package net.jstom.script;

import org.graalvm.polyglot.Context;
import org.graalvm.polyglot.HostAccess;
import org.graalvm.polyglot.Source;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class ScriptManager {
    private final File scriptsDir;
    private final Map<String, ScriptEnv> loadedScripts = new HashMap<>();

    public ScriptManager(File scriptsDir) {
        this.scriptsDir = scriptsDir;
    }

    public void load() {
        if (!scriptsDir.exists()) {
            scriptsDir.mkdirs();
        }

        File[] files = scriptsDir.listFiles((dir, name) -> name.endsWith(".js"));
        if (files != null) {
            for (File file : files) {
                loadScript(file);
            }
        }
    }

    public void loadScript(File file) {
        String fileName = file.getName();
        unloadScript(fileName); // Ensure clean slate if reloading

        System.out.println("[JStom] Loading script: " + fileName);
        
        ScriptApi api = new ScriptApi();
        Context context = Context.newBuilder("js")
                .allowHostAccess(HostAccess.ALL)
                .allowHostClassLookup(s -> true)
                .allowIO(true)
                .build();

        context.getBindings("js").putMember("server", api);

        try {
            context.eval(Source.newBuilder("js", file).build());
            loadedScripts.put(fileName, new ScriptEnv(context, api, file));
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            System.err.println("[JStom] Error executing script " + fileName);
            e.printStackTrace();
            // Cleanup if failed
            api.cleanup();
            context.close();
        }
    }

    public void unloadScript(String fileName) {
        ScriptEnv env = loadedScripts.remove(fileName);
        if (env != null) {
            env.api.cleanup();
            env.context.close();
            System.out.println("[JStom] Unloaded script: " + fileName);
        }
    }

    public void unload() {
        // Copy keys to avoid ConcurrentModificationException
        for (String fileName : new java.util.ArrayList<>(loadedScripts.keySet())) {
            unloadScript(fileName);
        }
    }

    public void reload() {
        unload();
        load();
    }
    
    public void reload(String fileName) {
        File file = new File(scriptsDir, fileName);
        if (file.exists()) {
            loadScript(file);
        } else {
            System.err.println("[JStom] File not found: " + fileName);
        }
    }

    private static class ScriptEnv {
        final Context context;
        final ScriptApi api;
        final File file;

        public ScriptEnv(Context context, ScriptApi api, File file) {
            this.context = context;
            this.api = api;
            this.file = file;
        }
    }
}