using System;
using System.IO;
using UnityEngine;
using UnityEngine.SceneManagement;

public partial class ThirdPersonOrbitInput
{
    // --- Persistence: third-person camera orbit (rotation + distance) ---
    //
    // Saved on quit / play-stop and restored on the next start, so the camera resumes at the same
    // view. The camera is a CinemachineOrbitalFollow whose world position/rotation are derived each
    // frame from the orbit axes (yaw/pitch) and radius relative to the follow target - so saving the
    // literal transform would be pointless (Cinemachine overwrites it). The canonical state is the
    // orbit yaw/pitch (= rotation) and radius (= distance); combined with the persisted player
    // position this reproduces the exact same view. Small structured state -> human-readable JSON
    // (like PlayerCharacterController.Persistence), not the painter's raw byte dump.

    [Header("Persistence")]
    [Tooltip("Save the camera orbit (yaw/pitch rotation and zoom distance) on quit / play-stop and " +
             "restore it on the next start. Off = the camera starts at its authored orbit state.")]
    public bool persistCamera = true;

    [Tooltip("Save file identifier. Empty = derived from the active scene + object name. Set " +
             "explicitly to keep a save stable across object renames.")]
    public string cameraSaveId = "";

    private const int CameraFileVersion = 1;
    private bool _cameraSavedOnTeardown; // guards a double save across OnApplicationQuit + OnDestroy

    private static string CameraSaveDir => Path.Combine(Application.persistentDataPath, "MeshPaint");

    private string CameraSavePath()
    {
        string key = string.IsNullOrEmpty(cameraSaveId)
            ? SanitizeCameraKey(SceneManager.GetActiveScene().name + "_" + gameObject.name)
            : SanitizeCameraKey(cameraSaveId);
        return Path.Combine(CameraSaveDir, key + ".camera");
    }

    private static string SanitizeCameraKey(string s)
    {
        foreach (char c in Path.GetInvalidFileNameChars()) s = s.Replace(c, '_');
        return s.Replace(' ', '_');
    }

    [Serializable]
    private class CameraState
    {
        public int version = CameraFileVersion;
        public float yaw;      // CinemachineOrbitalFollow.HorizontalAxis.Value
        public float pitch;    // CinemachineOrbitalFollow.VerticalAxis.Value
        public float radius;   // CinemachineOrbitalFollow.Radius (zoom distance)
    }

    void Start() => RestoreCameraState();

    private void OnApplicationQuit() => SaveCameraOnTeardown();
    private void OnDestroy() => SaveCameraOnTeardown();

    /// <summary>Saves once during teardown (OnApplicationQuit and OnDestroy both call this; only the first writes).</summary>
    private void SaveCameraOnTeardown()
    {
        if (_cameraSavedOnTeardown) return;
        _cameraSavedOnTeardown = true;
        SaveCameraState();
    }

    /// <summary>Writes the current orbit yaw/pitch and radius to disk.</summary>
    public void SaveCameraState()
    {
        if (!persistCamera || !_orbit) return;

        try
        {
            var state = new CameraState
            {
                yaw = _orbit.HorizontalAxis.Value,
                pitch = _orbit.VerticalAxis.Value,
                radius = _orbit.Radius,
            };

            Directory.CreateDirectory(CameraSaveDir);
            File.WriteAllText(CameraSavePath(), JsonUtility.ToJson(state, true));
        }
        catch (Exception e)
        {
            Debug.LogWarning($"[ThirdPersonOrbitInput] Saving camera state failed: {e.Message}", this);
        }
    }

    /// <summary>Restores the saved orbit yaw/pitch and radius, or does nothing if there is no save.</summary>
    private void RestoreCameraState()
    {
        if (!persistCamera || !_orbit) return;

        var state = LoadCameraState();
        if (state == null) return;

        _orbit.HorizontalAxis.Value = state.yaw;
        _orbit.VerticalAxis.Value = state.pitch;

        // Clamp into the current zoom range (min/max may have changed in the inspector since saving)
        // and seed the eased zoom target so the radius doesn't drift back toward the authored value.
        float radius = Mathf.Clamp(state.radius, minRadius, maxRadius);
        _orbit.Radius = radius;
        _targetRadius = radius;
        _zoomInit = true;
    }

    private CameraState LoadCameraState()
    {
        string path = CameraSavePath();
        if (!File.Exists(path)) return null;

        try
        {
            var state = JsonUtility.FromJson<CameraState>(File.ReadAllText(path));
            if (state == null || state.version != CameraFileVersion) return null;
            return state;
        }
        catch (Exception e)
        {
            Debug.LogWarning($"[ThirdPersonOrbitInput] Loading camera state failed: {e.Message}", this);
            return null;
        }
    }

    /// <summary>Deletes the saved camera state (next start uses the authored orbit). Editor convenience.</summary>
    [ContextMenu("Clear Saved Camera State")]
    public void ClearSavedCameraState()
    {
        try
        {
            string path = CameraSavePath();
            if (File.Exists(path)) File.Delete(path);
            Debug.Log($"[ThirdPersonOrbitInput] Cleared saved camera state: {path}", this);
        }
        catch (Exception e)
        {
            Debug.LogWarning($"[ThirdPersonOrbitInput] Clearing saved camera state failed: {e.Message}", this);
        }
    }
}