using System;
using System.Text;
using System.Reflection.Emit;


/* Z# Symbol Table Nodes:
 * Every named object in a program is stored in an Symbol node.
 * Every scope has a list of Symbols declared within it.
 */

public class Symbol
{
    public enum Kind { Const, Global, Field, Arg, Local, Type, Meth, Prog }

    public Kind kind;
    public string name;
    public Struct type;
    public Symbol next;                // next Symbol node in this scope
    public int val;                    // Const: value;
    public int adr;                    // Field, Arg, Local: order of declaration in scope
    public int nArgs;                  // Meth: # of arguments
    public int nLocs;                  // Meth: # of local variables
    public Symbol locals;              // Meth: arguments, then local variables; Prog: symbol table of program

    // these fields are necessary for the building the assembly with System.Reflection.Emit
    internal MethodBuilder meth;       // Method: builder for metadata and CIL
    internal FieldBuilder fld;         // Field: builder for metadata
    internal ConstructorBuilder ctor;  // Type: builder for metadata and CIL

    public Symbol (Kind kind, string name, Struct type)
    {
        this.kind = kind;
        this.name = name;
        this.type = type;
    }

    public override string ToString ()
    {
        Symbol cur;
        StringBuilder sb = new StringBuilder();

        sb.AppendFormat("{0}: {1}, {2}", name, kind, type);
        switch (kind) {
            case Kind.Const:
                sb.AppendFormat(" ={0}", val);
                break;
            case Kind.Arg: case Kind.Local:
                sb.AppendFormat(", {0}", adr);
                break;
            case Kind.Meth:
                sb.AppendFormat(", {0}, {1}", nArgs, nLocs);
                cur = locals;
                int i = 0;
                while (cur != null) {
                    sb.AppendFormat("{0}-----{3}[{1}]={2}", Environment.NewLine, i, cur,
                            (cur.kind == Kind.Arg) ? "arg" : "loc");
                    cur = cur.next;
                    ++i;
                }
                if (nArgs + nLocs > 0) {
                    sb.AppendFormat("{0}", Environment.NewLine);
                }
                break;
            case Kind.Prog:
                sb.AppendFormat("{0}Declarations in program:{0}", Environment.NewLine);
                cur = locals;
                while (cur != null) {
                    sb.AppendFormat("{1}{0}", Environment.NewLine, cur.ToString());
                    cur = cur.next;
                }
                sb.AppendFormat("End of program.{0}", Environment.NewLine);
                break;
        }

        return sb.ToString();
    }
}