import java.io.*;
import java.util.*;

public class x86coder implements amvisitor<String>
{
    PrintWriter pr;
    codeblock cb=null; // code
    ArrayList<String> strs; // string constants in the program

    String println(String s)  // encapsulate try-catch
    { 
	try {
	    pr.println(s);
	} catch (Exception ie) {System.out.println(ie); System.exit(1);}
	return s;
    }

    // should let amcoder collect all strings
    public x86coder(String prefix, codeblock c, ArrayList<String> scs)
    {
	cb = c;  strs = scs;  setup(prefix);
    }

    void setup(String prefix)
    {
	am7c.wordsize=32; 
	am7c.regpool = new String[4];
	am7c.regpool[0]="edx";
	am7c.regpool[1]="ebx";
	am7c.regpool[2]="ecx";
	am7c.regpool[3]="edi";
	am7c.sp = new register("esp"); // top of stack
	am7c.bp = new register("ebp"); // base of stack
	am7c.thisp = new register("esi"); // "this" object
	am7c.rtp = new register("eax"); // return val 
	am7c.reserved = new register("eax");
	try {
	    String fname = prefix+".s";
	    pr = new PrintWriter(new FileWriter(fname));

	    pr.println("\t.file\t\""+fname+"\"");
	    pr.println("\t.section\t .rodata");
	    for(int i=0;i<strs.size();i++)
		{
		    pr.println(".STR"+i+":");
		    pr.println("\t.string \""+strs.get(i)+"\"");
		}
	    pr.println("\t.text");
	} catch (IOException ie) {System.out.println(ie); System.exit(1);}
    }//constructor (with setup

    public void visitall() throws Exception
    {
	if (cb!=null)
	    { cb.accept(this); }
	pr.close();
    }

    public String visit(directive d)
    {
	return println(".globl "+d.val);
    }
    public String visit(label lab)
    {
	return println(lab.val+":");
    }
    public String visit(immediate imm)
    {
	if (imm.lab!=null) return "$"+imm.lab;
	else return "$"+imm.val;
    }
    public String visit(mem m)
    {
	String s = "";
	if (m.base!=null) s=m.base.accept(this);
	if (m.index!=null) 
	    {
		s=s+","+m.index.accept(this);
		if (m.increment!=0) s+= ","+m.increment;
	    }
	s = "(" + s + ")";
	if (m.offset!=0) s = m.offset+""+s;
	return s;
    }
    public String visit(register r)
    {
	if (r.ri>=0) return "%"+am7c.regpool[r.ri];
	//	else return "%"+r.special;
	switch(r.special)
	    {
	    case "sp": return "%esp";
	    case "bp": return "%ebp";
	    case "thisp": return "%esi";
	    default: return "%eax";
	    }
    }
    public String visit(fcall fc)
    {
	return println("\tcall  "+fc.dst.val);
    }
    public String visit(freturn fr)
    {
	return println("\tret");
    }
    public String visit(aluop op)
    {
	String src=null;
	if (op.src!=null) src = op.src.accept(this);
	String dst = op.dst.accept(this);
	String s="";
	switch(op.opcode)
	    {
	    case "+": s="addl"; break;
	    case "*": s="imul"; break;
	    case "-": s="subl"; break;
	    case "/": s="idiv"; break; // not supported
	    case "&&": s="andl"; break;
	    case "||": s="orl"; break; // not supported
	    case "!":  s="not"; break;
	    case "cmp": s="cmp"; break;
	    default: s=null;
	    }
	if (s==null)  // must be compare op
	    {
		s = "\txor   %eax, %eax\n";
		s += "\tcmp   "+src+", "+dst+"\n";
		if (op.opcode.equals("=="))
		    s+= "\tsete  %al";
		else if (op.opcode.equals("<")) // opcode must be <
		    s+= "\tsetl  %al";
		return println(s);
	    }	
	if (s.equals("not"))
	    {
		s = "\tbtc   $0, "+dst;
		return println(s);
	    }
	if (src!=null)
	    {  //if (s.equals("cmp")) s = "\t"+s+"   "+dst+", "+src; else 
	       s = "\t"+s+ "  "+src+", "+dst;
	    }
	else s = "\t"+s+"  "+dst;
	return println(s);
    }//aluop
    public String visit(stackalloc sa)
    {
	int abssize = sa.size;
	if (abssize==0) return "";
	if (abssize<0) abssize *=-1;
	int size = stackalloc.align(abssize) * stackalloc.direction;
	if (sa.size<0) size *= -1;
	return println("\taddl  $"+size+", %esp");
    }
    public String visit(move mv)
    {
	String s = mv.src.accept(this);
	String d = mv.dst.accept(this);
	if (s.equals(d)) return "";
	if ((mv.src instanceof mem) && (mv.dst instanceof mem)) // mem-mem op
	    {
		String t = "\tmovl  "+s+", %eax\n";
		t+= "\tmovl  %eax, "+d;
		return println(t);
	    }
	return println("\tmovl  "+s+", "+d);
    }
    public String visit(push ph)
    {
	if (ph.src!=null) return println("\tpushl  "+ph.src.accept(this));
	String s = "\tpushl  %edx\n\tpushl  %ebx\n";
	s += "\tpushl  %ecx\n\tpushl  %esi";
	return println(s);
    }
    public String visit(pop ph)
    {
	if (ph.dst!=null) return println("\tpopl  "+ph.dst.accept(this));
	String s = "\tpopl  %esi\n\tpopl  %ecx\n";
	s += "\tpopl  %ebx\n\tpopl  %edx";
	return println(s);
    }
    public String visit(jump j)
    {
	String dst;
	if (j.operdst!=null) dst = j.operdst.accept(this);
	else dst = j.dst.val;
	if (j.cond==null) return println("\tjmp   "+dst);
	return println("\tj"+j.cond+"    "+dst);
    }

    public String visit(nop n)
    {
	return println("\tnop");
    }

    public String visit(nothing n) { return ""; }

    public String visit(unpush up)
    {
	String s="\tsubl  $"+(stackalloc.direction*am7c.wordsize/8)+", %esp";
	return println(s);
    }

    public String visit(codeblock cb)
    {
	//System.out.println("CODEBLOCK: "+cb.comment);      
	String s ="";
	if (cb.comment.equals("main")) 
	    s += ".globl "+cb.comment;
	if (!s.equals("")) println(s);
	for(operation op:cb.ops) 
	    {
		op.accept(this);
	    }
	return s;
    }
}//x86coder