#!/usr/bin/env bash
# godot-docker.sh — run Godot Linux headless inside a freeze-proof Docker container.
#
# Why: `godot --headless --import` and similar commands kernel-panicked plum
# twice and freeze apricot when run cold. Containers on macOS run inside a
# Linux VM with its own kernel, fully isolated from macOS — no chance of
# tripping the GPU/video kexts that caused the panics. Cgroup limits below
# also keep the VM from starving itself.
#
# See: ~/.claude/plans/godot-container-runner.md
#
# Usage:
#   scripts/godot-docker.sh [args...]                 # passed straight to godot
#   scripts/godot-docker.sh --version                 # smoke test
#   scripts/godot-docker.sh --headless --import       # warm the import cache
#   scripts/godot-docker.sh --headless --script res://addons/gut/gut_cmdln.gd -gexit -gtest=res://engine/tests/unit/test_city_buildable_helper.gd

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
DOCKERFILE="$REPO_ROOT/tools/docker/Dockerfile.godot"

IMAGE="mc-godot:4.6.2"
VOLUME="mc-godot-cache"
WORKDIR_IN_CONTAINER="/work/src/game"

# Cgroup hard caps so the container can't starve the host VM.
# Defaults sized for Docker Desktop with ≥7 GiB allocated.
CPUS="${MC_GODOT_CPUS:-4}"
MEMORY="${MC_GODOT_MEMORY:-6g}"
PIDS_LIMIT="${MC_GODOT_PIDS:-256}"

ensure_image() {
    if docker image inspect "$IMAGE" >/dev/null 2>&1; then
        return 0
    fi
    echo "[godot-docker] image $IMAGE not found — building..." >&2
    docker build \
        --tag "$IMAGE" \
        --file "$DOCKERFILE" \
        "$REPO_ROOT/tools/docker"
}

ensure_volume() {
    if docker volume inspect "$VOLUME" >/dev/null 2>&1; then
        return 0
    fi
    echo "[godot-docker] creating named volume $VOLUME for warm import cache" >&2
    docker volume create "$VOLUME" >/dev/null
}

ensure_docker_running() {
    if ! docker info >/dev/null 2>&1; then
        echo "ERROR: Docker daemon not reachable. Start Docker Desktop first." >&2
        exit 2
    fi
}

main() {
    ensure_docker_running
    ensure_image
    ensure_volume

    # Force a TTY only when stdout is a terminal; CI invocations stay non-interactive.
    local tty_flag=""
    if [[ -t 1 ]]; then
        tty_flag="-t"
    fi

    docker run \
        --rm \
        -i $tty_flag \
        --cpus "$CPUS" \
        --memory "$MEMORY" \
        --memory-swap "$MEMORY" \
        --pids-limit "$PIDS_LIMIT" \
        --volume "$REPO_ROOT:/work" \
        --volume "$VOLUME:/work/src/game/.godot" \
        --workdir "$WORKDIR_IN_CONTAINER" \
        "$IMAGE" \
        "$@"
}

main "$@"