//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="ExpSwitchToken.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Text;

namespace StgSharp.Script.Express
{
    public class ExpSwitchToken : ExpToken
    {

        private Dictionary<ExpToken, List<ExpToken>> _cases;
        private ExpToken _target;
        private List<ExpToken> _default;

        public ExpSwitchToken(
                       string name,
                       ExpSchema context,
                       ExpToken target,
                       IEnumerable<ExpToken> @default,
                       params (ExpToken label, IEnumerable<ExpToken> op)[] cases )
            : base( name, context )
        {
            _target = target;
            if( @default == null ) {
                _default = new List<ExpToken>();
            } else {
                _default = new List<ExpToken>( @default );
            }
            _cases = new Dictionary<ExpToken, List<ExpToken>>();
            foreach( (ExpToken label, IEnumerable<ExpToken> op) item in cases ) {
                if( item.op == null ) {
                    _cases.Add( item.label, new List<ExpToken>() );
                } else {
                    _cases.Add( item.label, new List<ExpToken>( item.op ) );
                }
            }
        }

        public List<ExpToken> this[ ExpToken index ]
        {
            get
            {
                if( _cases.TryGetValue( index, out List<ExpToken>? ret ) ) {
                    return ret;
                }
                return _default;
            }
        }

        /// <summary>
        /// Adds an expression to certain <see langword="case" />. The added expression will be run
        /// at last.
        /// </summary>
        /// <param name="label"> Label of case to add operation </param>
        /// <param name="expressionRoot"> Root token of the expression to be added. </param>
        /// <exception cref="ExpCaseNotFoundException"> Cannot fine the case label in current witch expression. </exception>
        public void AddOperationToCase(
                            ExpToken label,
                            ExpToken expressionRoot )
        {
            AssertSchemaInclude( expressionRoot );
            if( _cases.TryGetValue( label, out List<ExpToken>? op ) ) {
                op.Add( expressionRoot );
            } else {
                throw new ExpCaseNotFoundException( this, label );
            }
        }

        public void AddOperationToDefault( ExpToken expressionRoot )
        {
            if( expressionRoot != null ) {
                _default.Add( expressionRoot );
            }
        }

        public bool ContainsCase( ExpToken token )
        {
            return _cases.ContainsKey( token );
        }

    }
}