using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
using TMPro;
using Newtonsoft.Json;
using CommanderAILab.Models;
using CommanderAILab.Services;

namespace CommanderAILab.UI
{
  /// <summary>
  /// Scanner scene — live camera feed, capture frame, POST /api/scanner/scan,
  /// display result card overlay, add to collection or deck.
  /// </summary>
  public class ScannerController : MonoBehaviour
  {
    [Header("Navigation")]
    [SerializeField] private Button backButton;

    [Header("Camera Feed")]
    [SerializeField] private RawImage   cameraFeedImage;
    [SerializeField] private Button     captureButton;
    [SerializeField] private Button     toggleCameraButton;
    [SerializeField] private TMP_Text   cameraStatusText;
    [SerializeField] private GameObject scanOverlay;     // animated scan line

    [Header("Result Panel")]
    [SerializeField] private GameObject resultPanel;
    [SerializeField] private Image      resultCardImage;
    [SerializeField] private TMP_Text   resultCardName;
    [SerializeField] private TMP_Text   resultManaCost;
    [SerializeField] private TMP_Text   resultType;
    [SerializeField] private TMP_Text   resultSet;
    [SerializeField] private TMP_Text   resultOracleText;
    [SerializeField] private TMP_Text   resultConfidence;
    [SerializeField] private Button     addToCollectionButton;
    [SerializeField] private Button     addToDeckButton;
    [SerializeField] private Button     scanAgainButton;

    [Header("Scan History")]
    [SerializeField] private Transform  historyParent;
    [SerializeField] private GameObject historyRowPrefab;

    [Header("Error")]
    [SerializeField] private GameObject errorPanel;
    [SerializeField] private TMP_Text   errorText;
    [SerializeField] private Button     retryButton;

    private WebCamTexture  _webcam;
    private int            _cameraIndex = 0;
    private CardModel      _scannedCard;
    private bool           _isScanning  = false;
    private readonly List<CardModel>    _history     = new();
    private readonly List<GameObject>   _historyRows = new();

    private void Start()
    {
      backButton.onClick.AddListener(OnBack);
      captureButton.onClick.AddListener(OnCapture);
      toggleCameraButton.onClick.AddListener(ToggleCamera);
      addToCollectionButton.onClick.AddListener(OnAddToCollection);
      addToDeckButton.onClick.AddListener(OnAddToDeck);
      scanAgainButton.onClick.AddListener(OnScanAgain);
      retryButton.onClick.AddListener(OnCapture);

      resultPanel.SetActive(false);
      errorPanel.SetActive(false);
      scanOverlay.SetActive(false);

      StartCamera(_cameraIndex);
    }

    private void OnDestroy()
    {
      if (_webcam != null && _webcam.isPlaying) _webcam.Stop();
    }

    // ── Camera ────────────────────────────────────────────────────────
    private void StartCamera(int idx)
    {
      if (_webcam != null && _webcam.isPlaying) _webcam.Stop();

      var devices = WebCamTexture.devices;
      if (devices.Length == 0)
      {
        cameraStatusText.text = "No camera found";
        captureButton.interactable = false;
        return;
      }

      idx = Mathf.Clamp(idx, 0, devices.Length - 1);
      _webcam = new WebCamTexture(devices[idx].name, 1280, 720, 30);
      _webcam.Play();
      cameraFeedImage.texture = _webcam;
      cameraStatusText.text = $"Camera: {devices[idx].name}";
      captureButton.interactable = true;
    }

    private void ToggleCamera()
    {
      var devices = WebCamTexture.devices;
      if (devices.Length < 2) return;
      _cameraIndex = (_cameraIndex + 1) % devices.Length;
      StartCamera(_cameraIndex);
    }

    // ── Capture & Scan ────────────────────────────────────────────────
    private void OnCapture()
    {
      if (_isScanning || _webcam == null || !_webcam.isPlaying) return;
      _isScanning = true;
      errorPanel.SetActive(false);
      resultPanel.SetActive(false);
      scanOverlay.SetActive(true);
      captureButton.interactable = false;

      // Grab frame and encode to JPEG
      var tex = new Texture2D(_webcam.width, _webcam.height);
      tex.SetPixels(_webcam.GetPixels());
      tex.Apply();
      byte[] jpegBytes = tex.EncodeToJPG(85);
      Destroy(tex);

      ApiClient.Instance.ScanCard(jpegBytes,
        json =>
        {
          scanOverlay.SetActive(false);
          _isScanning = false;
          captureButton.interactable = true;
          try
          {
            var result = JsonConvert.DeserializeObject<ScanResult>(json);
            if (result?.card != null) ShowResult(result.card, result.confidence);
            else ShowError("Card not recognized. Try again.");
          }
          catch (Exception e) { ShowError($"Parse error: {e.Message}"); }
        },
        err =>
        {
          scanOverlay.SetActive(false);
          _isScanning = false;
          captureButton.interactable = true;
          ShowError($"Scan failed:\n{err}");
        });
    }

    // ── Result ────────────────────────────────────────────────────────
    private void ShowResult(CardModel card, float confidence)
    {
      _scannedCard = card;
      resultPanel.SetActive(true);

      resultCardName.text   = card.name;
      resultManaCost.text   = card.manaCost;
      resultType.text       = card.typeLine;
      resultSet.text        = card.set;
      resultOracleText.text = card.oracleText;
      resultConfidence.text = $"Confidence: {confidence:P0}";

      if (!string.IsNullOrEmpty(card.imageUrl))
        ImageCache.Instance.GetSprite(card.imageUrl, s =>
        {
          if (resultCardImage != null) resultCardImage.sprite = s;
        });

      AddToHistory(card);
    }

    private void AddToHistory(CardModel card)
    {
      _history.Add(card);
      var row = Instantiate(historyRowPrefab, historyParent);
      _historyRows.Add(row);
      var lbl = row.GetComponentInChildren<TMP_Text>();
      if (lbl) lbl.text = card.name;
      var btn = row.GetComponentInChildren<Button>();
      var captured = card;
      if (btn) btn.onClick.AddListener(() => ShowResult(captured, 1f));
    }

    private void OnScanAgain()
    {
      resultPanel.SetActive(false);
      _scannedCard = null;
    }

    // ── Add to Collection / Deck ──────────────────────────────────────
    private void OnAddToCollection()
    {
      if (_scannedCard == null) return;
      // POST to collection endpoint (add quantity 1)
      var body = JsonConvert.SerializeObject(new { card_id = _scannedCard.id, qty = 1 });
      StartCoroutine(ApiClient.Instance.PostRaw("/api/collection/add", body,
        _ => cameraStatusText.text = $"Added {_scannedCard.name} to collection",
        err => ShowError($"Add to collection failed:\n{err}")));
    }

    private void OnAddToDeck()
    {
      if (_scannedCard == null) return;
      PlayerPrefs.SetString("PendingAddCard", JsonConvert.SerializeObject(_scannedCard));
      PlayerPrefs.Save();
      SceneManager.LoadScene("DeckBuilder");
    }

    private void OnBack()
    {
      if (_webcam != null && _webcam.isPlaying) _webcam.Stop();
      SceneManager.LoadScene("MainMenu");
    }

    private void ShowError(string msg)
    {
      errorText.text = msg;
      errorPanel.SetActive(true);
      Debug.LogWarning($"[ScannerController] {msg}");
    }

    [Serializable] private class ScanResult
    {
      public CardModel card;
      public float     confidence;
    }
  }
}