import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/** Project-owned configuration for the shared engineering mechanisms. */
final class Recipe {
    private Recipe() {}

    static Map<String, String> environment(final Path root, final Map<String, String> input) throws Exception {
        final var result = new HashMap<String, String>(input);
        final Path file = root.resolve("engineering.properties");
        if (Files.exists(file)) {
            final var properties = new Properties();
            try (final var stream = Files.newInputStream(file)) {
                properties.load(stream);
            }
            for (final String key : properties.stringPropertyNames()) {
                result.putIfAbsent(
                        key, properties.getProperty(key).replace("${user.home}", System.getProperty("user.home")));
            }
        }
        if (result.containsKey("PROJECT_NAME")) {
            project(result);
            for (final String role : roles(result)) {
                final Path module = Path.of(result.get(role.toUpperCase() + "_MODULE"));
                Pipeline.check(
                        !module.isAbsolute() && !module.normalize().startsWith(".."),
                        "Module must stay in the project");
            }
            Pipeline.check(
                    !enabled(result, "BROWSER_TESTS") || roles(result).size() == 2,
                    "Browser coverage requires both backend and frontend");
        }
        return result;
    }

    static String project(final Map<String, String> env) {
        final String name = Setup.required(env, "PROJECT_NAME");
        Pipeline.check(name.matches("[a-z][a-z0-9-]*"), "Invalid project name");
        return name;
    }

    static List<String> roles(final Map<String, String> env) {
        final var roles = new ArrayList<String>();
        for (final String role : List.of("backend", "frontend")) {
            if (!env.getOrDefault(role.toUpperCase() + "_MODULE", "").isBlank()) {
                roles.add(role);
            }
        }
        Pipeline.check(!roles.isEmpty(), "Configure BACKEND_MODULE, FRONTEND_MODULE, or both");
        return roles;
    }

    static boolean enabled(final Map<String, String> env, final String key) {
        return Boolean.parseBoolean(env.getOrDefault(key, "false"));
    }
}