#!/usr/bin/env bash

# panama-server against a throwaway HOME, a fixture catalog, and a stubbed
# systemctl -- the behaviors that protect a machine's live services:
#
#   * enable seeds .env from .env.example and REFUSES to start while a
#     CHANGE_ME placeholder survives -- a service brought up with the
#     placeholder as its database password runs, wrongly, forever
#   * a completed enable links exactly the tracked files (compose.yml and the
#     unit), reloads systemd, and enables the unit
#   * disable removes the unit and nothing else: the .env and data stay
#   * relink refreshes links for enabled services only, and names a service
#     whose definition changed since the machine last looked -- without
#     restarting anything

set -uo pipefail

repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
panama_server="$repo_dir/bin/panama-server"

findings=()
note() { findings+=("$1"); }

[[ -x "$panama_server" ]] || { printf 'panama-server contract: %s is not executable\n' "$panama_server" >&2; exit 1; }

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

home="$work/home"
catalog="$work/catalog"
stub_dir="$work/bin"
calls="$work/calls"
mkdir -p "$home" "$stub_dir" "$catalog/Example"
: >"$calls"

cat >"$catalog/Example/compose.yml" <<'YML'
services:
  example:
    image: docker.io/library/nginx:latest
    environment:
      DB_PASSWORD: ${DB_PASSWORD}
YML
cat >"$catalog/Example/.env.example" <<'ENV'
DB_PASSWORD=CHANGE_ME
ENV
cat >"$catalog/Example/podman-example.service" <<'UNIT'
[Unit]
Description=Podman Compose: Example
[Service]
Type=oneshot
WorkingDirectory=%h/Server/Example
ExecStart=/usr/bin/podman compose up -d
ExecStop=/usr/bin/podman compose down
RemainAfterExit=yes
[Install]
WantedBy=default.target
UNIT

# The stub records every invocation; is-active answers 'inactive' so nothing
# here depends on a real systemd.
cat >"$stub_dir/systemctl" <<STUB
#!/usr/bin/env bash
printf 'systemctl %s\n' "\$*" >>"$calls"
case "\$*" in
    *is-active*)  echo inactive; exit 3 ;;
    *is-enabled*) exit 1 ;;
esac
exit 0
STUB
cat >"$stub_dir/podman" <<STUB
#!/usr/bin/env bash
printf 'podman %s\n' "\$*" >>"$calls"
exit 0
STUB
chmod +x "$stub_dir/systemctl" "$stub_dir/podman"

run() {
    HOME="$home" XDG_CONFIG_HOME="$home/.config" XDG_STATE_HOME="$home/.local/state" \
    PANAMA_SERVER_DIR="$catalog" PANAMA_SERVER_TARGET="$home/Server" \
    PATH="$stub_dir:$PATH" "$panama_server" "$@"
}

unit_link="$home/.config/systemd/user/podman-example.service"

# ── enable stops on placeholders ─────────────────────────────────────────────

run enable Example >/dev/null 2>&1 \
    && note 'enable exited zero with CHANGE_ME still in the .env'

[[ -f "$home/Server/Example/.env" ]] \
    || note 'enable did not seed .env from .env.example'
[[ -L "$home/Server/Example/compose.yml" ]] \
    || note 'enable did not link compose.yml into ~/Server'
[[ -e "$unit_link" ]] \
    && note 'enable installed the unit despite the placeholder refusal'
grep -q 'systemctl .*enable' "$calls" \
    && note 'enable reached systemctl despite the placeholder refusal'

# ── a filled .env enables ────────────────────────────────────────────────────

printf 'DB_PASSWORD=s3cret\n' >"$home/Server/Example/.env"
: >"$calls"
run enable Example >/dev/null 2>&1 \
    || note 'enable failed with a completed .env'

[[ -L "$unit_link" ]] \
    || note 'enable did not link the unit into the systemd user directory'
grep -q 'systemctl --user daemon-reload' "$calls" \
    || note 'enable did not daemon-reload'
grep -q 'systemctl --user enable --now podman-example.service' "$calls" \
    || note 'enable did not enable --now the unit'
[[ "$(cat "$home/Server/Example/.env")" == "DB_PASSWORD=s3cret" ]] \
    || note 'enable rewrote an .env that already existed'

# ── relink names a changed definition, restarts nothing ──────────────────────

printf '    # a changed line\n' >>"$catalog/Example/compose.yml"
: >"$calls"
relink_out="$(run relink 2>&1)" || note 'relink failed'
grep -q 'Example' <<<"$relink_out" \
    || note 'relink did not name the service whose definition changed'
grep -q 'restart' "$calls" \
    && note 'relink restarted something; the restart is deliberately manual'

# A second relink with nothing new must not cry wolf.
relink_out="$(run relink 2>&1)" || note 'a repeat relink failed'
grep -q 'restart podman-example' <<<"$relink_out" \
    && note 'relink reports the same change twice'

# ── disable removes the unit and only the unit ───────────────────────────────

mkdir -p "$home/Server/Example/data"
printf 'precious\n' >"$home/Server/Example/data/keep"
: >"$calls"
run disable Example >/dev/null 2>&1 || note 'disable failed'

[[ -e "$unit_link" ]] \
    && note 'disable left the unit installed'
grep -q 'systemctl --user disable --now podman-example.service' "$calls" \
    || note 'disable did not stop the unit'
[[ -f "$home/Server/Example/.env" ]] \
    || note 'disable removed the .env'
[[ -f "$home/Server/Example/data/keep" ]] \
    || note 'disable removed data'

# ── an unknown service is a real answer ──────────────────────────────────────

run enable NoSuchThing >/dev/null 2>&1 \
    && note 'enabling an unknown service exited zero'

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

if (( ${#findings[@]} > 0 )); then
    mapfile -t findings < <(printf '%s\n' "${findings[@]}" | sort -u)
    printf 'panama-server contract: %d finding(s)\n' "${#findings[@]}" >&2
    printf '  - %s\n' "${findings[@]}" >&2
    exit 1
fi

printf 'panama-server contract: PASS\n'