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 around the follow target like a classic third-person camera.
///
/// How the orbit is driven is controlled by <see cref="LookMode"/>:
///  * AlwaysActive        - rotates with every mouse move, cursor locked/hidden.
///  * HoldRightMouseButton - rotates only while the right mouse button is held;
///    the cursor is free otherwise (so the left button can paint).
///  * Disabled            - no rotation, cursor free.
///
/// The look mode is normally set by the GameModeManager when switching modes,
/// but can also be configured directly in the Inspector for standalone use.
///
/// Horizontal/vertical mouse movement drives the orbital axes (yaw/pitch); the
/// mouse wheel zooms by changing the orbit radius. The script reads the new Input
/// System (Mouse.current / Keyboard.current) when enabled and falls back to the
/// legacy Input Manager otherwise. The project currently runs the new Input System only.
///
/// Attach this to the same GameObject as the CinemachineCamera /
/// CinemachineOrbitalFollow (the camera rig, not the player).
/// </summary>
[RequireComponent(typeof(CinemachineOrbitalFollow))]
[DisallowMultipleComponent]
public class ThirdPersonOrbitInput : MonoBehaviour
{
    /// <summary>How the camera orbit is driven.</summary>
    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:\n" +
             "AlwaysActive = rotates with every mouse move (cursor locked).\n" +
             "HoldRightMouseButton = rotates only while RMB is held (cursor free otherwise).\n" +
             "Disabled = no rotation.")]
    [SerializeField] private OrbitLookMode lookMode = OrbitLookMode.AlwaysActive;

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

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

    [Tooltip("If ON, moving the mouse up tilts the camera down (inverted pitch).")]
    public bool invertY = false;

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

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

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

    [Tooltip("Farthest the camera can zoom out (orbit radius in units).")]
    public float maxRadius = 8f;

    [Header("Cursor")]
    [Tooltip("If ON, the cursor is locked and hidden while the camera is actively " +
             "rotating, and freed otherwise so you can use the mouse normally.")]
    public bool manageCursor = true;

    CinemachineOrbitalFollow _orbit;

    /// <summary>
    /// How the camera orbit is currently driven. Setting this also updates the
    /// cursor state immediately (e.g. when GameModeManager switches modes).
    /// </summary>
    public OrbitLookMode LookMode
    {
        get => lookMode;
        set { lookMode = value; ApplyCursorState(); }
    }

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

    void OnEnable()
    {
        ApplyCursorState();
    }

    void OnDisable()
    {
        // Make sure we never leave the cursor locked/hidden when this is turned off.
        SetCursorLocked(false);
    }

    void Update()
    {
        if (_orbit == null)
            return;

        bool rotating = ShouldRotate();

        // Keep the cursor in sync every frame: in HoldRightMouseButton mode the
        // lock state follows the right mouse button.
        if (manageCursor)
            SetCursorLocked(rotating);

        if (rotating)
        {
            Vector2 delta = ReadMouseDelta();
            if (delta.sqrMagnitude > 0f)
            {
                ApplyAxisDelta(ref _orbit.HorizontalAxis, delta.x * horizontalSensitivity);
                float pitch = delta.y * verticalSensitivity * (invertY ? 1f : -1f);
                ApplyAxisDelta(ref _orbit.VerticalAxis, pitch);
            }
        }

        if (enableZoom)
        {
            float scroll = ReadScroll();
            if (!Mathf.Approximately(scroll, 0f))
            {
                // One wheel notch = one zoom step. Use only the sign so the step
                // size is exactly zoomSpeed regardless of the platform's raw wheel
                // magnitude (the new Input System reports ~1 per notch, the legacy
                // Windows path used ~120). Scrolling up (positive) zooms in.
                _orbit.Radius = Mathf.Clamp(_orbit.Radius - Mathf.Sign(scroll) * zoomSpeed, minRadius, maxRadius);
            }
        }
    }

    /// <summary>Whether the camera should orbit this frame, based on the look mode.</summary>
    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 <paramref name="amount"/> to an input axis, respecting its range:
    /// wrapping axes (e.g. yaw) wrap around, non-wrapping axes (e.g. pitch) clamp.
    /// </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
    }

    Vector2 ReadMouseDelta()
    {
#if ENABLE_INPUT_SYSTEM
        // Mouse.current.delta is already the per-frame pixel movement (no deltaTime).
        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 in Update (one notch = one zoom
        // step), so the platform-dependent magnitude does not matter here.
        return Mouse.current != null ? Mouse.current.scroll.ReadValue().y : 0f;
#else
        return Input.GetAxis("Mouse ScrollWheel");
#endif
    }
}