/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.juneau.bct.assertions;

import static org.apache.juneau.commons.reflect.ReflectionUtils.*;
import static org.apache.juneau.commons.utils.ClassUtils.*;
import static org.apache.juneau.commons.utils.Shorts.*;
import static org.apache.juneau.commons.utils.StringUtils.*;

import java.io.*;
import java.util.*;
import java.util.function.*;

import org.apache.juneau.commons.function.*;
import org.apache.juneau.commons.utils.*;

/**
 * Used for fluent assertion calls against POJOs.
 *
 * <h5 class='section'>Test Methods:</h5>
 * <p>
 * <ul class='javatree'>
 *    <li class='jc'>{@link FluentObjectAssertion}
 *    <ul class='javatreec'>
 *       <li class='jm'>{@link FluentObjectAssertion#isExists() isExists()}
 *       <li class='jm'>{@link FluentObjectAssertion#is(Object) is(Object)}
 *       <li class='jm'>{@link FluentObjectAssertion#is(Predicate) is(Predicate)}
 *       <li class='jm'>{@link FluentObjectAssertion#isNot(Object) isNot(Object)}
 *       <li class='jm'>{@link FluentObjectAssertion#isAny(Object...) isAny(Object...)}
 *       <li class='jm'>{@link FluentObjectAssertion#isNotAny(Object...) isNotAny(Object...)}
 *       <li class='jm'>{@link FluentObjectAssertion#isNull() isNull()}
 *       <li class='jm'>{@link FluentObjectAssertion#isNotNull() isNotNull()}
 *       <li class='jm'>{@link FluentObjectAssertion#isString(String) isString(String)}
 *       <li class='jm'>{@link FluentObjectAssertion#isSame(Object) isSame(Object)}
 *       <li class='jm'>{@link FluentObjectAssertion#isSameSerializedAs(Object, ThrowingFunction) isSameSerializedAs(Object, ThrowingFunction)}
 *       <li class='jm'>{@link FluentObjectAssertion#isType(Class) isType(Class)}
 *       <li class='jm'>{@link FluentObjectAssertion#isExactType(Class) isExactType(Class)}
 *    </ul>
 * </ul>
 *
 * <h5 class='section'>Transform Methods:</h5>
 * <p>
 * <ul class='javatree'>
 *    <li class='jc'>{@link FluentObjectAssertion}
 *    <ul class='javatreec'>
 *       <li class='jm'>{@link FluentObjectAssertion#asString() asString()}
 *       <li class='jm'>{@link FluentObjectAssertion#asString(ThrowingFunction) asString(ThrowingFunction)}
 *       <li class='jm'>{@link FluentObjectAssertion#asTransformed(UnaryOperator) asTransformed(UnaryOperator)}
 *       <li class='jm'>{@link FluentObjectAssertion#asAny() asAny()}
 * </ul>
 * </ul>
 *
 * <h5 class='section'>Configuration Methods:</h5>
 * <p>
 * <ul class='javatree'>
 *    <li class='jc'>{@link Assertion}
 *    <ul class='javatreec'>
 *       <li class='jm'>{@link Assertion#setMsg(String, Object...) setMsg(String, Object...)}
 *       <li class='jm'>{@link Assertion#setOut(PrintStream) setOut(PrintStream)}
 *       <li class='jm'>{@link Assertion#setSilent() setSilent()}
 *       <li class='jm'>{@link Assertion#setStdOut() setStdOut()}
 *       <li class='jm'>{@link Assertion#setThrowable(Class) setThrowable(Class)}
 *    </ul>
 * </ul>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauEcosystemOverview">Juneau Ecosystem</a>
 * </ul>
 *
 * @param <T> The object type.
 * @param <R> The return type.
 */
@SuppressWarnings({
   "java:S115", // Constants use UPPER_snakeCase convention
   "java:S1192" // Duplicated literals (argument/property names) read more clearly inline than as constants
})
public class FluentObjectAssertion<T,R> extends FluentAssertion<R> {

   private static final Messages MESSAGES = Messages.of(FluentObjectAssertion.class, "Messages");
   private static final String MSG_unexpectedType = MESSAGES.getString("unexpectedType");
   private static final String MSG_unexpectedComparison = MESSAGES.getString("unexpectedComparison");
   private static final String MSG_unexpectedValue = MESSAGES.getString("unexpectedValue");
   private static final String MSG_unexpectedValueDidNotExpect = MESSAGES.getString("unexpectedValueDidNotExpect");
   private static final String MSG_notTheSameValue = MESSAGES.getString("notTheSameValue");
   private static final String MSG_valueWasNull = MESSAGES.getString("valueWasNull");
   private static final String MSG_valueWasNotNull = MESSAGES.getString("valueWasNotNull");
   private static final String MSG_expectedValueNotFound = MESSAGES.getString("expectedValueNotFound");
   private static final String MSG_unexpectedValueFound = MESSAGES.getString("unexpectedValueFound");
   private static final String MSG_unexpectedValue2 = MESSAGES.getString("unexpectedValue2");

   private final T value;

   /**
    * Chained constructor.
    *
    * <p>
    * Used when transforming one assertion into another so that the assertion config can be used by the new assertion.
    *
    * @param creator
    *    The assertion that created this assertion.
    *    <br>Should be <jk>null</jk> if this is the top-level assertion.
    * @param value
    *    The object being tested.
    *    <br>Can be <jk>null</jk> (assertions such as {@code isNull()} then operate on the absence of a value).
    * @param returns
    *    The object to return after a test method is called.
    *    <br>If <jk>null</jk>, the test method returns this object allowing multiple test method calls to be
    * used on the same assertion.
    */
   public FluentObjectAssertion(Assertion creator, T value, R returns) {
      super(creator, returns);
      this.value = value;
   }

   /**
    * Constructor.
    *
    * @param value
    *    The object being tested.
    *    <br>Can be <jk>null</jk> (assertions such as {@code isNull()} then operate on the absence of a value).
    * @param returns
    *    The object to return after a test method is called.
    *    <br>If <jk>null</jk>, the test method returns this object allowing multiple test method calls to be
    * used on the same assertion.
    */
   public FluentObjectAssertion(T value, R returns) {
      this(null, value, returns);
   }

   /**
    * Converts this assertion into an {@link FluentAnyAssertion} so that it can be converted to other assertion types.
    *
    * @return This object.
    */
   public FluentAnyAssertion<T,R> asAny() {
      return new FluentAnyAssertion<>(this, orElse(null), returns());
   }

   /**
    * Converts this object to a string using {@link Object#toString} and returns it as a new assertion.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Validates that the specified object is "foobar" after converting to a string.</jc>
    *    <jsm>assertObject</jsm>(<jv>myPojo</jv>)
    *       .asString()
    *       .is(<js>"foobar"</js>);
    * </p>
    *
    * @return A new fluent string assertion.
    */
   public FluentStringAssertion<R> asString() {
      return new FluentStringAssertion<>(this, valueAsString(), returns());
   }

   /**
    * Converts this object to a string using the specified function and returns it as a new assertion.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Validates that the specified object is "foobar" after converting to a string.</jc>
    *    <jsm>assertObject</jsm>(<jv>myPojo</jv>)
    *       .asString(<jv>x</jv>-&gt;<jv>x</jv>.toString())
    *       .is(<js>"foobar"</js>);
    * </p>
    *
    * @param function The conversion function.  May throw a checked exception.
    * @return A new fluent string assertion.
    */
   public FluentStringAssertion<R> asString(ThrowingFunction<? super T,String> function) {
      return new FluentStringAssertion<>(this, function.apply(value), returns());
   }

   /**
    * Applies a transform on the inner object and returns a new inner object.
    *
    * @param function The function to apply.
    * @return This object.
    */
   public FluentObjectAssertion<T,R> asTransformed(UnaryOperator<T> function) {
      return new FluentObjectAssertion<>(this, function.apply(orElse(null)), returns());
   }

   /**
    * Applies a transform on the inner object and returns a new inner object.
    *
    * @param <T2> The transform-to type.
    * @param function The function to apply.
    * @return This object.
    */
   public <T2> FluentObjectAssertion<T2,R> asTransformedTo(Function<T,T2> function) {
      return new FluentObjectAssertion<>(this, function.apply(orElse(null)), returns());
   }

   /**
    * Asserts that the value passes the specified predicate test.
    *
    * @param test The predicate to use to test the value.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R is(Predicate<T> test) throws AssertionError {
      if (nn(test) && ! test.test(value))
         throw error(getFailureMessage(test, value));
      return returns();
   }

   /**
    * Asserts that the value equals the specified value.
    *
    * @param value The value to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R is(T value) throws AssertionError {
      if (this.value == value)
         return returns();
      if (! equals(orElse(null), value))
         throw error(MSG_unexpectedValue, r(value), r(this.value));
      return returns();
   }

   /**
    * Asserts that the value is one of the specified values.
    *
    * @param values The values to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   @SafeVarargs
   public final R isAny(T...values) throws AssertionError {
      for (var v : values)
         if (equals(orElse(null), v))
            return returns();
      throw error(MSG_expectedValueNotFound, r(values), r(value));
   }

   /**
    * Asserts that the object is an instance of the specified class.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Validates that the specified object is an instance of MyBean.</jc>
    *    <jsm>assertObject</jsm>(<jv>myPojo</jv>).isExactType(MyBean.<jk>class</jk>);
    * </p>
    *
    * @param type The value to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isExactType(Class<?> type) throws AssertionError {
      reqnn("type", type);
      if (value().getClass() != type)
         throw error(MSG_unexpectedType, cn(type), cn(value));
      return returns();
   }

   /**
    * Asserts that the object is not null.
    *
    * <p>
    * Equivalent to {@link #isNotNull()}.
    *
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isExists() throws AssertionError { return isNotNull(); }

   /**
    * Asserts that the value does not equal the specified value.
    *
    * @param value The value to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isNot(T value) throws AssertionError {
      if (equals(orElse(null), value))
         throw error(MSG_unexpectedValueDidNotExpect, r(value), r(orElse(null)));
      return returns();
   }

   /**
    * Asserts that the value is not one of the specified values.
    *
    * @param values The values to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   @SafeVarargs
   public final R isNotAny(T...values) throws AssertionError {
      for (var v : values)
         if (equals(orElse(null), v))
            throw error(MSG_unexpectedValueFound, r(v), r(value));
      return returns();
   }

   /**
    * Asserts that the object is not null.
    *
    * <p>
    * Equivalent to {@link #isNotNull()}.
    *
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isNotNull() throws AssertionError {
      if (value == null)
         throw error(MSG_valueWasNull);
      return returns();
   }

   /**
    * Asserts that the object i null.
    *
    * <p>
    * Equivalent to {@link #isNotNull()}.
    *
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isNull() throws AssertionError {
      if (nn(value))
         throw error(MSG_valueWasNotNull);
      return returns();
   }

   /**
    * Asserts that the specified object is the same object as this object.
    *
    * @param value The value to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isSame(T value) throws AssertionError {
      if (this.value == value)
         return returns();
      throw error(MSG_notTheSameValue, r(value), id(value), r(this.value), id(this.value));
   }

   /**
    * Asserts that the specified object is the same as this object after converting both to strings using the specified function.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jsm>assertObject</jsm>(<jv>myPojo</jv>).isSameSerializedAs(<jv>other</jv>, <jv>x</jv> -&gt; <jv>x</jv>.toString());
    * </p>
    *
    * @param o The object to compare against.
    * @param function The function to use to serialize the objects.  May throw a checked exception.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   @SuppressWarnings({
      "unchecked" // Comparison function is applied to both the typed value and the untyped comparison object.
   })
   public R isSameSerializedAs(Object o, ThrowingFunction<? super T,String> function) {
      var s1 = function.apply(value);
      var s2 = function.apply((T)o);
      if (neq(s1, s2))
         throw error(MSG_unexpectedComparison, s2, s1);
      return returns();
   }

   /**
    * Asserts that the value converted to a string equals the specified value.
    *
    * @param value The value to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isString(String value) {
      return asString().is(value);
   }

   /**
    * Asserts that the object is an instance of the specified class.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Validates that the specified object is an instance of MyBean.</jc>
    *    <jsm>assertObject</jsm>(<jv>myPojo</jv>).isType(MyBean.<jk>class</jk>);
    * </p>
    *
    * @param parent The value to check against.
    * @return The fluent return object.
    * @throws AssertionError If assertion failed.
    */
   public R isType(Class<?> parent) throws AssertionError {
      reqnn("parent", parent);
      if (! info(value()).isAssignableTo(parent))
         throw error(MSG_unexpectedType, cn(parent), cn(value));
      return returns();
   }

   @Override /* Overridden from Assertion */
   public FluentObjectAssertion<T,R> setMsg(String msg, Object...args) {
      super.setMsg(msg, args);
      return this;
   }

   @Override /* Overridden from Assertion */
   public FluentObjectAssertion<T,R> setOut(PrintStream value) {
      super.setOut(value);
      return this;
   }

   @Override /* Overridden from Assertion */
   public FluentObjectAssertion<T,R> setSilent() {
      super.setSilent();
      return this;
   }

   @Override /* Overridden from Assertion */
   public FluentObjectAssertion<T,R> setStdOut() {
      super.setStdOut();
      return this;
   }

   @Override /* Overridden from Assertion */
   public FluentObjectAssertion<T,R> setThrowable(Class<? extends RuntimeException> value) {
      super.setThrowable(value);
      return this;
   }

   /**
    * Returns the string form of the inner object.
    * Subclasses can override this method to affect the {@link #asString()} method (and related).
    */
   @Override /* Overridden from Object */
   public String toString() {
      return valueAsString();
   }

   /**
    * Checks two objects for equality.
    *
    * @param o1 The first object.
    * @param o2 The second object.
    * @return <jk>true</jk> if the objects are equal.
    */
   protected boolean equals(Object o1, Object o2) {
      if (o1 == o2)
         return true;
      if (o1 == null || o2 == null)
         return false;
      if (o1.equals(o2))
         return true;
      if (isArray(o1))
         return readable(o1).equals(readable(o2));
      return false;
   }

   /**
    * Returns the predicate failure message.
    *
    * <p>
    * If the predicate extends from {@link AssertionPredicate}, then the message comes from {@link AssertionPredicate#getFailureMessage()}.
    * Otherwise, returns a generic <js>"Unexpected value: x"</js> message.
    *
    * @param p The function to run against the value.
    * @param value The value that failed the test.
    * @return The result, never <jk>null</jk>.
    */
   protected String getFailureMessage(Predicate<?> p, Object value) {
      if (p instanceof AssertionPredicate<?> p2)
         return p2.getFailureMessage();
      return f(MSG_unexpectedValue2, r(value));
   }

   /**
    * Returns the result of running the specified function against the value and returns the result.
    *
    * @param <T2> The mapper-to type.
    * @param mapper The function to run against the value.
    * @return The result, never <jk>null</jk>.
    */
   protected <T2> Optional<T2> map(Function<? super T,? extends T2> mapper) {
      return opt().map(mapper);
   }

   /**
    * Returns the value wrapped in an {@link Optional}.
    *
    * @return The value wrapped in an {@link Optional}.
    */
   protected Optional<T> opt() {
      return Shorts.o(value);  // NOAI
   }

   /**
    * Returns the inner value or the other value if the value is <jk>null</jk>.
    *
    * @param other The other value.
    * @return The inner value.
    */
   protected T orElse(T other) {
      return value == null ? other : value;
   }

   /**
    * Returns the inner value after asserting it is not <jk>null</jk>.
    *
    * @return The inner value.
    * @throws AssertionError If inner value was <jk>null</jk>.
    */
   protected T value() throws AssertionError {
      isExists();
      return value;
   }

   /**
    * Returns the inner value as a string.
    *
    * @return The inner value as a string, or <jk>null</jk> if the value was null.
    */
   protected String valueAsString() {
      return readable(value);
   }

   /**
    * Returns <jk>true</jk> if the inner value is not null.
    *
    * @return <jk>true</jk> if the inner value is not null.
    */
   protected boolean valueIsNotNull() {
      return nn(value);
   }

   /**
    * Returns <jk>true</jk> if the inner value is null.
    *
    * @return <jk>true</jk> if the inner value is null.
    */
   protected boolean valueIsNull() {
      return value == null;
   }
}