using System.Text;
using Microsoft.AspNetCore.Authentication;
using SharepointToolbox.Web.Core.Models;
using SharepointToolbox.Web.Infrastructure.Persistence;
using SharepointToolbox.Web.Services.Export;
using SharepointToolbox.Web.Services.Session;

namespace SharepointToolbox.Web.Services.Audit;

public class AuditService : IAuditService
{
    private readonly AuditRepository _repo;
    private readonly IUserContextAccessor _userContext;

    public AuditService(AuditRepository repo, IUserContextAccessor userContext)
    {
        _repo        = repo;
        _userContext = userContext;
    }

    public async Task LogAsync(string action, string clientName, IEnumerable<string> sites, string details = "")
    {
        var entry = new AuditEntry
        {
            Action      = action,
            ClientName  = clientName,
            Sites       = sites.ToList(),
            Details     = details,
            UserEmail   = _userContext.Email,
            UserDisplay = _userContext.DisplayName,
            UserRole    = _userContext.Role
        };
        await _repo.AppendAsync(entry);
    }

    public Task<IReadOnlyList<AuditEntry>> GetAllAsync() => _repo.LoadAllAsync();

    public async Task<string> ExportCsvAsync()
    {
        var entries = await _repo.LoadAllAsync();
        var sb = new StringBuilder();
        sb.AppendLine("Timestamp,UserEmail,UserDisplay,UserRole,Action,Client,Sites,Details");
        foreach (var e in entries.OrderByDescending(x => x.Timestamp))
        {
            // CsvSanitizer adds spreadsheet formula-injection guards (= + - @) on top of
            // RFC 4180 quoting; the user/display/client/site fields are user-controlled.
            sb.AppendLine(string.Join(",",
                CsvSanitizer.Escape(e.Timestamp.ToLocalTime().ToString("yyyy-MM-dd HH:mm:ss")),
                CsvSanitizer.Escape(e.UserEmail),
                CsvSanitizer.Escape(e.UserDisplay),
                CsvSanitizer.Escape(e.UserRole.ToString()),
                CsvSanitizer.Escape(e.Action),
                CsvSanitizer.Escape(e.ClientName),
                CsvSanitizer.Escape(string.Join("; ", e.Sites)),
                CsvSanitizer.Escape(e.Details)));
        }
        return sb.ToString();
    }
}