package net.rustnotmc.client;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import net.minecraft.client.Minecraft;
import net.minecraft.client.entity.EntityPlayerSP;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.client.renderer.RenderGlobal;
import net.minecraft.client.renderer.debug.DebugRenderer;
import net.minecraft.entity.Entity;
import net.rustnotmc.protocol.Hitbox;
import net.rustnotmc.protocol.Packets;

/**
 * Draws the boxes of the models.
 *
 * The boxes are the editor: the server reads them from a file and sends them
 * here, and they are drawn around the things they belong to. A model that
 * does not fit is changed in the file, the file is read again, and the new
 * numbers are on the screen.
 *
 * The command is:
 *
 * <pre>
 *   /rsx hitboxes on        show the boxes
 *   /rsx hitboxes off       hide them
 *   /rsx hitboxes reload    ask the server to read its file again
 *   /rsx hitboxes list      what the server knows
 *   /rsx hitboxes show NAME put one model in front of the player
 * </pre>
 */
public final class RsxHitboxDebug {

    /** The model whose boxes describe a player. */
    private static final String PLAYER_MODEL = "player";

    /** The height the player model is written for. */
    private static final float PLAYER_MODEL_HEIGHT = 1.8F;

    private static final Map<String, Packets.HitboxModel> MODELS =
            new LinkedHashMap<String, Packets.HitboxModel>();
    private static final List<Packets.HitboxInstance> INSTANCES =
            new ArrayList<Packets.HitboxInstance>();

    private static boolean visible;
    private static String preview;

    private RsxHitboxDebug() {
    }

    /** Takes the boxes of the models from the server. */
    public static void accept(Packets.Hitboxes boxes) {
        MODELS.clear();
        for (int i = 0; i < boxes.models.length; i++) {
            MODELS.put(boxes.models[i].name, boxes.models[i]);
        }
    }

    /** Takes the places where the models stand. */
    public static void accept(Packets.HitboxInstances instances) {
        INSTANCES.clear();
        for (int i = 0; i < instances.instances.length; i++) {
            INSTANCES.add(instances.instances[i]);
        }
    }

    /** True when the boxes are being drawn. */
    public static boolean visible() {
        return visible;
    }

    /**
     * Shows or hides the boxes.
     *
     * The right to look at them belongs to the administrators, so when the
     * right is taken away the boxes go at once.
     */
    public static void setVisible(boolean value) {
        visible = value;
        if (!value) {
            preview = null;
        }
    }

    /** How many models the server has sent. */
    public static int modelCount() {
        return MODELS.size();
    }

    /**
     * Carries out one of our commands.
     *
     * Returns true when the line was ours, so that the mods do not see it.
     */
    public static boolean command(String line) {
        if (line == null || !line.startsWith("/")) {
            return false;
        }
        String[] parts = line.substring(1).trim().split("\\s+");
        if (parts.length < 2 || !"rsx".equalsIgnoreCase(parts[0])
                || !"hitboxes".equalsIgnoreCase(parts[1])) {
            return false;
        }
        String what = parts.length > 2 ? parts[2].toLowerCase() : "";

        if ("on".equals(what)) {
            visible = true;
            say("hitboxes on (" + MODELS.size() + " models)");
            return true;
        }
        if ("off".equals(what)) {
            visible = false;
            say("hitboxes off");
            return true;
        }
        if ("reload".equals(what)) {
            net.rustnotmc.client.net.RsxNetworkManager.sendHitboxesReload();
            say("the server was asked to read its file again");
            return true;
        }
        if ("list".equals(what)) {
            StringBuilder names = new StringBuilder();
            for (String name : MODELS.keySet()) {
                if (names.length() > 0) {
                    names.append(", ");
                }
                names.append(name);
            }
            say("models: " + (names.length() == 0 ? "none" : names.toString()));
            return true;
        }
        if ("show".equals(what)) {
            if (parts.length < 4) {
                say("usage: /rsx hitboxes show NAME");
                return true;
            }
            preview = parts[3];
            visible = true;
            say("showing " + preview);
            return true;
        }
        say("usage: /rsx hitboxes on|off|reload|list|show NAME");
        return true;
    }

    private static void say(String message) {
        net.rustnotmc.loader.Log.info("hitboxes: " + message);
        Minecraft mc = Minecraft.getMinecraft();
        if (mc.ingameGUI != null) {
            mc.ingameGUI.addChatMessage(net.minecraft.util.text.ChatType.CHAT,
                    new net.minecraft.util.text.TextComponentString(message));
        }
    }

    /**
     * Draws the boxes.
     *
     * Called from the frame hook, so this is after the world and after the
     * interface: the lines are drawn over both, which is what a debug view
     * should do.
     */
    public static void draw(Minecraft mc) {
        if (!visible || mc.player == null || mc.world == null) {
            return;
        }
        Entity view = mc.getRenderViewEntity();
        if (view == null) {
            return;
        }
        float partial = mc.getRenderPartialTicks();
        double camX = view.lastTickPosX + (view.posX - view.lastTickPosX) * partial;
        double camY = view.lastTickPosY + (view.posY - view.lastTickPosY) * partial;
        double camZ = view.lastTickPosZ + (view.posZ - view.lastTickPosZ) * partial;

        GlStateManager.enableBlend();
        GlStateManager.tryBlendFuncSeparate(GlStateManager.SourceFactor.SRC_ALPHA,
                GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA,
                GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO);
        GlStateManager.glLineWidth(2.0F);
        GlStateManager.disableTexture2D();
        GlStateManager.depthMask(false);

        for (int i = 0; i < INSTANCES.size(); i++) {
            Packets.HitboxInstance instance = INSTANCES.get(i);
            Packets.HitboxModel model = MODELS.get(instance.model);
            if (model == null) {
                continue;
            }
            drawModel(model, instance.x, instance.y, instance.z, instance.yaw,
                    camX, camY, camZ, 1.0F);
        }

        if (preview != null) {
            Packets.HitboxModel model = MODELS.get(preview);
            if (model != null) {
                EntityPlayerSP player = mc.player;
                drawModel(model, player.posX + 1.0D, player.posY, player.posZ,
                        player.rotationYaw, camX, camY, camZ, 1.0F);
            }
        }

        // and the players, with the zones the damage is counted by
        Packets.HitboxModel player = MODELS.get(PLAYER_MODEL);
        if (player != null) {
            List<Entity> players = mc.world.getLoadedEntityList();
            for (int i = 0; i < players.size(); i++) {
                Entity entity = players.get(i);
                if (!(entity instanceof EntityPlayerSP)) {
                    continue;
                }
                float scale = entity.height / PLAYER_MODEL_HEIGHT;
                drawModel(player, entity.posX, entity.posY, entity.posZ,
                        entity.rotationYaw, camX, camY, camZ, scale);
            }
        }

        GlStateManager.depthMask(true);
        GlStateManager.enableTexture2D();
        GlStateManager.disableBlend();
    }

    /**
     * Draws one model.
     *
     * The boxes of the model are turned by the yaw of the thing and moved to
     * where it stands, and then drawn relative to the camera, because that is
     * how the world is drawn too.
     */
    private static void drawModel(Packets.HitboxModel model, double x, double y, double z,
                                  float yaw, double camX, double camY, double camZ, float scale) {
        double cos = Math.cos(Math.toRadians(yaw));
        double sin = Math.sin(Math.toRadians(yaw));
        for (int i = 0; i < model.boxes.length; i++) {
            Hitbox box = model.boxes[i];
            float[] colour = colourOf(box.part);
            double minX = turn(box.minX * scale, box.minZ * scale, cos, sin);
            double minZ = turn(box.minZ * scale, -box.minX * scale, cos, sin);
            double maxX = turn(box.maxX * scale, box.maxZ * scale, cos, sin);
            double maxZ = turn(box.maxZ * scale, -box.maxX * scale, cos, sin);
            double minY = box.minY * scale;
            double maxY = box.maxY * scale;

            RenderGlobal.drawBoundingBox(
                    x + minX - camX, y + minY - camY, z + minZ - camZ,
                    x + maxX - camX, y + maxY - camY, z + maxZ - camZ,
                    colour[0], colour[1], colour[2], 0.9F);

            if (!box.name.isEmpty()) {
                DebugRenderer.renderDebugText(box.name,
                        x + minX, y + maxY, z + minZ, 0.02F, 0xFFFFFFFF);
            }
        }
    }

    /** Turns a point around the vertical axis. */
    private static double turn(double along, double across, double cos, double sin) {
        return along * cos + across * sin;
    }

    /** The colour of a box: the head is red, the body yellow, the legs blue. */
    private static float[] colourOf(String part) {
        if (Hitbox.PART_HEAD.equals(part)) {
            return new float[]{1.0F, 0.25F, 0.25F};
        }
        if (Hitbox.PART_BODY.equals(part)) {
            return new float[]{1.0F, 0.9F, 0.2F};
        }
        if (Hitbox.PART_LEGS.equals(part)) {
            return new float[]{0.3F, 0.55F, 1.0F};
        }
        return new float[]{0.3F, 1.0F, 0.4F};
    }
}