using System.Collections.Generic;

namespace Elsa.Models
{
    public class Variables : Dictionary<string, Variable>
    {
        public static readonly Variables Empty = new Variables();

        public Variables()
        {
        }

        public Variables(Variables other) : this((IEnumerable<KeyValuePair<string, Variable>>) other)
        {
        }

        public Variables(IEnumerable<KeyValuePair<string, Variable>> dictionary)
        {
            foreach (var item in dictionary)
                this[item.Key] = item.Value;
        }
        
        public Variables(IEnumerable<KeyValuePair<string, object>> dictionary)
        {
            foreach (var item in dictionary)
                SetVariable(item.Key, item.Value);
        }

        public object GetVariable(string name)
        {
            return ContainsKey(name) ? this[name].Value : default;
        }

        public T GetVariable<T>(string name)
        {
            object value = GetVariable(name);
            return (value != default) 
                ? (T)System.Convert.ChangeType(value, typeof(T))
                : default(T);
        }

        public Variable SetVariable(string name, object value)
        {
            return this[name] = new Variable(value);
        }

        public Variable SetVariable(string name, Variable variable)
        {
            return SetVariable(name, variable.Value);
        }

        public void SetVariables(Variables variables) =>
            SetVariables((IEnumerable<KeyValuePair<string, Variable>>) variables);

        public void SetVariables(IEnumerable<KeyValuePair<string, Variable>> variables)
        {
            foreach (var variable in variables)
                SetVariable(variable.Key, variable.Value);
        }

        public bool HasVariable(string name)
        {
            return ContainsKey(name);
        }
    }
}