package p149;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import java.io.*;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import net.jqwik.api.*;
import net.jqwik.api.lifecycle.AfterContainer;
import p149.GroundTruth;

public class TestCaseGenerator {

    static class TestCase {
        Map<String, Object> Inputs;
        Object Expected;
        TestCase(Map<String, Object> inputs, Object expected) {
            this.Inputs = inputs;
            this.Expected = expected;
        }
    }

    static List<TestCase> generatedCases = new ArrayList<>();
    static AtomicInteger caseCount = new AtomicInteger(0);
    static final int MAX_CASES = 500;

    @Property(tries = 10000)
    void generateTestCases(@ForAll("hexBytes") byte[] hex) {
        if (caseCount.get() >= MAX_CASES) {
            return;
        }

        int result;
        try {
            result = GroundTruth.unhex(hex);
        } catch (Exception e) {
            return;
        }

        Map<String, Object> inputs = new LinkedHashMap<>();
        inputs.put("hex", hex);
        generatedCases.add(new TestCase(inputs, result));
        caseCount.incrementAndGet();
    }

    @Example
    void example1() {
        generateTestCases(new byte[] {'0', '1', '2', '3'});
    }

    @Example
    void example2() {
        generateTestCases(new byte[] {'a', 'b', 'c', 'd'});
    }

    @Example
    void example3() {
        generateTestCases(new byte[] {'A', 'B', 'C', 'D'});
    }

    @Example
    void example4() {
        generateTestCases(new byte[] {'g', 'h', 'i', 'j'});
    }

    @Provide
    Arbitrary<byte[]> hexBytes() {
        return Arbitraries.bytes()
                .between((byte) '0', (byte) '9')
                .array(byte[].class).ofSize(4)
                .flatMap(bytes -> {
                    byte[] result = new byte[4];
                    for (int i = 0; i < 4; i++) {
                        result[i] = bytes[i];
                    }
                    return Arbitraries.just(result);
                });
    }

    @AfterContainer
    static void saveTestCases() throws IOException {
        if (generatedCases.isEmpty()) {
            return;
        }
        String dirPath = "src/test/java/test_cases";
        File dir = new File(dirPath);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        String filePath = dirPath + "/test_cases.json";
        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        try (Writer writer = new FileWriter(filePath)) {
            gson.toJson(generatedCases, writer);
        }
        System.out.println("✅ Saved " + generatedCases.size() + " test cases to " + filePath);
    }
}