import eu.mhsl.minecraft.pixelpics.assets.*;
import eu.mhsl.minecraft.pixelpics.assets.font.FontLoader;
import eu.mhsl.minecraft.pixelpics.render.entity.*;
import eu.mhsl.minecraft.pixelpics.render.entity.cem.BlockEntityBaker;
import eu.mhsl.minecraft.pixelpics.render.entity.cem.CemBaker;
import eu.mhsl.minecraft.pixelpics.render.entity.cem.CemModelLoader;
import eu.mhsl.minecraft.pixelpics.render.render.DefaultScreenRenderer;
import eu.mhsl.minecraft.pixelpics.render.render.RenderJob;
import eu.mhsl.minecraft.pixelpics.render.sky.SkyContext;
import eu.mhsl.minecraft.pixelpics.render.snapshot.WorldSnapshot;
import eu.mhsl.minecraft.pixelpics.render.tint.BiomeTintProvider;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.block.data.BlockData;
import org.bukkit.util.Vector;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Proxy;
import java.util.List;
import java.util.Map;
import java.util.function.IntFunction;
import java.util.logging.Logger;

/**
 * Shared setup of the standalone render tools (no server: EntityTestRender, BlockEntityTestRender,
 * ObjectTestRender, EntityBenchmark). Renders with the test server's resource pack and the repo's model JSONs.
 *
 * <p>Build/run from the repo root with a JDK 25: {@code CP=build/classes/java/main:build/resources/main:$(./gradlew -q
 * printCompileClasspath)}, {@code javac -d <cls> -cp $CP $(ls tools/*.java | grep -v VanillaModelDump)},
 * {@code java -cp <cls>:$CP [-Dout=<dir>] <Tool> [args]}.
 */
final class Harness {

    static final String PACK_ROOT = "/home/elias/Dokumente/mcTestServer/plugins/PixelPics";
    static final int SSAA = 3;
    static final double V_FOV_HALF = Math.toRadians(DefaultScreenRenderer.V_FOV_DEG / 2);
    static final SkyContext NOON = new SkyContext(6000, 0, 6000);

    final Logger log;
    final ResourcePack pack;
    final AssetReader reader;
    final TextureCache textures;
    final BlockModelRegistry registry;
    final CemModelLoader geo = new CemModelLoader();
    final CemBaker baker;
    final BlockEntityBaker beBaker;
    final DefaultScreenRenderer renderer;

    Harness(String logName) throws IOException {
        log = Logger.getLogger(logName);
        pack = ResourcePackLoader.load(new File(PACK_ROOT, "resourcepack"), log).orElseThrow();
        reader = new AssetReader(pack);
        textures = new TextureCache(pack);
        registry = new BlockModelRegistry(reader, textures);
        // Template set = entity fallback only; the vanilla dump is the primary model source.
        for (String f : new String[] {"cem_template_models.json", "vanilla_entity_models.json"}) {
            try (InputStream in = new FileInputStream("src/main/resources/cem/" + f)) {
                geo.load(in, log);
            }
        }
        SkinCache skins = new SkinCache();
        baker = new CemBaker(geo, textures, skins);
        beBaker = new BlockEntityBaker(geo, textures, skins, FontLoader.load(pack, textures, log));
        renderer = new DefaultScreenRenderer(registry, new BiomeTintProvider(textures), textures, baker, beBaker, log);
    }

    /**
     * Server-free BlockData stand-in: material + blockstate string are all the model registry needs. (Each proxy
     * kind gets its own handler class: a shared generic one made the hot getMaterial/hashCode calls megamorphic and
     * EntityBenchmark measurably slower.)
     */
    static BlockData block(Material m, String state) {
        String s = "minecraft:" + m.getKey().getKey() + (state == null ? "" : "[" + state + "]");
        return (BlockData) Proxy.newProxyInstance(Harness.class.getClassLoader(),
            new Class<?>[]{BlockData.class}, (p, meth, a) -> switch (meth.getName()) {
                case "getMaterial" -> m;
                case "getAsString", "toString" -> s;
                case "equals" -> p == a[0];
                case "hashCode" -> System.identityHashCode(p);
                default -> defaultValue(meth.getReturnType());
            });
    }

    /** false / 0 / null for an unstubbed proxy method. */
    static Object defaultValue(Class<?> rt) {
        if (rt == boolean.class) return false;
        return rt.isPrimitive() ? 0 : null;
    }

    static WorldSnapshot emptyWorld(int minY, int maxY) {
        return new WorldSnapshot(Map.of(), minY, maxY, block(Material.AIR, null));
    }

    /** Render job looking from {@code cam} at {@code look}, {@link #SSAA}x supersampled. */
    static RenderJob job(WorldSnapshot world, Vector cam, Vector look, int w, int h, List<EntityState> mobs,
                         List<BlockEntityState> bes, List<DecorationState> decos, List<ObjectState> objects) {
        Location loc = new Location(null, cam.getX(), cam.getY(), cam.getZ());
        loc.setDirection(look.clone().subtract(cam));
        List<Vector> rayMap = DefaultScreenRenderer.buildRayMap(loc, w * SSAA, h * SSAA);
        return new RenderJob(world, rayMap, cam, w, h, NOON, mobs, bes, decos, objects);
    }

    /** Distance at which a box of extent {@code ext} (at least 0.5) fills the view, scaled {@code mul}, plus {@code add}. */
    static double frameDistance(double[] min, double[] max, double mul, double add) {
        double ext = 0.5;
        for (int a = 0; a < 3; a++) ext = Math.max(ext, max[a] - min[a]);
        return ext / (2 * Math.tan(V_FOV_HALF)) * mul + add;
    }

    static Vector center(double[] min, double[] max) {
        return new Vector((min[0] + max[0]) / 2, (min[1] + max[1]) / 2, (min[2] + max[2]) / 2);
    }

    /** Copy of an entity state with some record components replaced (by name). */
    static EntityState copy(EntityState s, Map<String, Object> overrides) throws ReflectiveOperationException {
        var comps = EntityState.class.getRecordComponents();
        Object[] vals = new Object[comps.length];
        Class<?>[] types = new Class<?>[comps.length];
        for (int i = 0; i < comps.length; i++) {
            types[i] = comps[i].getType();
            String n = comps[i].getName();
            vals[i] = overrides.containsKey(n) ? overrides.get(n) : comps[i].getAccessor().invoke(s);
        }
        return EntityState.class.getDeclaredConstructor(types).newInstance(vals);
    }

    static ItemSpec item(String id) {
        return new ItemSpec(id, null, null, false);
    }

    /** The views side by side under a 20 px label. */
    static BufferedImage labelCell(String key, BufferedImage... views) {
        int w = 0, labelH = 20;
        for (BufferedImage v : views) w += v.getWidth();
        BufferedImage cell = new BufferedImage(w, views[0].getHeight() + labelH, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = cell.createGraphics();
        g.setColor(new Color(25, 25, 30));
        g.fillRect(0, 0, cell.getWidth(), cell.getHeight());
        for (int i = 0, x = 0; i < views.length; x += views[i].getWidth(), i++) g.drawImage(views[i], x, labelH, null);
        g.setColor(Color.WHITE);
        g.setFont(new Font("SansSerif", Font.BOLD, 13));
        g.drawString(key, 4, 15);
        g.dispose();
        return cell;
    }

    /** Contact sheets of {@code cols} columns, {@code perPage} cells each, named {@code name(page)}. */
    static void writeSheets(List<BufferedImage> cells, int cols, int perPage, File dir, IntFunction<String> name)
            throws IOException {
        int cw = cells.get(0).getWidth(), ch = cells.get(0).getHeight();
        for (int page = 0, idx = 0; idx < cells.size(); page++, idx += perPage) {
            int count = Math.min(perPage, cells.size() - idx);
            BufferedImage sheet = new BufferedImage(cols * cw, (count + cols - 1) / cols * ch, BufferedImage.TYPE_INT_RGB);
            Graphics2D g = sheet.createGraphics();
            g.setColor(new Color(40, 40, 48));
            g.fillRect(0, 0, sheet.getWidth(), sheet.getHeight());
            for (int i = 0; i < count; i++) g.drawImage(cells.get(idx + i), (i % cols) * cw, (i / cols) * ch, null);
            g.dispose();
            File f = new File(dir, name.apply(page));
            ImageIO.write(sheet, "png", f);
            System.out.println("WROTE " + f);
        }
    }
}