using FreeSql.DataAnnotations;
using FreeSql.DatabaseModel;
using FreeSql.Internal;
using FreeSql.Internal.Model;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace FreeSql.Sqlite {

	class SqliteCodeFirst : ICodeFirst {
		IFreeSql _orm;
		protected CommonUtils _commonUtils;
		protected CommonExpression _commonExpression;
		public SqliteCodeFirst(IFreeSql orm, CommonUtils commonUtils, CommonExpression commonExpression) {
			_orm = orm;
			_commonUtils = commonUtils;
			_commonExpression = commonExpression;
		}

		public bool IsAutoSyncStructure { get; set; } = true;
		public bool IsQuoteSqlName { get; set; } = true;
		public bool IsSyncStructureToLower { get; set; } = false;
		public bool IsLazyLoading { get; set; } = false;

		static object _dicCsToDbLock = new object();
		static Dictionary<string, (DbType type, string dbtype, string dbtypeFull, bool? isUnsigned, bool? isnullable, object defaultValue)> _dicCsToDb = new Dictionary<string, (DbType type, string dbtype, string dbtypeFull, bool? isUnsigned, bool? isnullable, object defaultValue)>() {
				{ typeof(bool).FullName,  (DbType.Boolean, "boolean","boolean NOT NULL", null, false, false) },{ typeof(bool?).FullName,  (DbType.Boolean, "boolean","boolean", null, true, null) },

				{ typeof(sbyte).FullName,  (DbType.SByte, "smallint", "smallint NOT NULL", false, false, 0) },{ typeof(sbyte?).FullName,  (DbType.SByte, "smallint", "smallint", false, true, null) },
				{ typeof(short).FullName,  (DbType.Int16, "smallint","smallint NOT NULL", false, false, 0) },{ typeof(short?).FullName,  (DbType.Int16, "smallint", "smallint", false, true, null) },
				{ typeof(int).FullName,  (DbType.Int32, "integer", "integer NOT NULL", false, false, 0) },{ typeof(int?).FullName,  (DbType.Int32, "integer", "integer", false, true, null) },
				{ typeof(long).FullName,  (DbType.Int64, "integer","integer NOT NULL", false, false, 0) },{ typeof(long?).FullName,  (DbType.Int64, "integer","integer", false, true, null) },

				{ typeof(byte).FullName,  (DbType.Byte, "int2","int2 NOT NULL", true, false, 0) },{ typeof(byte?).FullName,  (DbType.Byte, "int2","int2", true, true, null) },
				{ typeof(ushort).FullName,  (DbType.UInt16, "unsigned","unsigned NOT NULL", true, false, 0) },{ typeof(ushort?).FullName,  (DbType.UInt16, "unsigned", "unsigned", true, true, null) },
				{ typeof(uint).FullName,  (DbType.Decimal, "decimal(10,0)", "decimal(10,0) NOT NULL", true, false, 0) },{ typeof(uint?).FullName,  (DbType.Decimal, "decimal(10,0)", "decimal(10,0)", true, true, null) },
				{ typeof(ulong).FullName,  (DbType.Decimal, "decimal(21,0)", "decimal(21,0) NOT NULL", true, false, 0) },{ typeof(ulong?).FullName,  (DbType.Decimal, "decimal(21,0)", "decimal(21,0)", true, true, null) },

				{ typeof(double).FullName,  (DbType.Double, "double", "double NOT NULL", false, false, 0) },{ typeof(double?).FullName,  (DbType.Double, "double", "double", false, true, null) },
				{ typeof(float).FullName,  (DbType.Single, "float","float NOT NULL", false, false, 0) },{ typeof(float?).FullName,  (DbType.Single, "float","float", false, true, null) },
				{ typeof(decimal).FullName,  (DbType.Decimal, "decimal", "decimal(10,2) NOT NULL", false, false, 0) },{ typeof(decimal?).FullName,  (DbType.Decimal, "decimal", "decimal(10,2)", false, true, null) },

				{ typeof(TimeSpan).FullName,  (DbType.Time, "bigint","bigint NOT NULL", false, false, 0) },{ typeof(TimeSpan?).FullName,  (DbType.Time, "bigint", "bigint",false, true, null) },
				{ typeof(DateTime).FullName,  (DbType.DateTime, "datetime", "datetime NOT NULL", false, false, new DateTime(1970,1,1)) },{ typeof(DateTime?).FullName,  (DbType.DateTime, "datetime", "datetime", false, true, null) },

				{ typeof(byte[]).FullName,  (DbType.Binary, "blob", "blob", false, null, new byte[0]) },
				{ typeof(string).FullName,  (DbType.String, "nvarchar", "nvarchar(255)", false, null, "") },

				{ typeof(Guid).FullName,  (DbType.Guid, "character", "character(36) NOT NULL", false, false, Guid.Empty) },{ typeof(Guid?).FullName,  (DbType.Guid, "character", "character(36)", false, true, null) },
			};

		public (int type, string dbtype, string dbtypeFull, bool? isnullable, object defaultValue)? GetDbInfo(Type type) {
			if (_dicCsToDb.TryGetValue(type.FullName, out var trydc)) return new (int, string, string, bool?, object)?(((int)trydc.type, trydc.dbtype, trydc.dbtypeFull, trydc.isnullable, trydc.defaultValue));
			if (type.IsArray) return null;
			var enumType = type.IsEnum ? type : null;
			if (enumType == null && type.IsNullableType() && type.GenericTypeArguments.Length == 1 && type.GenericTypeArguments.First().IsEnum) enumType = type.GenericTypeArguments.First();
			if (enumType != null) {
				var newItem = enumType.GetCustomAttributes(typeof(FlagsAttribute), false).Any() ?
					(DbType.Int64, "bigint", $"bigint{(type.IsEnum ? " NOT NULL" : "")}", false, type.IsEnum ? false : true, Enum.GetValues(enumType).GetValue(0)) :
					(DbType.Int32, "mediumint", $"mediumint{(type.IsEnum ? " NOT NULL" : "")}", false, type.IsEnum ? false : true, Enum.GetValues(enumType).GetValue(0));
				if (_dicCsToDb.ContainsKey(type.FullName) == false) {
					lock (_dicCsToDbLock) {
						if (_dicCsToDb.ContainsKey(type.FullName) == false)
							_dicCsToDb.Add(type.FullName, newItem);
					}
				}
				return ((int)newItem.Item1, newItem.Item2, newItem.Item3, newItem.Item5, newItem.Item6);
			}
			return null;
		}

		public string GetComparisonDDLStatements<TEntity>() => this.GetComparisonDDLStatements(typeof(TEntity));
		public string GetComparisonDDLStatements(params Type[] entityTypes) {
			var sb = new StringBuilder();
			var sbDeclare = new StringBuilder();
			foreach (var entityType in entityTypes) {
				if (sb.Length > 0) sb.Append("\r\n");
				var tb = _commonUtils.GetTableByEntity(entityType);
				var tbname = tb.DbName.Split(new[] { '.' }, 2);
				if (tbname?.Length == 1) tbname = new[] { "main", tbname[0] };

				var tboldname = tb.DbOldName?.Split(new[] { '.' }, 2); //旧表名
				if (tboldname?.Length == 1) tboldname = new[] { "main", tboldname[0] };

				var sbalter = new StringBuilder();
				var istmpatler = false; //创建临时表，导入数据，删除旧表，修改
				var isIndent = false;
				if (_orm.Ado.ExecuteScalar(CommandType.Text, $" select 1 from {tbname[0]}.sqlite_master where type='table' and name='{tbname[1]}'") == null) { //表不存在
					if (tboldname != null) {
						if (_orm.Ado.ExecuteScalar(CommandType.Text, $" select 1 from {tboldname[0]}.sqlite_master where type='table' and name='{tboldname[1]}'") == null)
							//模式或表不存在
							tboldname = null;
					}
					if (tboldname == null) {
						//创建表
						sb.Append("CREATE TABLE IF NOT EXISTS ").Append(_commonUtils.QuoteSqlName($"{tbname[0]}.{tbname[1]}")).Append(" (");
						foreach (var tbcol in tb.Columns.Values) {
							sb.Append(" \r\n  ").Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(" ");
							sb.Append(tbcol.Attribute.DbType);
							if (tbcol.Attribute.IsIdentity == true && tbcol.Attribute.DbType.IndexOf("AUTOINCREMENT", StringComparison.CurrentCultureIgnoreCase) == -1) {
								isIndent = true;
								sb.Append(" PRIMARY KEY AUTOINCREMENT");
							}
							sb.Append(",");
						}
						if (isIndent || tb.Primarys.Any() == false)
							sb.Remove(sb.Length - 1, 1);
						else {
							sb.Append(" \r\n  PRIMARY KEY (");
							foreach (var tbcol in tb.Primarys) sb.Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(", ");
							sb.Remove(sb.Length - 2, 2).Append(")");
						}
						sb.Append("\r\n) \r\n;\r\n");
						continue;
					}
					//如果新表，旧表在一个模式下，直接修改表名
					if (string.Compare(tbname[0], tboldname[0], true) == 0)
						sbalter.Append("ALTER TABLE ").Append(_commonUtils.QuoteSqlName($"{tboldname[0]}.{tboldname[1]}")).Append(" RENAME TO ").Append(_commonUtils.QuoteSqlName($"{tbname[1]}")).Append(";\r\n");
					else {
						//如果新表，旧表不在一起，创建新表，导入数据，删除旧表
						istmpatler = true;
					}
				} else
					tboldname = null; //如果新表已经存在，不走改表名逻辑

				//对比字段，只可以修改类型、增加字段、有限的修改字段名；保证安全不删除字段
				var tbtmp = tboldname ?? tbname;
				var dsql = _orm.Ado.ExecuteScalar(CommandType.Text, $" select sql from {tbtmp[0]}.sqlite_master where type='table' and name='{tbtmp[1]}'")?.ToString();
				var ds = _orm.Ado.ExecuteArray(CommandType.Text, $"PRAGMA {_commonUtils.QuoteSqlName(tbtmp[0])}.table_info({_commonUtils.QuoteSqlName(tbtmp[1])})");
				var tbstruct = ds.ToDictionary(a => string.Concat(a[1]), a => {
					var is_identity = false;
					var dsqlIdx = dsql?.IndexOf($"\"{a[1]}\" ");
					if (dsqlIdx > 0) {
						var dsqlLastIdx = dsql.IndexOf('\n', dsqlIdx.Value);
						if (dsqlLastIdx > 0) is_identity = dsql.Substring(dsqlIdx.Value, dsqlLastIdx - dsqlIdx.Value).Contains("AUTOINCREMENT");
					}
					return new {
						column = string.Concat(a[1]),
						sqlType = string.Concat(a[2]).ToUpper(),
						is_nullable = string.Concat(a[3]) == "0",
						is_identity
					};
				}, StringComparer.CurrentCultureIgnoreCase);

				if (istmpatler == false) {
					foreach (var tbcol in tb.Columns.Values) {
						var dbtypeNoneNotNull = Regex.Replace(tbcol.Attribute.DbType, @"NOT\s+NULL", "NULL");
						if (tbstruct.TryGetValue(tbcol.Attribute.Name, out var tbstructcol) ||
						string.IsNullOrEmpty(tbcol.Attribute.OldName) == false && tbstruct.TryGetValue(tbcol.Attribute.OldName, out tbstructcol)) {
							if (tbcol.Attribute.DbType.StartsWith(tbstructcol.sqlType, StringComparison.CurrentCultureIgnoreCase) == false)
								istmpatler = true;
							if (tbcol.Attribute.IsNullable != tbstructcol.is_nullable)
								istmpatler = true;
							if (tbcol.Attribute.IsIdentity != tbstructcol.is_identity)
								istmpatler = true;
							if (tbstructcol.column == tbcol.Attribute.OldName)
								//修改列名
								istmpatler = true;
							continue;
						}
						//添加列
						istmpatler = true;
					}
				}
				if (istmpatler == false) {
					sb.Append(sbalter);
					continue;
				}

				//创建临时表，数据导进临时表，然后删除原表，将临时表改名为原表名
				var tablename = tboldname == null ? _commonUtils.QuoteSqlName($"{tbname[0]}.{tbname[1]}") : _commonUtils.QuoteSqlName($"{tboldname[0]}.{tboldname[1]}");
				var tmptablename = _commonUtils.QuoteSqlName($"{tbname[0]}._FreeSqlTmp_{tbname[1]}");
				//创建临时表
				//创建表
				isIndent = false;
				sb.Append("CREATE TABLE IF NOT EXISTS ").Append(tmptablename).Append(" (");
				foreach (var tbcol in tb.Columns.Values) {
					sb.Append(" \r\n  ").Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(" ");
					sb.Append(tbcol.Attribute.DbType);
					if (tbcol.Attribute.IsIdentity == true && tbcol.Attribute.DbType.IndexOf("AUTOINCREMENT", StringComparison.CurrentCultureIgnoreCase) == -1) {
						isIndent = true;
						sb.Append(" PRIMARY KEY AUTOINCREMENT");
					}
					sb.Append(",");
				}
				if (isIndent || tb.Primarys.Any() == false)
					sb.Remove(sb.Length - 1, 1);
				else {
					sb.Append(" \r\n  PRIMARY KEY (");
					foreach (var tbcol in tb.Primarys) sb.Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(", ");
					sb.Remove(sb.Length - 2, 2).Append(")");
				}
				sb.Append("\r\n) \r\n;\r\n");
				sb.Append("INSERT INTO ").Append(tmptablename).Append(" (");
				foreach (var tbcol in tb.Columns.Values)
					sb.Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(", ");
				sb.Remove(sb.Length - 2, 2).Append(")\r\nSELECT ");
				foreach (var tbcol in tb.Columns.Values) {
					var insertvalue = "NULL";
					if (tbstruct.TryGetValue(tbcol.Attribute.Name, out var tbstructcol) ||
						string.IsNullOrEmpty(tbcol.Attribute.OldName) == false && tbstruct.TryGetValue(tbcol.Attribute.OldName, out tbstructcol)) {
						insertvalue = _commonUtils.QuoteSqlName(tbstructcol.column);
						if (tbcol.Attribute.DbType.StartsWith(tbstructcol.sqlType, StringComparison.CurrentCultureIgnoreCase) == false) {
							var dbtypeNoneNotNull = Regex.Replace(tbcol.Attribute.DbType, @"(NOT\s+)?NULL", "");
							insertvalue = $"cast({insertvalue} as {dbtypeNoneNotNull})";
						}
						if (tbcol.Attribute.IsNullable != tbstructcol.is_nullable)
							insertvalue = $"ifnull({insertvalue},{_commonUtils.FormatSql("{0}", tbcol.Attribute.DbDefautValue)})";
					} else if (tbcol.Attribute.IsNullable == false)
						insertvalue = _commonUtils.FormatSql("{0}", tbcol.Attribute.DbDefautValue);
					sb.Append(insertvalue).Append(", ");
				}
				sb.Remove(sb.Length - 2, 2).Append(" FROM ").Append(tablename).Append(";\r\n");
				sb.Append("DROP TABLE ").Append(tablename).Append(";\r\n");
				sb.Append("ALTER TABLE ").Append(tmptablename).Append(" RENAME TO ").Append(_commonUtils.QuoteSqlName($"{tbname[1]}")).Append(";\r\n");
			}
			return sb.Length == 0 ? null : sb.ToString();
		}

		static object syncStructureLock = new object();
		ConcurrentDictionary<string, bool> dicSyced = new ConcurrentDictionary<string, bool>();
		public bool SyncStructure<TEntity>() => this.SyncStructure(typeof(TEntity));
		public bool SyncStructure(params Type[] entityTypes) {
			if (entityTypes == null) return true;
			var syncTypes = entityTypes.Where(a => dicSyced.ContainsKey(a.FullName) == false).ToArray();
			if (syncTypes.Any() == false) return true;
			lock (syncStructureLock) {
				var ddl = this.GetComparisonDDLStatements(syncTypes);
				if (string.IsNullOrEmpty(ddl)) {
					foreach (var syncType in syncTypes) dicSyced.TryAdd(syncType.FullName, true);
					return true;
				}
				var affrows = _orm.Ado.ExecuteNonQuery(CommandType.Text, ddl);
				foreach (var syncType in syncTypes) dicSyced.TryAdd(syncType.FullName, true);
				return affrows > 0;
			}
		}
		public ICodeFirst ConfigEntity<T>(Action<TableFluent<T>> entity) => _commonUtils.ConfigEntity(entity);
		public ICodeFirst ConfigEntity(Type type, Action<TableFluent> entity) => _commonUtils.ConfigEntity(type, entity);
	}
}