//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="ExpSyntaxAnalyzer.CaseOf.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.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using ExpKeyword = StgSharp.Script.Express.ExpressCompile.Keyword;

namespace StgSharp.Script.Express
{
    public partial class ExpSyntaxAnalyzer
    {

        private bool AppendToken_CaseOf( Token t )
        {
            Token op;
            ExpSyntaxNode root;
            switch( t.Value )
            {
                case ExpKeyword.Case:
                    CaseOfStateCache state = new CaseOfStateCache( t );
                    _cache.CurrentDepthMark.StateCache = state;
                    state.CurrentState = t.Value;
                    return true;
                case ExpKeyword.Of:
                    state = _cache.StateOfCurrentDepth<CaseOfStateCache>();
                    while( _cache.TryPopOperator( out op ) ) {
                        ConvertAndPushOneOperator( op );
                    }
                    _cache.PopOperand( out _, out root );
                    state.CaseExpression = root;
                    state.CurrentState = t.Value;
                    return true;
                case ":":
                    state = _cache.StateOfCurrentDepth<CaseOfStateCache>();
                    if( state.CurrentState != ExpKeyword.Of && state.CurrentState !=
                        ExpKeyword.Otherwise )
                    {
                        root = _cache.PackAllStatements();
                        state.CloseCurrentCase( root );
                    }
                    while( _cache.TryPopOperator( out op ) ) {
                        ConvertAndPushOneOperator( op );
                    }
                    if( !_cache.PopOperand( out _, out root ) )
                    {
                        // sth wrong, case expression cannot generate;
                    }
                    state.CurrentCase = root;
                    return true;
                case ExpKeyword.Otherwise:
                    state = _cache.StateOfCurrentDepth<CaseOfStateCache>();
                    root = _cache.PackAllStatements();
                    state.CloseCurrentCase( root );
                    state.CurrentState = t.Value;
                    return true;
                case ExpKeyword.EndCase:
                    state = _cache.StateOfCurrentDepth<CaseOfStateCache>();
                    root = _cache.PackAllStatements();
                    state.CloseCurrentCase( root );
                    root = new ExpSwitchNode(
                        state.Begin, state.CaseExpression, state.DefaultCase, state.Cases );
                    _cache.DecreaseDepth();
                    _cache.StatementsInDepth.Push( root );
                    return true;
                default:
                    AppendToken_common( t );
                    return true;
            }
        }

        private class CaseOfStateCache : ICompileDepthState
        {

            public CaseOfStateCache( Token t )
            {
                Begin = t;
            }

            public Dictionary<ExpSyntaxNode, ExpSyntaxNode> Cases { get; } = new Dictionary<ExpSyntaxNode, ExpSyntaxNode>(
                );

            public ExpSyntaxNode CaseExpression { get; set; }

            public ExpSyntaxNode DefaultCase { get; set; }

            public ExpSyntaxNode CurrentCase { get; set; }

            public string CurrentState { get; set; }

            public Token Begin { get; init; }

            public void CloseCurrentCase( ExpSyntaxNode root )
            {
                Cases.Add( CurrentCase, root );
            }

        }

    }
}