using Microsoft.AspNetCore.Mvc;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json.Schema;
using System.Reflection;
using System.Text;
using DevLab.JmesPath;
using afd_2._0.webapi.example.JMESPathCustomFunctions;

namespace afd_2._0.webapi.example.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class ExampleCarInsuranceController : ControllerBase
    {
        private readonly JmesPath _jmesPath = new JmesPath();

        /// <summary>
        /// JMESPath expression to check if ageAtReferenceDate of policyHolder >= 18, 
        /// at reference date, which is an attribute of the commonFunctional.
        /// </summary>
        const string cJMESPathExpression =
            "(policy[].party[?entityType == 'policyHolder' && birthDate.ageAtReferenceDate(@, $.commonFunctional[0].referenceDate) >= `18`][] != `[]`)";

        /// <summary>
        /// Constructor
        /// </summary>
        public ExampleCarInsuranceController()
        {
            // Register JamesPath and its custom function.
            _jmesPath = new JmesPath();
            _jmesPath.FunctionRepository.Register<AgeAtReferenceDateFunction>();
        }

        /// <summary>
        /// Operation to add a new insurance
        /// </summary>
        /// <returns></returns>
        [HttpPost("new")]
        public IActionResult NewInsurance()
        {
            try
            {
                // Read example request and afd-schema from embedded resources.
                var request = JObject.Parse(ReadEmbeddedResource("submitPolicy_new_request.json"));
                var schema = JSchema.Parse(ReadEmbeddedResource("submitPolicy_new_request_schema.json"));

                // 1. Check request against AFD-schema
                if (!request.IsValid(schema))
                {
                    return BadRequest(new { message = "The request is invalid against AFD-schema." });
                }

                // 2. Check request against JMESPath Expression(s) using JmesPath custom function ageAtReferenceDate
                if (!bool.Parse(_jmesPath.Transform(request.ToString(), cJMESPathExpression)))
                {
                    return BadRequest(new { message = $"The request is invalid against JMESPath expression."});
                }

                return Ok();
            }
            catch (Exception ex)
            {
                return BadRequest(new { message = $"request failed: {ex.Message}" });
            }
        }

        /// <summary>
        /// </summary>
        /// <param name="request"></param>
        /// <returns></returns>
        private bool ValidateAgainstJmesPath(JObject request)
        {
            var requestJsonString = request.ToString();
            const string PolicyHolderIsOlderThan18AtReferenceDateRule =
                "(policy[].party[?entityType == 'policyHolder' && birthDate.ageAtReferenceDate(@, $.commonFunctional[0].referenceDate) >= `18`][] != `[]`)";
            bool result = bool.Parse(
                _jmesPath.Transform(requestJsonString,
                PolicyHolderIsOlderThan18AtReferenceDateRule
                ));
            return result;
        }

        /// <summary>
        /// Read file 'fileName' from embedded resource
        /// </summary>
        /// <returns>The example request</returns>
        private static string ReadEmbeddedResource(string fileName)
        {
            var resourceName = Assembly.GetExecutingAssembly().GetManifestResourceNames().Single(str => str.EndsWith(fileName));
            using var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName) ?? throw new Exception($"Could not read resourd: {resourceName}");
            using var streamReader = new StreamReader(stream, Encoding.UTF8);
            return streamReader.ReadToEnd();
        }

    }
}