/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.codegen;

import static java.util.Objects.requireNonNull;
import static org.neo4j.codegen.TypeReference.VOID;
import static org.neo4j.codegen.TypeReference.typeReference;

public class Parameter {
    public static Parameter param(Class<?> type, String name) {
        return param(typeReference(type), name);
    }

    public static Parameter param(TypeReference type, String name) {
        return new Parameter(requireNonNull(type, "TypeReference"), requireValidName(name));
    }

    static final Parameter[] NO_PARAMETERS = new Parameter[0];

    private final TypeReference type;
    private final String name;

    private Parameter(TypeReference type, String name) {
        if (type == VOID) {
            throw new IllegalArgumentException("Variables cannot be declared as void.");
        }
        this.type = type;
        this.name = name;
    }

    @Override
    public String toString() {
        return writeTo(new StringBuilder()).toString();
    }

    StringBuilder writeTo(StringBuilder result) {
        result.append("Parameter[ ");
        type.writeTo(result);
        return result.append(' ').append(name).append(" ]");
    }

    public TypeReference type() {
        return type;
    }

    public String name() {
        return name;
    }

    static String requireValidName(String name) {
        if (name == null) {
            throw new NullPointerException("name");
        }
        notKeyword(name);
        if (!Character.isJavaIdentifierStart(name.codePointAt(0))) {
            throw new IllegalArgumentException("Invalid name: " + name);
        }
        for (int i = 0, cp; i < name.length(); i += Character.charCount(cp)) {
            if (!Character.isJavaIdentifierPart(cp = name.codePointAt(i))) {
                throw new IllegalArgumentException("Invalid name: " + name);
            }
        }
        return name;
    }

    private static void notKeyword(String name) {
        switch (name) {
            case "abstract":
            case "continue":
            case "for":
            case "new":
            case "switch":
            case "assert":
            case "default":
            case "goto":
            case "package":
            case "synchronized":
            case "boolean":
            case "do":
            case "if":
            case "private":
            case "break":
            case "double":
            case "implements":
            case "protected":
            case "throw":
            case "byte":
            case "else":
            case "import":
            case "public":
            case "throws":
            case "case":
            case "enum":
            case "instanceof":
            case "return":
            case "transient":
            case "catch":
            case "extends":
            case "int":
            case "short":
            case "try":
            case "char":
            case "final":
            case "interface":
            case "static":
            case "void":
            case "class":
            case "finally":
            case "long":
            case "strictfp":
            case "volatile":
            case "const":
            case "float":
            case "native":
            case "super":
            case "while":
                throw new IllegalArgumentException("'" + name + "' is a java keyword");
            case "this":
            case "null":
            case "true":
            case "false":
                throw new IllegalArgumentException("'" + name + "' is a reserved name");
            default:
                break;
        }
    }

    boolean isVarArg() {
        return false;
    }
}
