package io.trygvis.rules.engine.cli;

import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
import org.apache.commons.lang3.StringUtils;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.nio.file.Path;
import java.util.Objects;
import java.util.concurrent.Callable;
import java.util.stream.Collectors;

import static io.trygvis.rules.engine.cli.EngineFile.*;
import static picocli.CommandLine.Command;

@Command(name = "ninja")
public class NinjaCommand implements Callable<Integer> {

    public File basedir = null;

    public Path basepath;

    @Override
    public Integer call() throws Exception {
        basepath = Objects.requireNonNullElseGet(basedir, () -> new File("").getAbsoluteFile()).toPath();

        var factory = new YAMLFactory();
        factory.enable(YAMLGenerator.Feature.USE_NATIVE_TYPE_ID);
        factory.enable(YAMLGenerator.Feature.USE_NATIVE_OBJECT_ID);
        var mapper = new ObjectMapper(factory);
        mapper.enable(MapperFeature.AUTO_DETECT_FIELDS);

        var f = mapper.readValue(new File(basedir, "engine.yaml"), EngineFile.class);

        Path dbDir;
        if (StringUtils.trimToNull(f.dbDir) == null) {
            System.err.println("Missing required field: dbDir");
            return 1;
        } else {
            dbDir = Path.of(f.dbDir);
        }

        for (var job : f.jobs) {
            if (job.outputs.isEmpty()) {
                var output = new Output();
                output.name = job.name;
                output.includes = job.outputIncludes;
                job.outputIncludes = null;

                job.outputs.add(output);
            }
        }

        if (false) {
            System.out.println("----------------------------------------------------");
            System.out.println(f);
            System.out.println("----------------------------------------------------");
        }

        var buf = new StringWriter();
        var out = new PrintWriter(buf);

        out.println("# Generated");
        out.println("#");
        out.println("### engine.ninja");
        out.println("");
        out.println("rule engine-yaml-to-ninja");
        out.println("  command = engine ninja");
        out.println("");
        out.println("build engine.ninja: engine-yaml-to-ninja engine.yaml");
        out.println("");
        out.println("### engine.png");
        out.println("");
        out.println("rule ninja-to-dot");
        out.println("  command = ninja -t graph > $out");
        out.println("");
        out.println("rule dot-to-png");
        out.println(" command = dot -Tpng < $in > $out");
        out.println("");
        out.println("build engine.dot: ninja-to-dot build.ninja engine.ninja");
        out.println("");
        out.println("build engine.png: dot-to-png engine.dot");
        out.println("");
        out.println("rule engine-run");
        out.println("  command=engine run $name $inputs $output_state $output_includes $generated_output $agenda_groups $modules");
        out.println();
        out.println("### Jobs");

        for (var job : f.jobs) {
            out.println("");
            var dependencies = job.inputs.stream()
                    .map(s -> dbDir.resolve(s + ".yaml").toString())
                    .collect(Collectors.joining(" "));

            var generated = job.outputs.stream()
                    .map(output -> dbDir.resolve(output.name + ".yaml").toString())
                    .collect(Collectors.joining(" "));

            out.println("build %s: engine-run %s".formatted(generated, dependencies));
            out.println("  name=--name %s".formatted(job.name));

            if (!job.inputs.isEmpty()) {
                var is = job.inputs.stream()
                        .map(s -> "--input=" + dbDir.resolve(s + ".yaml"))
                        .collect(Collectors.joining(" $\n    ", "\n    ", ""));

                out.println("  inputs=$%s".formatted(is));
            }

            if (job.outputs.size() != 1) {
                System.err.println("Only one output supported for now.");
                return 1;
            }

            var output = job.outputs.get(0);

            out.println("  output_state=--output-state %s".formatted(dbDir.resolve(output.name + ".yaml")));
            if (!output.includes.isEmpty()) {
                var str = output.includes.stream()
                        .map(s -> "--output-include='" + s + "'")
                        .collect(Collectors.joining(" $\n    ", "\n    ", ""));

                out.println("  output_includes=$%s".formatted(str));
            }

            if (job.generatedOutput != null) {
                out.println("  generated_output=--generated-output %s".formatted(fixPath(job.generatedOutput)));
            }

            if (!job.agendaGroups.isEmpty()) {
                var ag = job.agendaGroups.stream()
                        .map(s -> "--agenda-group=" + s)
                        .collect(Collectors.joining(" $\n    ", "\n    ", ""));
                out.println("  agenda_groups=%s".formatted(ag));
            }

            if (!job.modules.isEmpty()) {
                var ms = job.modules.stream()
                        .map(this::fixPath)
                        .map(s -> "--module=" + s)
                        .collect(Collectors.joining(" $\n    ", "\n    ", ""));

                out.println("  modules=$%s".formatted(ms));
            }
        }

        var ninjaFile = new File(basedir, "engine.ninja");
        try (var writer = new FileWriter(ninjaFile)) {
            writer.write(buf.toString());
        }

        return 0;
    }

    private String fixPath(String s) {
        if (s.startsWith("$MODULE_HOME/")) {
            s = "$" + s;
        }

        var p = Path.of(s);

        if (p.isAbsolute()) {
            s = basepath.relativize(Path.of(s)).toString();
        }

        if (s.contains("*")) {
            s = "$$(echo " + s + ")";
        }

        return s;
    }
}