using System.Threading.Tasks;
using Newtonsoft.Json.Linq;
using Stopwatch = System.Diagnostics.Stopwatch;

namespace io.github.hatayama.uLoopMCP
{

    /// <summary>
    /// Class specialized in handling Unity API calls
    /// Supports new command-based structure
    /// 
    /// Design document reference: Packages/src/Editor/ARCHITECTURE.md
    /// 
    /// Related classes:
    /// - UnityCommandRegistry: Registry that manages all available Unity commands
    /// - CustomCommandManager: Provides access to the command registry singleton
    /// - JsonRpcProcessor: Receives JSON-RPC requests and delegates to this handler
    /// - IUnityCommand: Interface implemented by all command classes
    /// - AbstractUnityCommand: Base class for all Unity commands
    /// - BaseCommandResponse: Base response type for all commands
    /// - MainThreadSwitcher: Ensures command execution on Unity's main thread
    /// 
    /// Command execution flow:
    /// 1. JsonRpcProcessor receives request from TypeScript server
    /// 2. Delegates to ExecuteCommand method with command name and parameters
    /// 3. Looks up command in registry and executes asynchronously
    /// 4. Returns command response or error information
    /// </summary>
    public static class UnityApiHandler
    {
        /// <summary>
        /// Get command registry
        /// Use this registry when adding new commands
        /// </summary>
        public static UnityToolRegistry CommandRegistry => CustomToolManager.GetRegistry();

        /// <summary>
        /// Generic command execution method
        /// Uses new command-based structure
        /// </summary>
        /// <param name="commandName">Command name</param>
        /// <param name="paramsToken">Parameters</param>
        /// <returns>Execution result</returns>
        public static async Task<BaseToolResponse> ExecuteCommandAsync(string commandName, JToken paramsToken)
        {
            Stopwatch registryAcquireStopwatch = Stopwatch.StartNew();
            UnityToolRegistry registry = CustomToolManager.GetRegistry();
            registryAcquireStopwatch.Stop();

            Stopwatch registryExecuteStopwatch = Stopwatch.StartNew();
            BaseToolResponse response = await registry.ExecuteToolAsync(commandName, paramsToken);
            registryExecuteStopwatch.Stop();

            AppendExecuteDynamicCodeTimingsIfSupported(
                response,
                $"[Perf] RegistryAcquire: {registryAcquireStopwatch.Elapsed.TotalMilliseconds:F1}ms",
                $"[Perf] RegistryExecute: {registryExecuteStopwatch.Elapsed.TotalMilliseconds:F1}ms");
            return response;
        }

        private static void AppendExecuteDynamicCodeTimingsIfSupported(
            BaseToolResponse response,
            params string[] timingEntries)
        {
            if (response is not ExecuteDynamicCodeResponse executeDynamicCodeResponse)
            {
                return;
            }

            if (executeDynamicCodeResponse.Timings == null)
            {
                executeDynamicCodeResponse.Timings = new System.Collections.Generic.List<string>();
            }

            executeDynamicCodeResponse.Timings.AddRange(timingEntries);
        }
    }
}