using System.IO;
using UnityEngine;
using static UnityEngine.Debug;

public class FlyCamera : MonoBehaviour
{
    [Header("Movement Settings")]
    public float moveSpeed = 10f;
    public float fastMoveSpeed = 50f;
    public float mouseSensitivity = 2f;
    
    [Header("FOV Settings")]
    public float minFOV = 10f;
    public float maxFOV = 120f;
    public float fovScrollSpeed = 10f;
    
    [Header("Screenshot Settings")]
    public KeyCode screenshotKey = KeyCode.F2;

    [Header("Rough Mode")]
    [Tooltip("러프(느슨) 이동 모드. 켜면 이동/회전 입력을 즉각 반영하지 않고 둔하게 지연시켜 느슨하게 따라갑니다.")]
    public bool roughMode = false;
    [Tooltip("러프 모드 위치 추적 속도. 낮을수록 더 둔하고 묵직하게 따라갑니다.")]
    public float roughMoveSmoothing = 3f;
    [Tooltip("러프 모드 회전 추적 속도. 낮을수록 더 둔하고 묵직하게 따라갑니다.")]
    public float roughLookSmoothing = 5f;

    private Camera _cam;
    private float _rotationX;
    private float _rotationY;
    private Vector3 _targetPosition;
    private bool _isFlyCamEnabled = true;
    private float _screenshotFlashTime;
    private bool _showScreenshotFlash;
    
    private void Start()
    {
        _cam = GetComponent<Camera>();
        if (_cam == null)
        {
            _cam = Camera.main;
        }

        SyncRoughState();

        Cursor.lockState = CursorLockMode.Locked;
        Cursor.visible = false;
        
        CreateScreenshotDirectory();
    }
    
    private void Update()
    {
        if (!_isFlyCamEnabled) return;
        
        HandleMouseLook();
        HandleMovement();
        HandleFOVControl();
        HandleScreenshot();
        HandleScreenshotFlash();
        
        if (Input.GetKeyDown(KeyCode.Escape))
        {
            ToggleCursor();
        }
        
        if (Cursor.lockState != CursorLockMode.Locked && Input.GetMouseButtonDown(0))
        {
            Cursor.lockState = CursorLockMode.Locked;
            Cursor.visible = false;
        }
    }
    
    private void HandleMouseLook()
    {
        if (Cursor.lockState != CursorLockMode.Locked) return;
        
        float mouseX = Input.GetAxis("Mouse X") * mouseSensitivity;
        float mouseY = Input.GetAxis("Mouse Y") * mouseSensitivity;

        _rotationX -= mouseY;
        _rotationX = Mathf.Clamp(_rotationX, -90f, 90f);
        _rotationY += mouseX;

        Quaternion targetRotation = Quaternion.Euler(_rotationX, _rotationY, 0f);

        // 러프 모드면 회전을 둔하게 지연시켜 따라가고, 아니면 즉각 반영
        transform.rotation = roughMode
            ? Quaternion.Slerp(transform.rotation, targetRotation, roughLookSmoothing * Time.deltaTime)
            : targetRotation;
    }
    
    private void HandleMovement()
    {
        Vector3 movement = Vector3.zero;
        float currentSpeed = Input.GetKey(KeyCode.LeftShift) ? fastMoveSpeed : moveSpeed;
        
        if (Input.GetKey(KeyCode.W))
            movement += transform.forward;
        if (Input.GetKey(KeyCode.S))
            movement -= transform.forward;
        if (Input.GetKey(KeyCode.A))
            movement -= transform.right;
        if (Input.GetKey(KeyCode.D))
            movement += transform.right;
        if (Input.GetKey(KeyCode.Q))
            movement -= transform.up;
        if (Input.GetKey(KeyCode.E))
            movement += transform.up;

        Vector3 delta = movement * (currentSpeed * Time.deltaTime);

        if (roughMode)
        {
            // 입력은 목표 위치에 누적하고, 실제 위치는 둔하게 지연시켜 따라감
            _targetPosition += delta;
            transform.position = Vector3.Lerp(transform.position, _targetPosition, roughMoveSmoothing * Time.deltaTime);
        }
        else
        {
            transform.position += delta;
            _targetPosition = transform.position;
        }
    }
    
    private void HandleFOVControl()
    {
        float scroll = Input.GetAxis("Mouse ScrollWheel");
        if (scroll != 0f)
        {
            _cam.fieldOfView = Mathf.Clamp(_cam.fieldOfView - scroll * fovScrollSpeed, minFOV, maxFOV);
        }
    }
    
    private void HandleScreenshot()
    {
        if (Input.GetKeyDown(screenshotKey))
        {
            TakeScreenshot();
        }
    }
    
    private void CreateScreenshotDirectory()
    {
        string screenshotDir = Path.Combine(Application.dataPath, "..", "Screenshots");
        if (!Directory.Exists(screenshotDir))
        {
            Directory.CreateDirectory(screenshotDir);
        }
    }
    
    private void TakeScreenshot()
    {
        StartCoroutine(CaptureScreenshotDelayed());
    }
    
    // ReSharper disable Unity.PerformanceAnalysis
    private System.Collections.IEnumerator CaptureScreenshotDelayed()
    {
        yield return new WaitForEndOfFrame();
        
        string timestamp = System.DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss");
        string filename = $"Screenshot_{timestamp}.png";
        string screenshotDir = Path.Combine(Application.dataPath, "..", "Screenshots");
        string fullPath = Path.Combine(screenshotDir, filename);
        
        ScreenCapture.CaptureScreenshot(fullPath);
        Log($"Screenshot saved: {fullPath}");
        
        _showScreenshotFlash = true;
        _screenshotFlashTime = 0.2f;
    }
    
    private void HandleScreenshotFlash()
    {
        if (_showScreenshotFlash)
        {
            _screenshotFlashTime -= Time.deltaTime;
            if (_screenshotFlashTime <= 0f)
            {
                _showScreenshotFlash = false;
            }
        }
    }
    
    private void OnGUI()
    {
        if (_showScreenshotFlash)
        {
            GUI.color = new Color(1f, 1f, 1f, 0.8f);
            GUI.DrawTexture(new Rect(0, 0, Screen.width, Screen.height), Texture2D.whiteTexture);
            
            GUIStyle style = new GUIStyle();
            style.fontSize = 36;
            style.normal.textColor = Color.black;
            style.alignment = TextAnchor.MiddleCenter;
            
            GUI.Label(new Rect(0, Screen.height / 2 - 50, Screen.width, 100), "Screenshot Captured!", style);
        }
    }
    
    private void ToggleCursor()
    {
        if (Cursor.lockState == CursorLockMode.Locked)
        {
            Cursor.lockState = CursorLockMode.None;
            Cursor.visible = true;
        }
        else
        {
            Cursor.lockState = CursorLockMode.Locked;
            Cursor.visible = false;
        }
    }
    
    public void EnableFlyCamera(bool enable)
    {
        _isFlyCamEnabled = enable;
        if (enable)
        {
            // 비활성화 동안 외부에서 카메라가 이동했을 수 있으므로 러프 모드 점프 방지를 위해 동기화
            SyncRoughState();
            Cursor.lockState = CursorLockMode.Locked;
            Cursor.visible = false;
        }
        else
        {
            Cursor.lockState = CursorLockMode.None;
            Cursor.visible = true;
        }
    }

    /// <summary>
    /// 러프 모드의 목표 위치/회전 누적값을 현재 트랜스폼에 맞춰 동기화합니다. (점프 방지)
    /// </summary>
    private void SyncRoughState()
    {
        // eulerAngles.x는 0~360 범위라 위를 볼 때(예: 350°) 클램프에 걸려 튀므로 -180~180으로 정규화
        float pitch = transform.eulerAngles.x;
        if (pitch > 180f) pitch -= 360f;
        _rotationX = Mathf.Clamp(pitch, -90f, 90f);
        _rotationY = transform.eulerAngles.y;
        _targetPosition = transform.position;
    }

    /// <summary>러프(느슨) 이동 모드 활성 여부.</summary>
    public bool IsRoughMode => roughMode;

    /// <summary>러프 이동 모드를 토글합니다.</summary>
    public void ToggleRoughMode()
    {
        SetRoughMode(!roughMode);
    }

    /// <summary>러프 이동 모드를 명시적으로 켜거나 끕니다.</summary>
    public void SetRoughMode(bool enable)
    {
        if (roughMode == enable) return;
        // 토글 시점에 목표값을 현재 위치로 맞춰 전환 직후 튐 방지
        SyncRoughState();
        roughMode = enable;
    }
}