#!/bin/bash
# Build daedalus-v4l2-dkms_<ver>_all.deb (kernel module via DKMS).
#
# Installs kernel/ source tree to /usr/src/daedalus_v4l2-${PKGVER}/
# plus a dkms.conf.  Postinst registers with DKMS (dkms add + build +
# install).  Prerm deregisters.  Result: the daedalus_v4l2 module
# auto-rebuilds against any installed kernel headers without users
# needing to remember to dkms-add it.
#
# Architecture: all.  The kernel module itself is per-kernel-version,
# but the SOURCE package is arch-independent.
#
# Sibling Arch package: ../../arch/daedalus-v4l2-dkms/PKGBUILD
# Sibling userspace package: ../daedalus-v4l2/build-deb.sh
set -euo pipefail

UPSTREAM_COMMIT=872eec505eb91b561892d02a0526749348ddc121
PKGVER=0.1.0+r45+g872eec5
PKGREL=1  # reset for new upstream pin (872eec5 — PROTO_MAX_PAYLOAD 64 KiB -> 1 MiB, closes #19); lock-step with daedalus-v4l2 0.1.0+r45+g872eec5 REQUIRED
MODULE_NAME=daedalus_v4l2

HERE=$(dirname "$(readlink -f "$0")")

# Reproducible build.  2026-05-18 23:00 UTC — Phase 8.13 close.
export SOURCE_DATE_EPOCH=1779231600

work=$(mktemp -d)
trap "rm -rf $work" EXIT

cd "$work"
curl --connect-timeout 10 --max-time 600 --retry 3 --retry-delay 5 -sSLfo daedalus-v4l2.tar.gz \
    "https://git.reauktion.de/reauktion/daedalus-v4l2/archive/${UPSTREAM_COMMIT}.tar.gz"
tar xzf daedalus-v4l2.tar.gz
SRCDIR=daedalus-v4l2

ROOT="$work/pkgroot"
SRCROOT="$ROOT/usr/src/${MODULE_NAME}-${PKGVER}"

mkdir -p "$SRCROOT/include" \
         "$ROOT/DEBIAN" \
         "$ROOT/usr/share/doc/daedalus-v4l2-dkms"

# Copy kernel/ source files to the DKMS source dir.
cp -r "$work/$SRCDIR/kernel/." "$SRCROOT/"

# Embed the shared protocol header inline (rather than referencing
# ../include/ which doesn't exist after DKMS extracts the tree).
# Patch the Makefile to find it at $SRCROOT/include/ instead.
install -m 644 "$work/$SRCDIR/include/daedalus_v4l2_proto.h" \
    "$SRCROOT/include/daedalus_v4l2_proto.h"
sed -i 's|-I\$(src)/\.\./include|-I$(src)/include|' "$SRCROOT/Makefile"

# Generate dkms.conf with the actual version substituted.
cat > "$SRCROOT/dkms.conf" <<EOF
PACKAGE_NAME="${MODULE_NAME}"
PACKAGE_VERSION="${PKGVER}"

BUILT_MODULE_NAME[0]="${MODULE_NAME}"
DEST_MODULE_LOCATION[0]="/updates"

MAKE[0]="make KERNELDIR=/lib/modules/\${kernelver}/build all"
CLEAN="make KERNELDIR=/lib/modules/\${kernelver}/build clean"

AUTOINSTALL="yes"
EOF

# Doc
install -m 644 "$work/$SRCDIR/README.md" \
    "$ROOT/usr/share/doc/daedalus-v4l2-dkms/README.md"
install -Dm644 "$HERE/debian/copyright" "$ROOT/usr/share/doc/daedalus-v4l2-dkms/copyright"
install -Dm644 "$HERE/debian/changelog" "$ROOT/usr/share/doc/daedalus-v4l2-dkms/changelog.Debian"
gzip -9 -n "$ROOT/usr/share/doc/daedalus-v4l2-dkms/changelog.Debian"

# DKMS post-install / pre-remove hooks.
cat > "$ROOT/DEBIAN/postinst" <<EOF
#!/bin/sh
set -e

NAME=${MODULE_NAME}
VERSION=${PKGVER}

# Yellow + bold ANSI for the warning so it stands out in apt's
# stream of "Setting up" lines.  Disable colour on non-TTY.
if [ -t 1 ]; then
    Y=\$(printf '\\033[1;33m'); R=\$(printf '\\033[0m')
else
    Y=''; R=''
fi

warn() {
    printf '%s==> daedalus-v4l2-dkms: %s%s\\n' "\$Y" "\$1" "\$R" >&2
}

if [ "\$1" = "configure" ]; then
    if ! command -v dkms >/dev/null 2>&1; then
        warn "dkms not installed; module \$NAME/\$VERSION not registered."
        warn "Install 'dkms' then run: dkms add \$NAME/\$VERSION && dkms autoinstall"
        exit 0
    fi

    dkms add "\$NAME/\$VERSION" 2>/dev/null || true

    # Enumerate every kernel whose headers are actually present
    # (/lib/modules/<kver>/build resolves to a directory).  We iterate
    # all of them — not just \$(uname -r) — so that installing this
    # package after a kernel update covers the newly-installed kernel
    # too, and so that a later kernel-headers install for a previously
    # uncovered version gets picked up on dpkg-reconfigure.  Without
    # this, autoinstall (which targets only the running kernel) leaves
    # /dev/daedalus-v4l2 absent after a kernel switch + reboot
    # (marfrit/marfrit-packages#64).
    kvers=''
    for d in /lib/modules/*/build; do
        [ -d "\$d" ] || continue
        k=\$(basename "\$(dirname "\$d")")
        kvers="\$kvers \$k"
    done

    if [ -z "\$kvers" ]; then
        warn ""
        warn "No kernels with headers found under /lib/modules/*/build."
        warn "Install kernel headers (e.g. linux-headers-rpi-2712 on Pi OS)"
        warn "then finish with:"
        warn "  sudo dkms autoinstall \$NAME/\$VERSION"
        exit 0
    fi

    failed=''
    for k in \$kvers; do
        dkms autoinstall -k "\$k" "\$NAME/\$VERSION" >/dev/null 2>&1 || true
        s=\$(dkms status -m "\$NAME" -v "\$VERSION" -k "\$k" 2>/dev/null || true)
        if ! printf '%s\\n' "\$s" | grep -q -E 'installed|loaded'; then
            failed="\$failed \$k"
        fi
    done

    if [ -n "\$failed" ]; then
        warn ""
        warn "DKMS build did NOT land for kernel(s):\$failed"
        warn ""
        warn "Most likely cause: kernel headers missing for those versions."
        warn "  Raspberry Pi OS / Pi 5:  apt install linux-headers-rpi-2712"
        warn "  Debian generic:          apt install linux-headers-<version>"
        warn ""
        warn "After installing headers, finish with:"
        for k in \$failed; do
            warn "  sudo dkms autoinstall -k \$k \$NAME/\$VERSION"
        done
        warn "  sudo modprobe daedalus_v4l2  (after booting that kernel)"
        warn ""
        warn "Until then daedalus_v4l2 will NOT be loadable on those kernels"
        warn "and the userspace daedalus-v4l2 daemon will have nothing to talk to."
    fi
fi

#DEBHELPER#
EOF
chmod 755 "$ROOT/DEBIAN/postinst"

cat > "$ROOT/DEBIAN/prerm" <<EOF
#!/bin/sh
set -e

NAME=${MODULE_NAME}
VERSION=${PKGVER}

if [ "\$1" = "remove" ] && command -v dkms >/dev/null 2>&1; then
    dkms remove "\$NAME/\$VERSION" --all || true
fi

#DEBHELPER#
EOF
chmod 755 "$ROOT/DEBIAN/prerm"

cat > "$ROOT/DEBIAN/control" <<EOF
Package: daedalus-v4l2-dkms
Version: ${PKGVER}-${PKGREL}
Section: kernel
Priority: optional
Architecture: all
Depends: dkms (>= 2.1.0.0)
Recommends: daedalus-v4l2, linux-headers-rpi-2712 | linux-headers-rpi | linux-headers-generic | linux-headers
Maintainer: Markus Fritsche <mfritsche@reauktion.de>
Homepage: https://git.reauktion.de/reauktion/daedalus-v4l2
Description: V4L2 stateless decoder shim kernel module (DKMS) — Pi 5 / CM5
 Out-of-tree V4L2 m2m kernel module for the daedalus-v4l2 stack on
 Raspberry Pi 5 / CM5.  Registers /dev/videoNN (V4L2 stateless m2m
 decoder), /dev/mediaNN (media controller with request API), and
 /dev/daedalus-v4l2 (chardev bridge to the userspace daemon).
 .
 The actual decode happens in the userspace daemon shipped by the
 daedalus-v4l2 package — this module is just the kernel-side V4L2
 plumbing.  Install both to actually serve VAAPI / V4L2 clients.
 .
 Built via DKMS against the running kernel's headers.
EOF

DEB_OUT="daedalus-v4l2-dkms_${PKGVER}-${PKGREL}_all.deb"
dpkg-deb --root-owner-group --build "$ROOT" "$HERE/$DEB_OUT"
echo "built: $HERE/$DEB_OUT"