package kernel.service;

import kernel.log.Log;
import kernel.binstore.BinStore;
import lib.KVStore;

using tink.CoreApi;

class ServiceManager {
    public static var instance: ServiceManager;

    private final services:Map<String,Service> = new Map();

    @:allow(kernel.Init)
    private function new() {
        this.startAllEnabled();
    }
    
    /**
        Add a service to be automatically started.
    **/
    public function enable(name: String) {
        if (!this.services.exists(name)){
            return; // Service must be started
        }

        var store = KVStore.getStoreForClass();

        var enabled = store.get("enabled",[]);
        enabled.push(name);
        store.set("enabled",enabled);

        store.save();
    }

    /**
        Remove a service from being automatically started.
    **/
    private function disable(name: String) {
        var store = KVStore.getStoreForClass();
        var enabled: Array<String> = store.get("enabled");
        var index = enabled.indexOf(name);
        if (index == -1){
            return;
        }

        enabled.splice(index,1);
        store.save();
    }

    private function startAllEnabled() {
        var store = KVStore.getStoreForClass();
        var enabled: Array<String> = store.get("enabled",[]);
        for (name in enabled){
            this.start(name);
        }
    }

    private function load(name: String): Null<Service> {
        var store = new KVStore('service/${name}');
        store.load();
        if (!store.exists("service")){
            return null;
        }

        return store.get("service");
    }

    public function register(name: String, binName: String,args: Array<String>): Outcome<Noise,String> {
        if (BinStore.instance.getBinByAlias(binName) == null){
            return Failure("bin not found");
        }

        if (this.load(name) != null){
            return Failure("service already exists");
        }

        var service = new Service(binName,name,args);

        var store = new KVStore('service/${name}');
        store.set("service",service);
        store.save();

        Log.info('Service ${name} registered');
        return Success(Noise);
    }

    public function unregister(name: String): Outcome<Noise,String> {
        if (this.services.exists(name)){
            return Failure("service is running");
        }

        KVStore.removeNamespace('service/${name}');
        Log.info('Service ${name} unregistered');
        return Success(Noise);
    }
    
    public function start(name: String): Outcome<Noise,String> {
        var service = this.load(name);
        if (service == null){
            return Failure("service not found");
        }

        service.start();
        this.services.set(name,service);

        Log.info('Service ${name} started');
        return Success(Noise);
    }

    public function stop(name: String): Outcome<Noise,String> {
        if (!this.services.exists(name)){
            return Failure("service not found");
        }

        var service = this.services.get(name);
        service.stop();
        this.services.remove(name);

        Log.info('Service ${name} stopped');
        return Success(Noise);
    }

    public function listRunning(): Array<String> {
        var running = [];
        for (name in this.services.keys()){
            running.push(name);
        }
        return running;
    }
}