#!/bin/bash
# MCP Server Manager - Start, stop, and manage MCP servers

set -euo pipefail

MCP_DIR="${HOME}/.claude/mcp-servers"
REGISTRY="${MCP_DIR}/registry.json"
PID_DIR="${MCP_DIR}/pids"
LOG_DIR="${MCP_DIR}/logs"

mkdir -p "$PID_DIR" "$LOG_DIR"

log() {
    echo "[$(date -u +"%Y-%m-%d %H:%M:%S UTC")] [mcp-manager] $*" | tee -a "${LOG_DIR}/manager.log"
}

start_server() {
    local server_name="$1"
    local server_config
    
    # Get server config from registry
    server_config=$(jq -r ".servers.${server_name}" "$REGISTRY" 2>/dev/null)
    
    if [[ "$server_config" == "null" ]]; then
        log "ERROR: Server '${server_name}' not found in registry"
        return 1
    fi
    
    local enabled=$(echo "$server_config" | jq -r '.enabled // false')
    if [[ "$enabled" != "true" ]]; then
        log "Server '${server_name}' is disabled"
        return 0
    fi
    
    local pid_file="${PID_DIR}/${server_name}.pid"
    
    if [[ -f "$pid_file" ]]; then
        local pid=$(cat "$pid_file")
        if kill -0 "$pid" 2>/dev/null; then
            log "Server '${server_name}' already running (PID: ${pid})"
            return 0
        fi
    fi
    
    local command=$(echo "$server_config" | jq -r '.command')
    local args=$(echo "$server_config" | jq -r '.args[]' | sed 's/^/"/;s/$/" ' | tr '\n' ' ')
    
    log "Starting server '${server_name}': ${command} ${args}"
    
    eval "nohup ${command} ${args} > ${LOG_DIR}/${server_name}.log 2>&1 &"
    local pid=$!
    echo "$pid" > "$pid_file"
    sleep 1
    
    if kill -0 "$pid" 2>/dev/null; then
        log "Server '${server_name}' started (PID: ${pid})"
        return 0
    else
        log "ERROR: Failed to start server '${server_name}'"
        return 1
    fi
}

stop_server() {
    local server_name="$1"
    local pid_file="${PID_DIR}/${server_name}.pid"
    
    if [[ ! -f "$pid_file" ]]; then
        log "Server '${server_name}' not running"
        return 0
    fi
    
    local pid=$(cat "$pid_file")
    log "Stopping server '${server_name}' (PID: ${pid})..."
    kill "$pid" 2>/dev/null || true
    rm -f "$pid_file"
    log "Server '${server_name}' stopped"
}

start_all() {
    local servers=$(jq -r '.servers | keys[]' "$REGISTRY")
    for server in $servers; do
        start_server "$server" || true
    done
}

stop_all() {
    local pid_files
    pid_files=$(ls "$PID_DIR"/*.pid 2>/dev/null || true)
    
    for pid_file in $pid_files; do
        local server_name=$(basename "$pid_file" .pid)
        stop_server "$server_name"
    done
}

status() {
    echo "=== MCP Server Status ==="
    echo ""
    
    local servers=$(jq -r '.servers | keys[]' "$REGISTRY")
    for server in $servers; do
        local enabled=$(jq -r ".servers.${server}.enabled // false" "$REGISTRY")
        local pid_file="${PID_DIR}/${server}.pid"
        local status="stopped"
        
        if [[ -f "$pid_file" ]]; then
            local pid=$(cat "$pid_file")
            if kill -0 "$pid" 2>/dev/null; then
                status="running (PID: ${pid})"
            fi
        fi
        
        local icon="🔴"
        if [[ "$status" == "stopped" ]]; then
            [[ "$enabled" == "true" ]] && icon="⚪" || icon="⏸️"
        else
            icon="🟢"
        fi
        
        local name=$(jq -r ".servers.${server}.name" "$REGISTRY")
        local category=$(jq -r ".servers.${server}.category // \"other\"" "$REGISTRY")
        
        printf "%s %-20s [%-10s] %s\n" "$icon" "$server" "$category" "$status"
    done
}

main() {
    local command="${1:-status}"
    
    case "$command" in
        start)
            if [[ -n "${2:-}" ]]; then
                start_server "$2"
            else
                start_all
            fi
            ;;
        stop)
            if [[ -n "${2:-}" ]]; then
                stop_server "$2"
            else
                stop_all
            fi
            ;;
        restart)
            stop_all
            sleep 2
            start_all
            ;;
        status)
            status
            ;;
        list)
            jq -r '.servers | keys[]' "$REGISTRY"
            ;;
        *)
            echo "Usage: $0 {start|stop|restart|status|list} [server_name]"
            exit 1
            ;;
    esac
}

main "$@"