#!/bin/sh
# SPDX-FileCopyrightText: 2026 GPForum Contributors
# SPDX-License-Identifier: BSD-3-Clause

set -eu

# Locate Carton for lock updates, checks and bundles, or run from local/.
# Locked installation uses script/gpforum-cpm. The runtime selector accepts
# any supported Perl; native dependencies must match that interpreter's ABI.

root=$(CDPATH= cd -- "$(dirname "$0")/.." && pwd)

# libev reads LIBEV_FLAGS once, when EV loads, and morbo, Test::Mojo, yath or
# a profiler load it before any GPForum code can choose: on macOS and FreeBSD
# libev's own default is then select or poll. Choosing here, before any Perl
# starts, gives every tool run through this script the native backend that
# GPForum::OS::Reactor requires (keep the two tables equal; t/698 checks).
# Another system keeps whatever it inherited.
case $(uname -s) in
    Linux) native_backend=4 ;;
    Darwin | FreeBSD) native_backend=8 ;;
    *) native_backend= ;;
esac
if [ -n "$native_backend" ]; then
    LIBEV_FLAGS=$native_backend
    MOJO_REACTOR=Mojo::Reactor::EV
    export LIBEV_FLAGS MOJO_REACTOR
fi

if [ -n "${GPFORUM_CARTON:-}" ]; then
    if [ ! -x "${GPFORUM_CARTON}" ]; then
        echo "gpforum-carton: GPFORUM_CARTON is not executable: ${GPFORUM_CARTON}" >&2
        exit 1
    fi
    exec "${GPFORUM_CARTON}" "$@"
fi

perl_bin=$("$root/script/gpforum-system-perl" --require)
GPFORUM_PERL=$perl_bin
perl_dir=$(dirname "$perl_bin")

# Keep PATH lookups on the same interpreter for `perl -S carton`.
PATH="$perl_dir:$PATH"
export PATH GPFORUM_PERL

# Probe before adding local/ to @INC, so a mismatched XS module produces a
# rebuild instruction instead of a loader crash. Do not inherit Perl library
# overrides into the core-only compatibility check.
PERL5LIB= PERL5OPT= "$perl_bin" -I"$root/lib" -MGPForum::Infrastructure::PerlRuntime \
    -e 'GPForum::Infrastructure::PerlRuntime->check(shift)' "$root"

# `exec` only needs the locked tree on @INC, which local/ already provides, so
# it is reproduced here whether or not Carton is installed. Real `carton exec`
# parses the options that follow the command as its own: `exec prove -v`
# printed Carton's version instead of running the tests. Reproducing it also
# pins every Perl tool to the validated interpreter. Lock updates and checks
# still need Carton itself (below).
if [ "${1:-}" = "exec" ] && [ -d "$root/local/lib/perl5" ]; then
    shift
    PERL5LIB="$root/local/lib/perl5${PERL5LIB:+:$PERL5LIB}"
    export PERL5LIB
    # Anything launched from here — including a program whose shebang says
    # `#!/usr/bin/env perl` — must find the validated interpreter first, or it
    # loads XS built for a different Perl. A shim directory makes `perl` on
    # PATH mean exactly $perl_bin for the whole process tree.
    shim="$root/local/.perl-shim"
    if [ ! -x "$shim/perl" ] || [ "$(readlink "$shim/perl" 2>/dev/null)" != "$perl_bin" ]; then
        mkdir -p "$shim" && ln -sf "$perl_bin" "$shim/perl"
    fi
    PATH="$shim:$root/local/bin:$PATH"
    export PATH
    # `carton exec -- cmd` is valid; drop the separator before dispatching.
    if [ "${1:-}" = "--" ]; then
        shift
    fi
    # A bare `perl`, `prove` or other Perl tool found on PATH can belong to
    # an older interpreter than the one that validated above (macOS keeps
    # its own /usr/bin/perl next to Homebrew's). Pin every Perl tool to
    # $perl_bin.
    command_name=${1:-}
    case "$command_name" in
        */*)
            # An explicit path. A Perl entrypoint must run under the
            # interpreter that validated above, not under whatever its
            # shebang resolves to on this host, or it loads XS built for a
            # different Perl and dies with a handshake mismatch.
            if [ -r "$command_name" ] \
                && head -n 1 "$command_name" 2>/dev/null | grep -q 'perl'; then
                shift
                exec "$perl_bin" "$command_name" "$@"
            fi
            exec "$@"
            ;;
        perl)
            shift
            exec "$perl_bin" "$@"
            ;;
    esac
    if [ -n "$command_name" ] && [ ! -x "$perl_dir/$command_name" ] \
        && "$perl_bin" -e 'exit 0' >/dev/null 2>&1 \
        && "$perl_bin" -S "$command_name" --version >/dev/null 2>&1; then
        shift
        exec "$perl_bin" -S "$command_name" "$@"
    fi
    exec "$@"
fi

if [ -x "$perl_dir/carton" ]; then
    exec "$perl_bin" -I"$root/script/lib" -MGPForum::Tool::CartonHTTPS "$perl_dir/carton" "$@"
fi

if "$perl_bin" -S carton version >/dev/null 2>&1; then
    exec "$perl_bin" -I"$root/script/lib" -MGPForum::Tool::CartonHTTPS -S carton "$@"
fi

echo "gpforum-carton: Carton was not found for selected Perl $perl_bin." >&2
echo "Install it for this Perl with: $perl_bin -S cpanm -M https://cpan.metacpan.org/ Carton" >&2
exit 1