package noppes.npcs.janino;

import cpw.mods.fml.common.eventhandler.Event;
import io.github.somehussar.janinoloader.api.script.IScriptBodyBuilder;
import io.github.somehussar.janinoloader.api.script.IScriptClassBody;
import net.minecraft.nbt.NBTTagCompound;
import noppes.npcs.CustomNpcs;
import noppes.npcs.NBTTags;
import noppes.npcs.api.handler.IHookDefinition;
import noppes.npcs.config.ConfigScript;
import noppes.npcs.constants.EnumScriptType;
import noppes.npcs.controllers.ScriptController;
import noppes.npcs.controllers.ScriptHookController;
import noppes.npcs.controllers.data.IScriptUnit;
import org.codehaus.commons.compiler.InternalCompilerException;
import org.codehaus.commons.compiler.Sandbox;

import java.lang.invoke.MethodHandle;
import java.security.Permissions;
import java.security.PrivilegedAction;
import java.util.*;
import java.util.function.Supplier;

public abstract class JaninoScript<T> implements IScriptUnit {
    public boolean errored = false;
    private String language = "Java";
    public TreeMap<Long, String> console = new TreeMap();

    /**
     * Text written in the script GUI
     */
    public String script = "";
    /**
     * This script's selected external files
     *  stored in "world/customnpcs/scripts/java"
     */
    public List<String> externalScripts = new ArrayList<>();
    /**
     *  To evaluate if script/externalScripts were changed or not,
     *  and compile the fullScript freshly if so.
     */
    public boolean evaluated;

    public final Class<T> type;
    protected final Sandbox sandbox;
    public final IScriptBodyBuilder<T> builder;
    protected IScriptClassBody<T> scriptBody;

    private final JaninoHookResolver hookResolver;

    private final String[] defaultImports;

    // Hook definition cache for fast lookup (NEW)
    private Map<String, IHookDefinition> hookDefinitionCache;
    private int lastHookRevision = -1;

    protected JaninoScript(Class<T> type, String[] defaultImports, boolean isClient) {
        this.type = type;
        this.defaultImports = defaultImports != null ? defaultImports : new String[0];
        this.builder = IScriptBodyBuilder.getBuilder(type, isClient ? CustomNpcs.getClientCompiler() : CustomNpcs.getDynamicCompiler())
            .setDefaultImports(defaultImports);

        Permissions permissions = new Permissions();
        permissions.setReadOnly();
        sandbox = new Sandbox(permissions);

        this.scriptBody = builder.build();

        this.hookResolver = new JaninoHookResolver();
    }

    protected JaninoScript(Class<T> type, String[] defaultImports) {
        this(type, defaultImports, false);
    }

    // ==================== HOOK CONTEXT (Abstract) ====================

    /**
     * Get the hook context identifier for this script type.
     * Used to look up hook definitions from the registry.
     *
     * @return Context string, e.g., "npc", "player", "block"
     */
    protected abstract String getHookContext();

    // ==================== HOOK DEFINITION CACHE ====================

    /**
     * Get hook definition from cache, rebuilding cache if revision changed.
     *
     * @param hookName The hook name to look up
     * @return The hook definition, or null if not found
     */
    protected IHookDefinition getHookDefinition(String hookName) {
        if (ScriptHookController.Instance == null) {
            return null;
        }

        int currentRevision = ScriptHookController.Instance.getHookRevision();
        if (hookDefinitionCache == null || currentRevision != lastHookRevision) {
            rebuildHookDefinitionCache();
            lastHookRevision = currentRevision;
        }

        return hookDefinitionCache.get(hookName);
    }

    /**
     * Rebuild the hook definition cache from the registry.
     */
    private void rebuildHookDefinitionCache() {
        hookDefinitionCache = new HashMap<>();
        String context = getHookContext();

        if (context == null || context.isEmpty() || ScriptHookController.Instance == null) {
            return;
        }

        for (IHookDefinition def : ScriptHookController.Instance.getAllHookDefinitions(context)) {
            hookDefinitionCache.put(def.hookName(), def);
        }
    }

    /**
     * Get all required imports from hook definitions plus default imports.
     *
     * @return Array of all import statements needed
     */
    protected String[] collectAllImports() {
        Set<String> allImports = new LinkedHashSet<>();

        // Add default imports first
        Collections.addAll(allImports, defaultImports);

        // Add imports from all hook definitions for this context
        String context = getHookContext();
        if (context != null && !context.isEmpty() && ScriptHookController.Instance != null) {
            for (IHookDefinition def : ScriptHookController.Instance.getAllHookDefinitions(context)) {
                String[] imports = def.requiredImports();
                if (imports != null) {
                    Collections.addAll(allImports, imports);
                }
            }
        }

        return allImports.toArray(new String[0]);
    }

    protected T getUnsafe() {
        return scriptBody.get();
    }

    /**
     * Feed the code into the engine and compile it.
     * Rebuilds imports from hook definitions before compilation.
     */
    public void compileScript(String code) {

        try {
            // Rebuild imports from current hook definitions + defaults
            String[] allImports = collectAllImports();
            builder.setDefaultImports(allImports);

            // Rebuild scriptBody to apply new imports
            this.scriptBody = builder.build();
            scriptBody.setScript(code);
        } catch (InternalCompilerException e ) {
            Throwable parentCause = null;
            Throwable cause = e;

            appendConsole("Compilation error: " + e.getMessage());

            while (cause.getCause() != null) { parentCause = cause; cause = cause.getCause(); }
            Throwable rootCause = cause;

            if (e != cause) {
                appendConsole("\n");

                if (parentCause != null)
                    appendConsole(parentCause.getMessage());
                appendConsole(rootCause.getMessage());
            }
            hookResolver.clearResolutionCaches();
        } catch (Exception e) {
            appendConsole("Unknown error: " + e.getMessage());
            hookResolver.clearResolutionCaches();
        }
    }

    public void compileScript() {
        compileScript(getFullCode());
    }

    public void ensureCompiled() {
        int global = ScriptController.Instance.globalRevision;

        if (!evaluated || global != lastSeenGlobalRevision) {
            compileScript();
            lastSeenGlobalRevision = global;
            evaluated = true;
        }
    }

    /**
     * globalRevision is incremented on server
     * each time externalScripts are updated
     * then sent to client.
     */
    private int lastSeenGlobalRevision;

    private String getFullCode() {
        StringBuilder sb = new StringBuilder();

        if (ConfigScript.RunLoadedScriptsFirst)
            this.appendExternalScripts(sb);

        // Main script
        if (this.script != null && !this.script.isEmpty())
            sb.append(this.script).append("\n");

        if (!ConfigScript.RunLoadedScriptsFirst)
            this.appendExternalScripts(sb);

        return sb.toString();
    }

    private void appendExternalScripts(StringBuilder sb) {
        for (String scriptName : externalScripts) {
            String code = ScriptController.Instance.scripts.get(scriptName);
            if (code != null && !code.isEmpty())
                sb.append(code).append("\n");
        }
    }

    public void callByHookName(String hookName, Object arg) {
        callFunction(hookName, arg);
    }

    @Override
    public Object callFunction(String hookName, Object... args) {
        if (hookName == null || hookName.isEmpty())
            return null;

        ensureCompiled();
        T t = getUnsafe();
        if (t == null)
            return null;

        Object[] invokeArgs = args == null ? new Object[0] : args;

        MethodHandle handle = hookResolver.resolveHookHandle(hookName, invokeArgs, t);
        if (handle == null)
            return null;

        final MethodHandle finalHandle = handle;
        try {
            return sandbox.confine((PrivilegedAction<Object>) () -> {
                try {
                    // Prepend receiver to args for virtual method call
                    Object[] fullArgs = new Object[invokeArgs.length + 1];
                    fullArgs[0] = t;
                    System.arraycopy(invokeArgs, 0, fullArgs, 1, invokeArgs.length);
                    return finalHandle.invokeWithArguments(fullArgs);
                } catch (Throwable e) {
                    appendConsole("Error calling hook " + hookName + ": " + e.getMessage());
                    return null;
                }
            });
        } catch (Exception e) {
            appendConsole("Runtime Error in hook " + hookName + ": " + e.getMessage());
            return null;
        }
    }


    // ==================== IScriptUnit IMPLEMENTATION ====================

    /**
     * Execute this script unit for the given hook type and event.
     * Implementation of IScriptUnit.run(EnumScriptType, Event)
     *
     * @param type The script hook type
     * @param event The event object
     */
    @Override
    public void run(EnumScriptType type, Event event) {
        if (type == null)
            return;

        callFunction(type.function, event);
    }

    /**
     * Execute this script unit for the given hook name and event.
     * Implementation of IScriptUnit.run(String, Event)
     *
     * @param hookName The hook name (e.g., "init", "interact")
     * @param event The event object
     */
    @Override
    public void run(String hookName, Object event) {
        callFunction(hookName, event);
    }

    @Override
    public String getScript() {
        return this.script;
    }

    @Override
    public void setScript(String script) {
        this.script = script;
        this.evaluated = false;
        hookResolver.clearResolutionCaches();
    }

    @Override
    public List<String> getExternalScripts() {
        return this.externalScripts;
    }

    @Override
    public void setExternalScripts(List<String> externalScripts) {
        this.externalScripts = externalScripts;
        this.evaluated = false;
        hookResolver.clearResolutionCaches();
    }

    @Override
    public TreeMap<Long, String> getConsole() {
        return this.console;
    }

    @Override
    public void clearConsole() {
        console.clear();
    }

    @Override
    public void appendConsole(String message) {
        if (message != null && !message.isEmpty()) {
            long time = System.currentTimeMillis();
            if (this.console.containsKey(time)) {
                message = (String) this.console.get(time) + "\n" + message;
            }

            this.console.put(time, message);

            while (this.console.size() > 40) {
                this.console.remove(this.console.firstKey());
            }
        }
    }

    @Override
    public String getLanguage() {
        return this.language;
    }

    @Override
    public void setLanguage(String language) {
        // JaninoScript is always Java, ignore attempts to change
        // This method exists for IScriptUnit interface compatibility
    }

    @Override
    public boolean hasCode() {
        if (!externalScripts.isEmpty())
            return true;
        return script != null && !script.isEmpty();
    }

    @Override
    public String generateHookStub(String hookName, Object hookData) {
        // Look up in hook definition registry
        IHookDefinition def = getHookDefinition(hookName);
        if (def != null) {
            String typeName = def.getUsableTypeName();
            String[] params = def.paramNames();
            String paramName = (params != null && params.length > 0) ? params[0] : "event";

            if (typeName != null && !typeName.isEmpty()) {
                return String.format("public void %s(%s %s) {\n    \n}\n",
                    def.hookName(), typeName, paramName);
            }
        }

        // Fallback: generic Object parameter
        return String.format("public void %s(Object event) {\n    \n}\n", hookName);
    }


    public List<String> getHookList() {
        // Get hooks from registry based on context
        String context = getHookContext();
        if (context != null && !context.isEmpty() && ScriptHookController.Instance != null) {
            return ScriptHookController.Instance.getAllHooks(context);
        }
        return Collections.emptyList();
    }


    @Override
    public NBTTagCompound writeToNBT(NBTTagCompound compound) {
        compound.setString(IScriptUnit.NBT_TYPE_KEY, IScriptUnit.TYPE_JANINO);
        compound.setTag("console", NBTTags.NBTLongStringMap(this.console));
        compound.setTag("externalScripts", NBTTags.nbtStringList(this.externalScripts));
        compound.setString("script", script);
        return compound;
    }

    @Override
    public void readFromNBT(NBTTagCompound compound) {
        // Read legacy enabled field but ignore it (handler owns enabled now)
        this.console = NBTTags.GetLongStringMap(compound.getTagList("console", 10));
        setExternalScripts(NBTTags.getStringList(compound.getTagList("externalScripts", 10)));
        setScript(compound.getString("script"));
    }

    public static <T, S extends JaninoScript<T>> S readFromNBT(NBTTagCompound compound, S script, Supplier<S> factory) {
        if (compound.hasKey("Script")) {
            if (script == null)
                script = factory.get();

            script.readFromNBT(compound.getCompoundTag("Script"));
        }
        return script;
    }

    public static <T> NBTTagCompound writeToNBT(NBTTagCompound compound, JaninoScript<T> script) {
        if (script != null)
            compound.setTag("Script", script.writeToNBT(new NBTTagCompound()));

        return compound;
    }

    @Override
    public boolean hasErrored() {
        return this.errored;
    }

    @Override
    public void setErrored(boolean errored) {
        this.errored = errored;
    }
}