package org.zwobble.hobgoblin.compiler.config;

import org.zwobble.hobgoblin.compiler.output.generators.Generator;
import org.zwobble.hobgoblin.compiler.output.generators.errors.UnknownGeneratorError;
import org.zwobble.hobgoblin.compiler.output.generators.javapreciselymatchers.JavaPreciselyMatchersGenerator;
import org.zwobble.hobgoblin.compiler.output.generators.javatransient0.JavaTransient0Generator;
import org.zwobble.hobgoblin.compiler.output.generators.javatypes.JavaTypesGenerator;
import org.zwobble.hobgoblin.compiler.output.generators.rusttransient0.RustTransient0Generator;
import org.zwobble.hobgoblin.compiler.output.generators.rusttypes.RustTypesGenerator;
import org.zwobble.hobgoblin.compiler.sources.FileFragmentSource;
import org.zwobble.json5.reader.Json5ObjectReader;
import org.zwobble.sourcetext.SourceText;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;

public record ProjectConfig(
    List<OutputConfig> output
) {
    public static ProjectConfig read(Path projectRoot) throws IOException {
        var configPath = projectRoot.resolve("hobgoblin.json5");
        var contents = Files.readString(configPath);
        var sourceText = SourceText.fromString(configPath.toString(), contents);
        return fromSourceText(projectRoot, sourceText);
    }

    private static ProjectConfig fromSourceText(Path projectRoot, SourceText sourceText) {
        return fromJson5(projectRoot, Json5ObjectReader.parse(sourceText));
    }

    private static ProjectConfig fromJson5(Path projectRoot, Json5ObjectReader document) {
        var outputsJson = document.getObject("outputs");
        var generatorsJson = outputsJson.getArrayOfObjects("generators");
        var langsJson = outputsJson.getObjectOrNone("langs");

        var outputs = new ArrayList<OutputConfig>();
        for (var generatorJson : generatorsJson) {
            var generatorName = generatorJson.getString("generator");

            var output = switch (generatorName.value()) {
                case JavaTypesGenerator.NAME ->
                    JavaTypesGenerator.parseGeneratorConfig(projectRoot, generatorJson, langsJson);

                case JavaPreciselyMatchersGenerator.NAME ->
                    JavaPreciselyMatchersGenerator.parseGeneratorConfig(projectRoot, generatorJson, langsJson);

                case JavaTransient0Generator.NAME ->
                    JavaTransient0Generator.parseGeneratorConfig(projectRoot, generatorJson, langsJson);

                case RustTypesGenerator.NAME ->
                    RustTypesGenerator.parseGeneratorConfig(projectRoot, generatorJson, langsJson);

                case RustTransient0Generator.NAME ->
                    RustTransient0Generator.parseGeneratorConfig(projectRoot, generatorJson, langsJson);

                default ->
                    throw new UnknownGeneratorError(
                        generatorName.value(),
                        new FileFragmentSource(generatorName.sourceRange())
                    );
            };

            outputs.add(output);
        }

        return new ProjectConfig(outputs);
    }

    public List<Generator> createGenerators() {
        return this.output.stream()
            .map(output -> output.createGenerator())
            .toList();
    }
}