/*

 * Copyright (C) 2007-2010 Júlio Vilmar Gesser.

 * Copyright (C) 2011, 2013-2021 The JavaParser Team.

 *

 * This file is part of JavaParser.

 *

 * JavaParser can be used either under the terms of

 * a) the GNU Lesser General Public License as published by

 *     the Free Software Foundation, either version 3 of the License, or

 *     (at your option) any later version.

 * b) the terms of the Apache License

 *

 * You should have received a copy of both licenses in LICENCE.LGPL and

 * LICENCE.APACHE. Please refer to those files for details.

 *

 * JavaParser 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 Lesser General Public License for more details.

 */

package com.github.javaparser.printer.lexicalpreservation;

import com.github.javaparser.GeneratedJavaParserConstants;

import com.github.javaparser.ast.Modifier;

import com.github.javaparser.ast.Node;

import com.github.javaparser.ast.NodeList;

import com.github.javaparser.ast.expr.CharLiteralExpr;

import com.github.javaparser.ast.expr.StringLiteralExpr;

import com.github.javaparser.ast.expr.TextBlockLiteralExpr;

import com.github.javaparser.ast.observer.ObservableProperty;

import com.github.javaparser.ast.stmt.ExpressionStmt;

import com.github.javaparser.printer.ConcreteSyntaxModel;

import com.github.javaparser.printer.Stringable;

import com.github.javaparser.printer.SourcePrinter;

import com.github.javaparser.printer.concretesyntaxmodel.*;

import com.github.javaparser.printer.lexicalpreservation.changes.Change;

import com.github.javaparser.printer.lexicalpreservation.changes.ListAdditionChange;

import com.github.javaparser.printer.lexicalpreservation.changes.ListRemovalChange;

import com.github.javaparser.printer.lexicalpreservation.changes.ListReplacementChange;

import com.github.javaparser.printer.lexicalpreservation.changes.NoChange;

import com.github.javaparser.printer.lexicalpreservation.changes.PropertyChange;

import com.github.javaparser.utils.LineSeparator;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.List;

import java.util.Optional;

import static com.github.javaparser.TokenTypes.eolTokenKind;

class LexicalDifferenceCalculator {

    /**

     * The ConcreteSyntaxModel represents the general format. This model is a calculated version of the ConcreteSyntaxModel,

     * with no condition, no lists, just tokens and node children.

     */

    static class CalculatedSyntaxModel {

        final List<CsmElement> elements;

        CalculatedSyntaxModel(List<CsmElement> elements) {

            this.elements = elements;

        }

        public CalculatedSyntaxModel from(int index) {

            return new CalculatedSyntaxModel(new ArrayList<>(elements.subList(index, elements.size())));

        }

        @Override

        public String toString() {

            return "CalculatedSyntaxModel{" +

                    "elements=" + elements +

                    '}';

        }

        CalculatedSyntaxModel sub(int start, int end) {

            return new CalculatedSyntaxModel(elements.subList(start, end));

        }

        void removeIndentationElements() {

            elements.removeIf(el -> el instanceof CsmIndent || el instanceof CsmUnindent);

        }

    }

    static class CsmChild implements CsmElement {

        private final Node child;

        public Node getChild() {

            return child;

        }

        CsmChild(Node child) {

            this.child = child;

        }

        @Override

        public void prettyPrint(Node node, SourcePrinter printer) {

            throw new UnsupportedOperationException();

        }

        @Override

        public String toString() {

            return "child(" + child.getClass().getSimpleName()+")";

        }

        @Override

        public boolean equals(Object o) {

            if (this == o) return true;

            if (o == null || getClass() != o.getClass()) return false;

            CsmChild csmChild = (CsmChild) o;

            return child.equals(csmChild.child);

        }

        @Override

        public int hashCode() {

            return child.hashCode();

        }

    }

    List<DifferenceElement> calculateListRemovalDifference(ObservableProperty observableProperty, NodeList<?> nodeList, int index) {

        Node container = nodeList.getParentNodeForChildren();

        CsmElement element = ConcreteSyntaxModel.forClass(container.getClass());

        CalculatedSyntaxModel original = calculatedSyntaxModelForNode(element, container);

        CalculatedSyntaxModel after = calculatedSyntaxModelAfterListRemoval(element, observableProperty, nodeList, index);

        return DifferenceElementCalculator.calculate(original, after);

    }

    List<DifferenceElement> calculateListAdditionDifference(ObservableProperty observableProperty, NodeList<?> nodeList, int index, Node nodeAdded) {

        Node container = nodeList.getParentNodeForChildren();

        CsmElement element = ConcreteSyntaxModel.forClass(container.getClass());

        CalculatedSyntaxModel original = calculatedSyntaxModelForNode(element, container);

        CalculatedSyntaxModel after = calculatedSyntaxModelAfterListAddition(element, observableProperty, nodeList, index, nodeAdded);

        List<DifferenceElement> differenceElements = DifferenceElementCalculator.calculate(original, after);

        // Set the line separator character tokens

        LineSeparator lineSeparator = container.getLineEndingStyleOrDefault(LineSeparator.SYSTEM);

        replaceEolTokens(differenceElements, lineSeparator);

        return differenceElements;

    }

    private void replaceEolTokens(List<DifferenceElement> differenceElements, LineSeparator lineSeparator) {

        for (int i = 0; i < differenceElements.size(); i++) {

            DifferenceElement differenceElement = differenceElements.get(i);

            if (differenceElement.isAdded()) {

                CsmElement element = differenceElement.getElement();

                boolean isWhitespaceToken = element instanceof CsmToken && ((CsmToken) element).isNewLine();

                if (isWhitespaceToken) {

                    differenceElements.set(i, new Added(CsmElement.newline(lineSeparator)));

                }

            }

        }

    }

    List<DifferenceElement> calculateListReplacementDifference(ObservableProperty observableProperty, NodeList<?> nodeList, int index, Node newValue) {

        Node container = nodeList.getParentNodeForChildren();

        CsmElement element = ConcreteSyntaxModel.forClass(container.getClass());

        CalculatedSyntaxModel original = calculatedSyntaxModelForNode(element, container);

        CalculatedSyntaxModel after = calculatedSyntaxModelAfterListReplacement(element, observableProperty, nodeList, index, newValue);

        return DifferenceElementCalculator.calculate(original, after);

    }

    void calculatePropertyChange(NodeText nodeText, Node observedNode, ObservableProperty property, Object oldValue, Object newValue) {

        if (nodeText == null) {

            throw new NullPointerException();

        }

        CsmElement element = ConcreteSyntaxModel.forClass(observedNode.getClass());

        CalculatedSyntaxModel original = calculatedSyntaxModelForNode(element, observedNode);

        CalculatedSyntaxModel after = calculatedSyntaxModelAfterPropertyChange(element, observedNode, property, oldValue, newValue);

        List<DifferenceElement> differenceElements = DifferenceElementCalculator.calculate(original, after);

        Difference difference = new Difference(differenceElements, nodeText, observedNode);

        difference.apply();

    }

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelForNode(CsmElement csm, Node node) {

        List<CsmElement> elements = new LinkedList<>();

        calculatedSyntaxModelForNode(csm, node, elements, new NoChange());

        return new CalculatedSyntaxModel(elements);

    }

    CalculatedSyntaxModel calculatedSyntaxModelForNode(Node node) {

        return calculatedSyntaxModelForNode(ConcreteSyntaxModel.forClass(node.getClass()), node);

    }

    private void calculatedSyntaxModelForNode(CsmElement csm, Node node, List<CsmElement> elements, Change change) {

        if (csm instanceof CsmSequence) {

            CsmSequence csmSequence = (CsmSequence) csm;

            csmSequence.getElements().forEach(e -> calculatedSyntaxModelForNode(e, node, elements, change));

        } else if (csm instanceof CsmComment) {

            // nothing to do

        } else if (csm instanceof CsmSingleReference) {

            CsmSingleReference csmSingleReference = (CsmSingleReference)csm;

            Node child;

            if (change instanceof PropertyChange && ((PropertyChange)change).getProperty() == csmSingleReference.getProperty()) {

                child = (Node)((PropertyChange)change).getNewValue();

            } else {

                child = csmSingleReference.getProperty().getValueAsSingleReference(node);

            }

            if (child != null) {

                // fix issue #2374

                // Add node comment if needed (it's not very elegant but it works)

                // We need to be sure that the node is an ExpressionStmt because we can meet

                // this class definition

                // a line comment <This is my class, with my comment> followed by

                // class A {}

                // In this case keyworld [class] is considered as a token and [A] is a child element

                // So if we don't care that the node is an ExpressionStmt we could try to generate a wrong definition

                // like this [class // This is my class, with my comment A {}]

                if (node.getComment().isPresent() && node instanceof ExpressionStmt) {

                    LineSeparator lineSeparator = node.getLineEndingStyleOrDefault(LineSeparator.SYSTEM);

                    elements.add(new CsmChild(node.getComment().get()));

                    elements.add(new CsmToken(eolTokenKind(lineSeparator), lineSeparator.asRawString()));

                }

                elements.add(new CsmChild(child));

            }

        } else if (csm instanceof CsmNone) {

            // nothing to do

        } else if (csm instanceof CsmToken) {

            elements.add(csm);

        } else if (csm instanceof CsmOrphanCommentsEnding) {

            // nothing to do

        } else if (csm instanceof CsmList) {

            CsmList csmList = (CsmList) csm;

            if (csmList.getProperty().isAboutNodes()) {

                Object rawValue = change.getValue(csmList.getProperty(), node);

                NodeList<?> nodeList;

                if (rawValue instanceof Optional) {

                    Optional<?> optional = (Optional<?>)rawValue;

                    if (optional.isPresent()) {

                        if (!(optional.get() instanceof NodeList)) {

                            throw new IllegalStateException("Expected NodeList, found " + optional.get().getClass().getCanonicalName());

                        }

                        nodeList = (NodeList<?>) optional.get();

                    } else {

                        nodeList = new NodeList<>();

                    }

                } else {

                    if (!(rawValue instanceof NodeList)) {

                        throw new IllegalStateException("Expected NodeList, found " + rawValue.getClass().getCanonicalName());

                    }

                    nodeList = (NodeList<?>) rawValue;

                }

                if (!nodeList.isEmpty()) {

                    calculatedSyntaxModelForNode(csmList.getPreceeding(), node, elements, change);

                    for (int i = 0; i < nodeList.size(); i++) {

                        if (i != 0) {

                            calculatedSyntaxModelForNode(csmList.getSeparatorPre(), node, elements, change);

                        }

                        elements.add(new CsmChild(nodeList.get(i)));

                        if (i != (nodeList.size() - 1)) {

                            calculatedSyntaxModelForNode(csmList.getSeparatorPost(), node, elements, change);

                        }

                    }

                    calculatedSyntaxModelForNode(csmList.getFollowing(), node, elements, change);

                }

            } else {

                Collection<?> collection = (Collection<?>) change.getValue(csmList.getProperty(), node);

                if (!collection.isEmpty()) {

                    calculatedSyntaxModelForNode(csmList.getPreceeding(), node, elements, change);

                    boolean first = true;

                    for (Iterator<?> it = collection.iterator(); it.hasNext(); ) {

                        if (!first) {

                            calculatedSyntaxModelForNode(csmList.getSeparatorPre(), node, elements, change);

                        }

                        Object value = it.next();

                        if (value instanceof Modifier) {

                            Modifier modifier = (Modifier)value;

                            elements.add(new CsmToken(toToken(modifier)));

                        } else {

                            throw new UnsupportedOperationException(it.next().getClass().getSimpleName());

                        }

                        if (it.hasNext()) {

                            calculatedSyntaxModelForNode(csmList.getSeparatorPost(), node, elements, change);

                        }

                        first = false;

                    }

                    calculatedSyntaxModelForNode(csmList.getFollowing(), node, elements, change);

                }

            }

        } else if (csm instanceof CsmConditional) {

            CsmConditional csmConditional = (CsmConditional) csm;

            boolean satisfied = change.evaluate(csmConditional, node);

            if (satisfied) {

                calculatedSyntaxModelForNode(csmConditional.getThenElement(), node, elements, change);

            } else {

                calculatedSyntaxModelForNode(csmConditional.getElseElement(), node, elements, change);

            }

        } else if (csm instanceof CsmIndent) {

            elements.add(csm);

        } else if (csm instanceof CsmUnindent) {

            elements.add(csm);

        } else if (csm instanceof CsmAttribute) {

            CsmAttribute csmAttribute = (CsmAttribute) csm;

            Object value = change.getValue(csmAttribute.getProperty(), node);

            String text = value.toString();

            if (value instanceof Stringable) {

                text = ((Stringable) value).asString();

            }

            elements.add(new CsmToken(csmAttribute.getTokenType(node, value.toString(), text), text));

        } else if ((csm instanceof CsmString) && (node instanceof StringLiteralExpr)) {

            // fix #2382:

            // This method calculates the syntax model _after_ the change has been applied.

            // If the given change is a PropertyChange, the returned model should

            // contain the new value, otherwise the original/current value should be used.

            if (change instanceof PropertyChange) {

                elements.add(new CsmToken(GeneratedJavaParserConstants.STRING_LITERAL,

                        "\"" + ((PropertyChange) change).getNewValue() + "\""));

            } else {

                elements.add(new CsmToken(GeneratedJavaParserConstants.STRING_LITERAL,

                        "\"" + ((StringLiteralExpr) node).getValue() + "\""));

            }

        } else if ((csm instanceof CsmString) && (node instanceof TextBlockLiteralExpr)) {

            // FIXME: csm should be CsmTextBlock -- See also #2677

            if (change instanceof PropertyChange) {

                elements.add(new CsmToken(GeneratedJavaParserConstants.TEXT_BLOCK_LITERAL,

                        "\"\"\"" + ((PropertyChange) change).getNewValue() + "\"\"\""));

            } else {

                elements.add(new CsmToken(GeneratedJavaParserConstants.TEXT_BLOCK_LITERAL,

                        "\"\"\"" + ((TextBlockLiteralExpr) node).getValue() + "\"\"\""));

            }

        } else if ((csm instanceof CsmChar) && (node instanceof CharLiteralExpr)) {

            if (change instanceof PropertyChange) {

                elements.add(new CsmToken(GeneratedJavaParserConstants.CHAR,

                        "'" + ((PropertyChange) change).getNewValue() + "'"));

            } else {

                elements.add(new CsmToken(GeneratedJavaParserConstants.CHAR,

                        "'" + ((CharLiteralExpr) node).getValue() + "'"));

            }

        } else if (csm instanceof CsmMix) {

            CsmMix csmMix = (CsmMix)csm;

            List<CsmElement> mixElements = new LinkedList<>();

            csmMix.getElements().forEach(e -> calculatedSyntaxModelForNode(e, node, mixElements, change));

            elements.add(new CsmMix(mixElements));

        } else if (csm instanceof CsmChild) {

            elements.add(csm);

        } else {

            throw new UnsupportedOperationException(csm.getClass().getSimpleName()+ " " + csm);

        }

    }

    public static int toToken(Modifier modifier) {

        switch (modifier.getKeyword()) {

            case PUBLIC:

                return GeneratedJavaParserConstants.PUBLIC;

            case PRIVATE:

                return GeneratedJavaParserConstants.PRIVATE;

            case PROTECTED:

                return GeneratedJavaParserConstants.PROTECTED;

            case STATIC:

                return GeneratedJavaParserConstants.STATIC;

            case FINAL:

                return GeneratedJavaParserConstants.FINAL;

            case ABSTRACT:

                return GeneratedJavaParserConstants.ABSTRACT;

            case TRANSIENT:

                return GeneratedJavaParserConstants.TRANSIENT;

            case SYNCHRONIZED:

                return GeneratedJavaParserConstants.SYNCHRONIZED;

            case VOLATILE:

                return GeneratedJavaParserConstants.VOLATILE;

            case NATIVE:

                return GeneratedJavaParserConstants.NATIVE;

            case STRICTFP:

                return GeneratedJavaParserConstants.STRICTFP;

            case TRANSITIVE:

                return GeneratedJavaParserConstants.TRANSITIVE;

            default:

                throw new UnsupportedOperationException(modifier.getKeyword().name());

        }

    }

    ///

    /// Methods that calculate CalculatedSyntaxModel

    ///

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelAfterPropertyChange(Node node, ObservableProperty property, Object oldValue, Object newValue) {

        return calculatedSyntaxModelAfterPropertyChange(ConcreteSyntaxModel.forClass(node.getClass()), node, property, oldValue, newValue);

    }

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelAfterPropertyChange(CsmElement csm, Node node, ObservableProperty property, Object oldValue, Object newValue) {

        List<CsmElement> elements = new LinkedList<>();

        calculatedSyntaxModelForNode(csm, node, elements, new PropertyChange(property, oldValue, newValue));

        return new CalculatedSyntaxModel(elements);

    }

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelAfterListRemoval(CsmElement csm, ObservableProperty observableProperty, NodeList<?> nodeList, int index) {

        List<CsmElement> elements = new LinkedList<>();

        Node container = nodeList.getParentNodeForChildren();

        calculatedSyntaxModelForNode(csm, container, elements, new ListRemovalChange(observableProperty, index));

        return new CalculatedSyntaxModel(elements);

    }

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelAfterListAddition(CsmElement csm, ObservableProperty observableProperty, NodeList<?> nodeList, int index, Node nodeAdded) {

        List<CsmElement> elements = new LinkedList<>();

        Node container = nodeList.getParentNodeForChildren();

        calculatedSyntaxModelForNode(csm, container, elements, new ListAdditionChange(observableProperty, index, nodeAdded));

        return new CalculatedSyntaxModel(elements);

    }

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelAfterListAddition(Node container, ObservableProperty observableProperty, int index, Node nodeAdded) {

        CsmElement csm = ConcreteSyntaxModel.forClass(container.getClass());

        Object rawValue = observableProperty.getRawValue(container);

        if (!(rawValue instanceof NodeList)) {

            throw new IllegalStateException("Expected NodeList, found " + rawValue.getClass().getCanonicalName());

        }

        NodeList<?> nodeList = (NodeList<?>)rawValue;

        return calculatedSyntaxModelAfterListAddition(csm, observableProperty, nodeList, index, nodeAdded);

    }

    // Visible for testing

    CalculatedSyntaxModel calculatedSyntaxModelAfterListRemoval(Node container, ObservableProperty observableProperty, int index) {

        CsmElement csm = ConcreteSyntaxModel.forClass(container.getClass());

        Object rawValue = observableProperty.getRawValue(container);

        if (!(rawValue instanceof NodeList)) {

            throw new IllegalStateException("Expected NodeList, found " + rawValue.getClass().getCanonicalName());

        }

        NodeList<?> nodeList = (NodeList<?>)rawValue;

        return calculatedSyntaxModelAfterListRemoval(csm, observableProperty, nodeList, index);

    }

    // Visible for testing

    private CalculatedSyntaxModel calculatedSyntaxModelAfterListReplacement(CsmElement csm, ObservableProperty observableProperty, NodeList<?> nodeList, int index, Node newValue) {

        List<CsmElement> elements = new LinkedList<>();

        Node container = nodeList.getParentNodeForChildren();

        calculatedSyntaxModelForNode(csm, container, elements, new ListReplacementChange(observableProperty, index, newValue));

        return new CalculatedSyntaxModel(elements);

    }

}