using System.Security.Cryptography;
using System.Text;
using License.Api.Data;
using License.Api.Models;
using Microsoft.EntityFrameworkCore;

namespace License.Api.Services;

public class IdempotencyService
{
    private readonly AppDbContext _db;

    public IdempotencyService(AppDbContext db)
    {
        _db = db;
    }

    public async Task<IdempotencyKeyRecord?> GetAsync(string key)
    {
        return await _db.IdempotencyKeys
            .FirstOrDefaultAsync(x => x.IdempotencyKey == key && x.ExpiresAt > DateTime.UtcNow);
    }

    public async Task<IdempotencyKeyRecord> StoreAsync(string key, string path, string requestBodyHash, int responseCode, string responseBody)
    {
        var record = new IdempotencyKeyRecord
        {
            IdempotencyKey = key,
            RequestPath = path,
            RequestHash = requestBodyHash,
            ResponseCode = responseCode,
            ResponseBody = responseBody,
            CreatedAt = DateTime.UtcNow,
            ExpiresAt = DateTime.UtcNow.AddHours(24)
        };

        _db.IdempotencyKeys.Add(record);
        await _db.SaveChangesAsync();
        return record;
    }

    public static string ComputeRequestHash(string? body)
    {
        if (string.IsNullOrWhiteSpace(body))
            return string.Empty;
        var hash = SHA256.HashData(Encoding.UTF8.GetBytes(body));
        return Convert.ToHexString(hash).ToLowerInvariant();
    }
}