using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.SQLite;

namespace BizHawk.Client.ApiHawk
{
	public sealed class SqlApi : ISql
	{
		public SqlApi() : base()
		{ }

		SQLiteConnection m_dbConnection;
		string connectionString;

		public string CreateDatabase(string name)
		{
			try
			{
				SQLiteConnection.CreateFile(name);
				return "Database Created Successfully";
			}
			catch (SQLiteException sqlEX)
			{
				return sqlEX.Message;
			}

		}

		public string OpenDatabase(string name)
		{
			try
			{
				SQLiteConnectionStringBuilder connBuilder = new SQLiteConnectionStringBuilder();
				connBuilder.DataSource = name;
				connBuilder.Version = 3; //SQLite version 
				connBuilder.JournalMode = SQLiteJournalModeEnum.Wal;  //Allows for reads and writes to happen at the same time
				connBuilder.DefaultIsolationLevel = System.Data.IsolationLevel.ReadCommitted;  //This only helps make the database lock left. May be pointless now
				connBuilder.SyncMode = SynchronizationModes.Off; //This shortens the delay for do synchronous calls.
				m_dbConnection = new SQLiteConnection(connBuilder.ToString());
				connectionString = connBuilder.ToString();
				m_dbConnection.Open();
				m_dbConnection.Close();
				return "Database Opened Successfully";
			}
			catch (SQLiteException sqlEX)
			{
				return sqlEX.Message;
			}
		}

		public string WriteCommand(string query = "")
		{
			if (query == "")
			{
				return "query is empty";
			}
			try
			{
				m_dbConnection.Open();
				string sql = query;
				SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);
				command.ExecuteNonQuery();
				m_dbConnection.Close();

				return "Command ran successfully";

			}
			catch (NullReferenceException nullEX)
			{
				return "Database not open.";
			}
			catch (SQLiteException sqlEX)
			{
				m_dbConnection.Close();
				return sqlEX.Message;
			}
		}

		public dynamic ReadCommand(string query = "")
		{
			if (query == "")
			{
				return "query is empty";
			}
			try
			{
				var table = new Dictionary<string, object>();
				m_dbConnection.Open();
				string sql = "PRAGMA read_uncommitted =1;" + query;
				SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);
				SQLiteDataReader reader = command.ExecuteReader();
				bool rows = reader.HasRows;
				long rowCount = 0;
				var columns = new List<string>();
				for (int i = 0; i < reader.FieldCount; ++i) //Add all column names into list
				{
					columns.Add(reader.GetName(i));
				}
				while (reader.Read())
				{
					for (int i = 0; i < reader.FieldCount; ++i)
					{
						table[columns[i] + " " + rowCount.ToString()] = reader.GetValue(i);
					}
					rowCount += 1;
				}
				reader.Close();
				m_dbConnection.Close();
				if (rows == false)
				{
					return "No rows found";
				}

				return table;

			}
			catch (NullReferenceException)
			{
				return "Database not opened.";
			}
			catch (SQLiteException sqlEX)
			{
				m_dbConnection.Close();
				return sqlEX.Message;
			}
		}
	}
}