//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="ExpSyntaxAnalyzer.RepeatLoop"
// 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 Microsoft.CodeAnalysis.CSharp.Syntax;

using System;
using System.Collections.Generic;
using System.ComponentModel.Design.Serialization;
using System.Linq;
using System.Resources;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

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

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

        private Dictionary<string, ExpElementInstance> _tempVariableInLoops { get; } 
            = new Dictionary<string, ExpElementInstance>();

        private bool AppendToken_RepeatLoop(Token t)
        {
            RepeatLoopState state = _cache.StateOfCurrentDepth<RepeatLoopState>();
            if (state == null)
            {
                state = new RepeatLoopState(t);
                _cache.CurrentDepthMark.StateCache = state;
                state.CurrentState = t.Value;
                return true;
            }
            switch (state.CurrentState)
            {
                case ExpKeyword.Repeat:
                    return TryParseRepeatVariable(state, t);
                case ExpKeyword.To:
                    return TryParseRepeatEnding(state, t);
                case ExpKeyword.By:
                    return TryParseRepeatVariable(state, t);
                case ExpKeyword.Until:
                    return TryParseRepeatUntilRegulation(state, t);
                case ExpKeyword.Assignment:
                    return TryParseRepeatBeginning(state, t);
                case ExpKeyword.While:
                    return TryParseRepeatWhileRegulation(state, t);
                case ExpKeyword.Semicolon:
                    if (t.Value != ExpKeyword.EndRepeat)
                    {
                        AppendToken_Common(t);
                        return true;
                    }
                    break;
                default:
                    AppendToken_Common(t);
                    return false;
            }
            ExpSyntaxNode root = _cache.PackAllStatements();
            state.Body = root;
            _cache.DecreaseDepth();
            if (ExpTypeSource.IsNullOrVoid(state.IncrementVariableType))
            {
                root = ExpRepeatNode.Create(
                    state.Position, state.IncrementVariable, state.Begin, state.End, state.IncrementVariable,
                    state.Body, state.UntilExpression, state.WhileExpression);
            } else
            {
                root = ExpRepeatNode.Create(
                    state.Position, state.IncrementVariable.OriginObject, state.Begin, state.End,
                    state.IncrementVariable, state.Body, state.UntilExpression, state.WhileExpression);
            }
            _cache.StatementsInDepth.Push(root);
            _tempVariableInLoops.Remove(state.IncrementVariable.CodeConvertTemplate);
            return true;
        }

        private bool TryParseRepeatBeginning(RepeatLoopState state, Token t)
        {
            switch (t.Value)
            {
                case ExpKeyword.To:
                    state.CurrentState = ExpKeyword.To;
                    while (_cache.TryPopOperator(out Token op)) {
                        ConvertAndPushOneOperator(op);
                    }
                    _cache.PopOperand(out _, out ExpSyntaxNode? root);
                    state.Begin = root;
                    return true;
                default:
                    AppendToken_Common(t);
                    return true;
            }
        }

        private bool TryParseRepeatEnding(RepeatLoopState state, Token t)
        {
            switch (t.Value)
            {
                case ExpKeyword.By:
                    state.CurrentState = ExpKeyword.By;
                    break;
                case ExpKeyword.Until:
                    state.CurrentState = ExpKeyword.Until;
                    break;
                case ExpKeyword.While:
                    state.CurrentState = ExpKeyword.While;
                    break;
                default:
                    AppendToken_Common(t);
                    return true;
            }
            while (_cache.TryPopOperator(out Token op)) {
                ConvertAndPushOneOperator(op);
            }
            _cache.PopOperand(out _, out ExpSyntaxNode? root);
            state.End = root;
            return true;
        }

        private bool TryParseRepeatIncrement(RepeatLoopState state, Token t)
        {
            switch (t.Value)
            {
                case ExpKeyword.Semicolon:
                    state.CurrentState = ExpKeyword.Semicolon;
                    break;
                case ExpKeyword.Until:
                    state.CurrentState = ExpKeyword.Until;
                    break;
                case ExpKeyword.While:
                    state.CurrentState = ExpKeyword.While;
                    break;
                default:
                    AppendToken_Common(t);
                    return true;
            }
            while (_cache.TryPopOperator(out Token op)) {
                ConvertAndPushOneOperator(op);
            }
            _cache.PopOperand(out _, out ExpSyntaxNode? root);
            state.StepIncrement = root;
            return true;
        }

        private bool TryParseRepeatUntilRegulation(RepeatLoopState state, Token t)
        {
            switch (t.Value)
            {
                case ExpKeyword.Semicolon:
                    state.CurrentState = ExpKeyword.Semicolon;
                    break;
                default:
                    AppendToken_Common(t);
                    return true;
            }
            while (_cache.TryPopOperator(out Token op)) {
                ConvertAndPushOneOperator(op);
            }
            _cache.PopOperand(out _, out ExpSyntaxNode? root);
            state.UntilExpression = root;
            return true;
        }

        private bool TryParseRepeatVariable(RepeatLoopState state, Token t)
        {
            switch (t.Value)
            {
                case ExpKeyword.Integer:
                    state.IncrementVariableType = ExpressCompile.ExpInt;
                    return true;
                case
                    ExpKeyword.Real:
                    state.IncrementVariableType = ExpressCompile.ExpReal;
                    return true;
                case ExpKeyword.Assignment:
                    state.CurrentState = ExpKeyword.Assignment;
                    return true;
                default:
                    if (ExpTypeSource.IsNullOrVoid(state.IncrementVariableType))
                    {
                        if ((_local.TryGetMember(t.Value,
                                                   out ExpSyntaxNode? node) &&
                             node is ExpElementInstance instance) ||
                            _tempVariableInLoops.TryGetValue(t.Value, out instance))
                        {
                            state.IncrementVariable = ExpInstanceReferenceNode.MakeReferenceFrom(
                                t, instance);
                            return true;
                        } else
                        {
                            throw new ExpInvalidSyntaxException(
                                $"Variable {t.Value} is not declared or initialized.");
                        }
                    } else
                    {
                        ExpElementInstance variable = state.IncrementVariableType.CreateInstanceNode(t);
                        _tempVariableInLoops.Add(t.Value, variable);
                        state.IncrementVariable = ExpInstanceReferenceNode.MakeReferenceFrom(
                            t, variable);
                        return true;
                    }
            }
        }

        private bool TryParseRepeatWhileRegulation(RepeatLoopState state, Token t)
        {
            switch (t.Value)
            {
                case ExpKeyword.Until:
                    state.CurrentState = ExpKeyword.Until;
                    break;
                default:
                    AppendToken_Common(t);
                    return true;
            }
            while (_cache.TryPopOperator(out Token op)) {
                ConvertAndPushOneOperator(op);
            }
            _cache.PopOperand(out _, out ExpSyntaxNode? root);
            state.WhileExpression = root;
            return true;
        }

        private class RepeatLoopState : ICompileDepthState
        {

            public RepeatLoopState(Token t)
            {
                Position = t;
                UntilExpression = ExpSyntaxNode.Empty;
                WhileExpression = ExpSyntaxNode.Empty;
            }

            public ExpInstanceReferenceNode IncrementVariable { get; set; }

            public ExpSyntaxNode StepIncrement { get; set; }

            public ExpSyntaxNode Begin { get; set; }

            public ExpSyntaxNode End { get; set; }

            public ExpSyntaxNode UntilExpression { get; set; }

            public ExpSyntaxNode WhileExpression { get; set; }

            public ExpSyntaxNode Body { get; set; }

            public ExpTypeSource IncrementVariableType { get; set; }

            public string CurrentState { get; set; }

            public Token Position { get; set; }

        }

    }
}