using Comal.Classes;
using InABox.Core;
using InABox.Database;
using InABox.Scripting;
using Inflector;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Text;

namespace PRS.Shared.Events;

public class SaveEvent<T> : IEvent<SaveEventDataModel<T>>, IEntityEvent<T>
    where T : Entity, new()
{
    public Type Entity => typeof(T);

    public IEventDataModelDefinition DataModelDefinition()
    {
        return new SaveEventDataModelDefinition<T>(this);
    }

    public Notification GenerateNotification(SaveEventDataModel<T> model)
    {
        var notification = new Notification();
        notification.Title = $"Updated {typeof(T).Name}";
        notification.Description = $"Updated {typeof(T).Name}";

        if(model.Entity.ID != Guid.Empty)
        {
            notification.EntityType = CoreUtils.EntityName(model.EntityType);
            notification.EntityID = model.Entity.ID;
        }
        return notification;
    }

    public void Init(IStore store, Event ev, IEventData evData, SaveEventDataModel<T> model)
    {
        if (model.Entity.ID != Guid.Empty)
        {
            var loadCols = Columns.None<T>();

            IEnumerable<string> refVars = evData.ReferencedVariables;

            if (!ev.NotificationExpression.IsNullOrWhiteSpace())
            {
                var notificationExpression = new CoreExpression(ev.NotificationExpression);
                refVars = refVars.Concat(notificationExpression.ReferencedVariables);
            }

            var prefix = $"{typeof(T).Name}.";
            foreach (var variable in refVars)
            {
                if (variable.StartsWith(prefix))
                {
                    var varName = variable[prefix.Length..];
                    if (!model.Entity.HasOriginalValue(varName))
                    {
                        loadCols.Add(varName);
                    }
                }
            }

            var data = store.Provider.Query(
                new Filter<T>(x => x.ID).IsEqualTo(model.Entity.ID),
                loadCols);
            if(data.Rows.Count > 0)
            {
                data.Rows[0].FillObject(model.Entity);
            }
        }
    }
}

public class SaveEventDataModelDefinition<T>(SaveEvent<T> ev) : IEventDataModelDefinition
    where T : Entity, new()
{
    private IEventVariable[]? variables;

    public IEnumerable<IEventVariable> GetVariables()
    {
        if(variables is null)
        {
            variables = DatabaseSchema.AllProperties(ev.Entity).Select(x => new StandardEventVariable($"{typeof(T).Name}.{x.Name}", x.PropertyType)).ToArray();
            variables.SortBy(x => x.Name);
        }
        return variables;
    }

    public IEventVariable? GetVariable(string name)
    {
        if(variables is null)
        {
            var prefix = $"{typeof(T).Name}.";
            if (name.StartsWith(prefix))
            {
                name = name[prefix.Length..];
                var prop = DatabaseSchema.Property(ev.Entity, name);
                if(prop is null)
                {
                    return null;
                }
                else
                {
                    return new StandardEventVariable(prop.Name, prop.PropertyType);
                }
            }
            else
            {
                return null;
            }
        }
        else
        {
            return variables.FirstOrDefault(x => x.Name == name);
        }
    }
}

public class SaveEventDataModel<T>(T entity, IStore store) : IEventDataModel, ITypedEventDataModel
    where T : Entity, new()
{
    public T Entity { get; set; } = entity;

    public Type EntityType => typeof(T);

    public IStore Store { get; } = store;

    public bool TryGetVariable(string name, out object? value)
    {
        var prefix = $"{typeof(T).Name}.";
        if (name.StartsWith(prefix))
        {
            name = name[prefix.Length..];
            var prop = DatabaseSchema.Property(typeof(T), name);
            if(prop != null)
            {
                value = prop.Getter()(Entity);
                return true;
            }
        }
        value = null;
        return false;
    }
}

#region Triggers

[Caption("New Record")]
public class CreatedSaveEventTrigger<T> : IEventTrigger<SaveEvent<T>, SaveEventDataModel<T>>
    where T : Entity, new()
{
    public string Description => "New Record";

    public IEnumerable<string> ReferencedVariables => [];

    public bool Check(SaveEventDataModel<T> dataModel)
    {
        return dataModel.Entity.HasOriginalValue(x => x.ID);
    }
}

[Caption("Property Changed")]
public class PropertyChangedSaveEventTrigger<T> : IEventTrigger<SaveEvent<T>, SaveEventDataModel<T>>
    where T : Entity, new()
{
    [JsonIgnore]
    public IProperty? TriggerProperty { get; set; }

    [JsonProperty(PropertyName = "TriggerProperty")]
    private string? _property
    {
        get => TriggerProperty?.Name;
        set
        {
            TriggerProperty = value is null ? null : DatabaseSchema.PropertyStrict(typeof(T), value); 
        }
    }

    public string Description => TriggerProperty is null
        ? $"{typeof(T).GetCaption()} changed"
        : $"{typeof(T).GetCaption()}.{TriggerProperty.Name} changed";

    public IEnumerable<string> ReferencedVariables => [];

    public bool Check(SaveEventDataModel<T> dataModel)
    {
        if(TriggerProperty is null)
        {
            return false;
        }
        if (!dataModel.Entity.HasOriginalValue(TriggerProperty.Name))
        {
            return false;
        }
        return true;
    }
}

[Caption("Filter")]
public class FilterSaveEventTrigger<T> : IEventTrigger<SaveEvent<T>, SaveEventDataModel<T>>
    where T : Entity, new()
{
    public Filter<T>? Filter { get; set; }

    public IEnumerable<string> ReferencedVariables => GetReferencedProperties(Filter).Select(x => $"{typeof(T).Name}.{x}");

    public string Description => Filter?.ToString() ?? "Blank Filter";

    public bool Check(SaveEventDataModel<T> dataModel)
    {
        return Filter.Match(dataModel.Entity, dataModel.Store.GetQueryProviderFactory());
    }

    private IEnumerable<string> GetReferencedProperties(Filter<T>? filter)
    {
        if (filter is null) yield break;

        if(filter.Operator != Operator.All && filter.Operator != Operator.None
            && !filter.Property.IsNullOrWhiteSpace())
        {
            yield return filter.Property;
        }
        foreach(var prop in filter.Ands.Concat(filter.Ors).SelectMany(GetReferencedProperties))
        {
            yield return prop;
        }
    }
}

[Caption("Custom Script")]
public class ScriptSaveEventTrigger<T> : IEventTrigger<SaveEvent<T>, SaveEventDataModel<T>>
    where T : Entity, new()
{
    public string Description => "Custom Script";

    private ScriptDocument? _scriptDocument;
    private ScriptDocument? ScriptDocument
    {
        get
        {
            if(_scriptDocument is null && Script is not null)
            {
                _scriptDocument = new(Script);
                _scriptDocument.Compile();
            }
            return _scriptDocument;
        }
    }

    private string? _script;
    public string? Script
    {
        get => _script;
        set
        {
            if(_script != value)
            {
                _script = value;
                _scriptDocument = null;
            }
        }
    }

    public IEnumerable<string> ReferencedVariables
    {
        get
        {
            var method = ScriptDocument?.GetMethod(methodName: "RequiredColumns");
            if(method is not null)
            {
                var cols = Columns.None<T>();
                method.Invoke(ScriptDocument!.GetObject(), [cols]);
                return cols.ColumnNames().Select(x => $"{typeof(T).Name}.{x}");
            }
            else
            {
                return [];
            }
        }
    }

    public string DefaultScript()
    {
        return @"using PRS.Shared.Events;

public class Module
{
    public void RequiredColumns(Columns<" + typeof(T).Name + @"> columns)
    {
        // Modify 'columns' as required to get the required columns for the 'model.Entity'. If you don't provide these,
        // the data you require in 'Execute' may not be present. Example:

        // columns.Add(x => x.ID);
    }

    public bool Check(SaveEventDataModel<" + typeof(T).Name + @"> model)
    {
        // Return true if model.Entity meets the requirements for this event trigger.
        return true;
    }
}";
    }

    public bool Check(SaveEventDataModel<T> dataModel)
    {
        if (ScriptDocument is null) return false;

        return ScriptDocument.Execute(methodname: "Check", parameters: [dataModel]);
    }
}

#endregion

#region Actions

[Caption("Custom Script")]
public class ScriptSaveEventAction<T> : IEventAction<SaveEvent<T>>
    where T : Entity, new()
{
    private ScriptDocument? _scriptDocument;
    private ScriptDocument? ScriptDocument
    {
        get
        {
            if(_scriptDocument is null && Script is not null)
            {
                _scriptDocument = new(Script);
                _scriptDocument.SetValue("Result", null);
                _scriptDocument.Compile();
            }
            return _scriptDocument;
        }
    }

    private string? _script;
    public string? Script
    {
        get => _script;
        set
        {
            if(_script != value)
            {
                _script = value;
                _scriptDocument = null;
            }
        }
    }

    public IEnumerable<string> ReferencedVariables
    {
        get
        {
            var method = ScriptDocument?.GetMethod(methodName: "RequiredColumns");
            if(method is not null)
            {
                var cols = Columns.None<T>();
                method.Invoke(ScriptDocument!.GetObject(), [cols]);
                return cols.ColumnNames().Select(x => $"{typeof(T).Name}.{x}");
            }
            else
            {
                return [];
            }
        }
    }

    public string Description => "Custom Script";

    public string DefaultScript()
    {
        return @"using PRS.Shared.Events;

public class Module
{
    public object? Result { get; set; }

    public void RequiredColumns(Columns<" + typeof(T).Name + @"> columns)
    {
        // Modify 'columns' as required to get the required columns for the 'model.Entity'. If you don't provide these,
        // the data you require in 'Execute' may not be present. Example:

        // columns.Add(x => x.ID);
    }

    public bool Execute(SaveEventDataModel<" + typeof(T).Name + @"> model)
    {
        // Do anything you want with model.Entity, and then save return-value to 'Result', or leave it as 'null' if no return value is needed.
        return true;
    }
}";
    }

    public object? Execute(IEventDataModel dataModel)
    {
        if (ScriptDocument is null) return null;

        var model = dataModel.RootModel<SaveEventDataModel<T>>();
        if(ScriptDocument.Execute(methodname: "Execute", parameters: [model]))
        {
            return ScriptDocument.GetValue("Result");
        }
        else
        {
            return null;
        }
    }
}

[Caption("Create Entity")]
public class CreateEntitySaveEventAction<T> : IEventAction<SaveEvent<T>>
    where T : Entity, new()
{
    [JsonProperty(Order = 1)]
    public Type? EntityType { get; set; }

    [JsonIgnore]
    public List<PropertyInitializer> Initializers { get; set; } = new List<PropertyInitializer>();

    private ScriptDocument? _scriptDocument;
    private ScriptDocument? ScriptDocument
    {
        get
        {
            if(_scriptDocument is null && Script is not null)
            {
                _scriptDocument = new(Script);
                _scriptDocument.Compile();
            }
            return _scriptDocument;
        }
    }

    private string? _script;
    public string? Script
    {
        get => _script;
        set
        {
            if(_script != value)
            {
                _script = value;
                _scriptDocument = null;
            }
        }
    }

    private IEnumerable<string> ScriptReferencedVariables
    {
        get
        {
            var method = ScriptDocument?.GetMethod(methodName: "RequiredColumns");
            if(method is not null)
            {
                var cols = Columns.None<T>();
                method.Invoke(ScriptDocument!.GetObject(), [cols]);
                return cols.ColumnNames().Select(x => $"{typeof(T).Name}.{x}");
            }
            else
            {
                return [];
            }
        }
    }

    public string DefaultScript()
    {
        if (EntityType is null) return "Please select an entity type first.";

        return @"using PRS.Shared.Events;

public class Module
{
    public void RequiredColumns(Columns<" + typeof(T).Name + @"> columns)
    {
        // Modify 'columns' as required to get the required columns for the 'model.Entity'. If you don't provide these,
        // the data you require in 'Execute' may not be present. Example:

        // columns.Add(x => x.ID);
    }

    public void Execute(SaveEventDataModel<" + typeof(T).Name + @"> model, " + EntityType.Name + " new" + EntityType.Name + @")
    {
        // Modify new" + EntityType.Name + @" as you wish, using model.Entity to get the required data. This method runs after
        // the property initializers (in the previous screen) for the Create Entity action have run.
    }
}";
    }

    public string Description => $"Create New {EntityType?.Name ?? "Entity"}";

    public IEnumerable<string> ReferencedVariables => Initializers.SelectMany(x => x.ReferencedVariables).Concat(ScriptReferencedVariables);

    public object? Execute(IEventDataModel dataModel)
    {
        if(EntityType is null)
        {
            return null;
        }
        var entity = (Activator.CreateInstance(EntityType) as Entity)!;
        foreach(var initializer in Initializers)
        {
            initializer.Execute(entity, dataModel);
        }

        if(ScriptDocument is not null)
        {
            var model = dataModel.RootModel<SaveEventDataModel<T>>();

            ScriptDocument.Execute(methodname: "Execute", parameters: [model, entity]);
        }

        DbFactory.FindStore(EntityType, Guid.Empty, "", default, "", Logger.Main).Save(entity, "");
        return entity;
    }

    #region Serialization Stuff

    [JsonProperty(Order = 2, PropertyName = "Initializers")]
    private PropertyInitializerSerializationItem[] _initializers
    {
        get => Initializers.ToArray(x => new PropertyInitializerSerializationItem { Property = x.Property.Name, Value = x.Value });
        set
        {
            Initializers.Clear();
            Initializers.AddRange(value.Select(x => new PropertyInitializer(EntityType!, x)));
        }
    }

    #endregion
}

internal class PropertyInitializerSerializationItem
{
    public string Property { get; set; }

    public string Value { get; set; }
}

public class PropertyInitializer
{
    public IProperty Property { get; set; }

    private CoreExpression? _valueExpression;
    private CoreExpression ValueExpression
    {
        get
        {
            _valueExpression ??= new CoreExpression(Value, Property.PropertyType);
            return _valueExpression;
        }
    }

    private string _value;
    public string Value
    {
        get => _value;
        [MemberNotNull(nameof(_value))]
        set
        {
            if(value != _value)
            {
                _value = value;
                _valueExpression = null;
            }
        }
    }

    public IEnumerable<string> ReferencedVariables => ValueExpression.ReferencedVariables;

    internal PropertyInitializer(Type entityType, PropertyInitializerSerializationItem item)
    {
        Value = item.Value;
        Property = DatabaseSchema.PropertyStrict(entityType, item.Property);
    }

    public PropertyInitializer(IProperty property, string value)
    {
        Property = property;
        Value = value;
    }

    public void Execute(Entity entity, IEventDataModel dataModel)
    {
        Property.Setter()(entity, ValueExpression.Evaluate(dataModel));
    }
}

#endregion