using System.Text;
using System.Text.Json;
using SharepointToolbox.Web.Core.Models;

namespace SharepointToolbox.Web.Infrastructure.Persistence;

/// <summary>Append-only JSONL audit log. Each line is one AuditEntry JSON object.</summary>
public class AuditRepository
{
    private readonly string _filePath;
    private readonly SemaphoreSlim _writeLock = new(1, 1);
    private static readonly JsonSerializerOptions _opts = new()
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
        PropertyNameCaseInsensitive = true
    };

    public AuditRepository(string filePath) { _filePath = filePath; }

    public async Task AppendAsync(AuditEntry entry)
    {
        await _writeLock.WaitAsync();
        try
        {
            var dir = Path.GetDirectoryName(_filePath);
            if (!string.IsNullOrEmpty(dir)) Directory.CreateDirectory(dir);
            var line = JsonSerializer.Serialize(entry, _opts) + "\n";
            await File.AppendAllTextAsync(_filePath, line, Encoding.UTF8);
        }
        finally { _writeLock.Release(); }
    }

    public async Task<IReadOnlyList<AuditEntry>> LoadAllAsync()
    {
        if (!File.Exists(_filePath)) return Array.Empty<AuditEntry>();
        var lines = await File.ReadAllLinesAsync(_filePath, Encoding.UTF8);
        var result = new List<AuditEntry>(lines.Length);
        foreach (var line in lines)
        {
            if (string.IsNullOrWhiteSpace(line)) continue;
            try
            {
                var entry = JsonSerializer.Deserialize<AuditEntry>(line, _opts);
                if (entry != null) result.Add(entry);
            }
            catch { /* skip corrupt lines */ }
        }
        return result;
    }
}