/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * 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 com.android.ant;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.taskdefs.ExecTask;
import org.apache.tools.ant.types.FileSet;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.types.PatternSet.NameEntry;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

/**
 * Task to execute aidl.
 * <p>
 * It expects 3 attributes:<br>
 * 'executable' ({@link Path} with a single path) for the location of the aidl executable<br>
 * 'framework' ({@link Path} with a single path) for the "preprocessed" file containing all the
 *     parcelables exported by the framework<br>
 * 'genFolder' ({@link Path} with a single path) for the location of the gen folder.
 *
 * It also expects one or more inner elements called "source" which are identical to {@link Path}
 * elements.
 */
public class AidlExecTask extends Task {

    private String mExecutable;
    private String mFramework;
    private String mGenFolder;
    private final ArrayList<Path> mPaths = new ArrayList<Path>();

    /**
     * Sets the value of the "executable" attribute.
     * @param executable the value.
     */
    public void setExecutable(Path executable) {
        mExecutable = TaskHelper.checkSinglePath("executable", executable);
    }

    public void setFramework(Path value) {
        mFramework = TaskHelper.checkSinglePath("framework", value);
    }

    public void setGenFolder(Path value) {
        mGenFolder = TaskHelper.checkSinglePath("genFolder", value);
    }

    public Path createSource() {
        Path p = new Path(getProject());
        mPaths.add(p);
        return p;
    }

    @Override
    public void execute() throws BuildException {
        if (mExecutable == null) {
            throw new BuildException("AidlExecTask's 'executable' is required.");
        }
        if (mFramework == null) {
            throw new BuildException("AidlExecTask's 'framework' is required.");
        }
        if (mGenFolder == null) {
            throw new BuildException("AidlExecTask's 'genFolder' is required.");
        }

        Project taskProject = getProject();

        // build a list of all the source folders
        ArrayList<String> sourceFolders = new ArrayList<String>();
        for (Path p : mPaths) {
            String[] values = p.list();
            if (values != null) {
                sourceFolders.addAll(Arrays.asList(values));
            }
        }

        // gather all the aidl files from all the source folders.
        Set<String> sourceFiles = getFileListByExtension(taskProject, sourceFolders, "**/*.aidl");
        if (sourceFiles.size() > 0) {
            System.out.println(String.format("Found %d aidl files.", sourceFiles.size()));
        }

        // go look for all dependency files in the gen folder.
        Set<String> depFiles = getFileListByExtension(taskProject, mGenFolder, "**/*.d");

        // parse all the dep files and keep the ones that are aidl and check if they require
        // compilation again.
        ArrayList<String> toCompile = new ArrayList<String>();
        ArrayList<File> toRemove = new ArrayList<File>();
        ArrayList<String> depsToRemove = new ArrayList<String>();
        for (String depFile : depFiles) {
            DependencyGraph graph = new DependencyGraph(depFile, null /*watchPaths*/);

            // get the source file. it's the first item in the pre-reqs
            File sourceFile = graph.getFirstPrereq();
            String sourceFilePath = sourceFile.getAbsolutePath();

            // The gen folder may contain other dependency files not generated by aidl.
            // We only care if the first pre-rep is an aidl file.
            if (sourceFilePath.toLowerCase().endsWith(".aidl")) {
                // remove from the list of sourceFiles to mark as "processed" (but not compiled
                // yet, that'll be done by adding it to toCompile)
                if (sourceFiles.remove(sourceFilePath) == false) {
                    // looks like the source file does not exist anymore!
                    // we'll have to remove the output!
                    Set<File> outputFiles = graph.getTargets();
                    toRemove.addAll(outputFiles);

                    // also need to remove the dep file.
                    depsToRemove.add(depFile);
                } else if (graph.dependenciesHaveChanged(false /*printStatus*/)) {
                    // need to recompile!
                    toCompile.add(sourceFilePath);
                }
            }
        }

        // add to the list of files to compile, whatever is left in sourceFiles. Those are
        // new files that have never been compiled.
        toCompile.addAll(sourceFiles);

        if (toCompile.size() > 0) {
            System.out.println(String.format("Compiling %d aidl files.", toCompile.size()));

            for (String toCompilePath : toCompile) {
                ExecTask task = new ExecTask();
                task.setProject(taskProject);
                task.setOwningTarget(getOwningTarget());
                task.setExecutable(mExecutable);
                task.setTaskName("aidl");
                task.setFailonerror(true);

                task.createArg().setValue("-p" + mFramework);
                task.createArg().setValue("-o" + mGenFolder);
                // add all the source folders as import in case an aidl file in a source folder
                // imports a parcelable from another source folder.
                for (String importFolder : sourceFolders) {
                    task.createArg().setValue("-I" + importFolder);
                }

                // set auto dependency file creation
                task.createArg().setValue("-a");

                task.createArg().setValue(toCompilePath);

                // execute it.
                task.execute();
            }
        } else {
            System.out.println(String.format("No aidl files to compile."));
        }

        if (toRemove.size() > 0) {
            System.out.println(String.format("%d obsolete output files to remove.",
                    toRemove.size()));
            for (File toRemoveFile : toRemove) {
                if (toRemoveFile.delete() == false) {
                    System.err.println("Failed to remove " + toRemoveFile.getAbsolutePath());
                }
            }
        }

        // remove the dependency files that are obsolete
        if (depsToRemove.size() > 0) {
            System.out.println(String.format("%d obsolete dependency files to remove.",
                    depsToRemove.size()));
            for (String path : depsToRemove) {
                if (new File(path).delete() == false) {
                    System.err.println("Failed to remove " + path);
                }
            }
        }
    }

    private Set<String> getFileListByExtension(Project taskProject,
            List<String> sourceFolders, String filter) {
        HashSet<String> sourceFiles = new HashSet<String>();
        for (String sourceFolder : sourceFolders) {
            sourceFiles.addAll(getFileListByExtension(taskProject, sourceFolder, filter));
        }

        return sourceFiles;
    }

    private Set<String> getFileListByExtension(Project taskProject,
            String sourceFolder, String filter) {
        HashSet<String> sourceFiles = new HashSet<String>();

        // create a fileset to find all the files in the folder
        FileSet fs = new FileSet();
        fs.setProject(taskProject);
        fs.setDir(new File(sourceFolder));
        NameEntry include = fs.createInclude();
        include.setName(filter);

        // loop through the results of the file set
        Iterator<?> iter = fs.iterator();
        while (iter.hasNext()) {
            sourceFiles.add(iter.next().toString());
        }

        return sourceFiles;
    }


}