using System;
using System.Collections.Generic;
using System.Text;
using NeoModLoader.services;

namespace IdleSpectator;

/// <summary>
/// Ring buffer of why a beat stayed Layer B or failed to take / keep Layer A camera.
/// </summary>
public static class InterestDropLog
{
    public const int Capacity = 48;

    private static readonly string[] Buffer = new string[Capacity];
    private static int _write;
    private static int _count;
    private static float _lastPlayerLogAt = -999f;
    private const float PlayerLogInterval = 8f;

    public static int Count => _count;

    public static void Clear()
    {
        _write = 0;
        _count = 0;
        for (int i = 0; i < Capacity; i++)
        {
            Buffer[i] = null;
        }
    }

    public static void Record(string reason, string detail = "")
    {
        if (string.IsNullOrEmpty(reason))
        {
            return;
        }

        string line = string.IsNullOrEmpty(detail)
            ? reason
            : (reason + ": " + detail);
        Buffer[_write] = line;
        _write = (_write + 1) % Capacity;
        if (_count < Capacity)
        {
            _count++;
        }

        float now = UnityEngine.Time.unscaledTime;
        if (now - _lastPlayerLogAt >= PlayerLogInterval)
        {
            _lastPlayerLogAt = now;
            try
            {
                LogService.LogInfo("[IdleSpectator][DROP] " + line);
            }
            catch
            {
                // ignore log failures
            }
        }
    }

    /// <summary>Newest-first snapshot for harness / diagnostics.</summary>
    public static List<string> Snapshot(int max = 12)
    {
        var list = new List<string>(Math.Min(max, _count));
        if (_count == 0 || max <= 0)
        {
            return list;
        }

        int n = Math.Min(max, _count);
        for (int i = 0; i < n; i++)
        {
            int idx = (_write - 1 - i + Capacity) % Capacity;
            if (!string.IsNullOrEmpty(Buffer[idx]))
            {
                list.Add(Buffer[idx]);
            }
        }

        return list;
    }

    public static string FormatRecent(int max = 8)
    {
        List<string> lines = Snapshot(max);
        if (lines.Count == 0)
        {
            return "";
        }

        var sb = new StringBuilder();
        for (int i = 0; i < lines.Count; i++)
        {
            if (i > 0)
            {
                sb.Append(" | ");
            }

            sb.Append(lines[i]);
        }

        return sb.ToString();
    }
}