#!/usr/bin/env bash
# SilverMetal Linux — inner build step.
#
# Runs *inside* the silvermetal-builder container, as the unprivileged
# `user` (uid 1000). build.sh's docker-run cmd chowns the workspace and
# sudoes here. The container's PID 1 is systemd (upstream's
# systemd-in-container pattern), so any `systemctl` calls derivative-
# maker makes — to start approx, daemon-reload, etc. — actually do
# what they're supposed to. derivative-maker uses sudo internally for
# its privileged ops.
#
# Why this is its own file:
#   The previous incarnation lived as a heredoc inside build.sh's docker
#   run command. Once we needed to drop privileges from root to user,
#   the nested-heredoc / nested-quoting situation became unreadable; a
#   plain script with normal quoting is far easier to maintain.
#
# Required env vars (set by build.sh and forwarded into the container):
#   REPO_ROOT             — absolute path to the SilverMetal repo root
#   BUILD_DIR             — where to drop the resulting *.iso and manifests
#   SOURCE_DATE_EPOCH     — reproducibility timestamp (forwarded to live-build)
#   SNAPSHOT_TIMESTAMP    — apt snapshot pin (forwarded to live-build)

set -euo pipefail

: "${REPO_ROOT:?REPO_ROOT must be set}"
: "${BUILD_DIR:?BUILD_DIR must be set}"

# Explicit user_name pin.
# derivative-maker/help-steps/variables (lines 80-93) computes user_name
# from $SUDO_USER as its first non-empty fallback. We enter this script
# via `sudo --preserve-env -u user --` from root, which makes sudo set
# SUDO_USER=root (the *calling* user). Variables.sh then picks
# user_name="root" and computes HOMEVAR=/home/root — which doesn't exist
# (root's home is /root). The first thing that breaks under that path
# is the aptgetopt config tee in 1100_sanity-tests:
#     tee: /home/root/derivative-binary/30_derivative-maker.conf:
#     No such file or directory
# Setting user_name explicitly satisfies the first-priority check in
# variables.sh and short-circuits the SUDO_USER fallback.
export user_name=user

# Create the binary output directory derivative-maker writes into.
# variables.sh sets binary_build_folder_dist=$HOMEVAR/derivative-binary
# (= /home/user/derivative-binary), and 1100_sanity-tests / later steps
# expect it to exist. Upstream's docker-start does the equivalent
# `mkdir --parents -- "${HOME}/derivative-binary"`; we replicate that
# here so we don't depend on upstream's wrapper.
mkdir -p "${HOME}/derivative-binary"

# Import Debian developer keys into the user's GPG keyring.
# 2100_create-debian-packages calls `dm-reprepro-wrapper includedsc`
# on Debian source packages it pulls in (e.g. virtualbox_*.dsc, even
# for --target iso — see 2100_create-debian-packages line 114), and
# reprepro verifies each .dsc's signature against the user's keyring.
# Without this, every dsc with a Debian-uploader signature fails:
#   Could not check validity of signature with '<fingerprint>' in
#   '...virtualbox_7.2.8-dfsg-1.dsc' as public key missing!
#   There have been errors!
# debian-keyring (~40 MB, snapshot-pinned) provides the developer
# keys; importing it once at the start of the build seeds the keyring
# reprepro will consult.
if [ -d /usr/share/keyrings ]; then
    for f in /usr/share/keyrings/debian-keyring.gpg \
             /usr/share/keyrings/debian-maintainers.gpg \
             /usr/share/keyrings/debian-nonupload.gpg; do
        [ -f "$f" ] || continue
        gpg --quiet --no-tty --import "$f" 2>/dev/null || true
    done
fi

# shellcheck disable=SC1091
source "${REPO_ROOT}/linux/build/config/silvermetal-base.conf"

cd "${REPO_ROOT}/linux/build/derivative-maker"

# CLI grammar comes from derivative-maker/help-steps/parse-cmd. The
# valid options are a closed set; passing anything else (including
# --build, --dist, or --config) trips the "unknown option" guard at
# parse-cmd line 725. Spelling matters too: upstream uses --flavor
# (American), not --flavour. --freedom is mandatory for amd64/i386.
# Dist is implicit from --flavor (kicksecure-cli => trixie), and
# the silvermetal-base.conf is sourced into the env above rather than
# passed as a flag because derivative-maker has no --config option.
#
# --allow-untagged true / --allow-uncommitted true: the pinned upstream
# tag (18.1.7.4-developers-only — name says it all) deliberately ships
# with some submodules at intermediate / merge commits. sq-git still
# verifies every signature in the chain — these flags only relax the
# additional "must be at a release tag" check. Appropriate for a
# downstream consumer pinned to a developer tag.
./derivative-maker \
    --flavor            "${DERIVATIVE_FLAVOUR}" \
    --target            "${DERIVATIVE_BUILD_TARGET}" \
    --arch              "${DERIVATIVE_TARGET_ARCH}" \
    --freedom           "${DERIVATIVE_FREEDOM}" \
    --allow-untagged    true \
    --allow-uncommitted true

# derivative-maker writes its outputs into ${HOME}/derivative-binary
# (per help-steps/variables: binary_build_folder_dist=$HOMEVAR/derivative-binary),
# *not* into the source tree. Collect from there into BUILD_DIR.
# Exact upstream output paths can shift between tags — keep this tolerant.
find "${HOME}/derivative-binary" -maxdepth 6 -type f -name "*.iso" -print0 \
    | xargs -0 -I{} cp -av "{}" "${BUILD_DIR}/"

# Manifest of file metadata that lives inside the ISO. Useful when
# diagnosing reproducibility regressions without re-extracting.
find "${HOME}/derivative-binary" -maxdepth 6 -type f -name "*.manifest" -print0 \
    | xargs -0 -I{} cp -av "{}" "${BUILD_DIR}/" 2>/dev/null || true