#!/usr/bin/env bash
# Run a repo Python script under the activated Hermes environment.
#
# Shebang target for POSIX scripts:
#     #!/usr/bin/env -S bash -c 'exec "$BASH" "$(dirname "$0")/_hermes-python" "$0" "$@"'
#
# The kernel appends the invoking script, so `$1` is the Python file to run
# and `$@` its arguments. Activates when there is no environment to inherit, or
# when the inherited one predates its inputs; then execs the interpreter on the
# same file, so tracebacks and __file__ point at the real script.
set -u

target=${1:-}
if [ -z "$target" ]; then
    printf 'usage: %s <script.py> [args...]\n' "$0" >&2
    exit 2
fi
shift

_here="$(cd "$(dirname "$target")" && pwd)"
while [ "$_here" != / ] && [ ! -f "$_here/activate" ]; do _here="$(dirname "$_here")"; done
if [ ! -f "$_here/activate" ]; then
    printf '%s: no activate script above %s\n' "$0" "$target" >&2
    exit 1
fi

# pm records, beside the installed-state file named by __HERMES_ACTIVATED, one
# stamp per dependency input carrying the exact mtime that input had when the
# install was last verified against it (pm.environments.record_activation_inputs).
# Any input whose mtime DIFFERS from its stamp — newer or older, since a branch
# switch can move it either way — means the inherited environment may not match
# its inputs. `-nt`/`-ot` are bash builtins, so this costs no process spawn, and
# every successful activation re-records, so one re-activation settles it. No
# stamps (an install from before stamps existed), a missing input, a dangling
# sentinel or a legacy literal "1" all activate.
_needs_activation=1
if [ -n "${__HERMES_ACTIVATED:-}" ] && [ -e "${__HERMES_ACTIVATED}" ]; then
    _stamps="${__HERMES_ACTIVATED%/*}/inputs"
    _needs_activation=0
    _stamped=0
    for _stamp in "$_stamps"/* "$_stamps"/*/*; do
        [ -f "$_stamp" ] || continue
        _stamped=1
        _input="$_here/${_stamp#"$_stamps"/}"
        if [ ! -e "$_input" ] || [ "$_input" -nt "$_stamp" ] || [ "$_input" -ot "$_stamp" ]; then
            _needs_activation=1
            break
        fi
    done
    [ "$_stamped" = 1 ] || _needs_activation=1
fi

if [ "$_needs_activation" = 1 ]; then
    # shellcheck source=/dev/null
    . "$_here/activate" || exit 1
fi

exec python3 "$target" "$@"