using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;

namespace ChaosBot.Database
{
    public class QueryBuilderRaw
    {
        private StringBuilder _query;
        private Dictionary<string, object> _parameters;
        private int keyIndex = 0; 

        public QueryBuilderRaw()
        {
            _query = new StringBuilder();
            _parameters = new Dictionary<string, object>();
        }

        public QueryBuilderRaw Append(string text)
        {
            _query.Append(text);
            if (!text.EndsWith(" "))
                _query.Append(" ");
            return this;
        }

        public DataTable Run()
        {
            return Controller.RawQuery(_query.ToString(), _parameters);
        }

        public QueryBuilderRaw Select()
        {
            return Append("SELECT");
        }

        public QueryBuilderRaw Insert(string alternativeAction = null)
        {
            Append("INSERT");
            if (alternativeAction != null)
                Append(alternativeAction);
            return this;
        }

        public QueryBuilderRaw Update(string alternativeAction = null)
        {
            Append("UPDATE");
            if (alternativeAction != null)
                Append(alternativeAction);
            return this;
        }

        public QueryBuilderRaw Delete()
        {
            return Append("DELETE");
        }
        
        public QueryBuilderRaw Distinct()
        {
            return Append("DISTINCT");
        }

        public QueryBuilderRaw Table(string table)
        {
            return Append(table);
        }

        public QueryBuilderRaw FromTable(string table)
        {
            Append("FROM");
            return Table(table);
        }

        public QueryBuilderRaw IntoTable(string table)
        {
            Append("INTO");
            return Table(table);
        }

        public QueryBuilderRaw Columns(List<string> columnList)
        {
            Append("(");
            Append(String.Join(", ", columnList));
            Append(")");
            return this;
        }

        public QueryBuilderRaw Values(Dictionary<string, object> keyValueList)
        {
            Append("VALUES (");
            List<string> parameterKeys = new List<string>();
            foreach (KeyValuePair<string, object> pair in keyValueList)
            {
                string parameterName = AddParameterAndReturnKey(pair.Key, pair.Value);
                parameterKeys.Add(parameterName);
            }
            Append(string.Join(", ", parameterKeys));
            Append(")");
            return this;
        }

        public QueryBuilderRaw Set(Dictionary<string, object> keyValueList)
        {
            Append("SET");
            List<string> parameterKeys = new List<string>();
            foreach (KeyValuePair<string, object> pair in keyValueList)
            {
                string parameterName = AddParameterAndReturnKey(pair.Key, pair.Value);
                parameterKeys.Add($"{pair.Key} = {parameterName}");
            }
            Append(string.Join(", ", parameterKeys));
            return this;
        }

        public QueryBuilderRaw Where(Dictionary<string, FilterValue> whereCondition)
        {
            Append("WHERE");
            foreach (string key in whereCondition.Keys)
            {
                FilterValue value = whereCondition.GetValueOrDefault(key);
                string parameterName = AddParameterAndReturnKey(key, value.Value);
                Append($"{key} {value.Comparison ?? "="} {parameterName}");
            }

            return this;
        }

        public QueryBuilderRaw GroupBy(List<string> groupByList)
        {
            Append("GROUP BY");
            return Append(string.Join(", ", groupByList));
        }

        public QueryBuilderRaw OrderBy(List<string> orderKeys)
        {
            Append("ORDER BY");
            return Append(string.Join(", ", orderKeys));
        }

        public QueryBuilderRaw Limit(int limit)
        {
            return Append($"LIMIT {limit}");
        }

        public QueryBuilderRaw Limit(int limit, int offset)
        {
            return Append($"LIMIT {limit} OFFSET {offset}");
        }

        private void AddParameter(string parameterName, object value)
        {
            _parameters.Add(parameterName, value);
        }

        private string AddParameterAndReturnKey(string key, object value)
        {
            string parameterKey = GetUniqueParameterName(key);
            AddParameter(parameterKey, value);
            return parameterKey;
        }

        private string GetStaticParameterName(string key)
        {
            return $"@databasevalue{key}";
        }

        private string GetUniqueParameterName(string key)
        {
            return $"{GetStaticParameterName(key)}_{keyIndex++}";
        }
    }
}