/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package idea;

import org.apache.tools.ant.BuildEvent;

import org.apache.tools.ant.BuildListener;

import org.apache.tools.ant.DefaultLogger;

import org.apache.tools.ant.Project;

import java.util.EnumSet;

import java.util.Stack;

import static org.apache.tools.ant.Project.*;

/**

 * This class is used to wrap the IntelliJ ant logger in order to provide more meaningful

 * output when building langtools. The basic ant output in IntelliJ can be quite cumbersome to

 * work with, as it provides two separate views: (i) a tree view, which is good to display build task

 * in a hierarchical fashion as they are processed; and a (ii) plain text view, which gives you

 * the full ant output. The main problem is that javac-related messages are buried into the

 * ant output (which is made very verbose by IntelliJ in order to support the tree view). It is

 * not easy to figure out which node to expand in order to see the error message; switching

 * to plain text doesn't help either, as now the output is totally flat.

 *

 * This logger class removes a lot of verbosity from the IntelliJ ant logger by not propagating

 * all the events to the IntelliJ's logger. In addition, certain events are handled in a custom

 * fashion, to generate better output during the build.

 */

public final class LangtoolsIdeaAntLogger extends DefaultLogger {

    /**

     * This is just a way to pass in customized binary string predicates;

     *

     * TODO: replace with @code{BiPredicate<String, String>} and method reference when moving to 8

     */

    enum StringBinaryPredicate {

        CONTAINS() {

            @Override

            boolean apply(String s1, String s2) {

                return s1.contains(s2);

            }

        },

        STARTS_WITH {

            @Override

            boolean apply(String s1, String s2) {

                return s1.startsWith(s2);

            }

        };

        abstract boolean apply(String s1, String s2);

    }

    /**

     * Various kinds of ant messages that we shall intercept

     */

    enum MessageKind {

        /** a javac error */

        JAVAC_ERROR(StringBinaryPredicate.CONTAINS, MSG_ERR, "error:", "compiler.err"),

        /** a javac warning */

        JAVAC_WARNING(StringBinaryPredicate.CONTAINS, MSG_WARN, "warning:", "compiler.warn"),

        /** a javac note */

        JAVAC_NOTE(StringBinaryPredicate.CONTAINS, MSG_INFO, "note:", "compiler.note"),

        /** continuation of some javac error message */

        JAVAC_NESTED_DIAG(StringBinaryPredicate.STARTS_WITH, MSG_INFO, "  "),

        /** a javac crash */

        JAVAC_CRASH(StringBinaryPredicate.STARTS_WITH, MSG_ERR, "An exception has occurred in the compiler"),

        /** jtreg test success */

        JTREG_TEST_PASSED(StringBinaryPredicate.STARTS_WITH, MSG_INFO, "Passed: "),

        /** jtreg test failure */

        JTREG_TEST_FAILED(StringBinaryPredicate.STARTS_WITH, MSG_ERR, "FAILED: "),

        /** jtreg test error */

        JTREG_TEST_ERROR(StringBinaryPredicate.STARTS_WITH, MSG_ERR, "Error: "),

        /** jtreg report */

        JTREG_TEST_REPORT(StringBinaryPredicate.STARTS_WITH, MSG_INFO, "Report written");

        StringBinaryPredicate sbp;

        int priority;

        String[] keys;

        MessageKind(StringBinaryPredicate sbp, int priority, String... keys) {

            this.sbp = sbp;

            this.priority = priority;

            this.keys = keys;

        }

        /**

         * Does a given message string matches this kind?

         */

        boolean matches(String s) {

            for (String key : keys) {

                if (sbp.apply(s, key)) {

                    return true;

                }

            }

            return false;

        }

    }

    /**

     * This enum is used to represent the list of tasks we need to keep track of during logging.

     */

    enum Task {

        /** javac task - invoked during compilation */

        JAVAC("javac", MessageKind.JAVAC_ERROR, MessageKind.JAVAC_WARNING, MessageKind.JAVAC_NOTE,

                       MessageKind.JAVAC_NESTED_DIAG, MessageKind.JAVAC_CRASH),

        /** jtreg task - invoked during test execution */

        JTREG("jtreg", MessageKind.JTREG_TEST_PASSED, MessageKind.JTREG_TEST_FAILED, MessageKind.JTREG_TEST_ERROR, MessageKind.JTREG_TEST_REPORT),

        /** initial synthetic task when the logger is created */

        ROOT("") {

            @Override

            boolean matches(String s) {

                return false;

            }

        },

        /** synthetic task catching any other tasks not in this list */

        ANY("") {

            @Override

            boolean matches(String s) {

                return true;

            }

        };

        String taskName;

        MessageKind[] msgs;

        Task(String taskName, MessageKind... msgs) {

            this.taskName = taskName;

            this.msgs = msgs;

        }

        boolean matches(String s) {

            return s.equals(taskName);

        }

    }

    /**

     * This enum is used to represent the list of targets we need to keep track of during logging.

     * A regular expression is used to match a given target name.

     */

    enum Target {

        /** jtreg target - executed when launching tests */

        JTREG("jtreg") {

            @Override

            String getDisplayMessage(BuildEvent e) {

                return "Running jtreg tests: " + e.getProject().getProperty("jtreg.tests");

            }

        },

        /** build bootstrap tool target - executed when bootstrapping javac */

        BUILD_BOOTSTRAP_JAVAC("build-bootstrap-javac-classes") {

            @Override

            String getDisplayMessage(BuildEvent e) {

                return "Building bootstrap javac...";

            }

        },

        /** build classes target - executed when building classes of given tool */

        BUILD_ALL_CLASSES("build-all-classes") {

            @Override

            String getDisplayMessage(BuildEvent e) {

                return "Building all classes...";

            }

        },

        /** synthetic target catching any other target not in this list */

        ANY("") {

            @Override

            String getDisplayMessage(BuildEvent e) {

                return "Executing Ant target(s): " + e.getProject().getProperty("ant.project.invoked-targets");

            }

            @Override

            boolean matches(String msg) {

                return true;

            }

        };

        String targetName;

        Target(String targetName) {

            this.targetName = targetName;

        }

        boolean matches(String msg) {

            return msg.equals(targetName);

        }

        abstract String getDisplayMessage(BuildEvent e);

    }

    /**

     * A custom build event used to represent status changes which should be notified inside

     * Intellij

     */

    static class StatusEvent extends BuildEvent {

        /** the target to which the status update refers */

        Target target;

        StatusEvent(BuildEvent e, Target target) {

            super(new StatusTask(e, target.getDisplayMessage(e)));

            this.target = target;

            setMessage(getTask().getTaskName(), 2);

        }

        /**

         * A custom task used to channel info regarding a status change

         */

        static class StatusTask extends org.apache.tools.ant.Task {

            StatusTask(BuildEvent event, String msg) {

                setProject(event.getProject());

                setOwningTarget(event.getTarget());

                setTaskName(msg);

            }

        }

    }

    /** wrapped ant logger (IntelliJ's own logger) */

    DefaultLogger logger;

    /** flag - is this the first target we encounter? */

    boolean firstTarget = true;

    /** flag - should subsequenet failures be suppressed ? */

    boolean suppressTaskFailures = false;

    /** flag - have we ran into a javac crash ? */

    boolean crashFound = false;

    /** stack of status changes associated with pending targets */

    Stack<StatusEvent> statusEvents = new Stack<>();

    /** stack of pending tasks */

    Stack<Task> tasks = new Stack<>();

    public LangtoolsIdeaAntLogger(Project project) {

        for (Object o : project.getBuildListeners()) {

            if (o instanceof DefaultLogger) {

                this.logger = (DefaultLogger)o;

                project.removeBuildListener((BuildListener)o);

                project.addBuildListener(this);

            }

        }

        tasks.push(Task.ROOT);

    }

    @Override

    public void buildStarted(BuildEvent event) {

        //do nothing

    }

    @Override

    public void buildFinished(BuildEvent event) {

        //do nothing

    }

    @Override

    public void targetStarted(BuildEvent event) {

        EnumSet<Target> statusKinds = firstTarget ?

                EnumSet.allOf(Target.class) :

                EnumSet.complementOf(EnumSet.of(Target.ANY));

        String targetName = event.getTarget().getName();

        for (Target statusKind : statusKinds) {

            if (statusKind.matches(targetName)) {

                StatusEvent statusEvent = new StatusEvent(event, statusKind);

                statusEvents.push(statusEvent);

                logger.taskStarted(statusEvent);

                firstTarget = false;

                return;

            }

        }

    }

    @Override

    public void targetFinished(BuildEvent event) {

        if (!statusEvents.isEmpty()) {

            StatusEvent lastEvent = statusEvents.pop();

            if (lastEvent.target.matches(event.getTarget().getName())) {

                logger.taskFinished(lastEvent);

            }

        }

    }

    @Override

    public void taskStarted(BuildEvent event) {

        String taskName = event.getTask().getTaskName();

        for (Task task : Task.values()) {

            if (task.matches(taskName)) {

                tasks.push(task);

                return;

            }

        }

    }

    @Override

    public void taskFinished(BuildEvent event) {

        if (tasks.peek() == Task.ROOT) {

            //we need to 'close' the root task to get nicer output

            logger.taskFinished(event);

        } else if (!suppressTaskFailures && event.getException() != null) {

            //the first (innermost) task failure should always be logged

            event.setMessage(event.getException().toString(), 0);

            event.setException(null);

            //note: we turn this into a plain message to avoid stack trace being logged by Idea

            logger.messageLogged(event);

            suppressTaskFailures = true;

        }

        tasks.pop();

    }

    @Override

    public void messageLogged(BuildEvent event) {

        String msg = event.getMessage();

        boolean processed = false;

        if (!tasks.isEmpty()) {

            Task task = tasks.peek();

            for (MessageKind messageKind : task.msgs) {

                if (messageKind.matches(msg)) {

                    event.setMessage(msg, messageKind.priority);

                    processed = true;

                    if (messageKind == MessageKind.JAVAC_CRASH) {

                        crashFound = true;

                    }

                    break;

                }

            }

        }

        if (event.getPriority() == MSG_ERR || crashFound) {

            //we log errors regardless of owning task

            logger.messageLogged(event);

            suppressTaskFailures = true;

        } else if (processed) {

            logger.messageLogged(event);

        }

    }

}