using Canon.Core.CodeGenerators;
using Canon.Core.Enums;
using Canon.Core.SemanticParser;

namespace Canon.Core.SyntaxNodes;

public class VarDeclarations : NonTerminatedSyntaxNode
{
    public override NonTerminatorType Type => NonTerminatorType.VarDeclarations;

    /// <summary>
    /// 声明的变量列表
    /// </summary>
    public IEnumerable<(IdentifierList, TypeSyntaxNode)> Variables => EnumerateVariables();

    public static VarDeclarations Create(List<SyntaxNodeBase> children)
    {
        return new VarDeclarations { Children = children };
    }

    private IEnumerable<(IdentifierList, TypeSyntaxNode)> EnumerateVariables()
    {
        if (Children.Count == 0)
        {
            yield break;
        }

        VarDeclaration declaration = Children[1].Convert<VarDeclaration>();

        while (true)
        {
            yield return declaration.Variable;

            if (declaration.IsRecursive)
            {
                declaration = declaration.Children[0].Convert<VarDeclaration>();
            }
            else
            {
                break;
            }
        }
    }

    public override void GenerateCCode(CCodeBuilder builder)
    {
        foreach (var pair in Variables.Reverse())
        {
            //BasicType定义
            if (pair.Item2.Children.Count == 1)
            {
                //输出类型
                pair.Item2.GenerateCCode(builder);
                //输出idList
                pair.Item1.GenerateCCode(builder);
                builder.AddString(";");
            }
            //array定义
            else
            {
                //构造出C语言形式的数组下标定义
                string arrayPeriod = "";
                var ranges = pair.Item2.Children[2]
                    .Convert<Period>().Ranges;
                PascalType pascalType = pair.Item2.Children[5].Convert<BasicType>().TryGetPascalType();

                foreach (var range in ranges)
                {
                    int low = int.Parse(range.Item1.LiteralValue);
                    int high = int.Parse(range.Item2.LiteralValue);
                    arrayPeriod = "[" + System.Convert.ToString(high-low+1) + "]" + arrayPeriod;
                    pascalType = new PascalArrayType(pascalType, low, high); //嵌套地构造出多维数组
                }

                //依次定义每一个符号
                foreach (var id in pair.Item1.Identifiers.Reverse())
                {
                    pair.Item2.Children[5].GenerateCCode(builder);
                    builder.AddString(" " + id.IdentifierName + arrayPeriod + ";");
                    //写入符号表
                    builder.SymbolTable.TryAddSymbol(new Symbol()
                    {
                        SymbolName = id.IdentifierName, SymbolType = pascalType, Reference = false
                    });
                }
            }
        }
    }
}