using System;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;

/// <summary>
///     class that loads leaderboard data and displays it in the UI
/// </summary>
public class LeaderboardUI : MonoBehaviour
{
    /// <summary>
    ///     maximum number of entries to display in the leaderboard
    /// </summary>
    private const int MaxEntries = 10;
    
    /// <summary>
    ///     leaderboard data
    /// </summary>
    private List<Backend.LeaderboardEntry> _leaderboardData = new(MaxEntries);

    /// <summary>
    ///     register callbacks
    /// </summary>
    private void OnEnable()
    {
        UIManager.Instance.RegisterOnDisplayStateChangeCallback((_, newState) =>
        {
            if (newState == UIManager.DisplayState.LeaderboardView)
            {
                LoadLeaderboardData();
            }
        });
    }

    /// <summary>
    ///     load leaderboard data from the backend
    /// </summary>
    private void LoadLeaderboardData()
    {
        if (GameManager.Instance.Backend.Status != Backend.FirebaseConnectionStatus.Connected)
        {
            Debug.LogError("attempted to load leaderboard data without a connection to the backend");
            RenderLeaderboardData("Not connected to the backend, can't load leaderboard data.");
            return;
        }
        
        GameManager.Instance.Backend.GetLeaderboard((result, entries) =>
        {
            if (result == Backend.TransactionResult.Ok)
            {
                _leaderboardData = entries;
                RenderLeaderboardData();
            }
            else
            {
                Debug.LogError("failed to load leaderboard data");
                RenderLeaderboardData("An error occured, couldn't load leaderboard data.");
            }
        });
    }
    
    /// <summary>
    ///     render leaderboard data
    /// </summary>
    private void RenderLeaderboardData(string message = "")
    {
        // render leaderboard data
    }
}