using ManagerService.Data;
using ManagerService.Helpers;
using ManagerService.Service.Services;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Threading.Tasks;

namespace ManagerService.Services
{
    public class ApiKeyDatabaseService
    {
        private readonly MyInfoMateDbContext _db;
        private readonly IHexIdGeneratorService _idService = new HexIdGeneratorService();

        public ApiKeyDatabaseService(MyInfoMateDbContext db)
        {
            _db = db;
        }

        /// <summary>
        /// Creates a new API key with a hashed secret (returned once in plain text).
        /// </summary>
        public async Task<string> CreateAsync(string instanceId, string name, ApiKeyAppType appType)
        {
            var plainKey = "ak_" + Convert.ToBase64String(RandomNumberGenerator.GetBytes(32))
                .Replace("+", "-").Replace("/", "_").TrimEnd('=');

            var keyHash = TokensService.GenerateSHA256String(plainKey);

            var apiKey = new ApiKey
            {
                Id = _idService.GenerateHexId(),
                Name = name,
                InstanceId = instanceId,
                AppType = appType,
                Key = null,
                KeyHash = keyHash,
                IsActive = true,
                DateCreation = DateTime.UtcNow,
            };

            _db.ApiKeys.Add(apiKey);
            await _db.SaveChangesAsync();

            return plainKey;
        }

        /// <summary>
        /// Returns (or creates) a persistent plain-text key for a given instance + appType (PIN flow).
        /// </summary>
        public async Task<string> GetOrCreateByPinAsync(string instanceId, ApiKeyAppType appType)
        {
            var existing = await _db.ApiKeys.FirstOrDefaultAsync(k =>
                k.InstanceId == instanceId &&
                k.AppType == appType &&
                k.IsActive &&
                k.Key != null);

            if (existing != null)
                return existing.Key!;

            var plainKey = "ak_" + Convert.ToBase64String(RandomNumberGenerator.GetBytes(32))
                .Replace("+", "-").Replace("/", "_").TrimEnd('=');

            var apiKey = new ApiKey
            {
                Id = _idService.GenerateHexId(),
                Name = $"Auto-{appType}-{instanceId}",
                InstanceId = instanceId,
                AppType = appType,
                Key = plainKey,
                KeyHash = null,
                IsActive = true,
                DateCreation = DateTime.UtcNow,
            };

            _db.ApiKeys.Add(apiKey);
            await _db.SaveChangesAsync();

            return plainKey;
        }

        /// <summary>Returns all API keys for an instance (without secret values).</summary>
        public async Task<List<ApiKeyDTO>> GetByInstanceAsync(string instanceId)
        {
            return await _db.ApiKeys
                .Where(k => k.InstanceId == instanceId)
                .Select(k => new ApiKeyDTO
                {
                    Id = k.Id,
                    Name = k.Name,
                    AppType = k.AppType,
                    IsActive = k.IsActive,
                    DateCreation = k.DateCreation,
                    DateExpiration = k.DateExpiration,
                })
                .ToListAsync();
        }

        /// <summary>Revokes (deactivates) an API key, verifying ownership.</summary>
        public async Task<bool> RevokeAsync(string id, string callerInstanceId)
        {
            var key = await _db.ApiKeys.FindAsync(id);
            if (key == null || key.InstanceId != callerInstanceId)
                return false;

            key.IsActive = false;
            await _db.SaveChangesAsync();
            return true;
        }
    }

    public class ApiKeyDTO
    {
        public string Id { get; set; }
        public string Name { get; set; }
        public ApiKeyAppType AppType { get; set; }
        public bool IsActive { get; set; }
        public DateTime DateCreation { get; set; }
        public DateTime? DateExpiration { get; set; }
    }
}