using UnityEngine;
using UnityEngine.InputSystem;

public class CameraController : MonoBehaviour
{
    // Zoom settings
    public float minZoom = 5f;
    public float maxZoom = 25f;
    public float zoomSpeed = 2f;
    public float pinchZoomSpeed = 0.1f;

    // Pan settings
    public float panSpeed = 1f;

    Camera cam;
    Vector2 lastPanPosition;
    bool isPanning;
    float lastPinchDistance;
    bool isPinching;

    // Track if we started on a unit (don't pan if drawing route)
    bool startedOnUnit;

    void Start()
    {
        cam = Camera.main;
    }

    void Update()
    {
        HandleMouseInput();
        HandleTouchInput();
        ClampCameraPosition();
    }

    void HandleMouseInput()
    {
        var mouse = Mouse.current;
        if (mouse == null) return;

        // Scroll wheel zoom
        float scroll = mouse.scroll.ReadValue().y;
        if (Mathf.Abs(scroll) > 0.01f)
        {
            Zoom(-scroll * zoomSpeed * Time.deltaTime * 10f);
        }

        // Right-click pan (left-click is for route drawing)
        if (mouse.rightButton.wasPressedThisFrame)
        {
            lastPanPosition = mouse.position.ReadValue();
            isPanning = true;
        }
        else if (mouse.rightButton.wasReleasedThisFrame)
        {
            isPanning = false;
        }

        if (isPanning && mouse.rightButton.isPressed)
        {
            Vector2 currentPos = mouse.position.ReadValue();
            Vector2 delta = currentPos - lastPanPosition;
            Pan(-delta);
            lastPanPosition = currentPos;
        }
    }

    void HandleTouchInput()
    {
        var touch = Touchscreen.current;
        if (touch == null) return;

        int touchCount = 0;
        foreach (var t in touch.touches)
        {
            if (t.press.isPressed) touchCount++;
        }

        if (touchCount == 2)
        {
            // Two finger pinch zoom and pan
            var touch0 = touch.touches[0];
            var touch1 = touch.touches[1];

            Vector2 pos0 = touch0.position.ReadValue();
            Vector2 pos1 = touch1.position.ReadValue();
            float currentDistance = Vector2.Distance(pos0, pos1);

            if (!isPinching)
            {
                isPinching = true;
                lastPinchDistance = currentDistance;
                lastPanPosition = (pos0 + pos1) / 2f;
            }
            else
            {
                // Pinch zoom
                float deltaDistance = lastPinchDistance - currentDistance;
                Zoom(deltaDistance * pinchZoomSpeed);
                lastPinchDistance = currentDistance;

                // Two-finger pan
                Vector2 currentCenter = (pos0 + pos1) / 2f;
                Vector2 delta = currentCenter - lastPanPosition;
                Pan(-delta);
                lastPanPosition = currentCenter;
            }

            isPanning = false; // Don't single-finger pan while pinching
        }
        else if (touchCount == 1)
        {
            isPinching = false;

            var primaryTouch = touch.primaryTouch;
            Vector2 touchPos = primaryTouch.position.ReadValue();

            // Check if touch started on a unit
            if (primaryTouch.press.wasPressedThisFrame)
            {
                Vector2 worldPos = cam.ScreenToWorldPoint(touchPos);
                var hit = Physics2D.OverlapPoint(worldPos);
                startedOnUnit = hit != null && hit.GetComponent<Unit>() != null;

                if (!startedOnUnit)
                {
                    lastPanPosition = touchPos;
                    isPanning = true;
                }
            }
            else if (primaryTouch.press.wasReleasedThisFrame)
            {
                isPanning = false;
                startedOnUnit = false;
            }

            // Single finger pan (only if not drawing route)
            if (isPanning && !startedOnUnit && primaryTouch.press.isPressed)
            {
                Vector2 delta = touchPos - lastPanPosition;
                Pan(-delta);
                lastPanPosition = touchPos;
            }
        }
        else
        {
            isPinching = false;
            isPanning = false;
        }
    }

    void Zoom(float delta)
    {
        float newSize = cam.orthographicSize + delta;
        cam.orthographicSize = Mathf.Clamp(newSize, minZoom, maxZoom);
    }

    void Pan(Vector2 screenDelta)
    {
        // Convert screen delta to world delta
        float worldUnitsPerPixel = cam.orthographicSize * 2f / Screen.height;
        Vector3 worldDelta = new Vector3(
            screenDelta.x * worldUnitsPerPixel * panSpeed,
            screenDelta.y * worldUnitsPerPixel * panSpeed,
            0
        );

        cam.transform.position += worldDelta;
    }

    void ClampCameraPosition()
    {
        // Keep camera within map bounds (with some padding for zoom)
        float halfHeight = cam.orthographicSize;
        float halfWidth = halfHeight * cam.aspect;

        float minX = -Game.MapWidth / 2f + halfWidth;
        float maxX = Game.MapWidth / 2f - halfWidth;
        float minY = -Game.MapHeight / 2f + halfHeight;
        float maxY = Game.MapHeight / 2f - halfHeight;

        Vector3 pos = cam.transform.position;
        pos.x = Mathf.Clamp(pos.x, minX, maxX);
        pos.y = Mathf.Clamp(pos.y, minY, maxY);
        cam.transform.position = pos;
    }
}