#!/usr/bin/env bash
# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (C) 2026 Bryan Joshua Pedini

# apt.sh - APT e2e fixture for skeptical-updater (Debian/Ubuntu containers).
# Copy of discovery/apt/fixture.sh; the only changes are the SU_FIXTURE_STRICT_DEP knob
# (su-dummy-a 2.0 depends on plain su-dummy-b by default, like the pacman and rpm
# fixtures, so excluding su-dummy-b does not keep su-dummy-a back), SU_FIXTURE_ORPHAN and
# SU_FIXTURE_B_AUTO.
#
# Builds a local *flat* APT repository at /srv/su-repo containing dummy packages
# and installs the old (1.0) versions, so that after `apt-get update` the package
# manager reports deterministic upgrades:
#
#   su-dummy-a  1.0 -> 2.0   (Depends: su-dummy-b, ships a conffile;
#                            SU_FIXTURE_STRICT_DEP=1: 2.0 Depends: su-dummy-b (>= 2.0))
#   su-dummy-b  1.0 -> 2.0   (dependency of su-dummy-a)
#   su-dummy-c  1.0 -> 2.0   (standalone)
#
# Optional extras (SU_FIXTURE_EXTRA=1) for "kept back" / removal / virtual-package
# scenarios:
#   su-dummy-d  1.0 -> 2.0   2.0 adds a NEW dependency (su-dummy-newdep, not installed)
#                            => plain `upgrade` keeps it back, `--with-new-pkgs upgrade`
#                               and `dist-upgrade` install it
#   su-dummy-e  1.0 -> 2.0   2.0 Conflicts: su-dummy-f (installed, no 2.0 exists)
#                            => only `dist-upgrade` can do it (removes su-dummy-f) - except with apt 3.x
#                               solver3 (ubuntu:latest = 26.04) which refuses to remove the manually
#                               installed su-dummy-f and keeps su-dummy-e back even for dist-upgrade
#   su-dummy-f  1.0          installed, never upgradable
#   su-dummy-w  1.0 -> 2.0   Depends: su-virtual | su-dummy-alt   (virtual + alternative)
#   su-dummy-v  1.0          Provides: su-virtual
#   (+ su-dummy-newdep 1.0 and su-dummy-alt 1.0: only in the repo, never pre-installed)
#
# Environment knobs (all optional):
#   SU_REPO_DIR=/srv/su-repo         where the repo is created (wiped first; must match /srv/su-*, /tmp/su-*, /var/tmp/su-*)
#   SU_OLD_DIR=/srv/su-old           where the 1.0 .debs are kept (NOT in the repo)
#   SU_FIXTURE_INDEXER=shell         shell | scanpackages | ftparchive
#                                    shell        = no extra tools needed (dpkg-deb -f + sha256sum)
#                                    scanpackages = dpkg-scanpackages (installs dpkg-dev if missing)
#                                    ftparchive   = apt-ftparchive    (installs apt-utils if missing)
#   SU_FIXTURE_OFFLINE=1             disable the distro's real sources (hermetic: no network at all)
#   SU_FIXTURE_EXTRA=1               add the extra scenario packages listed above
#   SU_FIXTURE_BAD=1                 add su-dummy-bad: 1.0 installed, 2.0 has a postinst that fails
#                                    (apt-get upgrade then exits 100) - for error-path tests
#   SU_FIXTURE_STRICT_DEP=1          su-dummy-a 2.0 depends on "su-dummy-b (>= 2.0)" (as in discovery/apt):
#                                    holding su-dummy-b then also keeps su-dummy-a back
#   SU_FIXTURE_ORPHAN=1              also install su-dummy-orphan 1.0 marked automatically installed with
#                                    nothing depending on it (a pre-existing autoremove candidate)
#   SU_FIXTURE_B_AUTO=1              mark su-dummy-b automatically installed (a dependency of su-dummy-a,
#                                    like the pacman fixture's --asdeps)
#
# Must run as root inside a throwaway container, e.g.:
#   docker run --rm -i -v "$PWD/discovery/apt:/d:ro" debian:12 bash /d/fixture.sh
set -euo pipefail
export LC_ALL=C DEBIAN_FRONTEND=noninteractive

REPO_DIR=${SU_REPO_DIR:-/srv/su-repo}
OLD_DIR=${SU_OLD_DIR:-/srv/su-old}
INDEXER=${SU_FIXTURE_INDEXER:-shell}
OFFLINE=${SU_FIXTURE_OFFLINE:-0}
EXTRA=${SU_FIXTURE_EXTRA:-0}
BAD=${SU_FIXTURE_BAD:-0}
STRICT_DEP=${SU_FIXTURE_STRICT_DEP:-0}
ORPHAN=${SU_FIXTURE_ORPHAN:-0}
B_AUTO=${SU_FIXTURE_B_AUTO:-0}
SOURCES_FILE=/etc/apt/sources.list.d/su-repo.list
T0=$(date +%s)

log() { printf '[fixture] %s\n' "$*"; }
die() { printf '[fixture] ERROR: %s\n' "$*" >&2; exit 1; }

[ "$(id -u)" -eq 0 ] || die "must run as root"
command -v apt-get  >/dev/null || die "apt-get not found (not a Debian/Ubuntu image?)"
command -v dpkg-deb >/dev/null || die "dpkg-deb not found"
case $INDEXER in shell|scanpackages|ftparchive) ;; *) die "bad SU_FIXTURE_INDEXER=$INDEXER" ;; esac
# the directories are wiped with rm -rf: only accept obviously fixture-owned locations
for d in "$REPO_DIR" "$OLD_DIR"; do
    case $d in /srv/su-*|/tmp/su-*|/var/tmp/su-*) ;; *) die "refusing to wipe '$d' (must match /srv/su-*, /tmp/su-* or /var/tmp/su-*)" ;; esac
done

# ---------------------------------------------------------------- build debs
# mkdeb NAME VERSION OUTDIR [extra control line]...
# If $MKDEB_POSTINST is set it becomes the body of the package's postinst script.
mkdeb() {
    local name=$1 ver=$2 out=$3 root line
    shift 3
    root=$(mktemp -d)
    mkdir -p "$root/DEBIAN" "$root/usr/share/su-dummy" "$root/etc/su-dummy"
    {
        printf 'Package: %s\nVersion: %s\nSection: misc\nPriority: optional\n' "$name" "$ver"
        printf 'Architecture: all\nMaintainer: Skeptical Updater Fixture <su-fixture@example.invalid>\n'
        for line in "$@"; do printf '%s\n' "$line"; done
        printf 'Description: dummy package %s for skeptical-updater tests\n' "$name"
        printf ' This package only exists to exercise the package manager.\n'
        printf ' .\n'
        printf ' It ships one data file and one conffile (version %s).\n' "$ver"
    } > "$root/DEBIAN/control"
    echo "$ver" > "$root/usr/share/su-dummy/$name"
    echo "version=$ver" > "$root/etc/su-dummy/$name.conf"
    echo "/etc/su-dummy/$name.conf" > "$root/DEBIAN/conffiles"
    if [ -n "${MKDEB_POSTINST:-}" ]; then
        printf '#!/bin/sh\n%s\n' "$MKDEB_POSTINST" > "$root/DEBIAN/postinst"
        chmod 755 "$root/DEBIAN/postinst"
    fi
    mkdir -p "$out"
    # -Zgzip: readable by every dpkg in the supported images; --root-owner-group: files owned by root
    dpkg-deb --root-owner-group -Zgzip --build "$root" "$out/${name}_${ver}_all.deb" >/dev/null
    rm -rf "$root"
}

rm -rf "$REPO_DIR" "$OLD_DIR"
mkdir -p "$REPO_DIR" "$OLD_DIR"

# old versions (installed straight away with dpkg, NOT published in the repo)
mkdeb su-dummy-a 1.0 "$OLD_DIR" 'Depends: su-dummy-b'
mkdeb su-dummy-b 1.0 "$OLD_DIR"
mkdeb su-dummy-c 1.0 "$OLD_DIR"
# new versions (published in the repo)
if [ "$STRICT_DEP" = 1 ]; then
    mkdeb su-dummy-a 2.0 "$REPO_DIR" 'Depends: su-dummy-b (>= 2.0)'
else
    mkdeb su-dummy-a 2.0 "$REPO_DIR" 'Depends: su-dummy-b'
fi
mkdeb su-dummy-b 2.0 "$REPO_DIR"
mkdeb su-dummy-c 2.0 "$REPO_DIR"

if [ "$ORPHAN" = 1 ]; then
    mkdeb su-dummy-orphan 1.0 "$OLD_DIR"                       # installed, never upgradable
fi

if [ "$EXTRA" = 1 ]; then
    mkdeb su-dummy-d 1.0 "$OLD_DIR"
    mkdeb su-dummy-d 2.0 "$REPO_DIR" 'Depends: su-dummy-newdep'
    mkdeb su-dummy-newdep 1.0 "$REPO_DIR"                      # only in the repo, never pre-installed
    mkdeb su-dummy-e 1.0 "$OLD_DIR"
    mkdeb su-dummy-e 2.0 "$REPO_DIR" 'Conflicts: su-dummy-f'
    mkdeb su-dummy-f 1.0 "$OLD_DIR"
    mkdeb su-dummy-v 1.0 "$OLD_DIR" 'Provides: su-virtual'
    mkdeb su-dummy-alt 1.0 "$REPO_DIR"                         # alternative target, not installed
    mkdeb su-dummy-w 1.0 "$OLD_DIR" 'Depends: su-virtual | su-dummy-alt'
    mkdeb su-dummy-w 2.0 "$REPO_DIR" 'Depends: su-virtual | su-dummy-alt'
fi

if [ "$BAD" = 1 ]; then
    mkdeb su-dummy-bad 1.0 "$OLD_DIR"
    # shellcheck disable=SC2016 # the postinst body is expanded by the package's /bin/sh, not here
    MKDEB_POSTINST='[ "$1" = configure ] && { echo "su-dummy-bad: postinst failing on purpose" >&2; exit 1; }; exit 0' \
        mkdeb su-dummy-bad 2.0 "$REPO_DIR"
fi

# ---------------------------------------------------------------- real sources
if [ "$OFFLINE" = 1 ]; then
    mkdir -p /srv/su-disabled-sources
    for f in /etc/apt/sources.list /etc/apt/sources.list.d/*.sources /etc/apt/sources.list.d/*.list; do
        [ -e "$f" ] || continue
        case $f in "$SOURCES_FILE") continue ;; esac
        mv "$f" "/srv/su-disabled-sources/$(basename "$f")"
    done
    log "OFFLINE: real sources moved to /srv/su-disabled-sources"
fi

# ---------------------------------------------------------------- indexing
install_tool() { # install_tool PACKAGE : needs the real mirrors
    [ "$OFFLINE" = 1 ] && die "SU_FIXTURE_INDEXER=$INDEXER needs network to install $1; use shell with OFFLINE"
    log "installing $1 (needs network)"
    apt-get update -qq >/dev/null
    apt-get install -y -qq --no-install-recommends "$1" >/dev/null
}

index_shell() {
    local f
    : > Packages
    for f in ./*.deb; do
        f=${f#./}
        dpkg-deb -f "$f" >> Packages
        printf 'Filename: ./%s\nSize: %s\nMD5sum: %s\nSHA256: %s\n\n' \
            "$f" "$(stat -c %s "$f")" "$(md5sum < "$f" | cut -d' ' -f1)" "$(sha256sum < "$f" | cut -d' ' -f1)" >> Packages
    done
    {
        printf 'Origin: su-fixture\nLabel: su-fixture\nSuite: su-repo\nCodename: su-repo\n'
        printf 'Date: %s\n' "$(date -u '+%a, %d %b %Y %H:%M:%S UTC')"
        printf 'SHA256:\n %s %s Packages\n' "$(sha256sum < Packages | cut -d' ' -f1)" "$(stat -c %s Packages)"
    } > Release
}

index_scanpackages() {
    command -v dpkg-scanpackages >/dev/null || install_tool dpkg-dev
    dpkg-scanpackages --multiversion . /dev/null > Packages 2>/dev/null
    # dpkg-scanpackages does not write a Release file; make a minimal one
    {
        printf 'Origin: su-fixture\nLabel: su-fixture\nSuite: su-repo\nCodename: su-repo\n'
        printf 'Date: %s\n' "$(date -u '+%a, %d %b %Y %H:%M:%S UTC')"
        printf 'SHA256:\n %s %s Packages\n' "$(sha256sum < Packages | cut -d' ' -f1)" "$(stat -c %s Packages)"
    } > Release
}

index_ftparchive() {
    command -v apt-ftparchive >/dev/null || install_tool apt-utils
    apt-ftparchive packages . > Packages
    apt-ftparchive \
        -o APT::FTPArchive::Release::Origin=su-fixture \
        -o APT::FTPArchive::Release::Label=su-fixture \
        -o APT::FTPArchive::Release::Suite=su-repo \
        -o APT::FTPArchive::Release::Codename=su-repo \
        release . > Release
}

( cd "$REPO_DIR" && "index_$INDEXER" )
log "repo $REPO_DIR indexed with '$INDEXER': $(grep -c '^Package:' "$REPO_DIR/Packages") packages"

echo "deb [trusted=yes] file:$REPO_DIR ./" > "$SOURCES_FILE"

# ---------------------------------------------------------------- install old versions
# --force-confnew + </dev/null: never block on a conffile prompt if the fixture is re-run in a dirty container
dpkg --force-confnew -i "$OLD_DIR"/*.deb >/dev/null </dev/null
if [ "$ORPHAN" = 1 ]; then
    apt-mark auto su-dummy-orphan >/dev/null
fi
if [ "$B_AUTO" = 1 ]; then
    apt-mark auto su-dummy-b >/dev/null
fi
log "installed (old): $(dpkg-query -W -f '${db:Status-Abbrev} ${Package}=${Version}\n' 'su-dummy-*' 2>/dev/null | awk '$1 == "ii" {printf "%s ", $2}')"

# ---------------------------------------------------------------- refresh + verify
# drop stale lists of our own repo first: apt compares mtimes of file: indexes with 1s resolution,
# so a repo regenerated within the same second would otherwise be seen as "unchanged"
rm -f /var/lib/apt/lists/"$(printf '%s' "$REPO_DIR" | tr / _)"_*
apt-get update -qq >/dev/null

fail=0
upg=$(apt list --upgradable 2>/dev/null | awk -F/ '/^su-dummy-/{print $1}' | sort | tr '\n' ' ')
for p in su-dummy-a su-dummy-b su-dummy-c; do
    case " $upg" in *" $p "*) ;; *) log "MISSING from upgradable: $p"; fail=1 ;; esac
done
sim=$(apt-get -s --with-new-pkgs upgrade 2>/dev/null | awk '/^Inst su-dummy-(a|b|c) /{n++} END{print n+0}')
[ "$sim" -ge 3 ] || { log "simulated upgrade only covers $sim of 3 core packages"; fail=1; }
[ "$fail" -eq 0 ] || die "fixture verification failed"

log "upgradable dummy packages: $upg"
if [ "$ORPHAN" = 1 ]; then
    apt-get -s autoremove 2>/dev/null | grep -q '^Remv su-dummy-orphan ' || die "su-dummy-orphan is not an autoremove candidate"
    log "pre-existing orphan (autoremove candidate): su-dummy-orphan"
fi
real=$(apt list --upgradable 2>/dev/null | awk -F/ 'NR>1 && $1 !~ /^su-dummy-/{print $1}' | tr '\n' ' ')
if [ -n "$real" ]; then
    log "NOTE: real-world upgradable packages present in this base image: $real"
else
    log "NOTE: no real-world upgradable packages in this base image right now"
fi
# shellcheck source=/dev/null
log "OK in $(( $(date +%s) - T0 ))s (image: $(. /etc/os-release; echo "$PRETTY_NAME"))"