/*
 * Copyright (C) 2011 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 org.codehaus.gmavenplus.mojo;

import org.apache.maven.plugins.annotations.Parameter;
import org.codehaus.gmavenplus.groovyworkarounds.DotGroovyFile;
import org.codehaus.gmavenplus.model.IncludeClasspath;
import org.codehaus.gmavenplus.model.internal.Version;
import org.codehaus.gmavenplus.util.FileUtils;

import java.io.File;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import static org.codehaus.gmavenplus.util.ReflectionUtils.findConstructor;
import static org.codehaus.gmavenplus.util.ReflectionUtils.findMethod;
import static org.codehaus.gmavenplus.util.ReflectionUtils.invokeConstructor;
import static org.codehaus.gmavenplus.util.ReflectionUtils.invokeMethod;


/**
 * The base generate stubs mojo, which all generate stubs mojos extend.
 *
 * @author Keegan Witt
 * @since 1.0-beta-1
 */
public abstract class AbstractGenerateStubsMojo extends AbstractGroovyStubSourcesMojo {

    /**
     * Groovy 4.0.6 version.
     */
    protected static final Version GROOVY_4_0_6 = new Version(4, 0, 6);

    /**
     * Groovy 4.0.2 version.
     */
    protected static final Version GROOVY_4_0_2 = new Version(4, 0, 2);

    /**
     * Groovy 4.0.0 beta-1 version.
     */
    protected static final Version GROOVY_4_0_0_BETA1 = new Version(4, 0, 0, "beta-1");

    /**
     * Groovy 4.0.0 alpha-3 version.
     */
    protected static final Version GROOVY_4_0_0_ALPHA3 = new Version(4, 0, 0, "alpha-3");

    /**
     * Groovy 4.0.0 alpha-1 version.
     */
    protected static final Version GROOVY_4_0_0_ALPHA1 = new Version(4, 0, 0, "alpha-1");

    /**
     * Groovy 3.0.8 version.
     */
    protected static final Version GROOVY_3_0_8 = new Version(3, 0, 8);

    /**
     * Groovy 3.0.6 version.
     */
    protected static final Version GROOVY_3_0_6 = new Version(3, 0, 6);

    /**
     * Groovy 3.0.3 version.
     */
    protected static final Version GROOVY_3_0_3 = new Version(3, 0, 3);

    /**
     * Groovy 3.0.0 beta-2 version.
     */
    protected static final Version GROOVY_3_0_0_BETA2 = new Version(3, 0, 0, "beta-2");

    /**
     * Groovy 3.0.0 beta-1 version.
     */
    protected static final Version GROOVY_3_0_0_BETA1 = new Version(3, 0, 0, "beta-1");

    /**
     * Groovy 3.0.0 alpha-4 version.
     */
    protected static final Version GROOVY_3_0_0_ALPHA4 = new Version(3, 0, 0, "alpha-4");

    /**
     * Groovy 3.0.0 alpha-2 version.
     */
    protected static final Version GROOVY_3_0_0_ALPHA2 = new Version(3, 0, 0, "alpha-2");

    /**
     * Groovy 3.0.0 alpha-1 version.
     */
    protected static final Version GROOVY_3_0_0_ALPHA1 = new Version(3, 0, 0, "alpha-1");

    /**
     * Groovy 2.6.0 alpha-4 version.
     */
    protected static final Version GROOVY_2_6_0_ALPHA4 = new Version(2, 6, 0, "alpha-4");

    /**
     * Groovy 2.6.0 alpha-1 version.
     */
    protected static final Version GROOVY_2_6_0_ALPHA1 = new Version(2, 6, 0, "alpha-1");

    /**
     * Groovy 2.5.7 version.
     */
    protected static final Version GROOVY_2_5_7 = new Version(2, 5, 7);

    /**
     * Groovy 2.5.3 version.
     */
    protected static final Version GROOVY_2_5_3 = new Version(2, 5, 3);

    /**
     * Groovy 2.3.3 version.
     */
    protected static final Version GROOVY_2_3_3 = new Version(2, 3, 3);

    /**
     * Groovy 2.1.3 version.
     */
    protected static final Version GROOVY_2_1_3 = new Version(2, 1, 3);

    /**
     * Groovy 2.9.0 beta-1 version.
     */
    protected static final Version GROOVY_1_9_0_BETA1 = new Version(1, 9, 0, "beta-1");

    /**
     * Groovy 1.9.0 beta-3 version.
     */
    protected static final Version GROOVY_1_9_0_BETA3 = new Version(1, 9, 0, "beta-3");

    /**
     * Groovy 1.8.2 version.
     */
    protected static final Version GROOVY_1_8_2 = new Version(1, 8, 2);

    /**
     * Groovy 1.8.3 version.
     */
    protected static final Version GROOVY_1_8_3 = new Version(1, 8, 3);

    /*
     * TODO: support Groovy 1.5.0 - 1.8.1?
     * For some reason, the JavaStubCompilationUnit is silently not creating my stubs
     * (although it does create the target directory) when I use other versions.
     */

    /**
     * The encoding of source files.
     */
    @Parameter(defaultValue = "${project.build.sourceEncoding}")
    protected String sourceEncoding;

    /**
     * The Groovy compiler bytecode compatibility. One of
     * <ul>
     *   <li>1.4 (or 4)</li>
     *   <li>1.5 (or 5)</li>
     *   <li>1.6 (or 6)</li>
     *   <li>1.7 (or 7)</li>
     *   <li>1.8 (or 8)</li>
     *   <li>9 (or 1.9)</li>
     *   <li>10</li>
     *   <li>11</li>
     *   <li>12</li>
     *   <li>13</li>
     *   <li>14</li>
     *   <li>15</li>
     *   <li>16</li>
     *   <li>17</li>
     *   <li>18</li>
     * </ul>
     * Using 1.6 (or 6) or 1.7 (or 7) requires Groovy &gt;= 2.1.3.
     * Using 1.8 (or 8) requires Groovy &gt;= 2.3.3.
     * Using 9 (or 1.9) requires Groovy &gt;= 2.5.3, or Groovy &gt;= 2.6.0 alpha 4, or Groovy &gt;= 3.0.0 alpha 2.
     * Using 9 (or 1.9) with invokedynamic requires Groovy &gt;= 2.5.3, or Groovy &gt;= 3.0.0 alpha 2, but not any 2.6 versions.
     * Using 10, 11, or 12 requires Groovy &gt;= 2.5.3, or Groovy &gt;= 3.0.0 alpha 4, but not any 2.6 versions.
     * Using 13 requires Groovy &gt;= 2.5.7, or Groovy &gt;= 3.0.0-beta-1, but not any 2.6 versions.
     * Using 14 requires Groovy &gt;= 3.0.0 beta-2.
     * Using 15 requires Groovy &gt;= 3.0.3.
     * Using 16 requires Groovy &gt;= 3.0.6.
     * Using 17 requires Groovy &gt;= 3.0.8 or Groovy &gt; 4.0.0-alpha-3.
     * Using 18 requires Groovy &gt; 4.0.0-beta-1.
     * Using 19 requires Groovy &gt; 4.0.2.
     * Using 20 requires Groovy &gt; 4.0.6.
     *
     * @since 1.0-beta-3
     */
    @Parameter(property = "maven.compiler.target", defaultValue = "1.8")
    protected String targetBytecode;

    /**
     * Whether to check that the version of Groovy used is able to use the requested <code>targetBytecode</code>.
     *
     * @since 1.9.0
     */
    @Parameter(property = "skipBytecodeCheck", defaultValue = "false")
    protected boolean skipBytecodeCheck;

    /**
     * Whether Groovy compiler should be set to debug.
     */
    @Parameter(defaultValue = "false")
    protected boolean debug;

    /**
     * Whether Groovy compiler should be set to verbose.
     */
    @Parameter(defaultValue = "false")
    protected boolean verbose;

    /**
     * Groovy compiler warning level. Should be one of:
     * <dl>
     *   <dt>0</dt>
     *     <dd>None</dd>
     *   <dt>1</dt>
     *     <dd>Likely Errors</dd>
     *   <dt>2</dt>
     *     <dd>Possible Errors</dd>
     *   <dt>3</dt>
     *     <dd>Paranoia</dd>
     * </dl>
     */
    @Parameter(defaultValue = "1")
    protected int warningLevel;

    /**
     * Groovy compiler error tolerance (the number of non-fatal errors (per unit) that should be tolerated before compilation is aborted).
     */
    @Parameter(defaultValue = "0")
    protected int tolerance;

    /**
     * What classpath to include. One of
     * <ul>
     *   <li>PROJECT_ONLY</li>
     *   <li>PROJECT_AND_PLUGIN</li>
     *   <li>PLUGIN_ONLY</li>
     * </ul>
     * Uses the same scope as the required dependency resolution of this mojo. Use only if you know what you're doing.
     *
     * @since 1.8.0
     */
    @Parameter(defaultValue = "PROJECT_ONLY")
    protected IncludeClasspath includeClasspath;

    /**
     * Performs the stub generation on the specified source files.
     *
     * @param stubSources     the sources to perform stub generation on
     * @param classpath       The classpath to use for compilation
     * @param outputDirectory the directory to write the stub files to
     * @throws ClassNotFoundException    when a class needed for stub generation cannot be found
     * @throws InstantiationException    when a class needed for stub generation cannot be instantiated
     * @throws IllegalAccessException    when a method needed for stub generation cannot be accessed
     * @throws InvocationTargetException when a reflection invocation needed for stub generation cannot be completed
     * @throws MalformedURLException     when a classpath element provides a malformed URL
     */
    protected synchronized void doStubGeneration(final Set<File> stubSources, final List<?> classpath, final File outputDirectory) throws ClassNotFoundException, InvocationTargetException, IllegalAccessException, InstantiationException, MalformedURLException {
        if (stubSources == null || stubSources.isEmpty()) {
            getLog().info("No sources specified for stub generation. Skipping.");
            return;
        }

        setupClassWrangler(classpath, includeClasspath);

        logPluginClasspath();
        classWrangler.logGroovyVersion(mojoExecution.getMojoDescriptor().getGoal());

        if (groovyVersionSupportsAction() && !skipBytecodeCheck) {
            verifyGroovyVersionSupportsTargetBytecode();
        } else {
            getLog().error("Your Groovy version (" + classWrangler.getGroovyVersionString() + ") doesn't support stub generation. The minimum version of Groovy required is " + minGroovyVersion + ". Skipping stub generation.");
            return;
        }

        // get classes we need with reflection
        Class<?> compilerConfigurationClass = classWrangler.getClass("org.codehaus.groovy.control.CompilerConfiguration");
        Class<?> javaStubCompilationUnitClass = classWrangler.getClass("org.codehaus.groovy.tools.javac.JavaStubCompilationUnit");
        Class<?> groovyClassLoaderClass = classWrangler.getClass("groovy.lang.GroovyClassLoader");

        // setup stub generation options
        Object compilerConfiguration = setupCompilerConfiguration(outputDirectory, compilerConfigurationClass);
        Object groovyClassLoader = invokeConstructor(findConstructor(groovyClassLoaderClass, ClassLoader.class, compilerConfigurationClass), classWrangler.getClassLoader(), compilerConfiguration);
        Object javaStubCompilationUnit = invokeConstructor(findConstructor(javaStubCompilationUnitClass, compilerConfigurationClass, groovyClassLoaderClass, File.class), compilerConfiguration, groovyClassLoader, outputDirectory);

        // add Groovy sources
        addGroovySources(stubSources, compilerConfigurationClass, javaStubCompilationUnitClass, compilerConfiguration, javaStubCompilationUnit);

        // generate the stubs
        invokeMethod(findMethod(javaStubCompilationUnitClass, "compile"), javaStubCompilationUnit);
    }

    /**
     * Sets up the CompilerConfiguration to use for stub generation.
     *
     * @param outputDirectory            the directory to write the stub files to
     * @param compilerConfigurationClass the CompilerConfiguration class
     * @return the CompilerConfiguration to use for stub generation
     * @throws InstantiationException    when a class needed for stub generation cannot be instantiated
     * @throws IllegalAccessException    when a method needed for stub generation cannot be accessed
     * @throws InvocationTargetException when a reflection invocation needed for stub generation cannot be completed
     */
    protected Object setupCompilerConfiguration(final File outputDirectory, final Class<?> compilerConfigurationClass) throws InvocationTargetException, IllegalAccessException, InstantiationException {
        Object compilerConfiguration = invokeConstructor(findConstructor(compilerConfigurationClass));
        invokeMethod(findMethod(compilerConfigurationClass, "setDebug", boolean.class), compilerConfiguration, debug);
        invokeMethod(findMethod(compilerConfigurationClass, "setVerbose", boolean.class), compilerConfiguration, verbose);
        invokeMethod(findMethod(compilerConfigurationClass, "setWarningLevel", int.class), compilerConfiguration, warningLevel);
        invokeMethod(findMethod(compilerConfigurationClass, "setTolerance", int.class), compilerConfiguration, tolerance);
        invokeMethod(findMethod(compilerConfigurationClass, "setTargetBytecode", String.class), compilerConfiguration, translateJavacTargetToTargetBytecode(targetBytecode));
        if (sourceEncoding != null) {
            invokeMethod(findMethod(compilerConfigurationClass, "setSourceEncoding", String.class), compilerConfiguration, sourceEncoding);
        }
        Map<String, Object> options = new HashMap<>();
        options.put("stubDir", outputDirectory);
        options.put("keepStubs", Boolean.TRUE);
        invokeMethod(findMethod(compilerConfigurationClass, "setJointCompilationOptions", Map.class), compilerConfiguration, options);

        return compilerConfiguration;
    }

    /**
     * Adds the Groovy sources to the CompilationUnit.
     *
     * @param stubSources                  the sources to perform stub generation on
     * @param compilerConfigurationClass   the CompilerConfiguration class
     * @param javaStubCompilationUnitClass the JavaStubCompilationUnit class
     * @param compilerConfiguration        the CompilerConfiguration to use for stub generation
     * @param javaStubCompilationUnit      the JavaStubCompilationUnit to use for stub generation
     * @throws IllegalAccessException    when a method needed for stub generation cannot be accessed
     * @throws InvocationTargetException when a reflection invocation needed for stub generation cannot be completed
     */
    protected void addGroovySources(final Set<File> stubSources, final Class<?> compilerConfigurationClass, final Class<?> javaStubCompilationUnitClass, final Object compilerConfiguration, final Object javaStubCompilationUnit) throws InvocationTargetException, IllegalAccessException {
        Set<String> scriptExtensions = new HashSet<>();
        for (File stubSource : stubSources) {
            scriptExtensions.add(FileUtils.getFileExtension(stubSource));
        }
        getLog().debug("Detected Groovy file extensions: " + scriptExtensions + ".");
        if (supportsSettingExtensions()) {
            invokeMethod(findMethod(compilerConfigurationClass, "setScriptExtensions", Set.class), compilerConfiguration, scriptExtensions);
        }
        getLog().debug("Adding Groovy to generate stubs for:");
        Method addSource = findMethod(javaStubCompilationUnitClass, "addSource", File.class);
        for (File stubSource : stubSources) {
            getLog().debug("    " + stubSource);
            if (supportsSettingExtensions()) {
                invokeMethod(addSource, javaStubCompilationUnit, stubSource);
            } else {
                DotGroovyFile dotGroovyFile = new DotGroovyFile(stubSource).setScriptExtensions(scriptExtensions);
                invokeMethod(addSource, javaStubCompilationUnit, dotGroovyFile);
            }
        }
    }

    /**
     * Determines whether the version of Groovy supports stub generation.
     *
     * @return <code>true</code> if the version of Groovy supports stub generation, <code>false</code> otherwise
     */
    protected boolean supportsSettingExtensions() {
        return groovyAtLeast(GROOVY_1_8_3) && (groovyOlderThan(GROOVY_1_9_0_BETA1) || groovyNewerThan(GROOVY_1_9_0_BETA3));
    }

    /**
     * Logs the stubs that have been generated.
     *
     * @param outputDirectory the output directory for the stubs
     */
    protected void logGeneratedStubs(File outputDirectory) {
        Set<File> stubs = getStubs(outputDirectory);
        getLog().info("Generated " + stubs.size() + " stub" + (stubs.size() != 1 ? "s" : "") + ".");
    }

    /**
     * This is a fix for http://jira.codehaus.org/browse/MGROOVY-187
     * It modifies the dates of the created stubs to 1/1/1970, ensuring that the Java compiler will not overwrite perfectly
     * good compiled Groovy just because it has a newer source stub. Basically, this prevents the stubs from causing a
     * side-effect with the Java compiler, but still allows stubs to work with JavaDoc.
     *
     * @param stubs the files on which to reset the modified date
     */
    protected void resetStubModifiedDates(final Set<File> stubs) {
        for (File stub : stubs) {
            boolean success = stub.setLastModified(0L);
            if (!success) {
                getLog().warn("Unable to set modified time on stub " + stub.getAbsolutePath() + ".");
            }
        }
    }

    /**
     * Throws an exception if targetBytecode is not supported with this version of Groovy. That is, when Groovy added
     * the option to org.codehaus.groovy.control.CompilerConfiguration and used it in
     * org.codehaus.groovy.classgen.asm.WriterController.
     */
    protected void verifyGroovyVersionSupportsTargetBytecode() {
        if ("20".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_4_0_6)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_4_0_6 + " or newer.");
            }
        } else if ("19".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_4_0_2)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_4_0_2 + " or newer.");
            }
        } else if ("18".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_4_0_0_BETA1)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_4_0_0_BETA1 + " or newer.");
            }
        } else if ("17".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_3_0_8) || (groovyAtLeast(GROOVY_4_0_0_ALPHA1) && groovyOlderThan(GROOVY_4_0_0_ALPHA3))) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_3_0_8 + "/" + GROOVY_4_0_0_ALPHA3 + " or newer.");
            }
        } else if ("16".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_3_0_6)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_3_0_6 + " or newer.");
            }
        } else if ("15".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_3_0_3)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_3_0_3 + " or newer.");
            }
        } else if ("14".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_3_0_0_BETA2)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_3_0_0_BETA2 + " or newer.");
            }
        } else if ("13".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_2_5_7) || (groovyAtLeast(GROOVY_2_6_0_ALPHA1) && groovyOlderThan(GROOVY_3_0_0_BETA1))) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_2_5_7 + "/" + GROOVY_3_0_0_BETA1 + " or newer. No 2.6 version is supported.");
            }
        } else if ("12".equals(targetBytecode) || "11".equals(targetBytecode) || "10".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_2_5_3) || (groovyAtLeast(GROOVY_2_6_0_ALPHA1) && groovyOlderThan(GROOVY_3_0_0_ALPHA4))) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_2_5_3 + "/" + GROOVY_3_0_0_ALPHA4 + " or newer. No 2.6 version is supported.");
            }
        } else if ("9".equals(targetBytecode) || "1.9".equals(targetBytecode)) {
            if (!isGroovyIndy() && (groovyOlderThan(GROOVY_2_5_3)
                    || (groovyAtLeast(GROOVY_2_6_0_ALPHA1) && groovyOlderThan(GROOVY_2_6_0_ALPHA4))
                    || (groovyAtLeast(GROOVY_3_0_0_ALPHA1) && groovyOlderThan(GROOVY_3_0_0_ALPHA2)))) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_2_5_3 + "/" + GROOVY_2_6_0_ALPHA4 + "/" + GROOVY_3_0_0_ALPHA2 + " or newer.");
            } else if (isGroovyIndy() && (groovyOlderThan(GROOVY_2_5_3) || (groovyAtLeast(GROOVY_2_6_0_ALPHA1) && groovyOlderThan(GROOVY_3_0_0_ALPHA4)))) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_2_5_3 + "/" + GROOVY_3_0_0_ALPHA4 + " or newer. No 2.6 version is supported.");
            }
        } else if ("8".equals(targetBytecode) || "1.8".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_2_3_3)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_2_3_3 + " or newer.");
            }
        } else if ("7".equals(targetBytecode) || "1.7".equals(targetBytecode) || "6".equals(targetBytecode) || "1.6".equals(targetBytecode)) {
            if (groovyOlderThan(GROOVY_2_1_3)) {
                throw new IllegalArgumentException("Target bytecode " + targetBytecode + " requires Groovy " + GROOVY_2_1_3 + " or newer.");
            }
        } else if (!"5".equals(targetBytecode) && !"1.5".equals(targetBytecode) && !"4".equals(targetBytecode) && !"1.4".equals(targetBytecode)) {
            throw new IllegalArgumentException("Unrecognized target bytecode: '" + targetBytecode + "'. This check can be skipped with 'skipBytecodeCheck', but this may result in a different target bytecode being used.");
        }
    }

    private static String translateJavacTargetToTargetBytecode(String targetBytecode) {
        Map<String, String> javacTargetToTargetBytecode = new HashMap<>();
        javacTargetToTargetBytecode.put("5", "1.5");
        javacTargetToTargetBytecode.put("6", "1.6");
        javacTargetToTargetBytecode.put("7", "1.7");
        javacTargetToTargetBytecode.put("8", "1.8");
        javacTargetToTargetBytecode.put("1.9", "9");
        return javacTargetToTargetBytecode.getOrDefault(targetBytecode, targetBytecode);
    }

}
