using GB5Shared.DateConverter;
using GB5Shared.DTO.Framework.Login;
using Microsoft.Extensions.Configuration;
using Newtonsoft.Json;
using System;
using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace PayRollBLL.Common
{
    // GB4 parity: gServiceHandler.CallServiceXml(ValidationUri, "POST", DTO), called by
    // ShiftPatternBLL.SaveShiftPattern/GratuityGroupBLL.SaveGratuityGroup before persisting —
    // if the validator doesn't return success, the save is aborted and its error is surfaced
    // as-is. gb4 posted XML and read a JSON-shaped ResponseStandardDTO back; gb5 posts JSON
    // (System.Text.Json, matching every other GB5 endpoint) since there's no XML consumer
    // to stay compatible with on this side. Base URI is read per-call from
    // EntityValidation:{configKey} (see PayRollSL/appsettings.json).
    public class EntityValidationClient : IEntityValidationClient
    {
        private static readonly JsonSerializerOptions _JsonOptions = GB5JsonOptions.CreateDefaultOptions();

        private readonly IHttpClientFactory _HttpClientFactory;
        private readonly IConfiguration _Configuration;

        public EntityValidationClient(IHttpClientFactory httpClientFactory, IConfiguration configuration)
        {
            _HttpClientFactory = httpClientFactory;
            _Configuration = configuration;
        }

        public async Task<(bool IsValid, string? ErrorMessage)> ValidateAsync(
            string configKey, object dto, LoginDTO loginDTO, CancellationToken ct = default)
        {
            var baseUri = _Configuration[$"EntityValidation:{configKey}"];
            if (string.IsNullOrWhiteSpace(baseUri))
            {
                // No validator configured for this entity yet — treat as a no-op pass,
                // matching gb4 environments where BaseXxxValidationUri was never set up.
                return (true, null);
            }

            var http = _HttpClientFactory.CreateClient();

            using var request = new HttpRequestMessage(HttpMethod.Post, baseUri)
            {
                Content = JsonContent.Create(dto, options: _JsonOptions)
            };
            request.Headers.Add("Login", JsonConvert.SerializeObject(loginDTO));

            using var response = await http.SendAsync(request, ct).ConfigureAwait(false);
            if (!response.IsSuccessStatusCode)
                return (false, $"Validation service returned {(int)response.StatusCode} {response.ReasonPhrase}.");

            var envelope = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: ct).ConfigureAwait(false);
            if (envelope.TryGetProperty("Status", out var statusProp) && statusProp.GetInt32() == 200)
                return (true, null);

            var errorMessage = envelope.TryGetProperty("ErrorBody", out var errProp)
                ? errProp.GetString()
                : "Entity validation failed.";
            return (false, errorMessage);
        }
    }
}