/*
 * Copyright (C) 2009-2013 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.core;

import java.lang.annotation.Annotation;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import lombok.core.AST.Kind;
import lombok.permit.Permit;

Represents a single annotation in a source file and can be used to query the parameters present on it.
Params:
A – The annotation that this class represents, such as lombok.Getter/**
 * Represents a single annotation in a source file and can be used to query the parameters present on it.
 * 
 * @param A The annotation that this class represents, such as {@code lombok.Getter}
 */
public class AnnotationValues<A extends Annotation> {
	private final Class<A> type;
	private final Map<String, AnnotationValue> values;
	private final LombokNode<?, ?, ?> ast;

	
Represents a single method on the annotation class. For example, the value() method on the Getter annotation.
/**
	 * Represents a single method on the annotation class. For example, the value() method on the Getter annotation.
	 */
	public static class AnnotationValue {
		
A list of the raw expressions. List is size 1 unless an array is provided. /** A list of the raw expressions. List is size 1 unless an array is provided. */
		public final List<String> raws;
		
		
Guesses for each raw expression. It's 'primitive' (String or primitive), an AV.ClassLiteral, an AV.FieldSelect, or an array of one of those. /** Guesses for each raw expression. It's 'primitive' (String or primitive), an AV.ClassLiteral, an AV.FieldSelect, or an array of one of those. */
		public final List<Object> valueGuesses;
		
		
A list of the actual expressions. List is size 1 unless an array is provided. /** A list of the actual expressions. List is size 1 unless an array is provided. */
		public final List<Object> expressions;
		
		private final LombokNode<?, ?, ?> node;
		private final boolean isExplicit;
		
		
Like the other constructor, but used for when the annotation method is initialized with an array value.
/**
		 * Like the other constructor, but used for when the annotation method is initialized with an array value.
		 */
		public AnnotationValue(LombokNode<?, ?, ?> node, List<String> raws, List<Object> expressions, List<Object> valueGuesses, boolean isExplicit) {
			this.node = node;
			this.raws = raws;
			this.expressions = expressions;
			this.valueGuesses = valueGuesses;
			this.isExplicit = isExplicit;
		}
		
		
 Override this if you want more specific behaviour (to get the source position just right).
Params:
message – English message with the problem.
valueIdx – The index into the values for this annotation key that caused the problem.
  -1 for a problem that applies to all values, otherwise the 0-based index into an array of values.
  If there is no array for this value (e.g. value=1 instead of value={1,2}), then always -1 or 0./**
		 *  Override this if you want more specific behaviour (to get the source position just right).
		 * 
		 * @param message English message with the problem.
		 * @param valueIdx The index into the values for this annotation key that caused the problem.
		 *   -1 for a problem that applies to all values, otherwise the 0-based index into an array of values.
		 *   If there is no array for this value (e.g. value=1 instead of value={1,2}), then always -1 or 0.
		 */
		public void setError(String message, int valueIdx) {
			node.addError(message);
		}
		
		
 Override this if you want more specific behaviour (to get the source position just right).
Params:
message – English message with the problem.
valueIdx – The index into the values for this annotation key that caused the problem.
  -1 for a problem that applies to all values, otherwise the 0-based index into an array of values.
  If there is no array for this value (e.g. value=1 instead of value={1,2}), then always -1 or 0./**
		 *  Override this if you want more specific behaviour (to get the source position just right).
		 * 
		 * @param message English message with the problem.
		 * @param valueIdx The index into the values for this annotation key that caused the problem.
		 *   -1 for a problem that applies to all values, otherwise the 0-based index into an array of values.
		 *   If there is no array for this value (e.g. value=1 instead of value={1,2}), then always -1 or 0.
		 */
		public void setWarning(String message, int valueIdx) {
			node.addError(message);
		}
		
		
{@inheritDoc} /** {@inheritDoc} */
		@Override public String toString() {
			return "raws: " + raws + " valueGuesses: " + valueGuesses;
		}
		
		public boolean isExplicit() {
			return isExplicit;
		}
	}
	
	
Creates a new AnnotationValues.
Params:
type – The annotation type. For example, "Getter.class"
values – a Map of method names to AnnotationValue instances, for example 'value -> annotationValue instance'.
ast – The Annotation node./**
	 * Creates a new AnnotationValues.
	 * 
	 * @param type The annotation type. For example, "Getter.class"
	 * @param values a Map of method names to AnnotationValue instances, for example 'value -> annotationValue instance'.
	 * @param ast The Annotation node.
	 */
	public AnnotationValues(Class<A> type, Map<String, AnnotationValue> values, LombokNode<?, ?, ?> ast) {
		this.type = type;
		this.values = values;
		this.ast = ast;
	}
	
	public static <A extends Annotation> AnnotationValues<A> of(Class<A> type) {
		return new AnnotationValues<A>(type, Collections.<String, AnnotationValue>emptyMap(), null);
	}
	
	
Creates a new annotation wrapper with all default values, and using the provided ast as lookup anchor for
class literals.
/**
	 * Creates a new annotation wrapper with all default values, and using the provided ast as lookup anchor for
	 * class literals.
	 */
	public static <A extends Annotation> AnnotationValues<A> of(Class<A> type, LombokNode<?, ?, ?> ast) {
		return new AnnotationValues<A>(type, Collections.<String, AnnotationValue>emptyMap(), ast);
	}
	
	
Thrown on the fly if an actual annotation instance procured via the AnnotationValues.getInstance() method is queried for a method for which this AnnotationValues instance either doesn't have a guess or can't manage to fit the guess into the required data type. /**
	 * Thrown on the fly if an actual annotation instance procured via the {@link #getInstance()} method is queried
	 * for a method for which this AnnotationValues instance either doesn't have a guess or can't manage to fit
	 * the guess into the required data type.
	 */
	public static class AnnotationValueDecodeFail extends RuntimeException {
		private static final long serialVersionUID = 1L;
		
		
The index into an array initializer (e.g. if the second value in an array initializer is
an integer constant expression like '5+SomeOtherClass.CONSTANT', this exception will be thrown,
and you'll get a '1' for idx. /** The index into an array initializer (e.g. if the second value in an array initializer is
		 * an integer constant expression like '5+SomeOtherClass.CONSTANT', this exception will be thrown,
		 * and you'll get a '1' for idx. */
		public final int idx;
		
		
The AnnotationValue object that goes with the annotation method for which the failure occurred. /** The AnnotationValue object that goes with the annotation method for which the failure occurred. */
		public final AnnotationValue owner;
		
		public AnnotationValueDecodeFail(AnnotationValue owner, String msg, int idx) {
			super(msg);
			this.idx = idx;
			this.owner = owner;
		}
	}
	
	private static AnnotationValueDecodeFail makeNoDefaultFail(AnnotationValue owner, Method method) {
		return new AnnotationValueDecodeFail(owner, 
				"No value supplied but " + method.getName() + " has no default either.", -1);
	}
	
	private A cachedInstance = null;
	
	public List<String> getAsStringList(String methodName) {
		AnnotationValue v = values.get(methodName);
		
		if (v == null) {
			String[] s = getDefaultIf(methodName, String[].class, new String[0]);
			return Collections.unmodifiableList(Arrays.asList(s));
		}
		
		List<String> out = new ArrayList<String>(v.valueGuesses.size());
		int idx = 0;
		for (Object guess : v.valueGuesses) {
			Object result = guess == null ? null : guessToType(guess, String.class, v, idx);
			if (result == null) {
				if (v.valueGuesses.size() == 1) {
					String[] s = getDefaultIf(methodName, String[].class, new String[0]);
					return Collections.unmodifiableList(Arrays.asList(s));
				} 
				throw new AnnotationValueDecodeFail(v, 
					"I can't make sense of this annotation value. Try using a fully qualified literal.", idx);
			}
			out.add((String) result);
		}
		
		return Collections.unmodifiableList(out);
	}
	
	public String getAsString(String methodName) {
		AnnotationValue v = values.get(methodName);
		if (v == null || v.valueGuesses.size() != 1) {
			return getDefaultIf(methodName, String.class, "");
		}
		
		Object guess = guessToType(v.valueGuesses.get(0), String.class, v, 0);
		if (guess instanceof String) return (String) guess;
		return getDefaultIf(methodName, String.class, "");
	}
	
	public boolean getAsBoolean(String methodName) {
		AnnotationValue v = values.get(methodName);
		if (v == null || v.valueGuesses.size() != 1) {
			return getDefaultIf(methodName, boolean.class, false);
		}
		
		Object guess = guessToType(v.valueGuesses.get(0), boolean.class, v, 0);
		if (guess instanceof Boolean) return ((Boolean) guess).booleanValue();
		return getDefaultIf(methodName, boolean.class, false);
	}
	
	public <T> T getDefaultIf(String methodName, Class<T> type, T defaultValue) {
		try {
			return type.cast(Permit.getMethod(type, methodName).getDefaultValue());
		} catch (Exception e) {
			return defaultValue;
		}
	}
	
	
Creates an actual annotation instance. You can use this to query any annotation methods, except for
those annotation methods with class literals, as those can most likely not be turned into Class objects.
If some of the methods cannot be implemented, this method still works; it's only when you call a method
that has a problematic value that an AnnotationValueDecodeFail exception occurs.
/**
	 * Creates an actual annotation instance. You can use this to query any annotation methods, except for
	 * those annotation methods with class literals, as those can most likely not be turned into Class objects.
	 * 
	 * If some of the methods cannot be implemented, this method still works; it's only when you call a method
	 * that has a problematic value that an AnnotationValueDecodeFail exception occurs.
	 */
	@SuppressWarnings("unchecked")
	public A getInstance() {
		if (cachedInstance != null) return cachedInstance;
		InvocationHandler invocations = new InvocationHandler() {
			public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
				AnnotationValue v = values.get(method.getName());
				if (v == null) {
					Object defaultValue = method.getDefaultValue();
					if (defaultValue != null) return defaultValue;
					throw makeNoDefaultFail(v, method);
				}
				
				boolean isArray = false;
				Class<?> expected = method.getReturnType();
				Object array = null;
				if (expected.isArray()) {
					isArray = true;
					expected = expected.getComponentType();
					array = Array.newInstance(expected, v.valueGuesses.size());
				}
				
				if (!isArray && v.valueGuesses.size() > 1) {
					throw new AnnotationValueDecodeFail(v, 
						"Expected a single value, but " + method.getName() + " has an array of values", -1);
				}
				
				if (v.valueGuesses.size() == 0 && !isArray) {
					Object defaultValue = method.getDefaultValue();
					if (defaultValue == null) throw makeNoDefaultFail(v, method);
					return defaultValue;
				}
				
				int idx = 0;
				for (Object guess : v.valueGuesses) {
					Object result = guess == null ? null : guessToType(guess, expected, v, idx);
					if (!isArray) {
						if (result == null) {
							Object defaultValue = method.getDefaultValue();
							if (defaultValue == null) throw makeNoDefaultFail(v, method);
							return defaultValue;
						}
						return result;
					} 
					if (result == null) {
						if (v.valueGuesses.size() == 1) {
							Object defaultValue = method.getDefaultValue();
							if (defaultValue == null) throw makeNoDefaultFail(v, method);
							return defaultValue;
						} 
						throw new AnnotationValueDecodeFail(v, 
							"I can't make sense of this annotation value. Try using a fully qualified literal.", idx);
					}
					Array.set(array, idx++, result);
				}
				
				return array;
			}
		};
		
		return cachedInstance = (A) Proxy.newProxyInstance(type.getClassLoader(), new Class[] { type }, invocations);
	}
	
	private Object guessToType(Object guess, Class<?> expected, AnnotationValue v, int pos) {
		if (expected == int.class || expected == Integer.class) {
			if (guess instanceof Integer || guess instanceof Short || guess instanceof Byte) {
				return ((Number) guess).intValue();
			}
		}
		
		if (expected == long.class || expected == Long.class) {
			if (guess instanceof Long || guess instanceof Integer || guess instanceof Short || guess instanceof Byte) {
				return ((Number) guess).longValue();
			}
		}
		
		if (expected == short.class || expected == Short.class) {
			if (guess instanceof Integer || guess instanceof Short || guess instanceof Byte) {
				int intVal = ((Number) guess).intValue();
				int shortVal = ((Number) guess).shortValue();
				if (shortVal == intVal) return shortVal;
			}
		}
		
		if (expected == byte.class || expected == Byte.class) {
			if (guess instanceof Integer || guess instanceof Short || guess instanceof Byte) {
				int intVal = ((Number) guess).intValue();
				int byteVal = ((Number) guess).byteValue();
				if (byteVal == intVal) return byteVal;
			}
		}
		
		if (expected == double.class || expected == Double.class) {
			if (guess instanceof Number) return ((Number) guess).doubleValue();
		}
		
		if (expected == float.class || expected == Float.class) {
			if (guess instanceof Number) return ((Number) guess).floatValue();
		}
		
		if (expected == boolean.class || expected == Boolean.class) {
			if (guess instanceof Boolean) return ((Boolean) guess).booleanValue();
		}
		
		if (expected == char.class || expected == Character.class) {
			if (guess instanceof Character) return ((Character) guess).charValue();
		}
		
		if (expected == String.class) {
			if (guess instanceof String) return guess;
		}
		
		if (Enum.class.isAssignableFrom(expected) ) {
			if (guess instanceof FieldSelect) {
				String fieldSel = ((FieldSelect) guess).getFinalPart();
				for (Object enumConstant : expected.getEnumConstants()) {
					String target = ((Enum<?>) enumConstant).name();
					if (target.equals(fieldSel)) return enumConstant;
				}
				throw new AnnotationValueDecodeFail(v,
					"Can't translate " + fieldSel + " to an enum of type " + expected, pos);
			}
		}
		
		if (expected == Class.class) {
			if (guess instanceof ClassLiteral) try {
				String classLit = ((ClassLiteral) guess).getClassName();
				return Class.forName(toFQ(classLit));
			} catch (ClassNotFoundException e) {
				throw new AnnotationValueDecodeFail(v,
					"Can't translate " + guess + " to a class object.", pos);
			}
		}
		
		if (guess instanceof AnnotationValues) {
			return ((AnnotationValues<?>) guess).getInstance();
		}
		
		if (guess instanceof FieldSelect) throw new AnnotationValueDecodeFail(v,
			"You must use constant literals in lombok annotations; they cannot be references to (static) fields.", pos);
		
		throw new AnnotationValueDecodeFail(v,
			"Can't translate a " + guess.getClass() + " to the expected " + expected, pos);
	}
	
	
Returns the raw expressions used for the provided annotationMethodName. You should use this method for annotation methods that return Class objects. Remember that class literals end in ".class" which you probably want to strip off. /**
	 * Returns the raw expressions used for the provided {@code annotationMethodName}.
	 * 
	 * You should use this method for annotation methods that return {@code Class} objects. Remember that
	 * class literals end in ".class" which you probably want to strip off.
	 */
	public List<String> getRawExpressions(String annotationMethodName) {
		AnnotationValue v = values.get(annotationMethodName);
		return v == null ? Collections.<String>emptyList() : v.raws;
	}
	
	
Returns the actual expressions used for the provided annotationMethodName. /**
	 * Returns the actual expressions used for the provided {@code annotationMethodName}.
	 */
	public List<Object> getActualExpressions(String annotationMethodName) {
		AnnotationValue v = values.get(annotationMethodName);
		return v == null ? Collections.<Object>emptyList() : v.expressions;
	}
	
	public boolean isExplicit(String annotationMethodName) {
		AnnotationValue annotationValue = values.get(annotationMethodName);
		return annotationValue != null && annotationValue.isExplicit();
	}
	
	
Convenience method to return the first result in a getRawExpressions(String) call. You should use this method if the annotation method is not an array type. /**
	 * Convenience method to return the first result in a {@link #getRawExpressions(String)} call.
	 * 
	 * You should use this method if the annotation method is not an array type.
	 */
	public String getRawExpression(String annotationMethodName) {
		List<String> l = getRawExpressions(annotationMethodName);
		return l.isEmpty() ? null : l.get(0);
	}
	
	
Convenience method to return the first result in a getActualExpressions(String) call. You should use this method if the annotation method is not an array type. /**
	 * Convenience method to return the first result in a {@link #getActualExpressions(String)} call.
	 * 
	 * You should use this method if the annotation method is not an array type.
	 */
	public Object getActualExpression(String annotationMethodName) {
		List<Object> l = getActualExpressions(annotationMethodName);
		return l.isEmpty() ? null : l.get(0);
	}

	
Returns the guessed value for the provided annotationMethodName. /**
	 * Returns the guessed value for the provided {@code annotationMethodName}.
	 */
	public Object getValueGuess(String annotationMethodName) {
		AnnotationValue v = values.get(annotationMethodName);
		return v == null || v.valueGuesses.isEmpty() ? null : v.valueGuesses.get(0);
	}
	
	
Generates an error message on the stated annotation value (you should only call this method if you know it's there!) /** Generates an error message on the stated annotation value (you should only call this method if you know it's there!) */
	public void setError(String annotationMethodName, String message) {
		setError(annotationMethodName, message, -1);
	}
	
	
Generates a warning message on the stated annotation value (you should only call this method if you know it's there!) /** Generates a warning message on the stated annotation value (you should only call this method if you know it's there!) */
	public void setWarning(String annotationMethodName, String message) {
		setWarning(annotationMethodName, message, -1);
	}
	
	
Generates an error message on the stated annotation value, which must have an array initializer.
The index-th item in the initializer will carry the error (you should only call this method if you know it's there!) /** Generates an error message on the stated annotation value, which must have an array initializer.
	 * The index-th item in the initializer will carry the error (you should only call this method if you know it's there!) */
	public void setError(String annotationMethodName, String message, int index) {
		AnnotationValue v = values.get(annotationMethodName);
		if (v == null) return;
		v.setError(message, index);
	}
	
	
Generates a warning message on the stated annotation value, which must have an array initializer.
The index-th item in the initializer will carry the error (you should only call this method if you know it's there!) /** Generates a warning message on the stated annotation value, which must have an array initializer.
	 * The index-th item in the initializer will carry the error (you should only call this method if you know it's there!) */
	public void setWarning(String annotationMethodName, String message, int index) {
		AnnotationValue v = values.get(annotationMethodName);
		if (v == null) return;
		v.setWarning(message, index);
	}
	
	
Attempts to translate class literals to their fully qualified names, such as 'Throwable.class' to 'java.lang.Throwable'.
This process is at best a guess, but it will take into account import statements.
/**
	 * Attempts to translate class literals to their fully qualified names, such as 'Throwable.class' to 'java.lang.Throwable'.
	 * 
	 * This process is at best a guess, but it will take into account import statements.
	 */
	public List<String> getProbableFQTypes(String annotationMethodName) {
		List<String> result = new ArrayList<String>();
		AnnotationValue v = values.get(annotationMethodName);
		if (v == null) return Collections.emptyList();
		
		for (Object o : v.valueGuesses) result.add(o == null ? null : toFQ(o.toString()));
		return result;
	}
	
	
Convenience method to return the first result in a getProbableFQType(String) call. You should use this method if the annotation method is not an array type. /**
	 * Convenience method to return the first result in a {@link #getProbableFQType(String)} call.
	 * 
	 * You should use this method if the annotation method is not an array type.
	 */
	public String getProbableFQType(String annotationMethodName) {
		List<String> l = getProbableFQTypes(annotationMethodName);
		return l.isEmpty() ? null : l.get(0);
	}
	
	/*
	 * Credit goes to Petr Jiricka of Sun for highlighting the problems with the earlier version of this method.
	 */
	private String toFQ(String typeName) {
		String prefix = typeName.indexOf('.') > -1 ? typeName.substring(0, typeName.indexOf('.')) : typeName;
		
		/* 1. Walk through type names in this source file at this level. */ {
			LombokNode<?, ?, ?> n = ast;
			walkThroughCU:
			while (n != null) {
				if (n.getKind() == Kind.TYPE) {
					String simpleName = n.getName();
					if (prefix.equals(simpleName)) {
						//We found a matching type name in the local hierarchy!
						List<String> outerNames = new ArrayList<String>();
						while (true) {
							n = n.up();
							if (n == null || n.getKind() == Kind.COMPILATION_UNIT) break;
							if (n.getKind() == Kind.TYPE) outerNames.add(n.getName());
							//If our type has a parent that isn't either the CompilationUnit or another type, then we are
							//a method-local class or an anonymous inner class literal. These technically do have FQNs
							//and we may, with a lot of effort, figure out their name, but, that's some fairly horrible code
							//style and these methods have 'probable' in their name for a reason.
							break walkThroughCU;
						}
						StringBuilder result = new StringBuilder();
						if (ast.getPackageDeclaration() != null) result.append(ast.getPackageDeclaration());
						if (result.length() > 0) result.append('.');
						Collections.reverse(outerNames);
						for (String outerName : outerNames) result.append(outerName).append('.');
						result.append(typeName);
						return result.toString();
					}
				}
				n = n.up();
			}
		}
		
		/* 2. Walk through non-star imports and search for a match. */ {
			if (prefix.equals(typeName)) {
				String fqn = ast.getImportList().getFullyQualifiedNameForSimpleName(typeName);
				if (fqn != null) return fqn;
			}
		}
		
		/* 3. Walk through star imports and, if they start with "java.", use Class.forName based resolution. */ {
			for (String potential : ast.getImportList().applyNameToStarImports("java", typeName)) {
				try {
					Class<?> c = Class.forName(potential);
					if (c != null) return c.getName();
				} catch (Throwable t) {
					//Class.forName failed for whatever reason - it most likely does not exist, continue.
				}
			}
		}
		
		/* 4. If the type name is a simple name, then our last guess is that it's another class in this package. */ {
			if (typeName.indexOf('.') == -1) return inLocalPackage(ast, typeName);
		}
		
		/* 5. It's either an FQN or a nested class in another class in our package. Use code conventions to guess. */ {
			char firstChar = typeName.charAt(0);
			if (Character.isTitleCase(firstChar) || Character.isUpperCase(firstChar)) {
				//Class names start with uppercase letters, so presume it's a nested class in another class in our package.
				return inLocalPackage(ast, typeName);
			}
			
			//Presume it's fully qualified.
			return typeName;
		}
	}
	
	private static String inLocalPackage(LombokNode<?, ?, ?> node, String typeName) {
		StringBuilder result = new StringBuilder();
		if (node != null && node.getPackageDeclaration() != null) result.append(node.getPackageDeclaration());
		if (result.length() > 0) result.append('.');
		result.append(typeName);
		return result.toString();
	}
}