using System.Collections.Generic;
using System.Linq;
using AyaNova.Biz;
using Newtonsoft.Json.Linq;
using AyaNova.Api.ControllerHelpers;
using Microsoft.AspNetCore.Mvc;
using AyaNova.Models;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using EnumsNET;

namespace AyaNova.DataList
{
    internal static class DataListFetcher
    {
        internal static async Task<ApiDataListResponse> GetResponseAsync(string DataListKey, AyContext ct, ListOptions listOptions, long UserId, AuthorizationRoles UserRoles)
        {

            var DataList = DataListFactory.GetAyaDataList(DataListKey);

            //was the name not found as a list?
            if (DataList == null)
            {
                throw new System.ArgumentOutOfRangeException($"DataList \"{DataListKey}\" specified does not exist");
            }

            //check rights

            if (!UserRoles.HasAnyFlags(DataList.AllowedRoles))
                throw new System.UnauthorizedAccessException("User roles insufficient for this datalist");

            //do we need to default the listView?
            if (string.IsNullOrWhiteSpace(listOptions.ListView))
            {
                listOptions.ListView = DataList.DefaultListView;
            }

            //parse the list view     
            var ListViewArray = JArray.Parse(listOptions.ListView);


            //Get the field key names in a list from the listview
            List<string> ListViewFieldList = DataList.GetFieldListFromListView(ListViewArray);

            //BUILD THE QUERY                     
            //SELECT FRAGMENT COLUMNS FROM TEMPLATE               
            var qSelectColumns = DataListSqlSelectBuilder.Build(DataList.FieldDefinitions, ListViewFieldList);

            //FROM CLAUSE             
            var qFrom = DataList.SQLFrom;

            var qWhere = string.Empty;
            var qOrderBy = string.Empty;

            //WHERE CLAUSE - FILTER            
            qWhere = DataListSqlFilterCriteriaBuilder.DataFilterToSQLCriteria(DataList.FieldDefinitions, ListViewArray, UserId);

            //ORDER BY CLAUSE - SORT 
            //BUILD ORDER BY 
            qOrderBy = DataListSqlFilterOrderByBuilder.DataFilterToSQLOrderBy(DataList.FieldDefinitions, ListViewArray);

            //LIMIT AND OFFSET CLAUSE - PAGING
            listOptions.Offset = listOptions.Offset ?? ListOptions.DefaultOffset;
            listOptions.Limit = listOptions.Limit ?? ListOptions.DefaultLimit;
            var qLimitOffset = $"LIMIT {listOptions.Limit} OFFSET {listOptions.Offset}";

            //PUT IT ALL TOGETHER
            string qDataQuery = string.Empty;
            string qTotalRecordsQuery = string.Empty;

            qDataQuery = $"{qSelectColumns} {qFrom} {qWhere} {qOrderBy} {qLimitOffset}".Replace("  ", " ");
            qTotalRecordsQuery = $"SELECT COUNT(*) {qFrom} {qWhere}".Replace("  ", " ");

            //RETURN OBJECTS                  
            int returnRowColumnCount = ListViewFieldList.Count();// + 1;//Templates don't have the DF column in them but we need it and it's in the query so plus one
            List<List<AyaFieldData>> rows = new List<List<AyaFieldData>>();
            long totalRecordCount = 0;

            //QUERY THE DB
            using (var command = ct.Database.GetDbConnection().CreateCommand())
            {
                await ct.Database.OpenConnectionAsync();

                //GET DATA RETURN ROWS
                command.CommandText = qDataQuery;
                using (var dr = await command.ExecuteReaderAsync())
                {
                    while (dr.Read())
                    {
                        List<AyaFieldData> row = new List<AyaFieldData>(returnRowColumnCount);

                        //PROCESS THE DF DEFAULT FIRST COLUMN
                        //first column is always the underlying id value of the default record to open for this row in the client ui
                        if (!dr.IsDBNull(0))
                        {
                            row.Add(new AyaFieldData() { v = dr.GetInt64(0) });
                        }
                        else
                        {
#if (DEBUG)
                            throw new System.ArgumentNullException($"DEV ERROR in DataListFetcher.cs: fetching df column for {DataListKey} df value is null, expecting long int record value");
#endif
                        }

                        //GetOrdinal by name is flakey in npgsql so just going by field definition and ordinal numerically
                        int nCurrentColumnPointer = 1;//start at 1 

                        //INSERT REMAINING FIELDS FROM TEMPLATE INTO THE RETURN ROWS LIST
                        foreach (string TemplateField in ListViewFieldList)
                        {
                            if (TemplateField == "df")
                                continue;
                            //get the AyaObjectFieldDefinition
                            AyaDataListFieldDefinition f = DataList.FieldDefinitions.FirstOrDefault(x => x.FieldKey == TemplateField);

                            AyaFieldData AyaField = new AyaFieldData();
                            AyaField.v = dr.GetValue(nCurrentColumnPointer);
                            nCurrentColumnPointer++;

                            if (f.SqlIdColumnName != null)//skip over df column id, it's not there
                            {
                                if (!await dr.IsDBNullAsync(nCurrentColumnPointer))
                                    AyaField.i = dr.GetInt64(nCurrentColumnPointer);

                                nCurrentColumnPointer++;
                            }
                            row.Add(AyaField);
                        }
                        rows.Add(row);
                    }
                }

                //GET TOTAL RECORD COUNT
                command.CommandText = qTotalRecordsQuery;
                using (var dr = await command.ExecuteReaderAsync())
                {
                    if (dr.Read())
                    {
                        totalRecordCount = dr.GetInt64(0);
                    }
                }
            }


            //BUILD THE COLUMNS RETURN PROPERTY JSON FRAGMENT          
            Newtonsoft.Json.Linq.JArray ColumnsJSON = null;

            ColumnsJSON = DataList.GenerateListColumnsJSONFromListView(ListViewArray);

            return new ApiDataListResponse(rows, totalRecordCount, ColumnsJSON);

        }


    }//eoc
}//eons