#!/usr/bin/env bash
# Generic external-player JSON-Lines harness for Magic Civilization.
#
# Spawns Godot headless with the `player_api_main` scene and pipes
# stdin/stdout. Any client that speaks the JSON-Lines wire protocol
# documented in `src/game/engine/docs/PLAYER_API.md` can drive a game
# slot through this harness — Claude Code via the
# `tooling/claude-player-mcp/` adapter, an OpenSpiel/RL trainer via a
# Python `subprocess.Popen`, a smoke-test shell script, etc.
#
# Env vars (see PLAYER_API.md for the full schema):
#   CP_SEED, CP_PLAYERS, CP_PLAYER_SLOT, CP_MAP_SIZE, CP_MAP_TYPE,
#   CP_OMNISCIENT, CP_TIMEOUT_SEC, CP_LOG_FILE.
#
# `CP_PLAYER_SLOT` is the env-var name the harness has used since p2-67;
# it identifies the externally-controlled player slot — kept as-is for
# backward compatibility with existing clients. Despite the name it is
# not Claude-specific.
#
# Exit code 0 on clean shutdown (shutdown request received or stdin EOF).
# Non-zero on protocol error or harness crash.

set -uo pipefail

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

# Wrap godot in heavy-tests.slice on Linux so a fleet of player_api workers
# (typical RL training spawns 16-64) cannot starve sshd / interactive work.
# See scripts/run/heavy-prefix.sh and ~/.config/systemd/user/heavy-tests.slice.
# shellcheck source=run/heavy-prefix.sh
source "${SCRIPT_DIR}/run/heavy-prefix.sh"

# Defaults — adapter overrides via env.
: "${CP_SEED:=42}"
: "${CP_PLAYERS:=2}"
: "${CP_PLAYER_SLOT:=0}"
: "${CP_MAP_SIZE:=duel}"
: "${CP_MAP_TYPE:=continents}"
: "${CP_OMNISCIENT:=0}"
: "${CP_TIMEOUT_SEC:=60}"
: "${CP_LOG_FILE:=}"

# Pure-headless mode — no Wayland needed. JSON-Lines speaks to stdout.
#
# Linux uses flatpak Godot (matches the rest of the apricot pipeline).
# macOS uses the locally-installed `godot` binary (Homebrew); a parallel
# flatpak runtime just for this harness is silly when native Godot 4
# works directly. Env-var passthrough is automatic for the native path.
export CP_SEED CP_PLAYERS CP_PLAYER_SLOT CP_MAP_SIZE CP_MAP_TYPE \
    CP_OMNISCIENT CP_TIMEOUT_SEC CP_LOG_FILE CP_VICTORY_MODE \
    CP_PLAYER_CONTROLLERS CP_PLAYER_SLOTS \
    MC_DATA_ROOT MC_LEARNED_POLICY_PATH

case "$(uname -s)" in
    Darwin)
        GODOT_BIN="${GODOT_BIN:-godot}"
        if ! command -v "$GODOT_BIN" >/dev/null 2>&1; then
            echo "ERROR: no godot binary on PATH (set GODOT_BIN or 'brew install godot')." >&2
            exit 1
        fi
        exec "$GODOT_BIN" \
            --path "$PROJECT_DIR/src/game" \
            --headless \
            --rendering-method gl_compatibility \
            res://engine/scenes/headless/player_api_main.tscn
        ;;
    *)
        # Build the flatpak invocation once (DRY across the slice / no-slice
        # dispatch below).
        FLATPAK_CMD=(flatpak run --user
            --env=CP_SEED="$CP_SEED"
            --env=CP_PLAYERS="$CP_PLAYERS"
            --env=CP_PLAYER_SLOT="$CP_PLAYER_SLOT"
            --env=CP_MAP_SIZE="$CP_MAP_SIZE"
            --env=CP_MAP_TYPE="$CP_MAP_TYPE"
            --env=CP_OMNISCIENT="$CP_OMNISCIENT"
            --env=CP_TIMEOUT_SEC="$CP_TIMEOUT_SEC"
            --env=CP_LOG_FILE="$CP_LOG_FILE"
            --env=CP_VICTORY_MODE="${CP_VICTORY_MODE:-}"
            --env=CP_PLAYER_CONTROLLERS="${CP_PLAYER_CONTROLLERS:-}"
            --env=CP_PLAYER_SLOTS="${CP_PLAYER_SLOTS:-}"
            --env=MC_DATA_ROOT="${MC_DATA_ROOT:-}"
            --env=MC_LEARNED_POLICY_PATH="${MC_LEARNED_POLICY_PATH:-}"
            org.godotengine.Godot
            --path "$PROJECT_DIR/src/game"
            --headless
            --rendering-method gl_compatibility
            res://engine/scenes/headless/player_api_main.tscn)

        # CP_NO_SLICE=1 runs Godot as a DIRECT child (no per-process systemd
        # scope) so the spawning client reaps the whole process group on
        # shutdown via os.killpg. The default `heavy_exec` path wraps each
        # Godot in its own `systemd-run --scope` unit (commit 8cb522c3c,
        # 2026-05-26) which orphans the Godot when the client kills only the
        # script PID — leaking one Godot per episode reset (gen0 contention
        # death, 2026-06-09; duel-v4 predates the scope wrapping and so never
        # leaked). RL trainers that contain resources at their OWN unit level
        # (CPUWeight/MemoryHigh on the train service) set CP_NO_SLICE=1 to get
        # back the deterministically-reaped model. Interactive / batch callers
        # leave it unset to keep the slice's sshd-preemption guarantee.
        if [ "${CP_NO_SLICE:-0}" = "1" ]; then
            exec "${FLATPAK_CMD[@]}"
        fi
        heavy_exec "player-api-$$" "${FLATPAK_CMD[@]}"
        ;;
esac