using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static ServiceShared.Models.Database.Results;
using static ServiceShared.Models.Response.Notification;

namespace ServiceShared.HL7
{
    public static class Parser
    {
        public static Models.HL7.MDM GetMDM(string filename)
        {
            Models.HL7.MDM result = null;

            try
            {
                if(!string.IsNullOrEmpty(filename) && File.Exists(filename))
                {
                    string[] lines = File.ReadAllLines(filename);

                    if(lines != null && lines.Length > 0)
                    {
                        result = new Models.HL7.MDM();
                        result.TimeStamp = DateTime.Now;

                        string base64Content = "";

                        foreach (string line in lines)
                        {
                            string[] values = line.Split('|');

                            if(values != null && values.Length > 0)
                            {
                                string segment = values[0].ToLower();

                                if(segment == "evn")
                                {
                                    if (values.Length > 2 && !string.IsNullOrEmpty(values[2]))
                                    {
                                        DateTime outTimestamp = default(DateTime);

                                        if (DateTime.TryParseExact(values[2], "yyyyMMddHHmmss", CultureInfo.InvariantCulture, DateTimeStyles.None, out outTimestamp) && outTimestamp != default(DateTime))
                                        {
                                            result.TimeStamp = outTimestamp;
                                        }
                                    }

                                    if (values.Length > 3 && !string.IsNullOrEmpty(values[3]))
                                    {
                                        string results_status = values[3];
                                        ResultsStatus outResultsStatus = ResultsStatus.NONE;

                                        if (!string.IsNullOrEmpty(results_status) && Enum.TryParse<ResultsStatus>(results_status, out outResultsStatus))
                                        {
                                            result.ResultsStatus = outResultsStatus;
                                        }
                                    }
                                }
                                else if(segment == "pid")
                                {
                                    result.PatId = (values.Length > 2 ? values[2] : null);
                                    result.Birthday = (values.Length > 3 ? values[3] : null);
                                    result.Zip = (values.Length > 4 ? values[4] : null);
                                    result.UDID = (values.Length > 5 ? values[5] : null);
                                }
                                else if (segment == "txa")
                                {
                                    result.SampleId = (values.Length > 2 ? values[2] : null);
                                    result.PGSInitial = (values.Length > 3 ? values[3] : null);
                                }
                                else if(segment == "obx" && values.Length > 5)
                                {
                                    base64Content += values[5].Replace("^Application^PDF^Base64^", "");
                                }
                                else if(segment != "msh" && segment != "evn" && segment != "pid" && segment != "txa" && segment != "obx")
                                {
                                    base64Content += line;
                                }
                            }
                        }

                        if(!string.IsNullOrEmpty(base64Content))
                        {
                            result.Base64Content = base64Content;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Log.Error(ex, "ServiceShared.HL7.Parser", "GetMDM");
            }

            if(result != null && 
               (string.IsNullOrEmpty(result.Zip) ||     
               string.IsNullOrEmpty(result.UDID) ||
               string.IsNullOrEmpty(result.Birthday) ||
               string.IsNullOrEmpty(result.SampleId) ||
               result.ResultsStatus == ResultsStatus.NONE))
            {
                result = null;
            }

            return result;
        }
    }
}