using UnityEngine;
using Unity.Cinemachine;
#if ENABLE_INPUT_SYSTEM
using UnityEngine.InputSystem;
#endif

/// <summary>
/// Feeds mouse input into a <see cref="CinemachineOrbitalFollow"/> so the camera
/// orbits the follow target. Mouse movement drives yaw/pitch, the wheel zooms.
/// The orbit behaviour depends on <see cref="LookMode"/> (usually set by the
/// GameModeManager). Attach to the camera rig (the CinemachineOrbitalFollow).
/// </summary>
[RequireComponent(typeof(CinemachineOrbitalFollow))]
[DisallowMultipleComponent]
public class ThirdPersonOrbitInput : MonoBehaviour
{
    public enum OrbitLookMode
    {
        /// <summary>Rotate with every mouse move; cursor locked/hidden.</summary>
        AlwaysActive,
        /// <summary>Rotate only while the right mouse button is held; cursor free otherwise.</summary>
        HoldRightMouseButton,
        /// <summary>No rotation; cursor free.</summary>
        Disabled
    }

    [Header("Look Mode")]
    [Tooltip("How the camera orbit is driven (usually set by GameModeManager).")]
    [SerializeField] private OrbitLookMode lookMode = OrbitLookMode.AlwaysActive;

    [Header("Rotation")]
    [Tooltip("Horizontal look sensitivity (degrees of yaw per pixel).")]
    public float horizontalSensitivity = 0.2f;

    [Tooltip("Vertical look sensitivity (degrees of pitch per pixel).")]
    public float verticalSensitivity = 0.15f;

    [Tooltip("Invert vertical look (mouse up tilts the camera down).")]
    public bool invertY = false;

    [Tooltip("Eases orbit rotation so quick mouse moves ramp in/out (higher = snappier, 0 = raw/instant).")]
    public float rotationSmoothing = 20f;

    [Header("Zoom")]
    [Tooltip("Mouse wheel zooms the camera in and out (changes orbit radius).")]
    public bool enableZoom = true;

    [Tooltip("World units the orbit radius changes per mouse wheel notch.")]
    public float zoomSpeed = 0.5f;

    [Tooltip("Eases the orbit radius toward the zoom target (higher = snappier, 0 = instant).")]
    public float zoomSmoothing = 10f;

    [Tooltip("Closest orbit radius (zoom in).")]
    public float minRadius = 1.5f;

    [Tooltip("Farthest orbit radius (zoom out).")]
    public float maxRadius = 8f;

    [Header("Cursor")]
    [Tooltip("Lock and hide the cursor while the camera is actively rotating.")]
    public bool manageCursor = true;

    CinemachineOrbitalFollow _orbit;
    Vector2 _smoothedLook;     // low-pass-filtered look delta (deg/frame) for eased rotation
    float _targetRadius;       // zoom radius the actual radius eases toward
    bool _zoomInit;            // _targetRadius seeded from the live radius yet?

    /// <summary>Current orbit mode. Setting it also refreshes the cursor state.</summary>
    public OrbitLookMode LookMode
    {
        get => lookMode;
        set { lookMode = value; ApplyCursorState(); }
    }

    /// <summary>
    /// While true, mouse-look is paused (orbit frozen) without changing the cursor
    /// state. The player controller sets this while dragging the wall-climb offset so
    /// the same mouse motion is not also spent orbiting the camera.
    /// </summary>
    public bool LookSuppressed { get; set; }

    void Awake()
    {
        _orbit = GetComponent<CinemachineOrbitalFollow>();
        if (!_orbit)
            Debug.LogError("[ThirdPersonOrbitInput] No CinemachineOrbitalFollow found on this GameObject.", this);
    }

    void OnEnable() => ApplyCursorState();

    void OnDisable() => SetCursorLocked(false);

    void Update()
    {
        if (!_orbit)
            return;

        bool modeWantsLook = ShouldRotate();

        if (manageCursor)
            SetCursorLocked(modeWantsLook);

        if (modeWantsLook && !LookSuppressed)
        {
            Vector2 delta = ReadMouseDelta() * MouseSensitivity.Multiplier;
            Vector2 raw = new Vector2(
                delta.x * horizontalSensitivity,
                delta.y * verticalSensitivity * (invertY ? 1f : -1f));

            // Ease the per-frame look toward the raw delta so fast flicks ramp in/out
            // instead of snapping; steady motion still converges to full sensitivity.
            Vector2 applied = rotationSmoothing > 0f
                ? (_smoothedLook = Vector2.Lerp(_smoothedLook, raw, 1f - Mathf.Exp(-rotationSmoothing * Time.deltaTime)))
                : raw;

            if (applied.sqrMagnitude > 0f)
            {
                ApplyAxisDelta(ref _orbit.HorizontalAxis, applied.x);
                ApplyAxisDelta(ref _orbit.VerticalAxis, applied.y);
            }
        }
        else
        {
            _smoothedLook = Vector2.zero;
        }

        if (enableZoom)
        {
            if (!_zoomInit)
            {
                _targetRadius = _orbit.Radius;
                _zoomInit = true;
            }

            // Shift+wheel is reserved for the paint brush resize (MeshPainter), so the orbit camera
            // ignores the wheel while Shift is held - otherwise it would zoom and resize at once.
            float scroll = ShiftHeld() ? 0f : ReadScroll();
            if (!Mathf.Approximately(scroll, 0f))
            {
                // One wheel notch = one zoom step (sign only), independent of the
                // platform's raw wheel magnitude. Scrolling up zooms in.
                _targetRadius = Mathf.Clamp(_targetRadius - Mathf.Sign(scroll) * zoomSpeed, minRadius, maxRadius);
            }

            // Ease the actual radius toward the target (frame-rate independent).
            _orbit.Radius = zoomSmoothing > 0f
                ? Mathf.Lerp(_orbit.Radius, _targetRadius, 1f - Mathf.Exp(-zoomSmoothing * Time.deltaTime))
                : _targetRadius;
        }
    }

    bool ShouldRotate()
    {
        switch (lookMode)
        {
            case OrbitLookMode.AlwaysActive: return true;
            case OrbitLookMode.HoldRightMouseButton: return IsRightMouseHeld();
            default: return false;
        }
    }

    void ApplyCursorState()
    {
        if (manageCursor)
            SetCursorLocked(ShouldRotate());
    }

    /// <summary>Adds to an input axis; wrapping axes wrap, others clamp to their range.</summary>
    static void ApplyAxisDelta(ref InputAxis axis, float amount)
    {
        float value = axis.Value + amount;
        float min = axis.Range.x;
        float max = axis.Range.y;

        if (axis.Wrap && max > min)
        {
            float span = max - min;
            value = ((value - min) % span + span) % span + min;
        }
        else
        {
            value = Mathf.Clamp(value, min, max);
        }

        axis.Value = value;
    }

    static void SetCursorLocked(bool locked)
    {
        Cursor.lockState = locked ? CursorLockMode.Locked : CursorLockMode.None;
        Cursor.visible = !locked;
    }

    bool IsRightMouseHeld()
    {
#if ENABLE_INPUT_SYSTEM
        return Mouse.current != null && Mouse.current.rightButton.isPressed;
#else
        return Input.GetMouseButton(1);
#endif
    }

    static bool ShiftHeld()
    {
#if ENABLE_INPUT_SYSTEM
        var kb = Keyboard.current;
        if (kb != null) return kb.leftShiftKey.isPressed || kb.rightShiftKey.isPressed;
#endif
#if ENABLE_LEGACY_INPUT_MANAGER
        return Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift);
#else
        return false;
#endif
    }

    Vector2 ReadMouseDelta()
    {
#if ENABLE_INPUT_SYSTEM
        return Mouse.current != null ? Mouse.current.delta.ReadValue() : Vector2.zero;
#else
        return new Vector2(Input.GetAxisRaw("Mouse X"), Input.GetAxisRaw("Mouse Y")) * 10f;
#endif
    }

    float ReadScroll()
    {
#if ENABLE_INPUT_SYSTEM
        // Raw wheel delta; only its sign is used (one notch = one zoom step).
        return Mouse.current != null ? Mouse.current.scroll.ReadValue().y : 0f;
#else
        return Input.GetAxis("Mouse ScrollWheel");
#endif
    }
}