package dev.loki.loparkour.ghost;

import dev.loki.loparkour.ghost.core.GhostManager;
import dev.loki.loparkour.ghost.model.GhostData;
import dev.loki.loparkour.ghost.model.GhostFrame;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.io.TempDir;

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import static org.junit.jupiter.api.Assertions.*;

/**
 * Unit tests for the per-player personal replay storage of {@link GhostManager}.
 */
class GhostManagerTest {

    private static final int EVICTION_CAP = 2;

    /**
     * A manager whose run cap is fixed, overriding the config-driven {@link #maxRuns()}.
     * Chosen over mutating {@code Config} statics, which the plugin initializes at
     * enable time and are not settable from unit tests.
     */
    private static final class FixedCapManager extends GhostManager {

        private FixedCapManager(File ghostFolder) {
            super(ghostFolder);
        }

        @Override
        public int maxRuns() {
            return EVICTION_CAP;
        }
    }

    private static GhostData run(UUID uuid, String name, int score, long timestamp) {
        final List<GhostFrame> frames = new ArrayList<>();
        frames.add(new GhostFrame(0, 0, 100, 0, 0, 0));
        return new GhostData(uuid, name, score, timestamp, "world", frames);
    }

    @Test
    void saveRunAndGetRunsReturnNewestFirst(@TempDir Path tempDir) throws IOException {
        final UUID uuid = UUID.randomUUID();
        final GhostManager manager = new GhostManager(tempDir.toFile());
        final long base = 1_700_000_000_000L;

        manager.saveRun(uuid, run(uuid, "A", 10, base));
        manager.saveRun(uuid, run(uuid, "B", 20, base + 1_000));
        manager.saveRun(uuid, run(uuid, "C", 30, base + 2_000));

        final List<GhostData> runs = manager.getRuns(uuid);

        assertEquals(3, runs.size());
        assertEquals(base + 2_000, runs.get(0).getTimestamp());
        assertEquals(30, runs.get(0).getScore());
        assertEquals(base, runs.get(2).getTimestamp());
        assertEquals(10, runs.get(2).getScore());
    }

    @Test
    void saveRunEvictsOldestBeyondCap(@TempDir Path tempDir) throws IOException {
        final UUID uuid = UUID.randomUUID();
        final GhostManager manager = new FixedCapManager(tempDir.toFile());
        final long base = 1_700_000_000_000L;

        for (int i = 0; i < 5; i++) {
            manager.saveRun(uuid, run(uuid, "P" + i, i * 10, base + i * 1_000L));
        }

        final List<GhostData> runs = manager.getRuns(uuid);

        assertEquals(EVICTION_CAP, runs.size(), "Old runs beyond the cap must be evicted");
        assertEquals(base + 4_000, runs.get(0).getTimestamp());
        assertEquals(base + 3_000, runs.get(1).getTimestamp());
    }

    @Test
    void getRunsWithEmptyFolderReturnsEmptyList(@TempDir Path tempDir) {
        final GhostManager manager = new GhostManager(tempDir.toFile());

        final List<GhostData> runs = manager.getRuns(UUID.randomUUID());

        assertTrue(runs.isEmpty(), "Player with no saved runs should return an empty list");
    }

    @Test
    void getRunsIgnoresStaleFormatFiles(@TempDir Path tempDir) throws IOException {
        final UUID uuid = UUID.randomUUID();
        final GhostManager manager = new GhostManager(tempDir.toFile());
        manager.saveRun(uuid, run(uuid, "New", 10, 1_700_000_000_000L));

        // Corrupt one file so it reads as an unsupported version
        final File playerFolder = new File(tempDir.toFile(), uuid.toString());
        final File[] files = playerFolder.listFiles((dir, name) -> name.endsWith(".ghost"));
        assertNotNull(files);
        try (DataOutputStream out = new DataOutputStream(
                new FileOutputStream(files[0], false))) {
            out.writeInt(2);
        }

        final List<GhostData> runs = manager.getRuns(uuid);

        assertTrue(runs.isEmpty(), "Stale-format files must be skipped and deleted");
    }
}