package ch.fhnw.thga.gradleplugins;

import static ch.fhnw.thga.gradleplugins.SharedTaskLogic.extractClassNameFromFregeModuleName;
import org.gradle.api.DefaultTask;
import org.gradle.api.file.DirectoryProperty;
import org.gradle.api.file.FileTree;
import org.gradle.api.file.RegularFileProperty;
import org.gradle.api.logging.Logger;
import org.gradle.api.logging.Logging;
import org.gradle.api.provider.Property;
import org.gradle.api.provider.Provider;
import org.gradle.api.tasks.Input;
import org.gradle.api.tasks.InputDirectory;
import org.gradle.api.tasks.InputFile;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.TaskAction;
import org.gradle.api.tasks.options.Option;

public abstract class ReplFregeTask extends DefaultTask {
    private static final Logger LOGGER         = Logging.getLogger(ReplFregeTask.class);
    public static final String REPL_MAIN_CLASS = "frege.repl.FregeRepl";

    @InputFile
    public abstract RegularFileProperty getFregeCompilerJar();

    @Input
    public abstract Property<String> getFregeDependencies();

    @InputDirectory
    public abstract DirectoryProperty getFregeOutputDir();

    @InputDirectory
    public abstract DirectoryProperty getFregeMainSourceDir();

    @Input
    @Option(option     = "replModule",
           description = "The full name of the module which you want to load into the repl, e.g. 'my.mod.Name'")
    public abstract Property<String> getReplModule();

    @Internal
    public final Provider<String> getReplClassName()
    {
        return getReplModule()
            .map(replSource -> extractClassNameFromFregeModuleName(replSource));
    }

    @Internal
    public final Provider<FileTree> getReplClassFiles()
    {
        return getFregeOutputDir()
            .map(outDir -> outDir.getAsFileTree())
            .map(tree   -> tree.matching(
                pattern -> pattern.include(
                    String.format(
                        "**/%s.class",
                        getReplClassName().get()
                    )
                )
            ));
    }

    @Internal
    public final Provider<FileTree> getReplJavaFiles()
    {
        return getFregeOutputDir()
            .map(outDir -> outDir.getAsFileTree())
            .map(tree   -> tree.matching(
                pattern -> pattern.include(
                    String.format(
                        "**/%s.java",
                        getReplClassName().get()
                    )
                ))
            );
    }

    @Internal
    public final Provider<FileTree> getReplFregeFile()
    {
        return getFregeMainSourceDir()
            .map(outDir -> outDir.getAsFileTree())
            .map(tree   -> tree.matching(
                pattern -> pattern.include(
                    String.format(
                        "**/%s.fr",
                        getReplClassName().get()
                    )
                ))
            );
    }

    @TaskAction
    public void printStartFregeReplCommand()
    {
        getProject().delete(getReplJavaFiles());
        getProject().delete(getReplClassFiles());
        LOGGER.lifecycle(
            "Execute the following command to start the Frege Repl and load the Frege module:");
        LOGGER.quiet(String.format(
            "(echo :l %s && cat) | java -cp %s %s",
            getReplFregeFile().get().getAsPath(),
            SharedTaskLogic.setupClasspath(
                getProject(),
                getFregeDependencies(),
                getFregeCompilerJar(),
                getFregeOutputDir())
            .get().getAsPath(),
            REPL_MAIN_CLASS)
        );
    }
}