#!/usr/bin/env bash
# run-services.sh — Manage the mc-magic-civilization background services.
#
# Usage:
#   tools/run-services.sh services:up     — start mcts-server (idempotent)
#   tools/run-services.sh services:down   — stop mcts-server
#   tools/run-services.sh services:status — print service status
#
# Environment:
#   MCTS_SOCKET_PATH   — Unix socket path (default: /tmp/mc-mcts.sock)
#   MCTS_SERVER_BIN    — Path to mcts-server binary (default: search PATH, then
#                        src/simulator/target/release/mcts-server)
#   MC_RUN_DIR         — Directory for PID and log files
#                        (default: <repo-root>/.local/run)

set -euo pipefail

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

MCTS_SOCKET_PATH="${MCTS_SOCKET_PATH:-/tmp/mc-mcts.sock}"
MC_RUN_DIR="${MC_RUN_DIR:-$PROJECT_DIR/.local/run}"
PID_FILE="$MC_RUN_DIR/mcts-server.pid"
LOG_FILE="$MC_RUN_DIR/mcts-server.log"

_find_mcts_server() {
    # 1. Caller-supplied path.
    if [ -n "${MCTS_SERVER_BIN:-}" ] && [ -x "$MCTS_SERVER_BIN" ]; then
        echo "$MCTS_SERVER_BIN"
        return 0
    fi
    # 2. On PATH.
    if command -v mcts-server >/dev/null 2>&1; then
        command -v mcts-server
        return 0
    fi
    # 3. Release build next to simulator workspace.
    local release_bin="$PROJECT_DIR/src/simulator/target/release/mcts-server"
    if [ -x "$release_bin" ]; then
        echo "$release_bin"
        return 0
    fi
    return 1
}

_is_running() {
    [ -f "$PID_FILE" ] || return 1
    local pid
    pid="$(cat "$PID_FILE")"
    kill -0 "$pid" 2>/dev/null
}

_cmd_up() {
    if _is_running; then
        local pid
        pid="$(cat "$PID_FILE")"
        echo "mcts-server already running (pid $pid)"
        return 0
    fi

    local bin
    if ! bin="$(_find_mcts_server)"; then
        echo "ERROR: mcts-server binary not found." >&2
        echo "  Build it with: cd src/simulator && cargo build --release -p mc-mcts-service" >&2
        echo "  Or set MCTS_SERVER_BIN=/path/to/mcts-server" >&2
        exit 1
    fi

    mkdir -p "$MC_RUN_DIR"
    echo "Starting mcts-server ($bin) → socket $MCTS_SOCKET_PATH"
    nohup "$bin" "$MCTS_SOCKET_PATH" >> "$LOG_FILE" 2>&1 &
    local pid=$!
    echo "$pid" > "$PID_FILE"
    echo "mcts-server started (pid $pid, log: $LOG_FILE)"
}

_cmd_down() {
    if ! _is_running; then
        echo "mcts-server not running"
        rm -f "$PID_FILE"
        return 0
    fi
    local pid
    pid="$(cat "$PID_FILE")"
    kill -TERM "$pid" 2>/dev/null || true
    rm -f "$PID_FILE"
    echo "mcts-server stopped (pid $pid)"
}

_cmd_status() {
    if _is_running; then
        local pid
        pid="$(cat "$PID_FILE")"
        echo "mcts-server running (pid $pid, socket: $MCTS_SOCKET_PATH)"
    else
        echo "mcts-server not running"
        rm -f "$PID_FILE" 2>/dev/null || true
    fi
}

CMD="${1:-}"
case "$CMD" in
    services:up)     _cmd_up ;;
    services:down)   _cmd_down ;;
    services:status) _cmd_status ;;
    *)
        echo "Usage: $0 {services:up|services:down|services:status}" >&2
        exit 1
        ;;
esac