import 'dart:core';
import '../Data/DC.dart';
import '../Data/Structure.dart';
import '../Data/AutoList.dart';
import './IStore.dart';
import './IResource.dart';
import '../Data/KeyList.dart';
import './StorageMode.dart';
import '../Data/ValueObject.dart';
import '../Core/IEventHandler.dart';
import '../Security/Permissions/Ruling.dart';
import '../Security/Permissions/IPermissionsManager.dart';
import '../Security/Permissions/ActionType.dart';
import './Template/ResourceTemplate.dart';
import './Template/PropertyTemplate.dart';
import './Template/FunctionTemplate.dart';
import './Template/EventTemplate.dart';

import '../Security/Authority/Session.dart';
import './Template/MemberTemplate.dart';
import '../Data/PropertyValue.dart';
import 'Warehouse.dart';

class Instance extends IEventHandler
{
    String _name;

    AutoList<IResource, Instance> _children;
    IResource _resource;
    IStore _store;
    AutoList<IResource, Instance> _parents;
    //bool inherit;
    ResourceTemplate _template;

    AutoList<IPermissionsManager, Instance> _managers;


    KeyList<String, dynamic> _attributes;

    List<int> _ages = new List<int>();
    List<DateTime> _modificationDates = new List<DateTime>();
    int _instanceAge;
    DateTime _instanceModificationDate;

    int _id;


    /// <summary>
    /// Instance attributes are custom properties associated with the instance, a place to store information by IStore.
    /// </summary>
    KeyList<String, dynamic> get attributes => _attributes;
    
    @override
    String toString() => _name + " (" + link + ")";
    

    bool removeAttributes([List<String> attributes = null])
    {
        if (attributes == null)
            this._attributes.clear();
        else
        {
            for (var attr in attributes)
                this.attributes.remove(attr);
        }

        return true;
    }

    Structure getAttributes([List<String> attributes = null])
    {
        var st = new Structure();

        if (attributes == null)
        {
            var clone = this.attributes.keys.toList();
            clone.add("managers");
            attributes = clone.toList();
        }

        for(var attr in attributes)
        {
            if (attr == "name")
                st["name"] = _name;
            else if (attr == "managers")
            {
                var mngrs = new List<Structure>();

                for (var i = 0; i < _managers.length; i++)
                {
                  var mst = new Structure();
                  mst["type"] = _managers[i].runtimeType;
                  mst["settings"] = _managers[i].settings;

                  mngrs.add(mst);
                }

                st["managers"] = mngrs;
            }
            else if (attr == "parents")
            {
                st["parents"] = _parents.toList();
            }
            else if (attr == "children")
            {
                st["children"] = _children.toList();
            }
            else if (attr == "childrenCount")
            {
                st["childrenCount"] = _children.count;
            }
            else if (attr == "type")
            {
                st["type"] = resource.runtimeType;
            }
            else
                st[attr] = _attributes[attr];
        }

        return st;
    }

    bool setAttributes(Structure attributes, [bool clearAttributes = false])
    {            
        try
        {

            if (clearAttributes)
                _attributes.clear();

            for (var attrKey in attributes.keys)
                if (attrKey == "name")
                    _name = attributes[attrKey];
                else if (attrKey == "managers")
                {
                    _managers.clear();

                    var mngrs = attributes[attrKey] as List;
                    // this is not implemented now, Flutter doesn't support mirrors, needs a workaround @ Warehouse.registerManager
                    /*
                    for (var mngr in mngrs)
                    {
                        var m = mngr as Structure;
                        var type = Type.GetType(m["type"] as string);
                        if (Codec.implementsInterface<type, typeof(IPermissionsManager)))
                        {
                            var settings = m["settings"] as Structure;
                            var manager = Activator.CreateInstance(type) as IPermissionsManager;
                            manager.Initialize(settings, this.resource);
                            this.managers.Add(manager);
                        }
                        else
                            return false;
                    }
                    */
                }
                else
                {
                    _attributes[attrKey] = attributes[attrKey];
                }
            
        }
        catch(ex)
        {
            return false;
        }

        return true;
    }
    
    /*
    public Structure GetAttributes()
    {
        var st = new Structure();
        foreach (var a in attributes.Keys)
            st[a] = attributes[a];

        st["name"] = name;

        var mngrs = new List<Structure>();

        foreach (var manager in managers)
        {
            var mngr = new Structure();
            mngr["settings"] = manager.Settings;
            mngr["type"] = manager.GetType().FullName;
            mngrs.Add(mngr);
        }

        st["managers"] = mngrs;

        return st;
    }*/

    /// <summary>
    /// Get the age of a given property index.
    /// </summary>
    /// <param name="index">Zero-based property index.</param>
    /// <returns>Age.</returns>
    int getAge(int index)
    {
        if (index < _ages.length)
            return _ages[index];
        else
            return 0;
    }

    /// <summary>
    /// Set the age of a property.
    /// </summary>
    /// <param name="index">Zero-based property index.</param>
    /// <param name="value">Age.</param>
    void setAge(int index, int value)
    {
        if (index < _ages.length)
        {
            _ages[index] = value;
            if (value > _instanceAge)
                _instanceAge = value;
        }
    }

    /// <summary>
    /// Set the modification date of a property.
    /// </summary>
    /// <param name="index">Zero-based property index.</param>
    /// <param name="value">Modification date.</param>
    void setModificationDate(int index, DateTime value)
    {
        if (index < _modificationDates.length)
        {
            _modificationDates[index] = value;
            if (_instanceModificationDate == null || value.millisecondsSinceEpoch > _instanceModificationDate.millisecondsSinceEpoch)
                _instanceModificationDate = value;
        }
    }

    /// <summary>
    /// Get modification date of a specific property.
    /// </summary>
    /// <param name="index">Zero-based property index</param>
    /// <returns>Modification date.</returns>
    DateTime getModificationDate(int index)
    {
        if (index < _modificationDates.length)
            return _modificationDates[index];
        else
            return new DateTime(0);
    }

    
    /// <summary>
    /// Load property value (used by stores)
    /// </summary>
    /// <param name="name">Property name</param>
    /// <param name="age">Property age</param>
    /// <param name="value">Property value</param>
    /// <returns></returns>
    bool loadProperty(String name, int age, DateTime modificationDate, dynamic value)
    {
        /*
        var pt = _template.getPropertyTemplate(name);

        if (pt == null)
            return false;

        if (pt.info.propertyType == typeof(DistributedPropertyContext))
            return false;
    
        try
        {
            if (pt.into.canWrite)
                pt.info.setValue(resource, DC.CastConvert(value, pt.Info.PropertyType));
        }
        catch(ex)
        {
            // 
        }

        setAge(pt.index, age);
        setModificationDate(pt.index, modificationDate);

      */
        return true;

    }

    /// <summary>
    /// Age of the instance, incremented by 1 in every modification.
    /// </summary>
    int get age => _instanceAge;
    // this must be internal
    set age (value) => _instanceAge = value;

    /// <summary>
    /// Last modification date.
    /// </summary>
    DateTime get modificationDate => _instanceModificationDate;
    
    /// <summary>
    /// Instance Id.
    /// </summary>
    int get id => _id;
    
    /// <summary>
    /// Import properties from bytes array.
    /// </summary>
    /// <param name="properties"></param>
    /// <returns></returns>
    bool deserialize(List<PropertyValue> properties)
    {
        for (var i = 0; i < properties.length; i++)
        {
            var pt = _template.getPropertyTemplateByIndex(i);
            if (pt != null)
            {
                var pv = properties[i];
                loadProperty(pt.name, pv.age, pv.date, pv.value);
            }
        }

        return true;
    }

    /// <summary>
    /// Export all properties with ResourceProperty attributed as bytes array.
    /// </summary>
    /// <returns></returns>
    List<PropertyValue> serialize()
    {
        List<PropertyValue> props = new List<PropertyValue>();

        for (var pt in _template.properties)
        {
         //   var rt = pt.info.getValue(resource, null);
           // props.add(new PropertyValue(rt, _ages[pt.index], _modificationDates[pt.index]));
        }

        return props;
    }
    /*
    public bool Deserialize(byte[] data, uint offset, uint length)
    {

        var props = Codec.ParseValues(data, offset, length);
        Deserialize(props);
        return true;
    }
    */
    /*
    public byte[] Serialize(bool includeLength = false, DistributedConnection sender = null)
    {

        //var bl = new BinaryList();
        List<object> props = new List<object>();

        foreach (var pt in template.Properties)
        {

            var pi = resource.GetType().GetProperty(pt.Name);

            var rt = pi.GetValue(resource, null);

            // this is a cool hack to let the property know the sender
            if (rt is Func<DistributedConnection, object>)
                rt = (rt as Func<DistributedConnection, object>)(sender);

            props.Add(rt);

          }

        if (includeLength)
        {
            return Codec.Compose(props.ToArray(), false);
        }
        else
        {
            var rt = Codec.Compose(props.ToArray(), false);
            return DC.Clip(rt, 4, (uint)(rt.Length - 4));
        }
    }

    public byte[] StorageSerialize()
    {

        var props = new List<object>();

        foreach(var pt in  template.Properties)
        {
            if (!pt.Storable)
                continue;

            var pi = resource.GetType().GetProperty(pt.Name);

            if (!pi.CanWrite)
                continue;

            var rt = pi.GetValue(resource, null);

            props.Add(rt);

          }

        return Codec.Compose(props.ToArray(), false);
    }
    */

    /// <summary>
    /// If True, the instance can be stored to disk.
    /// </summary>
    /// <returns></returns>
    bool isStorable()
    {
      return false;
    }


    void emitModification(PropertyTemplate pt, dynamic value)
    {
        _instanceAge++;
        var now = DateTime.now().toUtc();

        _ages[pt.index] = _instanceAge;
        _modificationDates[pt.index] = now;

        if (pt.storage == StorageMode.NonVolatile)
        {
            _store.modify(_resource, pt.name, value, _ages[pt.index], now);
        }
        else if (pt.storage == StorageMode.Recordable)
        { 
            _store.record(_resource, pt.name, value, _ages[pt.index], now);
        }

        emitArgs("resourceModified", [_resource, pt.name, value]);
        //_resource.emitArgs("modified", [pt.name, value]);
        _resource.emitArgs(":${pt.name}", [value]);
    }

    /// <summary>
    /// Notify listeners that a property was modified.
    /// </summary>
    /// <param name="propertyName"></param>
    /// <param name="newValue"></param>
    /// <param name="oldValue"></param>
    modified(String propertyName)
    {
        var valueObject = new ValueObject();
        if (getPropertyValue(propertyName, valueObject))
        {
            var pt = _template.getPropertyTemplateByName(propertyName);
            emitModification(pt, valueObject.value);
        }
    }

    emitResourceEvent(issuer, List<Session> receivers, String name, dynamic args)
    {
        emitArgs("resourceEventOccurred", [_resource, issuer, receivers, name, args]);
    }

    /// <summary>
    /// Get the value of a given property by name.
    /// </summary>
    /// <param name="name">Property name</param>
    /// <param name="value">Output value</param>
    /// <returns>True, if the resource has the property.</returns>
    bool getPropertyValue(String name, ValueObject valueObject)
    {
        var pt = _template.getPropertyTemplateByName(name);

        /*
        if (pt != null && pt.info != null)
        {
            valueObject.value = pt.info.getValue(_resource, null);
            return true;

        }*/

        valueObject.value = null;
        return false;
    }


    /*
    public bool Inherit
    {
        get { return inherit; }
    }*/

    /// <summary>
    /// List of parents.
    /// </summary>
    AutoList<IResource, Instance> get parents => _parents;
    

    /// <summary>
    /// Store responsible for creating and keeping the resource.
    /// </summary>
    IStore get store => _store;

    /// <summary>
    /// List of children.
    /// </summary>
    AutoList<IResource, Instance> get children => _children;
    
    /// <summary>
    /// The unique and permanent link to the resource.
    /// </summary>
    String get link
    {
        if (_store != null)
            return _store.link(_resource);
        else
        {
            var l = new List<String>();

            var p = _resource;

            while (true)
            {
                l.insert(0, p.instance.name);

                if (p.instance.parents.count == 0)
                    break;

                p = p.instance.parents.first();
            }

            return l.join("/");
        }
    
    }

    /// <summary>
    /// Instance name.
    /// </summary>
    String get name => _name;
    set name(value) => name = value;
    

    /// <summary>
    /// Resource managed by this instance.
    /// </summary>
    IResource get resource => _resource;
    
    
    /// <summary>
    /// Resource template describes the properties, functions and events of the resource.
    /// </summary>
    ResourceTemplate get template => _template;

    /// <summary>
    /// Check for permission.
    /// </summary>
    /// <param name="session">Caller sessions.</param>
    /// <param name="action">Action type</param>
    /// <param name="member">Function, property or event to check for permission.</param>
    /// <param name="inquirer">Permission inquirer.</param>
    /// <returns>Ruling.</returns>
    Ruling applicable(Session session, ActionType action, MemberTemplate member, [dynamic inquirer = null])
    {
        
        for(var i = 0; i < _managers.length; i++)
        {
            var r = _managers[i].applicable(this.resource, session, action, member, inquirer);
            if (r != Ruling.DontCare)
                return r;
        }

        return Ruling.DontCare;

    }

    /// <summary>
    /// Execution managers.
    /// </summary>
    AutoList<IPermissionsManager, Instance> get managers => _managers;

    /// <summary>
    /// Create new instance.
    /// </summary>
    /// <param name="id">Instance Id.</param>
    /// <param name="name">Name of the instance.</param>
    /// <param name="resource">Resource to manage.</param>
    /// <param name="store">Store responsible for the resource.</param>
    Instance(int id, String name, IResource resource, IStore store, [ResourceTemplate customTemplate = null, int age = 0])
    {
        _store = store;
        _resource = resource;
        _id = id;
        _name = name;
        _instanceAge = age;

        _attributes = new KeyList<String, dynamic>(this);
        _children = new AutoList<IResource, Instance>(this);
        _parents = new AutoList<IResource, Instance>(this);
        _managers = new AutoList<IPermissionsManager, Instance>(this);
        
        _children.on("add", children_OnAdd);
        _children.on("remove", children_OnRemoved);
        _parents.on("add", parents_OnAdd);
        _parents.on("remove", parents_OnRemoved);

        resource.on("destroy", resource_OnDestroy);

        if (customTemplate != null)
            _template = customTemplate;
        else
            _template = Warehouse.getTemplateByType(resource.runtimeType);
        
          // set ages
        for (int i = 0; i < _template.properties.length; i++)
        {
            _ages.add(0);
            _modificationDates.add(new DateTime(0));//DateTime.MinValue);
        }

        /*
        // connect events
        Type t = resource.runtimeType;

        var events = t.GetTypeInfo().GetEvents(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly);

        foreach (var evt in events)
        {
            //if (evt.EventHandlerType != typeof(ResourceEventHanlder))
            //    continue;


            if (evt.EventHandlerType == typeof(ResourceEventHanlder))
            {
                var ca = (ResourceEvent[])evt.GetCustomAttributes(typeof(ResourceEvent), true);
                if (ca.Length == 0)
                    continue;

                ResourceEventHanlder proxyDelegate = (args) => EmitResourceEvent(null, null, evt.Name, args);
                evt.AddEventHandler(resource, proxyDelegate);

            }
            else if (evt.EventHandlerType == typeof(CustomResourceEventHanlder))
            {
                var ca = (ResourceEvent[])evt.GetCustomAttributes(typeof(ResourceEvent), true);
                if (ca.Length == 0)
                    continue;

                CustomResourceEventHanlder proxyDelegate = (issuer, receivers, args) => EmitResourceEvent(issuer, receivers, evt.Name, args);
                evt.AddEventHandler(resource, proxyDelegate);
            }
      

        }
        */
    }

    void children_OnRemoved(Instance parent, IResource value)
    {
        value.instance.parents.remove(_resource);
    }

    void children_OnAdd(Instance parent, IResource value)
    {
        if (!value.instance.parents.contains(_resource))
            value.instance.parents.add(_resource);
    }

    void parents_OnRemoved(Instance parent, IResource value)
    {
        value.instance.children.remove(_resource);
    }

    void parents_OnAdd(Instance parent, IResource value)
    {
        if (!value.instance.children.contains(_resource))
            value.instance.children.add(_resource);
    }


    void resource_OnDestroy(sender)
    {
        emitArgs("resourceDestroyed", [sender]);
    }
}