using PostFundManagement.Domain.Errors;
using PostFundManagement.Domain.Security.Configuration;
using PostFundManagement.Domain.Security.Models;
using PostFundManagement.Domain.Security.Sdk;

namespace PostFundManagement.Application.Services.Shared;

public sealed class TokenService(ISecurityConnectApi connectApi, IOptions<SecurityClientSettings> clientOptions)
{
    private readonly SecurityClientSettings clientSettings = clientOptions.Value;

    public async Task<Result<Domain.Security.Models.TokenResponse>> GenerateAsync(CancellationToken cancellationToken = default) =>
        await Result.Try((Func<Task<Result<Domain.Security.Models.TokenResponse>>>)(async () =>
        {
            using var response = await connectApi.GetToken(new Domain.Security.Models.TokenRequest
            {
                ClientId = clientSettings.ClientId,
                ClientSecret = clientSettings.ClientSecret,
                GrantType = clientSettings.GrantType,
                Scope = clientSettings.Scope,
            }, cancellationToken);

            var contentRaw = await response.Content.ReadAsStringAsync(cancellationToken);

            if (string.IsNullOrWhiteSpace(contentRaw))
                return Result.Fail(ValidationError.Create($"The authentication endpoint returned an empty payload. Status code: {response.StatusCode}"));

            if (response.IsSuccessStatusCode)
            {
                var tokenResponse = JsonSerializer.Deserialize<Domain.Security.Models.TokenResponse>(contentRaw);

                return Result.FailIf(string.IsNullOrWhiteSpace(tokenResponse?.AccessToken),
                    NotFoundError.Create("Authentication succeeded, but no access token was found in the response payload."))
                            .ToResult(tokenResponse!);
            }

            return await Result.Try((Func<Task<Result<Domain.Security.Models.TokenResponse>>>)(async () =>
            {
                var errorResult = JsonSerializer.Deserialize<TokenErrorResponse>(contentRaw);

                return Result.OkIf(errorResult is not null, 
                    CreateError.Create($"{errorResult!.Error}: {errorResult.ErrorDescription}"));
            }));
        }));
}