#!/usr/bin/env bash
# server.sh — Non-blocking server management script for local-mcp.
#
# Usage:
#   ./server.sh start        # Start (no-op if already running)
#   ./server.sh stop         # Kill the running server
#   ./server.sh restart      # Stop then start
#   ./server.sh status       # Show PID, memory, and tail 20 log lines
#   ./server.sh logs [N]     # Tail last N lines of stdout log (default 40)
#   ./server.sh logs -f      # Follow log live (Ctrl-C to quit)

set -euo pipefail

# ── Paths ─────────────────────────────────────────────────────────────────

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PYTHON="$ROOT/.venv/bin/python"
ENTRY="$ROOT/main.py"
LOG_DIR="$ROOT/logs"
LOG_OUT="$LOG_DIR/server.log"
LOG_ERR="$LOG_DIR/server.err.log"
PID_FILE="$LOG_DIR/server.pid"
PORT=8000

# ── Colours ───────────────────────────────────────────────────────────────

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
CYAN='\033[0;36m'
GRAY='\033[0;90m'
NC='\033[0m' # No Colour

cecho() { printf "${1}${2}${NC}\n"; }

# ── Helpers ───────────────────────────────────────────────────────────────

ensure_log_dir() {
    mkdir -p "$LOG_DIR"
}

get_server_pid() {
    # Trust the PID file first; verify the process is alive
    if [[ -f "$PID_FILE" ]]; then
        local stored
        stored=$(cat "$PID_FILE" 2>/dev/null || true)
        if [[ "$stored" =~ ^[0-9]+$ ]]; then
            if kill -0 "$stored" 2>/dev/null; then
                echo "$stored"
                return
            fi
        fi
        rm -f "$PID_FILE"
    fi

    # Fallback: find a process listening on the port
    local pid
    pid=$(lsof -ti "TCP:$PORT" -s "TCP:LISTEN" 2>/dev/null | head -1 || true)
    if [[ -n "$pid" ]]; then
        echo "$pid"
        return
    fi

    echo ""
}

is_running() {
    local pid
    pid=$(get_server_pid)
    [[ -n "$pid" ]]
}

# ── Commands ──────────────────────────────────────────────────────────────

cmd_start() {
    local pid
    pid=$(get_server_pid)
    if [[ -n "$pid" ]]; then
        cecho "$GREEN" "Server already running  (PID $pid  http://localhost:$PORT)"
        return
    fi

    if [[ ! -x "$PYTHON" ]]; then
        cecho "$RED" "ERROR: Python venv not found at $PYTHON"
        cecho "$YELLOW" "Run: python -m venv .venv && .venv/bin/pip install -r requirements.txt"
        exit 1
    fi

    ensure_log_dir

    # Stamp the log files
    local stamp
    stamp="$(date '+%Y-%m-%d %H:%M:%S')  [server.sh] ---- starting ----"
    echo "$stamp" >> "$LOG_OUT"
    echo "$stamp" >> "$LOG_ERR"

    # Start detached: stdout → LOG_OUT, stderr → LOG_ERR
    nohup "$PYTHON" -u "$ENTRY" >> "$LOG_OUT" 2>> "$LOG_ERR" &
    local new_pid=$!
    echo "$new_pid" > "$PID_FILE"

    # Wait up to 6 s for the port to open
    local deadline=$(( $(date +%s) + 6 ))
    local ready=false
    while [[ $(date +%s) -lt $deadline ]]; do
        sleep 0.4
        if lsof -ti "TCP:$PORT" -s "TCP:LISTEN" &>/dev/null; then
            ready=true
            break
        fi
    done

    if $ready; then
        cecho "$GREEN" "Server started  (PID $new_pid  http://localhost:$PORT)"
    else
        cecho "$YELLOW" "Server process launched (PID $new_pid) but port $PORT not yet open."
        cecho "$YELLOW" "Check logs:  ./server.sh logs"
    fi
}

cmd_stop() {
    local pid
    pid=$(get_server_pid)
    if [[ -z "$pid" ]]; then
        cecho "$YELLOW" "Server is not running."
        return
    fi

    kill "$pid" 2>/dev/null || true
    rm -f "$PID_FILE"

    # Wait up to 4 s for the port to free
    local deadline=$(( $(date +%s) + 4 ))
    while [[ $(date +%s) -lt $deadline ]]; do
        sleep 0.3
        if ! lsof -ti "TCP:$PORT" -s "TCP:LISTEN" &>/dev/null; then
            break
        fi
    done

    cecho "$YELLOW" "Server stopped  (was PID $pid)"
}

cmd_restart() {
    cmd_stop
    sleep 0.5
    cmd_start
}

cmd_status() {
    local pid
    pid=$(get_server_pid)

    echo ""
    if [[ -n "$pid" ]]; then
        local mem="?"
        # Try to get RSS memory in MB (Linux: /proc, macOS: ps)
        if [[ -f "/proc/$pid/status" ]]; then
            local kb
            kb=$(grep -i VmRSS "/proc/$pid/status" 2>/dev/null | awk '{print $2}' || echo "0")
            mem="$(( kb / 1024 )) MB"
        elif command -v ps &>/dev/null; then
            local rss
            rss=$(ps -o rss= -p "$pid" 2>/dev/null | tr -d ' ' || echo "0")
            mem="$(( rss / 1024 )) MB"
        fi

        cecho "$GREEN" "  Status  : RUNNING"
        printf "  PID     : %s\n" "$pid"
        printf "  Memory  : %s\n" "$mem"
        printf "  URL     : http://localhost:%s\n" "$PORT"
        printf "  Logs    : %s\n" "$LOG_OUT"
        printf "            %s\n" "$LOG_ERR"
    else
        cecho "$RED" "  Status  : STOPPED"
    fi

    echo ""
    cecho "$GRAY" "--- Last 20 log lines (stdout) ---"
    if [[ -f "$LOG_OUT" ]]; then
        tail -n 20 "$LOG_OUT" | while IFS= read -r line; do
            cecho "$GRAY" "$line"
        done
    else
        cecho "$GRAY" "  (no log file yet)"
    fi

    if [[ -f "$LOG_ERR" ]]; then
        local err_lines
        err_lines=$(grep -E "ERROR|Exception|Traceback" "$LOG_ERR" 2>/dev/null | tail -5 || true)
        if [[ -n "$err_lines" ]]; then
            echo ""
            cecho "$RED" "--- Recent errors (stderr) ---"
            echo "$err_lines" | while IFS= read -r line; do
                cecho "$RED" "$line"
            done
        fi
    fi
    echo ""
}

cmd_logs() {
    local arg="${1:-}"
    ensure_log_dir

    if [[ "$arg" == "-f" ]]; then
        if [[ ! -f "$LOG_OUT" ]]; then
            cecho "$YELLOW" "No log file yet. Start the server first."
            return
        fi
        cecho "$CYAN" "Following $LOG_OUT  (Ctrl-C to stop)"
        tail -f -n 30 "$LOG_OUT"
    else
        local n=40
        if [[ "$arg" =~ ^[0-9]+$ ]]; then
            n="$arg"
        fi
        cecho "$CYAN" "--- stdout (last $n lines) ---"
        if [[ -f "$LOG_OUT" ]]; then
            tail -n "$n" "$LOG_OUT"
        else
            cecho "$GRAY" "  (empty)"
        fi
        echo ""
        cecho "$YELLOW" "--- stderr (last 20 lines) ---"
        if [[ -f "$LOG_ERR" ]]; then
            tail -n 20 "$LOG_ERR"
        else
            cecho "$GRAY" "  (empty)"
        fi
    fi
}

# ── Dispatch ──────────────────────────────────────────────────────────────

COMMAND="${1:-status}"
ARG="${2:-}"

case "$COMMAND" in
    start)   cmd_start ;;
    stop)    cmd_stop ;;
    restart) cmd_restart ;;
    status)  cmd_status ;;
    logs)    cmd_logs "$ARG" ;;
    *)
        echo "Usage: $0 {start|stop|restart|status|logs [N|-f]}"
        exit 1
        ;;
esac