using System.Text.Json;
using ProposalSystem.Application.Interfaces;
using ProposalSystem.Domain.Entities;
using ProposalSystem.Infrastructure.Data;

namespace ProposalSystem.Infrastructure.Services;

public class AuditService : IAuditService
{
    private readonly ProposalDbContext _db;
    private readonly ICurrentUserService _currentUser;

    public AuditService(ProposalDbContext db, ICurrentUserService currentUser)
    {
        _db = db;
        _currentUser = currentUser;
    }

    public async Task LogAsync(AuditAction action, Guid? proposalId, string? details = null, CancellationToken ct = default)
    {
        Stage(action, proposalId, details);
        await _db.SaveChangesAsync(ct);
    }

    public void Stage(AuditAction action, Guid? proposalId, string? details = null)
    {
        _db.AuditLogs.Add(BuildEntry(action, proposalId, details));
    }

    private AuditLog BuildEntry(AuditAction action, Guid? proposalId, string? details)
    {
        // Fix: API-M12 — accept pre-serialized JSON from callers that provide structured audit data.
        // If the details string is already valid JSON (starts with '{'), use it directly;
        // otherwise, wrap plain text in a JSON envelope for consistency.
        string? jsonDetails = null;
        if (details != null)
        {
            var trimmed = details.TrimStart();
            if (trimmed.StartsWith('{') || trimmed.StartsWith('['))
                jsonDetails = details;
            else
                jsonDetails = JsonSerializer.Serialize(new { message = details });
        }

        return new AuditLog
        {
            Id = Guid.NewGuid(),
            ProposalId = proposalId,
            UserId = _currentUser.UserId,
            Action = action,
            Details = jsonDetails,
            Timestamp = DateTime.UtcNow,
            IpAddress = _currentUser.IpAddress,
        };
    }
}