package slangc.model.expressions;

import slangc.api.BytecodeInstructionWriter;
import slangc.api.Reporter;
import slangc.bytecode.TypeSignature;
import slangc.model.ExpressionModel;
import slangc.model.ExpressionOwner;
import slangc.model.ExpressionResult;
import slangc.model.FieldModel;
import slangc.model.LocalStorageModel;
import slangc.model.Named;
import slangc.model.StorageSlot;
import slangc.model.TypeModel;
import slangc.model.UserTypeModel;
import slangc.parser.Branch;
import slangc.parser.ErrorType;
import slangc.parser.Node;

public class ReferenceExpression extends ExpressionModel {
	private String name;
	private Named resolvedNamedEntity;

	public ReferenceExpression(ExpressionOwner owner, Node source) {
		super(owner, source);
		name = UserTypeModel.plainName(((Branch)source).getSubnode(0));
		// This now waits until expressions are resolved later
		//resolvedNamedEntity = lookupSimpleName(name);
		//sourceFile.annotate(ErrorType.INTERNAL_ERROR, "Unrecognised expression (Internal error/TODO)");
	}

	@Override
	public void dump(Reporter reporter, String indent, String incr) {
		reporter.note("DUMP", indent + "> Reference expression '" + name + "' -> " + resolvedNamedEntity);
		dumpResolved(reporter, indent + incr, incr);
	}
	
	public String getName() {
		return name;
	}
	
	public Named getResolvedNamedEntity() {
		return resolvedNamedEntity;
	}
	
	@Override
	public ExpressionModel[] getSubexpressions() {
		return NO_SUBEXPRESSIONS;
	}

	@Override
	protected ExpressionResult resolveResult() {
		if (resolvedNamedEntity == null) {
			resolvedNamedEntity = lookupSimpleName(name);
		}
		//System.err.println("Resolved to " + resolvedNamedEntity);
		if (resolvedNamedEntity == null) {
			if (!(getOwner() instanceof SubreferenceExpression)) {
				getSource().annotate(ErrorType.INTERNAL_ERROR, "Failed to resolve '" + name + "'");
			}
			return new ExpressionResult.StartOfName(name);
		} else if (resolvedNamedEntity instanceof TypeModel) {
			return new ExpressionResult.PointsToType((TypeModel) resolvedNamedEntity);
		} else if (resolvedNamedEntity instanceof StorageSlot) {
			return new ExpressionResult.PointsToStorageSlot((StorageSlot) resolvedNamedEntity);
		} else {
			throw new Error("Reference resolved to invalid entity: " + resolvedNamedEntity);
		}
	}
	
	@Override
	public TypeSignature innerGenerate(BytecodeInstructionWriter w) {
		if (getResolvedNamedEntity() instanceof FieldModel) {
			FieldModel f = (FieldModel)getResolvedNamedEntity();
			if (!f.isStatic()) {
				OuterThisExpression.generatePossibleOuterThis(w, (UserTypeModel)getMethodOrField().getOwner(), f.getOwner());
			}
			w.genLoad(f.getFieldSignature());
			return f.getFieldSignature().storageType;
		} else if (getResolvedNamedEntity() instanceof LocalStorageModel) {
			LocalStorageModel l = (LocalStorageModel)getResolvedNamedEntity();
			// TODO: Handle upvalues!
			w.genLoadLocalOrParam(l.getStorageType().getTypeSignature(), l.getIndex());
			return l.getStorageType().getTypeSignature();
		} else {
			w.genError("TODO: innerGenerate for " + Type.of(this) + " with " + getResolvedNamedEntity());
		}
		return null;
	}
	
	@Override
	public void generateStore(BytecodeInstructionWriter w, TypeSignature storing) {
		if (getResolvedNamedEntity() instanceof FieldModel) {
			FieldModel f = (FieldModel)getResolvedNamedEntity();
			if (!f.isStatic()) {
				OuterThisExpression.generatePossibleOuterThis(w, (UserTypeModel)getMethodOrField().getOwner(), f.getOwner());
			}
			w.genStore(f.getFieldSignature());
		} else if (getResolvedNamedEntity() instanceof LocalStorageModel) {
			LocalStorageModel l = (LocalStorageModel)getResolvedNamedEntity();
			// TODO: Handle upvalues!
			w.genStoreLocalOrParam(l.getStorageType().getTypeSignature(), l.getIndex());
		} else {
			w.genError("TODO: generateStore for " + getResolvedNamedEntity());
		}
	}

	public TypeModel resolveType(Node n) {
		return super.resolveType(n); // TODO: Better support for interfaces
	}
}