using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlaneController : MonoBehaviour
{
    public GameObject planePrefab;
    public float flightDuration = 5f;
    public float arcHeight = 0.3f;
    public float hoverHeight = 0.2f;
    public float globeRadius = 5f;
    public float rotateToDuration = 1.5f;

    [Header("Camera Follow")]
    public float cameraDistance = 3f;
    public float cameraHeight = 0.5f;
    public float cameraSmoothing = 3f;

    private bool _flying = false;
    private GameObject _plane;
    private LineRenderer _trail;
    private Transform _globe;
    private Camera _mainCamera;
    private Vector3 _cameraStartPos;
    private Quaternion _cameraStartRot;

    void Start()
    {
        _globe = GameObject.Find("Globe")?.transform;
        _mainCamera = Camera.main;
        SpawnPlane();
        PlaceOverCountry("Ukraine");
    }

    void SpawnPlane()
    {
        if (planePrefab == null) return;
        _plane = Instantiate(planePrefab);
        if (_globe != null) _plane.transform.SetParent(_globe);

        _trail = _plane.AddComponent<LineRenderer>();
        _trail.positionCount = 0;
        _trail.startWidth = 0.03f;
        _trail.endWidth = 0.03f;
        _trail.useWorldSpace = true;
        _trail.material = new Material(Shader.Find("Sprites/Default"));
        _trail.material.color = new Color(1f, 1f, 1f, 0.8f);
    }

    Vector3 GetLocalDirection(CountryData c)
    {
        Renderer rend = c.GetComponentInChildren<Renderer>();
        Vector3 worldCenter = rend != null ? rend.bounds.center : c.transform.position;
        if (_globe == null) return worldCenter.normalized;
        return _globe.InverseTransformPoint(worldCenter).normalized;
    }

    public void PlaceOverCountry(string countryName)
    {
        if (_plane == null) return;
        CountryData[] all = FindObjectsOfType<CountryData>();
        foreach (CountryData c in all)
        {
            if (c.countryName == countryName)
            {
                SnapToSurface(c);
                return;
            }
        }
    }

    void SnapToSurface(CountryData country)
    {
        if (_plane == null || _globe == null) return;
        Vector3 dir = GetLocalDirection(country);
        _plane.transform.localPosition = dir * (globeRadius + hoverHeight);
        _plane.transform.up = (_plane.transform.position - _globe.position).normalized;
    }

    public void Fly(CountryData fromCountry, CountryData toCountry, System.Action onArrived)
    {
        if (_flying || _plane == null) return;
        StartCoroutine(FlyCoroutine(fromCountry, toCountry, onArrived));
    }

    IEnumerator FlyCoroutine(CountryData fromCountry, CountryData toCountry, System.Action onArrived)
    {
        _flying = true;
        _trail.positionCount = 0;

        _cameraStartPos = _mainCamera.transform.position;
        _cameraStartRot = _mainCamera.transform.rotation;

        Vector3 fromDir = GetLocalDirection(fromCountry);
        float elapsed = 0f;

        while (elapsed < flightDuration)
        {
            elapsed += Time.deltaTime;
            float t = Mathf.Clamp01(elapsed / flightDuration);
            float smoothT = Mathf.SmoothStep(0f, 1f, t);

            Vector3 toDir = GetLocalDirection(toCountry);
            Vector3 onSphere = Vector3.Slerp(fromDir, toDir, smoothT);
            float arc = Mathf.Sin(smoothT * Mathf.PI) * arcHeight;
            _plane.transform.localPosition = onSphere * (globeRadius + hoverHeight + arc);

            float tNext = Mathf.Min(smoothT + 0.02f, 1f);
            Vector3 nextOnSphere = Vector3.Slerp(fromDir, toDir, tNext);
            float nextArc = Mathf.Sin(tNext * Mathf.PI) * arcHeight;
            Vector3 nextWorld = _globe.TransformPoint(nextOnSphere * (globeRadius + hoverHeight + nextArc));

            Vector3 worldForward = (nextWorld - _plane.transform.position).normalized;
            Vector3 worldUp = (_plane.transform.position - _globe.position).normalized;
            if (worldForward.magnitude > 0.001f)
                _plane.transform.rotation = Quaternion.LookRotation(worldForward, worldUp);

            Vector3 sideDir = Vector3.Cross(worldForward, worldUp).normalized;
            Vector3 desiredPos = _plane.transform.position
                + sideDir * cameraDistance
                + worldUp * cameraHeight;
            Quaternion desiredRot = Quaternion.LookRotation(
                _plane.transform.position - desiredPos, worldUp);

            _mainCamera.transform.position = Vector3.Lerp(
                _mainCamera.transform.position, desiredPos,
                Time.deltaTime * cameraSmoothing);
            _mainCamera.transform.rotation = Quaternion.Slerp(
                _mainCamera.transform.rotation, desiredRot,
                Time.deltaTime * cameraSmoothing);

            _trail.positionCount++;
            _trail.SetPosition(_trail.positionCount - 1, _plane.transform.position);

            yield return null;
        }

        SnapToSurface(toCountry);
        _trail.positionCount = 0;

        yield return StartCoroutine(RestoreCamera());
        yield return StartCoroutine(RotateGlobeToCountry(toCountry));

        _flying = false;
        onArrived?.Invoke();
    }

    IEnumerator RestoreCamera()
    {
        float elapsed = 0f;
        float duration = 0.8f;
        Vector3 fromPos = _mainCamera.transform.position;
        Quaternion fromRot = _mainCamera.transform.rotation;

        while (elapsed < duration)
        {
            elapsed += Time.deltaTime;
            float t = Mathf.SmoothStep(0f, 1f, elapsed / duration);
            _mainCamera.transform.position = Vector3.Lerp(fromPos, _cameraStartPos, t);
            _mainCamera.transform.rotation = Quaternion.Slerp(fromRot, _cameraStartRot, t);
            yield return null;
        }
        _mainCamera.transform.position = _cameraStartPos;
        _mainCamera.transform.rotation = _cameraStartRot;
    }

    IEnumerator RotateGlobeToCountry(CountryData country)
    {
        if (_globe == null || _mainCamera == null) yield break;

        Vector3 countryWorldPos = _globe.TransformPoint(GetLocalDirection(country) * globeRadius);
        Vector3 globeCenter = _globe.position;
        Vector3 camDir = (_mainCamera.transform.position - globeCenter).normalized;

        Quaternion startRot = _globe.rotation;
        Quaternion targetRot = Quaternion.FromToRotation(
            (countryWorldPos - globeCenter).normalized, camDir) * _globe.rotation;

        float elapsed = 0f;
        while (elapsed < rotateToDuration)
        {
            elapsed += Time.deltaTime;
            float t = Mathf.SmoothStep(0f, 1f, elapsed / rotateToDuration);
            _globe.rotation = Quaternion.Slerp(startRot, targetRot, t);
            yield return null;
        }
        _globe.rotation = targetRot;
    }

    public bool IsFlying() => _flying;
}