using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;

namespace FreedomFighter;

public record HighScoreEntry(string Name, int Score);

/// <summary>High score table; JSON replaces the original Highscore.dat record file.</summary>
public class HighScores
{
    const string FileName = "highscore.json";
    public HighScoreEntry[] List = new HighScoreEntry[10];

    public void Load()
    {
        if (File.Exists(FileName))
        {
            try
            {
                var loaded = JsonSerializer.Deserialize<HighScoreEntry[]>(File.ReadAllText(FileName));
                if (loaded is { Length: 10 }) { List = loaded; return; }
            }
            catch { /* fall through to defaults */ }
        }
        for (int i = 0; i < 10; i++)
            List[i] = new HighScoreEntry("Nameless", 0);
        Save();
    }

    public void Save() => File.WriteAllText(FileName, JsonSerializer.Serialize(List));

    public bool Qualifies(int score) => score > List[9].Score;

    public void Add(int num, string name, int score)
    {
        for (int i = 9; i >= num + 1; i--)
            List[i] = List[i - 1];
        List[num] = new HighScoreEntry(name, score);
    }

    /// <summary>Port of EnterHighScoreList: insert from the bottom up.</summary>
    public void Enter(string name, int score)
    {
        for (int i = 8; i >= 0; i--)
        {
            if (score <= List[i].Score)
            {
                Add(i + 1, name, score);
                break;
            }
            if (i == 0)
            {
                Add(i, name, score);
                break;
            }
        }
        Save();
    }
}