using Microsoft.Extensions.Logging;
using PARR.DAL.CacheServices;
using PARR.DAL.DomainServices.Interfaces;
using PARR.DAL.Settings;
using System.Security.Cryptography;
using System.Text;

namespace PARR.DAL.DomainServices.Implementations
{
    public class GroupedShortcodesCacheService : IGroupedShortcodesCacheService
    {
        private readonly IRedisCacheService cacheService;
        private readonly GroupedShortcodesCacheSettings settings;
        private readonly ILogger<GroupedShortcodesCacheService> logger;

        public GroupedShortcodesCacheService(
            IRedisCacheService cacheService,
            GroupedShortcodesCacheSettings settings,
            ILogger<GroupedShortcodesCacheService> logger)
        {
            this.cacheService = cacheService;
            this.settings = settings;
            this.logger = logger;
        }

        public async Task<string> GetAggregatedValueAsync(
            Guid jobGroupId,
            Guid unitId,
            string shortcode,
            Func<Task<string>> computeIfMissing)
        {
            if (string.IsNullOrEmpty(shortcode))
                throw new ArgumentException("Ключ шорткода должен быть указан.", nameof(shortcode));

            var cacheKey = GetCacheKey(jobGroupId, unitId, shortcode);

            try
            {
                var cachedValue = await cacheService.GetCachedDataAsync<string>(cacheKey);
                if (cachedValue != null)
                {
                    logger.LogDebug(
                        "Попадание в кэш для шорткода '{ShortcodeKey}': unit={UnitId} → '{Value}'",
                        shortcode, unitId, cachedValue);
                    return cachedValue;
                }

                logger.LogDebug(
                    "Промах кэша для шорткода '{ShortcodeKey}': unit={UnitId}. Вычисление...",
                    shortcode, unitId);

                var computedValue = await computeIfMissing();

                await cacheService.SetCachedDataAsync(cacheKey, computedValue, settings.ValueTtl);

                logger.LogDebug(
                    "Вычислено и сохранено значение для '{ShortcodeKey}': unit={UnitId} → '{Value}' (срок хранения={Ttl})",
                    shortcode, unitId, computedValue, settings.ValueTtl);

                return computedValue;
            }
            catch (Exception ex)
            {
                logger.LogWarning(
                    ex,
                    "Ошибка при получении или вычислении значения для шорткода '{ShortcodeKey}' (unit={UnitId}). Возвращена пустая строка.",
                    shortcode, unitId);

                return string.Empty;
            }
        }

        private static string GetCacheKey(Guid jobGroupId, Guid unitId, string shortcodeKey)
        {
            var safeKey = shortcodeKey
                .Trim()
                .Replace(":", "_")
                .Replace(" ", "_")
                .Replace(".", "_")
                .Replace("%", "")
                .Replace("[", "_")
                .Replace("]", "_")
                .Replace("/", "_")
                .Replace("\\", "_");

            // ✅ SHA256 от safeKey
            using var sha256 = SHA256.Create();
            var hashBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes(safeKey));
            var hashHex = BitConverter.ToString(hashBytes).Replace("-", "").ToLower();

            // ✅ Новый формат ключа
            return $"gr_shcd_{jobGroupId:N}{unitId:N}_{hashHex}";
        }
    }
}