#!/usr/bin/env bash
# perfsmoke.sh — assert PLAN.md §11 *Performance budgets* against the
# built AppImage. Run via `make perf` or as a CI step before publishing
# a release. The numbers below are the budgets; override via env vars
# when measuring on slow shared runners (with care — they exist for a
# reason).

set -euo pipefail

APPIMAGE="${1:-$(dirname "${BASH_SOURCE[0]}")/../build/Todo-x86_64.AppImage}"
APPIMAGE="$(readlink -f "$APPIMAGE")"
[ -x "$APPIMAGE" ] || { echo "AppImage not found: $APPIMAGE" >&2; exit 1; }

: "${PERF_COLD_START_MS:=2000}"
: "${PERF_IDLE_MEM_MB:=200}"
: "${PERF_BUNDLE_MB:=200}"
: "${PERF_BACKEND_PORT:=8765}"
: "${PERF_HEALTHZ_DEADLINE_MS:=5000}"

DATA_DIR="$(mktemp -d)"
trap 'cleanup' EXIT INT TERM

PID=""
cleanup() {
    trap - EXIT INT TERM
    if [ -n "$PID" ] && kill -0 "$PID" 2>/dev/null; then
        kill -TERM "$PID" 2>/dev/null || true
        for _ in 1 2 3 4 5 6 7 8 9 10; do
            kill -0 "$PID" 2>/dev/null || break
            sleep 0.2
        done
        kill -KILL "$PID" 2>/dev/null || true
    fi
    rm -rf "$DATA_DIR"
}

step() { echo "→ $*"; }
fail() { echo "✗ $*" >&2; exit 1; }

# ── Bundle size ──────────────────────────────────────────────────────
SIZE_BYTES=$(stat -c %s "$APPIMAGE")
SIZE_MB=$(( SIZE_BYTES / 1024 / 1024 ))
step "bundle size: ${SIZE_MB} MB (cap ${PERF_BUNDLE_MB} MB)"
[ "$SIZE_MB" -le "$PERF_BUNDLE_MB" ] || fail "bundle ${SIZE_MB} MB exceeds ${PERF_BUNDLE_MB} MB"

# ── Boot under Xvfb if no display is available ───────────────────────
RUNNER=()
if [ -z "${DISPLAY:-}" ]; then
    if command -v xvfb-run >/dev/null; then
        RUNNER=(xvfb-run -a)
    else
        # Fall back to Qt's offscreen platform (the AppImage build
        # bundles libqoffscreen.so via EXTRA_PLATFORM_PLUGINS).
        export QT_QPA_PLATFORM=offscreen
        echo "no DISPLAY / xvfb-run — falling back to QT_QPA_PLATFORM=offscreen" >&2
    fi
fi

# Use an isolated user data dir so the smoke doesn't trample dev state.
export XDG_DATA_HOME="$DATA_DIR/share"
export XDG_CACHE_HOME="$DATA_DIR/cache"
export APPIMAGE_EXTRACT_AND_RUN=1
mkdir -p "$XDG_DATA_HOME" "$XDG_CACHE_HOME"
# Force the port so the curl probe below can hit a known address —
# the supervisor would otherwise negotiate a free ephemeral port and
# we'd have to read it back from the sentinel file.
export BRIDGE_PORT="$PERF_BACKEND_PORT"

step "launching AppImage (${RUNNER[*]:-direct})"
START_NS=$(date +%s%N)
"${RUNNER[@]}" "$APPIMAGE" > "$DATA_DIR/run.log" 2>&1 &
PID=$!

# ── Cold start: time to first /healthz 200 ───────────────────────────
DEADLINE_NS=$(( START_NS + PERF_HEALTHZ_DEADLINE_MS * 1000000 ))
ELAPSED_MS=""
while true; do
    NOW_NS=$(date +%s%N)
    if [ "$NOW_NS" -ge "$DEADLINE_NS" ]; then
        sed 's/^/    /' "$DATA_DIR/run.log" >&2 || true
        fail "cold start exceeded ${PERF_HEALTHZ_DEADLINE_MS} ms deadline"
    fi
    if ! kill -0 "$PID" 2>/dev/null; then
        sed 's/^/    /' "$DATA_DIR/run.log" >&2 || true
        fail "host died during boot"
    fi
    if curl -fsS -m 1 "http://127.0.0.1:${PERF_BACKEND_PORT}/healthz" >/dev/null 2>&1; then
        END_NS=$(date +%s%N)
        ELAPSED_MS=$(( (END_NS - START_NS) / 1000000 ))
        break
    fi
    sleep 0.05
done
step "cold start: ${ELAPSED_MS} ms (budget ${PERF_COLD_START_MS} ms)"
[ "$ELAPSED_MS" -le "$PERF_COLD_START_MS" ] \
    || fail "cold start ${ELAPSED_MS} ms exceeds ${PERF_COLD_START_MS} ms"

# ── Idle memory: measure host + descendants after a 2 s settle ───────
sleep 2
TOTAL_KB=0
PGID=$(ps -o pgid= -p "$PID" | tr -d ' ')
while IFS= read -r p; do
    [ -r "/proc/$p/status" ] || continue
    R=$(awk '/^VmRSS:/ {print $2}' "/proc/$p/status" 2>/dev/null || echo 0)
    TOTAL_KB=$(( TOTAL_KB + R ))
done < <(pgrep -g "$PGID" 2>/dev/null)
TOTAL_MB=$(( TOTAL_KB / 1024 ))
step "idle memory (host + children): ${TOTAL_MB} MB (budget ${PERF_IDLE_MEM_MB} MB)"
[ "$TOTAL_MB" -le "$PERF_IDLE_MEM_MB" ] \
    || fail "idle memory ${TOTAL_MB} MB exceeds ${PERF_IDLE_MEM_MB} MB"

echo
echo "✓ perf smoke OK — bundle=${SIZE_MB}MB cold=${ELAPSED_MS}ms idle=${TOTAL_MB}MB"