using System;
using System.Linq;
using UnityEditor;
using UnityEngine;
using LLM.Editor.Data;
using System.Reflection;
using LLM.Editor.Commands;
using System.Collections.Generic;

namespace LLM.Editor.Core
{
    /// <summary>
    /// Responsible for finding and executing commands from the session queue.
    /// </summary>
    [InitializeOnLoad]
    public static class CommandExecutor
    {
        private static List<CommandData> _commandQueue;
        private static CommandContext _currentContext;

        public static Action OnQueueUpdated;

        static CommandExecutor()
        {
            // This will run when the editor loads, including after a recompile.
            EditorApplication.delayCall += Initialize;
        }

        private static void Initialize()
        {
            Debug.Log("[CommandExecutor] Initializing...");
            if (SessionManager.HasActiveSession())
            {
                _commandQueue = SessionManager.LoadCommandQueue();
                if (!_commandQueue.Any())
                {
                    SessionManager.EndSession();
                    return;
                }
                Debug.Log($"[CommandExecutor] Resuming session with {_commandQueue.Count} commands in queue.");
                _currentContext = new CommandContext();
                OnQueueUpdated?.Invoke();
            }
            else
            {
                _commandQueue = new List<CommandData>();
            }
        }

        public static void SetQueue(List<CommandData> commands)
        {
            _commandQueue = commands;
            _currentContext = new CommandContext();
            SessionManager.SaveCommandQueue(_commandQueue);
            OnQueueUpdated?.Invoke();
        }

        private static void ClearQueue()
        {
            _commandQueue.Clear();
            SessionManager.SaveCommandQueue(_commandQueue);
            OnQueueUpdated?.Invoke();
        }

        public static bool HasPendingCommands() => _commandQueue != null && _commandQueue.Any();
        
        public static CommandData GetNextCommand() => HasPendingCommands() ? _commandQueue.First() : null;

        public static void ExecuteNextCommand()
        {
            if (!HasPendingCommands())
            {
                Debug.LogWarning("[CommandExecutor] No commands to execute.");
                return;
            }

            var commandData = _commandQueue.First();
            _commandQueue.RemoveAt(0);

            try
            {
                var commandInstance = CreateCommandInstance(commandData);
                if (commandInstance != null)
                {
                    Debug.Log($"[CommandExecutor] Executing: {commandData.commandName}");
                    var outcome = commandInstance.Execute(_currentContext);
                    var message = outcome == CommandOutcome.Success ? commandData.messages?.onSuccess : commandData.messages?.onError;
                    new DisplayMessageCommand(new DisplayMessageParams { message = message, outcome = outcome }).Execute(_currentContext);
                    
                    if (outcome == CommandOutcome.Error)
                    {
                        Debug.LogError($"[CommandExecutor] Command '{commandData.commandName}' failed. Clearing remaining command queue.");
                        ClearQueue();
                    }
                }
                else
                {
                    Debug.LogError($"[CommandExecutor] Could not create instance for command: {commandData.commandName}");
                }
            }
            catch(Exception e)
            {
                Debug.LogError($"[CommandExecutor] Failed to execute command '{commandData.commandName}'. Error: {e.Message}");
                ClearQueue();
            }
            
            // Save the modified queue
            SessionManager.SaveCommandQueue(_commandQueue);
            OnQueueUpdated?.Invoke();
        }

        private static ICommand CreateCommandInstance(CommandData data)
        {
            // Use reflection to find the command class in the Commands namespace
            // This makes the system extensible without needing a giant switch statement.
            var commandClassName = $"{data.commandName}Command";
            var type = Assembly.GetExecutingAssembly().GetTypes()
                .FirstOrDefault(t => t.Namespace == "LLM.Editor.Commands" && t.Name == commandClassName);

            if (type != null)
            {
                // Assumes commands have a constructor that takes a single string (the JSON parameters)
                return (ICommand)Activator.CreateInstance(type, data.jsonData);
            }

            Debug.LogError($"[CommandExecutor] Command type '{commandClassName}' not found.");
            return null;
        }
    }
}