package slangc.model.statements;

import java.util.ArrayList;

import slangc.api.BytecodeInstructionWriter;
import slangc.api.Reporter;
import slangc.bytecode.TypeSignature;
import slangc.model.ClauseModel;
import slangc.model.ExpressionModel;
import slangc.model.ExpressionOwner;
import slangc.model.InnerTypeScope;
import slangc.model.MemberModel;
import slangc.model.StatementModel;
import slangc.model.StatementOwner;
import slangc.model.TypeModel;
import slangc.model.clauses.SwitchMembers;
import slangc.model.expressions.BinaryExpression;
import slangc.parser.Branch;
import slangc.parser.Node;

public class SwitchStatement extends StatementModel implements StatementOwner, ExpressionOwner {
	private ExpressionModel condition;
	private SwitchMembers innerStatement;

	public SwitchStatement(StatementOwner owner, Branch source) {
		super(owner, source);
		condition = ExpressionModel.construct(this, source.getSubnode(1));
		innerStatement = (SwitchMembers) ClauseModel.construct(this, source.getSubnode(3));
	}

	@Override
	public void dump(Reporter reporter, String indent, String incr) {
		reporter.note("DUMP", indent + "> Switch:");
		condition.dump(reporter, indent + incr, incr);
		innerStatement.dump(reporter, indent + incr, incr);
	}
	
	@Override
	public int resolveExpressions() {
		return condition.resolveExpressions() + innerStatement.resolveExpressions();
	}

	//@Override
	public TypeModel resolveType(Node subnode) {
		return getOwner().resolveType(subnode);
	}

	//@Override
	public MemberModel getMethodOrField() {
		return getOwner().getMethodOrField();
	}

	//@Override
	public InnerTypeScope getTypeScope() {
		return getOwner().getTypeScope();
	}
	
	//@Override
	public TypeModel getExpectedResult(ExpressionModel e) {
		// TODO Auto-generated method stub
		return null;
	}
	
	public int countCaseLabels() {
		int nlabels = 0;
		
		for (int i = 0; i < innerStatement.countMembers(); i++) {
			StatementModel s = innerStatement.getMember(i);
			if (s instanceof CaseLabelStatement) {
				nlabels++;
			}
		}
		
		return nlabels;
	}
	
	public CaseLabelStatement[] findCaseLabels() {
		CaseLabelStatement[] labels = new CaseLabelStatement[countCaseLabels()];
		int labelIndex = 0;
		
		for (int i = 0; i < innerStatement.countMembers(); i++) {
			StatementModel s = innerStatement.getMember(i);
			if (s instanceof CaseLabelStatement) {
				labels[labelIndex] = (CaseLabelStatement)s;
				labelIndex++;
			}
		}
		
		return labels;
	}
	
	public DefaultLabelStatement findDefaultLabel() {
		for (int i = 0; i < innerStatement.countMembers(); i++) {
			StatementModel s = innerStatement.getMember(i);
			if (s instanceof DefaultLabelStatement) {
				return (DefaultLabelStatement) s;
			}
		}
		return null;
	}
	
	@Override
	public void innerGenerate(BytecodeInstructionWriter w) {
		BytecodeInstructionWriter.Label defaultLabelA = w.newLabel("switch_defaultA");
		BytecodeInstructionWriter.Label defaultLabelB = w.newLabel("switch_defaultB");
		BytecodeInstructionWriter.Label endLabel = w.newLabel("switch_end");
		
		BytecodeInstructionWriter.Label[] caseLabelsA = new BytecodeInstructionWriter.Label[countCaseLabels()];
		BytecodeInstructionWriter.Label[] caseLabelsB = new BytecodeInstructionWriter.Label[countCaseLabels()];
		for (int i = 0; i < caseLabelsA.length; i++) {
			caseLabelsA[i] = w.newLabel("switch_casea");
			caseLabelsB[i] = w.newLabel("switch_caseb");
		}
		
		CaseLabelStatement[] caseLabelStatemtents = findCaseLabels();
		DefaultLabelStatement defaultLabelStatement = findDefaultLabel();
		
		w.pushBreak(endLabel);
		
		TypeSignature xt = condition.generate(w);
		TypeModel xtm = condition.getResult().getValueType();
		for (int i = 0; i < caseLabelStatemtents.length; i++) {
			w.genDup(xt);
			CaseLabelStatement l = caseLabelStatemtents[i];
			TypeSignature cxt = l.getExpression().generate(w);
			BinaryExpression.generateALUOp(w, xtm, "==", l.getExpression().getResult().getValueType());
			w.genJump(BytecodeInstructionWriter.JumpOp.IFTRUE, caseLabelsA[i]);
		}
		//w.genDrop(xt);
		w.genJump(BytecodeInstructionWriter.JumpOp.GOTO, defaultLabelA);
		
		int currentLabelIndex = 0;
		for (int i = 0; i < innerStatement.countMembers(); i++) {
			StatementModel s = innerStatement.getMember(i);
			if (s instanceof CaseLabelStatement) {
                                w.genJump(BytecodeInstructionWriter.JumpOp.GOTO, caseLabelsB[currentLabelIndex]);
                                w.labelHere(caseLabelsA[currentLabelIndex]);
                                w.genDrop(xt);
                                w.labelHere(caseLabelsB[currentLabelIndex]);
				currentLabelIndex++;
			} else if (s instanceof DefaultLabelStatement) {
				w.genJump(BytecodeInstructionWriter.JumpOp.GOTO, defaultLabelB);
                                w.labelHere(defaultLabelA);
                                w.genDrop(xt);
                                w.labelHere(defaultLabelB);
			} else {
				s.generate(w);
			}
		}
		
		if (defaultLabelStatement == null) {
                        w.genJump(BytecodeInstructionWriter.JumpOp.GOTO, defaultLabelB);
			w.labelHere(defaultLabelA);
                        w.genDrop(xt);
                        w.labelHere(defaultLabelB);
		}
		
		w.popBreak(endLabel);
		
		w.labelHere(endLabel);
	}

/*
	public MethodModel[] lookupSimpleMethod(String name) {
		// TODO: Better interface support
		return super.lookupSimpleMethod(name);
	}

	public slangc.model.Named lookupSimpleName(String name) {
		// TODO: Better interface support
		return super.lookupSimpleName(name);
	}*/
}