using System.Collections.Generic;
using System.Text;
using System.Linq;
using Sockeye.Models;

namespace Sockeye.DataList
{
    internal class SqlSelectBuilderResult
    {
        internal Dictionary<string, int> map { get; set; }
        internal string Select { get; set; }
    }
    internal static class DataListSqlSelectBuilder
    {

        //Build the SELECT portion of a list query based on the columns
        internal static SqlSelectBuilderResult BuildForDataTableListResponse(List<DataListFieldDefinition> objectFieldsList, List<string> columns)
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("SELECT ");
            //keep track of which custom fields columns were added already
            //this ensures that if there is more than one set of custom fields like from two different objects in the list
            //only unique ones will be returned by query           
            //map sql column name to ordinal name
            Dictionary<string, int> map = new Dictionary<string, int>();
            int nOrdinal = 0;

            var firstColumnAdded = false;
            foreach (string ColumnName in columns)
            {
                DataListFieldDefinition o = objectFieldsList.FirstOrDefault(z => z.FieldKey == ColumnName);
#if (DEBUG)
                //Developers little helper
                if (o == null)
                {                     
                    throw new System.ArgumentNullException($"## DEV ERROR in DataListSqlSelectBuilder.cs:BuildForDataTableListResponse() field {ColumnName} specified in columns was NOT found in the data list's ObjectFields list, a defined fieldkey name differs from the columns key name");
                }
#endif
                if (o != null)
                {//Ignore missing fields in production
                    if (o.IsCustomField)
                    { //if any are custom field then add custom fields column to query
                        var CustomFieldSqlColumnName = o.GetSqlValueColumnName();
                        //has it been added yet?
                        if (!map.ContainsKey(CustomFieldSqlColumnName))
                        { //nope
                            if (firstColumnAdded)
                                sb.Append(", ");
                            sb.Append(CustomFieldSqlColumnName);
                            firstColumnAdded = true;
                            map.Add(CustomFieldSqlColumnName, nOrdinal++);
                        }
                    }
                    else
                    {
                        var valueColumnName = o.GetSqlValueColumnName();
                        if (!map.ContainsKey(valueColumnName))
                        {
                            if (firstColumnAdded)
                                sb.Append(", ");
                            sb.Append(valueColumnName);
                            firstColumnAdded = true;
                            map.Add(valueColumnName, nOrdinal++);
                        }

                        //does it also have an ID column?
                        var idColumnName = o.SqlIdColumnName;
                        if (!string.IsNullOrWhiteSpace(idColumnName))
                        {
                            if (!map.ContainsKey(idColumnName))
                            {
                                if (firstColumnAdded)
                                    sb.Append(", ");
                                sb.Append(idColumnName);
                                firstColumnAdded = true;
                                map.Add(idColumnName, nOrdinal++);
                            }
                        }

                        //does it also have an openable SockType column?
                        var sockTypeColumnName = o.SqlATypeColumnName;
                        if (!string.IsNullOrWhiteSpace(sockTypeColumnName))
                        {
                            if (!map.ContainsKey(sockTypeColumnName))
                            {
                                if (firstColumnAdded)
                                    sb.Append(", ");
                                sb.Append(sockTypeColumnName);
                                firstColumnAdded = true;
                                map.Add(sockTypeColumnName, nOrdinal++);
                            }
                        }

                        //does it also have a Color column?
                        var ayaColorColumnName = o.SqlColorColumnName;
                        if (!string.IsNullOrWhiteSpace(ayaColorColumnName))
                        {
                            if (!map.ContainsKey(ayaColorColumnName))
                            {
                                if (firstColumnAdded)
                                    sb.Append(", ");
                                sb.Append(ayaColorColumnName);
                                firstColumnAdded = true;
                                map.Add(ayaColorColumnName, nOrdinal++);
                            }
                        }
                    }
                }
            }
            return new SqlSelectBuilderResult() { map = map, Select = sb.ToString() };
        }//eom


        //Build the SELECT portion of a list query but only to return rowid's
        internal static string BuildForIdListResponse(List<DataListFieldDefinition> fieldDefinitions, DataListSelectedProcessingOptions dataListSelectionOptions)
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("SELECT ");
            //note: only need rowid column for these queries, the where conditions don't rely on any defined column names as they explicitly refer to the exact identifier known to postgres      
            //Note: IsRowId field should *always* exist for any list that is intended to be used in an idlist response
            var o = fieldDefinitions.FirstOrDefault(z => z.IsRowId == true);
            sb.Append(o.SqlIdColumnName);
            return sb.ToString();
        }//eom
    }//eoc
}//ens