/*******************************************************************************
 * Copyright (c) 2011,2012 NumberFour AG
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     NumberFour AG - initial API and Implementation (Alex Panchenko)
 *******************************************************************************/
package org.eclipse.dltk.javascript.typeinfo;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.dltk.javascript.core.Types;
import org.eclipse.dltk.javascript.typeinfo.model.ParameterKind;

class RFunctionType extends RType implements IRFunctionType {

	private final ITypeSystem typeSystem;
	private final List<IRParameter> parameters;
	private final IRType returnType;

	public RFunctionType(ITypeSystem typeSystem, List<IRParameter> parameters,
			IRType returnType) {
		this.typeSystem = typeSystem;
		this.parameters = parameters;
		this.returnType = returnType;
	}

	public ITypeSystem getTypeSystem() {
		return typeSystem;
	}

	@Override
	public String toString(Set<RType> processed) {
		if (!processed.add(this))
			return JSDocTypeParser.FUNCTION + "(_self)";
		final StringBuilder sb = new StringBuilder();
		sb.append(JSDocTypeParser.FUNCTION);
		sb.append('(');
		int index = 0;
		for (IRParameter parameter : parameters) {
			if (++index != 1) {
				sb.append(", ");
			}
			if (parameter.getKind() == ParameterKind.VARARGS) {
				sb.append("...");
			}
			if (parameter.getType() instanceof RType) {
				sb.append(((RType) parameter.getType()).toString(processed));
			} else {
				sb.append(parameter.getType());
			}
			if (parameter.getKind() == ParameterKind.OPTIONAL) {
				sb.append("=");
			}
		}
		sb.append(')');
		if (returnType != null) {
			sb.append(':');
			if (returnType instanceof RType) {
				sb.append(((RType) returnType).toString(processed));
			} else {
				sb.append(returnType);
			}
		}
		return sb.toString();
	}

	public String getName() {
		return toString(new HashSet<RType>());
	}

	@Override
	public TypeCompatibility isAssignableFrom(IRType type) {
		if (super.isAssignableFrom(type).ok()) {
			return TypeCompatibility.TRUE;
		} else if (type instanceof RFunctionType) {
			RFunctionType funcType = (RFunctionType) type;
			// if return type is null or it is a IRRecordType instance then it
			// is always just fine.
			// RecordType is hard to check, can be type defs with fluent typing.
			TypeCompatibility returnType = (getReturnType() == null || getReturnType() instanceof IRRecordType) ? TypeCompatibility.TRUE
					: TypeCompatibility.FALSE;
			if (returnType == TypeCompatibility.FALSE
					&& funcType.getReturnType() != null
					&& getReturnType() != null) {
				returnType = getReturnType().isAssignableFrom(
						funcType.getReturnType());
			}
			TypeCompatibility paramsType = TypeCompatibility.TRUE;
			if (returnType == TypeCompatibility.TRUE) {
				paramsType = ((funcType.getParameters() == null || funcType
						.getParameters().size() == 0) && (getParameters() == null || getParameters()
						.size() == 0)) ? TypeCompatibility.TRUE
						: TypeCompatibility.FALSE;
				if ((funcType.getParameters() != null && funcType
						.getParameters().size() > 0)
						&& (getParameters() != null && getParameters().size() > 0)) {
					paramsType = TypeCompatibility.TRUE;
					for (int i = 0; i < getParameters().size(); i++) {
						IRParameter parameter = getParameters().get(i);
						if (parameter.getType() != null) {
							if (i < funcType.getParameters().size()) {
								IRParameter funcParam = funcType
										.getParameters().get(i);
								if (funcParam.getType() != null) {
									if (funcParam.getType().isAssignableFrom(
											parameter.getType()) == TypeCompatibility.FALSE) {
										paramsType = TypeCompatibility.FALSE;
										break;
									}
								} else {
									paramsType = TypeCompatibility.FALSE;
									break;
								}
							} else if (!parameter.isOptional()) {
								paramsType = TypeCompatibility.FALSE;
								break;
							}
						}
					}
				}
			}
			return (returnType == TypeCompatibility.TRUE && paramsType == TypeCompatibility.TRUE) ? TypeCompatibility.TRUE
					: TypeCompatibility.FALSE;
		} else if (type instanceof IRSimpleType) {
			// TODO (alex) convert when creating type
			return TypeCompatibility
					.valueOf(Types.FUNCTION == ((IRSimpleType) type)
							.getTarget());
		} else {
			return TypeCompatibility.FALSE;
		}
	}

	public IRType getReturnType() {
		return returnType;
	}

	public List<IRParameter> getParameters() {
		return parameters;
	}

	@Override
	public int hashCode() {
		return parameters.hashCode();
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		RFunctionType other = (RFunctionType) obj;
		if (!parameters.equals(other.parameters))
			return false;
		if (returnType == null) {
			if (other.returnType != null)
				return false;
		} else if (!returnType.equals(other.returnType))
			return false;
		return true;
	}

}