#!/bin/bash
# SPDX-License-Identifier: GPL-3.0-or-later
# Run pacman-level maint remedy scenarios in a systemd-nspawn container
# Author: Craig Jennings <craigmartinjennings@gmail.com>
# License: GNU GPLv3
#
# The fast lane for the maint scenario suite: pure pacman-level cases (the
# "packages" scenario group — cache trims, orphan removal, pacnew deletion)
# don't need a booted machine, so they run in seconds against a pacstrap'd
# rootfs instead of minutes against the VM. Everything else (systemd, logs)
# needs pid 1 and journald — that stays in run-maint-scenarios.sh.
#
# The scenario files are shared with the VM runner and see the same helpers
# (mexec/mmaint/mfix/massert_metric); only the transport differs — the
# helper trio is deliberately duplicated between the two runners rather
# than abstracted over ssh-vs-nspawn.
#
# The rootfs is cached at $NSPAWN_ROOT and rebuilt with --fresh. Building
# and running need root (pacstrap, systemd-nspawn) via sudo.
#
# Usage: run-maint-nspawn.sh [--list] [--fresh]
#   --list   print the validated scenario plan and exit (no root needed)
#   --fresh  delete the cached rootfs and pacstrap a new one
# Env: MAINT_SCENARIO_DIR   scenario dir (default: maint-scenarios/)
#      MAINT_SRC            maint package source tree
#                           (default: ~/.dotfiles/maint/src/maint)
#      NSPAWN_ROOT          rootfs dir (default: /var/tmp/archsetup-maint-nspawn)

set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"

source "$SCRIPT_DIR/lib/logging.sh"

SCENARIO_DIR="${MAINT_SCENARIO_DIR:-$SCRIPT_DIR/maint-scenarios}"
MAINT_SRC="${MAINT_SRC:-$HOME/.dotfiles/maint/src/maint}"
THRESHOLDS_TOML="$PROJECT_ROOT/configs/maintenance-thresholds.toml"
NSPAWN_ROOT="${NSPAWN_ROOT:-/var/tmp/archsetup-maint-nspawn}"
NSPAWN_GROUP="packages"

LIST_ONLY=false
FRESH=false

usage() {
    echo "Usage: $0 [--list] [--fresh]"
    echo "  --list   print the validated scenario plan and exit"
    echo "  --fresh  rebuild the cached rootfs from scratch"
    echo "Env: MAINT_SCENARIO_DIR, MAINT_SRC, NSPAWN_ROOT"
}

while [[ $# -gt 0 ]]; do
    case $1 in
        --list)  LIST_ONLY=true; shift ;;
        --fresh) FRESH=true; shift ;;
        *) usage; exit 1 ;;
    esac
done

# ─── Plan: the pacman-level subset ───────────────────────────────────
# Same contract validation as the VM runner; the selection rule is the
# group name — "packages" is pacman-level by construction.

S_FILES=() S_NAMES=() S_DESCS=()

_scenario_var() {  # <file> <varname>
    bash -c 'set -eu; source "$1" || exit 9; eval "printf %s \"\${$2-}\""' \
        _probe "$1" "$2" 2>/dev/null
}

_validate_scenario() {  # <file> -> fatal on contract violation
    local f="$1" base probe_err
    base=$(basename "$f")
    probe_err=$(bash -c 'set -eu; source "$1"
        : "${SCENARIO_DESC:?missing SCENARIO_DESC}"
        : "${SCENARIO_GROUP:?missing SCENARIO_GROUP}"
        : "${SCENARIO_PROFILES:?missing SCENARIO_PROFILES}"
        for p in $SCENARIO_PROFILES; do
            case "$p" in btrfs|zfs|any) ;; *)
                echo "bad profile token: $p" >&2; exit 1 ;;
            esac
        done
        declare -f scenario_break scenario_fix scenario_assert >/dev/null \
            || { echo "missing scenario_break/fix/assert" >&2; exit 1; }' \
        _probe "$f" 2>&1 >/dev/null) \
        || fatal "scenario contract violation in $base: $probe_err"
}

build_plan() {
    [ -d "$SCENARIO_DIR" ] || fatal "scenario dir not found: $SCENARIO_DIR"
    local f base
    for f in "$SCENARIO_DIR"/*.sh; do
        [ -e "$f" ] || break
        _validate_scenario "$f"
        [ "$(_scenario_var "$f" SCENARIO_GROUP)" = "$NSPAWN_GROUP" ] || continue
        base=$(basename "$f" .sh)
        S_FILES+=("$f")
        S_NAMES+=("${base#[0-9][0-9]-}")
        S_DESCS+=("$(_scenario_var "$f" SCENARIO_DESC)")
    done
    [ ${#S_FILES[@]} -gt 0 ] \
        || fatal "no '$NSPAWN_GROUP'-group scenarios in $SCENARIO_DIR"
}

print_plan() {
    local i
    echo "maint nspawn scenario plan (group: $NSPAWN_GROUP)"
    for i in "${!S_FILES[@]}"; do
        echo "  ${S_NAMES[$i]} — ${S_DESCS[$i]}"
    done
}

if [ "$LIST_ONLY" = "true" ]; then
    LOGFILE=/dev/null
    build_plan
    print_plan
    exit 0
fi

# ─── Run ─────────────────────────────────────────────────────────────

TIMESTAMP=$(date +'%Y%m%d-%H%M%S')
RESULTS_DIR="$PROJECT_ROOT/test-results/maint-nspawn-$TIMESTAMP"
mkdir -p "$RESULTS_DIR"
LOGFILE="$RESULTS_DIR/scenarios.log"
init_logging "$LOGFILE"

build_plan

section "Maint Remedy Scenarios (nspawn): $TIMESTAMP"
info "Rootfs: $NSPAWN_ROOT"
info "Maint source: $MAINT_SRC"
print_plan | tee -a "$LOGFILE"

command -v pacstrap >/dev/null \
    || fatal "pacstrap not found — pacman -S arch-install-scripts"
command -v systemd-nspawn >/dev/null || fatal "systemd-nspawn not found"
[ -d "$MAINT_SRC" ] || fatal "maint source tree not found: $MAINT_SRC"
[ -f "$THRESHOLDS_TOML" ] || fatal "thresholds TOML not found: $THRESHOLDS_TOML"
sudo -n true 2>/dev/null || fatal "needs passwordless sudo (pacstrap/nspawn)"

# ─── Target helpers (available to scenario scripts) ──────────────────

mexec() {  # run a command in the container as root
    sudo systemd-nspawn -q -D "$NSPAWN_ROOT" --pipe \
        /bin/bash -c "$*" 2>> "$LOGFILE"
}

mmaint() {
    mexec "cd /root/maint-pkg && MAINT_SUDO= PYTHONPATH=/root/maint-pkg python3 -m maint $*"
}

mfix() {
    local id="$1"; shift || true
    step "maint fix $id ${*:+$* }--dry-run"
    mmaint fix "$id" "$@" --dry-run >> "$LOGFILE" 2>&1 \
        || { error "dry-run failed: maint fix $id $*"; return 1; }
    step "maint fix $id $*"
    mmaint fix "$id" "$@" 2>&1 | tee -a "$LOGFILE"
    return "${PIPESTATUS[0]}"
}

massert_metric() {  # <metric-id> <expected-severity>
    local mid="$1" want="$2" got
    got=$(mmaint status --json | python3 -c "
import json, sys
env = json.load(sys.stdin)
ms = [m for m in env['metrics'] if m['id'] == '$mid']
print(ms[0]['severity'] if ms else 'MISSING')
")
    if [ "$got" = "$want" ]; then
        success "metric $mid is $want"
        return 0
    fi
    error "metric $mid: expected $want, got $got"
    return 1
}

# ─── Rootfs ──────────────────────────────────────────────────────────

if [ "$FRESH" = "true" ] && [ -d "$NSPAWN_ROOT" ]; then
    step "Removing cached rootfs (--fresh)"
    sudo rm -rf "$NSPAWN_ROOT"
fi

if [ ! -x "$NSPAWN_ROOT/usr/bin/python3" ]; then
    section "Building rootfs (pacstrap)"
    sudo mkdir -p "$NSPAWN_ROOT"
    # shellcheck disable=SC2024  # the log is user-owned by design
    sudo pacstrap -c -K "$NSPAWN_ROOT" base python pacman-contrib expac \
        >> "$LOGFILE" 2>&1 || fatal "pacstrap failed (see $LOGFILE)"
    success "Rootfs built"
else
    info "Reusing cached rootfs (--fresh to rebuild)"
fi

section "Installing maint tree + thresholds into the container"
sudo rm -rf "$NSPAWN_ROOT/root/maint-pkg"
sudo mkdir -p "$NSPAWN_ROOT/root/maint-pkg" "$NSPAWN_ROOT/root/.config/archsetup"
sudo cp -r "$MAINT_SRC" "$NSPAWN_ROOT/root/maint-pkg/"
sudo find "$NSPAWN_ROOT/root/maint-pkg" -name '__pycache__' -type d \
    -exec rm -rf {} + 2>/dev/null || true
sudo cp "$THRESHOLDS_TOML" \
    "$NSPAWN_ROOT/root/.config/archsetup/maintenance-thresholds.toml"

step "Smoke: maint status --json runs in the container"
mmaint status --json > "$RESULTS_DIR/bootstrap-status.json" \
    || fatal "maint status failed in the container"
success "Container ready"

# ─── Execution ───────────────────────────────────────────────────────

PASS=() FAIL=()

run_scenario() {  # <index>
    local i="$1" name="${S_NAMES[$1]}" f="${S_FILES[$1]}"
    section "Scenario: $name — ${S_DESCS[$1]}"
    # shellcheck disable=SC1090
    source "$f"
    local ok=true
    step "break"
    if ! scenario_break; then
        error "$name: break step failed"
        ok=false
    fi
    if [ "$ok" = "true" ]; then
        step "fix"
        if ! scenario_fix; then
            error "$name: fix step failed"
            ok=false
        fi
    fi
    if [ "$ok" = "true" ]; then
        step "assert"
        if ! scenario_assert; then
            error "$name: post-state assertion failed"
            ok=false
        fi
    fi
    unset -f scenario_break scenario_fix scenario_assert
    unset SCENARIO_DESC SCENARIO_GROUP SCENARIO_PROFILES
    if [ "$ok" = "true" ]; then
        success "PASS: $name"
        PASS+=("$name")
    else
        error "FAIL: $name"
        FAIL+=("$name")
    fi
}

for i in "${!S_FILES[@]}"; do
    run_scenario "$i"
done

# ─── Report ──────────────────────────────────────────────────────────

section "Results"
for n in "${PASS[@]}"; do success "PASS $n"; done
for n in "${FAIL[@]}"; do error "FAIL $n"; done
info "Log: $LOGFILE"
info "Rootfs kept for reuse: $NSPAWN_ROOT (--fresh to rebuild)"

if [ ${#FAIL[@]} -gt 0 ]; then
    error "${#FAIL[@]} scenario(s) failed, ${#PASS[@]} passed"
    exit 1
fi
success "All ${#PASS[@]} scenarios passed"
exit 0