/* Copyright 2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package grails.util;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;

/**
 * Utility methods for converting between different name types,
 * for example from class names -> property names and vice-versa. The
 * key aspect of this class is that it has no dependencies outside the JDK!
 */
public class GrailsNameUtils {

    private static final String PROPERTY_SET_PREFIX = "set";

    /**
     * Retrieves the name of a setter for the specified property name
     * @param propertyName The property name
     * @return The setter equivalent
     */
    public static String getSetterName(String propertyName) {
        return PROPERTY_SET_PREFIX+propertyName.substring(0,1).toUpperCase()+ propertyName.substring(1);
    }

    /**
     * Calculate the name for a getter method to retrieve the specified property
     * @param propertyName
     * @return The name for the getter method for this property, if it were to exist, i.e. getConstraints
     */
    public static String getGetterName(String propertyName) {
        final String suffix;
        if(propertyName.length() > 1 && 
                Character.isLowerCase(propertyName.charAt(0)) && 
                Character.isUpperCase(propertyName.charAt(1))) {
            suffix = propertyName;
        } else {
            suffix = Character.toUpperCase(propertyName.charAt(0)) + propertyName.substring(1);
        }
        return "get" + suffix;
    }

    /**
     * Returns the class name for the given logical name and trailing name. For example "person" and "Controller" would evaluate to "PersonController"
     *
     * @param logicalName The logical name
     * @param trailingName The trailing name
     * @return The class name
     */
    public static String getClassName(String logicalName, String trailingName) {
        if (isBlank(logicalName)) {
            throw new IllegalArgumentException("Argument [logicalName] cannot be null or blank");
        }

        String className = logicalName.substring(0,1).toUpperCase() + logicalName.substring(1);
        if (trailingName != null) {
            className = className + trailingName;
        }
        return className;
    }

    /**
     * Returns the class name representation of the given name
     *
     * @param name The name to convert
     * @return The property name representation
     */
    public static String getClassNameRepresentation(String name) {

        StringBuilder buf = new StringBuilder();
        if (name != null && name.length() > 0) {
            String[] tokens = name.split("[^\\w\\d]");
            for (String token1 : tokens) {
                String token = token1.trim();
                buf.append(token.substring(0, 1).toUpperCase(Locale.ENGLISH))
                   .append(token.substring(1));
            }
        }

        return buf.toString();
    }

    /**
     * Converts foo-bar into FooBar. Empty and null strings are returned as-is.
     *
     * @param name The lower case hyphen separated name
     * @return The class name equivalent.
     */
    private static String getClassNameForLowerCaseHyphenSeparatedName(String name) {
        // Handle null and empty strings.
        if (isBlank(name)) return name;

        if (name.indexOf('-') > -1) {
            StringBuilder buf = new StringBuilder();
            String[] tokens = name.split("-");
            for (String token : tokens) {
                if (token == null || token.length() == 0) continue;
                buf.append(token.substring(0, 1).toUpperCase())
                   .append(token.substring(1));
            }
            return buf.toString();
        }

        return name.substring(0,1).toUpperCase() + name.substring(1);
    }

    /**
     * Retrieves the logical class name of a Grails artifact given the Grails class
     * and a specified trailing name
     *
     * @param clazz The class
     * @param trailingName The trailing name such as "Controller" or "TagLib"
     * @return The logical class name
     */
    public static String getLogicalName(Class<?> clazz, String trailingName) {
        return getLogicalName(clazz.getName(), trailingName);
    }

    /**
     * Retrieves the logical name of the class without the trailing name
     * @param name The name of the class
     * @param trailingName The trailing name
     * @return The logical name
     */
    public static String getLogicalName(String name, String trailingName) {
        if (!isBlank(trailingName)) {
            String shortName = getShortName(name);
            if (shortName.indexOf(trailingName) > - 1) {
                return shortName.substring(0, shortName.length() - trailingName.length());
            }
        }
        return name;
    }

    public static String getLogicalPropertyName(String className, String trailingName) {
        if (!isBlank(className) && !isBlank(trailingName)) {
            if (className.length() == trailingName.length() + 1 && className.endsWith(trailingName)) {
                return className.substring(0, 1).toLowerCase();
            }
        }
        return getLogicalName(getPropertyName(className), trailingName);
    }

    /**
     * Shorter version of getPropertyNameRepresentation.
     * @param name The name to convert
     * @return The property name version
     */
    public static String getPropertyName(String name) {
        return getPropertyNameRepresentation(name);
    }

    /**
     * Shorter version of getPropertyNameRepresentation.
     * @param clazz The clazz to convert
     * @return The property name version
     */
    public static String getPropertyName(Class<?> clazz) {
        return getPropertyNameRepresentation(clazz);
    }

    /**
     * Returns the property name equivalent for the specified class.
     *
     * @param targetClass The class to get the property name for
     * @return A property name reperesentation of the class name (eg. MyClass becomes myClass)
     */
    public static String getPropertyNameRepresentation(Class<?> targetClass) {
        String shortName = getShortName(targetClass);
        return getPropertyNameRepresentation(shortName);
    }

    /**
     * Returns the property name representation of the given name.
     *
     * @param name The name to convert
     * @return The property name representation
     */
    public static String getPropertyNameRepresentation(String name) {
        // Strip any package from the name.
        int pos = name.lastIndexOf('.');
        if (pos != -1) {
            name = name.substring(pos + 1);
        }

        // Check whether the name begins with two upper case letters.
        if (name.length() > 1 && Character.isUpperCase(name.charAt(0)) && Character.isUpperCase(name.charAt(1)))  {
            return name;
        }

        String propertyName = name.substring(0,1).toLowerCase(Locale.ENGLISH) + name.substring(1);
        if (propertyName.indexOf(' ') > -1) {
            propertyName = propertyName.replaceAll("\\s", "");
        }
        return propertyName;
    }

    /**
     * Converts foo-bar into fooBar.
     *
     * @param name The lower case hyphen separated name
     * @return The property name equivalent
     */
    public static String getPropertyNameForLowerCaseHyphenSeparatedName(String name) {
        return getPropertyName(getClassNameForLowerCaseHyphenSeparatedName(name));
    }

    /**
     * Returns the class name without the package prefix.
     *
     * @param targetClass The class to get a short name for
     * @return The short name of the class
     */
    public static String getShortName(Class<?> targetClass) {
        String className = targetClass.getName();
        return getShortName(className);
    }

    /**
     * Returns the class name without the package prefix.
     *
     * @param className The class name to get a short name for
     * @return The short name of the class
     */
    public static String getShortName(String className) {
        int i = className.lastIndexOf(".");
        if (i > -1) {
            className = className.substring(i + 1, className.length());
        }
        return className;
    }

    /**
     * Retrieves the script name representation of the supplied class. For example
     * MyFunkyGrailsScript would be my-funky-grails-script.
     *
     * @param clazz The class to convert
     * @return The script name representation
     */
    public static String getScriptName(Class<?> clazz) {
        if (clazz == null) {
            return null;
        }
        return getScriptName(clazz.getName());
    }

    /**
     * Retrieves the script name representation of the given class name.
     * For example MyFunkyGrailsScript would be my-funky-grails-script.
     *
     * @param name The class name to convert.
     * @return The script name representation.
     */
    public static String getScriptName(String name) {
        if (name == null) {
            return null;
        }

        if (name.endsWith(".groovy")) {
            name = name.substring(0, name.length()-7);
        }
        String naturalName = getNaturalName(name);
        return naturalName.replaceAll("\\s", "-").toLowerCase();
    }

    /**
     * Calculates the class name from a script name in the form my-funk-grails-script.
     *
     * @param scriptName The script name
     * @return A class name
     */
    public static String getNameFromScript(String scriptName) {
        return getClassNameForLowerCaseHyphenSeparatedName(scriptName);
    }

    /**
     * Returns the name of a plugin given the name of the *GrailsPlugin.groovy
     * descriptor file. For example, "DbUtilsGrailsPlugin.groovy" gives
     * "db-utils".
     * @param descriptorName The simple name of the plugin descriptor.
     * @return The plugin name for the descriptor, or <code>null</code>
     * if <i>descriptorName</i> is <code>null</code>, or an empty string
     * if <i>descriptorName</i> is an empty string.
     * @throws IllegalArgumentException if the given descriptor name is
     * not valid, i.e. if it doesn't end with "GrailsPlugin.groovy".
     */
    public static String getPluginName(String descriptorName) {
        if (descriptorName == null || descriptorName.length() == 0) {
            return descriptorName;
        }

        if (!descriptorName.endsWith("GrailsPlugin.groovy")) {
            throw new IllegalArgumentException("Plugin descriptor name is not valid: " + descriptorName);
        }

        int pos = descriptorName.indexOf("GrailsPlugin.groovy");
        return getScriptName(descriptorName.substring(0, pos));
    }

    /**
     * Converts a property name into its natural language equivalent eg ('firstName' becomes 'First Name')
     * @param name The property name to convert
     * @return The converted property name
     */
    public static String getNaturalName(String name) {
        name = getShortName(name);
        List<String> words = new ArrayList<String>();
        int i = 0;
        char[] chars = name.toCharArray();
        for (int j = 0; j < chars.length; j++) {
            char c = chars[j];
            String w;
            if (i >= words.size()) {
                w = "";
                words.add(i, w);
            }
            else {
                w = words.get(i);
            }

            if (Character.isLowerCase(c) || Character.isDigit(c)) {
                if (Character.isLowerCase(c) && w.length() == 0) {
                    c = Character.toUpperCase(c);
                }
                else if (w.length() > 1 && Character.isUpperCase(w.charAt(w.length() - 1))) {
                    w = "";
                    words.add(++i,w);
                }

                words.set(i, w + c);
            }
            else if (Character.isUpperCase(c)) {
                if ((i == 0 && w.length() == 0) || Character.isUpperCase(w.charAt(w.length() - 1))) {
                    words.set(i, w + c);
                }
                else {
                    words.add(++i, String.valueOf(c));
                }
            }
        }

        StringBuilder buf = new StringBuilder();
        for (Iterator<String> j = words.iterator(); j.hasNext();) {
            String word = j.next();
            buf.append(word);
            if (j.hasNext()) {
                buf.append(' ');
            }
        }
        return buf.toString();
    }

    /**
     * <p>Determines whether a given string is <code>null</code>, empty,
     * or only contains whitespace. If it contains anything other than
     * whitespace then the string is not considered to be blank and the
     * method returns <code>false</code>.</p>
     * <p>We could use Commons Lang for this, but we don't want GrailsNameUtils
     * to have a dependency on any external library to minimise the number of
     * dependencies required to bootstrap Grails.</p>
     * @param str The string to test.
     * @return <code>true</code> if the string is <code>null</code>, or
     * blank.
     */
    public static boolean isBlank(String str) {
        return str == null || str.trim().length() == 0;
    }
}
