using System.Data;
using System.Text.RegularExpressions;
using Database.Common;
using Insight.Database;

namespace Database.RolesPermissionSystem
{
	public class Setup
	{
		private readonly IDbConnection _db;

		public Setup(IDbConnection db)
		{
			_db = db ?? throw new ArgumentNullException(nameof(db));
		}

		/// <summary>
		/// Creates the system tables in the specified schema within a transaction.
		/// </summary>
		/// <param name="schema">The schema name where the tables will be created.</param>
		public void CreateSystem(string schema)
		{
			if (!Validations.IsValidSchemaName(schema))
				throw new ArgumentException("Invalid schema name", nameof(schema));

			using (var transaction = _db.BeginTransaction())
			{
				try
				{
					CreateRolesTable(schema, transaction);
					CreatePermissionsTable(schema, transaction);
					CreatePermissionTypesTable(schema, transaction);
					CreateRolePermissionsTable(schema, transaction);

					transaction.Commit();
				}
				catch (Exception ex)
				{
					transaction.Rollback();
					throw new InvalidOperationException("Failed to create system tables.", ex);
				}
			}
		}


		private void ExecuteSql(string sql, IDbTransaction transaction)
		{
			if (string.IsNullOrEmpty(sql))
				throw new ArgumentNullException(nameof(sql));

			_db.Execute(sql, transaction: transaction);
		}

		private void CreatePermissionTypesTable(string schema, IDbTransaction transaction)
		{
			var sql = $@"
            CREATE TABLE IF NOT EXISTS {schema}.permission_types (
                id SERIAL PRIMARY KEY,
                name VARCHAR(100) NOT NULL UNIQUE
            )";
			ExecuteSql(sql, transaction);
		}

		private void CreatePermissionsTable(string schema, IDbTransaction transaction)
		{
			var sql = $@"
            CREATE TABLE IF NOT EXISTS {schema}.permissions (
                id SERIAL PRIMARY KEY,
                name VARCHAR(100) NOT NULL UNIQUE,
                type_id INTEGER NOT NULL,
                FOREIGN KEY (type_id) REFERENCES {schema}.permission_types(id)
            )";
			ExecuteSql(sql, transaction);
		}

		private void CreateRolesTable(string schema, IDbTransaction transaction)
		{
			var sql = $@"
            CREATE TABLE IF NOT EXISTS {schema}.roles (
                id SERIAL PRIMARY KEY,
                name VARCHAR(100) NOT NULL UNIQUE
            )";
			ExecuteSql(sql, transaction);
		}

		private void CreateRolePermissionsTable(string schema, IDbTransaction transaction)
		{
			var sql = $@"
            CREATE TABLE IF NOT EXISTS {schema}.role_permissions (
                role_id INTEGER NOT NULL,
                permission_id INTEGER NOT NULL,
                PRIMARY KEY (role_id, permission_id),
                FOREIGN KEY (role_id) REFERENCES {schema}.roles(id),
                FOREIGN KEY (permission_id) REFERENCES {schema}.permissions(id)
            )";
			ExecuteSql(sql, transaction);
		}
	}
}