/*
 
Copyright (c) 2019 Ahmed Kh. Zamil

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/

import '../Data/AutoList.dart';
import './Template/ResourceTemplate.dart';
import '../Data/Guid.dart';
import '../Data/KeyList.dart';
import '../Data/Structure.dart';
import '../Security/Permissions/IPermissionsManager.dart';
import 'IResource.dart';
import 'Instance.dart';
import 'IStore.dart';
import '../Core/AsyncReply.dart';
import '../Core/AsyncBag.dart';
import 'ResourceTrigger.dart';

import '../Net/IIP/DistributedConnection.dart';

// Centeral Resource Issuer
class Warehouse
{
    static AutoList<IResource, Instance> _stores = new AutoList<IResource, Instance>(null);
    static Map<int, IResource> _resources = new Map<int, IResource>();
    static int resourceCounter = 0;

    static KeyList<Guid, ResourceTemplate> _templates = new KeyList<Guid, ResourceTemplate>();

    static bool storeIsOpen = false;

    //public delegate void StoreConnectedEvent(IStore store, string name);
    //public delegate void StoreDisconnectedEvent(IStore store);
    
    //public static event StoreConnectedEvent StoreConnected;
    ///public static event StoreDisconnectedEvent StoreDisconnected;

    static KeyList<String, IStore Function()> protocols = getProtocols();

    /// <summary>
    /// Get a store by its name.
    /// </summary>
    /// <param name="name">Store instance name</param>
    /// <returns></returns>
    static IStore getStore(String name)
    {
        for(var s in _stores)
          if (s.instance.name == name)
            return s;
        return null;
    }

    /// <summary>
    /// Get a resource by instance Id.
    /// </summary>
    /// <param name="id">Instance Id</param>
    /// <returns></returns>
    static AsyncReply<IResource> getById(int id)
    {
        if (_resources.containsKey(id))
            return new AsyncReply<IResource>.ready(_resources[id]);
        else
            return new AsyncReply<IResource>.ready(null);
    }

    /// <summary>
    /// Open the warehouse.
    /// This function issues the initialize trigger to all stores and resources.
    /// </summary>
    /// <returns>True, if no problem occurred.</returns>
    static AsyncReply<bool> open()
    {
        var bag = new AsyncBag<bool>();


        for(var s in _stores)
          bag.add(s.trigger(ResourceTrigger.Initialize));



        bag.seal();

        var rt = new AsyncReply<bool>();
        bag.then((x)
        {
            for (var b in x)
                if (!b)
                {
                    rt.trigger(false);
                    return;
                }

            var rBag = new AsyncBag<bool>();
            for (var rk in _resources.keys)
                rBag.add(_resources[rk].trigger(ResourceTrigger.SystemInitialized));

            rBag.seal();

            rBag.then((y)
            {
                for (var b in y)
                    if (!b)
                    {
                        rt.trigger(false);
                        return;
                    }

                rt.trigger(true);
                storeIsOpen = true;
            });

        });

        return rt;
    }

    /// <summary>
    /// Close the warehouse.
    /// This function issues terminate trigger to all resources and stores.
    /// </summary>
    /// <returns>True, if no problem occurred.</returns>
    static AsyncReply<bool> close()
    {

        var bag = new AsyncBag<bool>();

        for (var resource in _resources.values)
            if (!(resource is IStore))
                bag.add(resource.trigger(ResourceTrigger.Terminate));

        for (var s in _stores)
            bag.add(s.trigger(ResourceTrigger.Terminate));

        for (var resource in _resources.values)
            if (!(resource is IStore))
                bag.add(resource.trigger(ResourceTrigger.SystemTerminated));

        for (var store in _stores)
            bag.add(store.trigger(ResourceTrigger.SystemTerminated));

        bag.seal();

        var rt = new AsyncReply<bool>();
        bag.then((x)
        {
            for (var b in x)
                if (!b)
                {
                    rt.trigger(false);
                    return;
                }

            rt.trigger(true);
        });

        return rt;
    }


    static List<IResource> qureyIn(List<String> path, int index, AutoList<IResource, Instance> resources)
    {
        var rt = new List<IResource>();

        if (index == path.length - 1)
        {
            if (path[index] == "")
                for (var child in resources)
                  rt.add(child);
              else
                for (var child in resources)
                    if (child.instance.name == path[index])
                        rt.add(child);
        }
        else
            for (var child in resources)
                if (child.instance.name == path[index])
                    rt.addAll(qureyIn(path, index+1, child.instance.children));

        return rt;
    }

    static AsyncReply<List<IResource>> query(String path)
    {


        if (path == null || path == "")
        {
            var roots = _stores.where((s) => s.instance.parents.length == 0).toList();
            return new AsyncReply<List<IResource>>.ready(roots);
        }
        else
        {
            var rt = new AsyncReply<List<IResource>>();
            get(path).then((x)
            {
                var p = path.split('/');

                if (x == null)
                {
                    rt.trigger(qureyIn(p, 0, _stores));
                }
                else
                {
                    var ar =  qureyIn(p, 0, _stores).where((r) => r != x).toList();
                    ar.insert(0, x);
                    rt.trigger(ar);
                }
            });

            return rt;

        }

    }

    /// <summary>
    /// Get a resource by its path.
    /// Resource path is sperated by '/' character, e.g. "system/http".
    /// </summary>
    /// <param name="path"></param>
    /// <returns>Resource instance.</returns>
    static AsyncReply<dynamic> get(String path, [attributes = null, IResource parent = null, IPermissionsManager manager = null])
    {

        var p = path.split('/');
        IResource res;

        for(IStore d in _stores)
            if (p[0] == d.instance.name)
            {
                var i = 1;
                res = d;
                while(p.length > i)
                {
                    var si = i;

                    for (IResource r in res.instance.children)
                        if (r.instance.name == p[i])
                        {
                            i++;
                            res = r;
                            break;
                        }

                    if (si == i)
                        // not found, ask the store
                        return d.get(path.substring(p[0].length + 1));
                }

                return new AsyncReply<IResource>.ready(res);
            }

        // Should we create a new store ?
        if (path.contains("://"))
        {
            var url = path.split("://");
            var hostname = url[1].split('/')[0];
            var pathname = url[1].split('/').skip(1).join("/");

            var rt = new AsyncReply<IResource>();

            if (protocols.containsKey(url[0]))
            {
                var handler = protocols[url[0]];

                var store = handler();
                put(store, url[0] + "://" + hostname, null, parent, null, 0, manager, attributes);


                store.trigger(ResourceTrigger.Open).then((x){
                    if (pathname.length > 0 && pathname != "")
                        store.get(pathname).then((r) => rt.trigger(r)
                            ).error((e) => 
                            
                            rt.triggerError(e)
                            
                            );
                    else
                        rt.trigger(store);
                }).error((e) {
                    rt.triggerError(e);
                    Warehouse.remove(store);
                });
            }

            return rt;
        }


        return new AsyncReply<IResource>.ready(null);
    }

    /// <summary>
    /// Put a resource in the warehouse.
    /// </summary>
    /// <param name="resource">Resource instance.</param>
    /// <param name="name">Resource name.</param>
    /// <param name="store">IStore that manages the resource. Can be null if the resource is a store.</param>
    /// <param name="parent">Parent resource. if not presented the store becomes the parent for the resource.</param>
    static void put(IResource resource, String name, [IStore store = null, IResource parent = null, ResourceTemplate customTemplate = null, int age = 0, IPermissionsManager manager = null, attributes = null])
    {
        resource.instance = new Instance(resourceCounter++, name, resource, store, customTemplate, age);

        if (attributes != null)
            resource.instance.setAttributes(Structure.fromMap(attributes));

        if (manager != null)
            resource.instance.managers.add(manager);

        if (store == parent)
            parent = null;

        if (parent == null)
        {
            if (!(resource is IStore))
                store.instance.children.add(resource);
        }
        else
            parent.instance.children.add(resource);


        if (resource is IStore)
        {
            _stores.add(resource);
            //StoreConnected?.Invoke(resource as IStore, name);
        }
        else
            store.put(resource);

        _resources[resource.instance.id] = resource;

        //if (!storeIsOpen)
        //      resource.trigger(ResourceTrigger.Initialize);

    }

    static T New<T extends IResource>(String name, [IStore store = null, IResource parent = null, IPermissionsManager manager = null, Structure attributes = null])
    {
      /*
        var type = ResourceProxy.GetProxy<T>();
        var res = Activator.CreateInstance(type) as IResource;
        put(res, name, store, parent, null, 0, manager, attributes);
        return (T)res;
      */
    }

    /// <summary>
    /// Put a resource template in the templates warehouse.
    /// </summary>
    /// <param name="template">Resource template.</param>
    static void putTemplate(ResourceTemplate template)
    {
        if (!_templates.containsKey(template.classId))
            _templates.add(template.classId, template);
    }


    /// <summary>
    /// Get a template by type from the templates warehouse. If not in the warehouse, a new ResourceTemplate is created and added to the warehouse.
    /// </summary>
    /// <param name="type">.Net type.</param>
    /// <returns>Resource template.</returns>
    static ResourceTemplate getTemplateByType(Type type)
    {
        // loaded ?
        for (var t in _templates.values)
            if (t.className == type.toString())
                return t;

        var template = new ResourceTemplate.fromType(type);
        _templates.add(template.classId, template);

        return template;
    }

    /// <summary>
    /// Get a template by class Id from the templates warehouse. If not in the warehouse, a new ResourceTemplate is created and added to the warehouse.
    /// </summary>
    /// <param name="classId">Class Id.</param>
    /// <returns>Resource template.</returns>
    static AsyncReply<ResourceTemplate> getTemplateByClassId(Guid classId)
    {
        if (_templates.containsKey(classId))
            return new AsyncReply<ResourceTemplate>.ready(_templates[classId]);
        return null;
    }

    /// <summary>
    /// Get a template by class name from the templates warehouse. If not in the warehouse, a new ResourceTemplate is created and added to the warehouse.
    /// </summary>
    /// <param name="className">Class name.</param>
    /// <returns>Resource template.</returns>
    static AsyncReply<ResourceTemplate> getTemplateByClassName(String className)
    {
        for (var t in _templates.values)
            if (t.className == className)
                return new AsyncReply<ResourceTemplate>.ready(t);

        return null; 
    }

    static bool remove(IResource resource)
    {

        if (resource.instance == null)
            return false;

        if (_resources.containsKey(resource.instance.id)) 
            _resources.remove(resource.instance.id);
        else
            return false;

        if (resource is IStore)
        {
            _stores.remove(resource);

            // remove all objects associated with the store
            var toBeRemoved = _resources.values.where((x) => x.instance.store == resource);
            for (var o in toBeRemoved)
                remove(o);

           // StoreDisconnected?.Invoke(resource as IStore);
        }
        
        if (resource.instance.store != null)
            resource.instance.store.remove(resource);

        resource.destroy();

        return true;
      }
}

KeyList<String, IStore Function()> getProtocols()
{
  var rt = new KeyList<String, IStore Function()>();
  rt.add("iip", () => new DistributedConnection());
  return rt;
}