"; do
    [ -r "${vimrc}" ] || continue
    export VIMINIT="source ${vimrc}"
done

# Ignore vimrc if none was found to be readable.
EDIT_IGNORE_RC=""
if [ -z "${VIMINIT:-""}" ]; then
    EDIT_IGNORE_RC="--clean"
fi

# Run the editor.
exec vim.tiny -Z ${EDIT_IGNORE_RC} "${EDIT_PATH}"