using System;
using System.Collections.Generic;
using System.Reflection;

namespace ln.application
{
    /// <summary>
    /// Argument container.
    /// </summary>
    /// <remarks>
    /// This class parses command line arguments to a list of predefined well known arguments.
    /// Remaining arguments will be found in <c>AdditionalArguments</c>.
    /// 
    /// <c>ArgumentContainer</c> also provides a global command line option:
    ///   --change-static <para>typename</para> <para>fieldname</para> <para>value</para>
    /// It may be used multiple times on the command line.
    /// It will load the type referenced by the qualified name <para>typename</para> and try to set the static field <para>fieldname</para> to <para>value</para>.
    /// <para>value</para> will be casted to field type via Convert.ChangeType(...)
    /// </remarks>
    public class ArgumentContainer
    {
        private Dictionary<char, IArgument> shortOptionArguments = new Dictionary<char, IArgument>();
        private Dictionary<string, IArgument> longOptionArguments = new Dictionary<string, IArgument>();

        public ArgumentContainer()
        {
        }
        public ArgumentContainer(IEnumerable<Argument> argumentDefinitions)
        {
            AddRange(argumentDefinitions);
        }

        public ArgumentContainer(Type type)
        {
            AddStaticOptions(type);
        }

        public IArgument this[string optionName] => longOptionArguments[optionName];
        public IArgument this[char option] => shortOptionArguments[option];

        public bool Contains(string optionName) =>longOptionArguments.ContainsKey(optionName);
        public bool Contains(char option) => shortOptionArguments.ContainsKey(option);

        public ArgumentContainer AddRange(IEnumerable<IArgument> arguments)
        {
            foreach (IArgument argument in arguments)
                Add(argument);

            return this;
        }
        
        public ArgumentContainer Add(IArgument argument)
        {
            if (argument.OptionName > 0)
                shortOptionArguments.Add(argument.OptionName,argument);
            if (argument.LongOptionName != null)
                longOptionArguments.Add(argument.LongOptionName, argument);
            
            return this;
        }
        public ArgumentContainer Add(char shortName) => Add(new Argument(shortName, null));
        public ArgumentContainer Add(string longName) => Add(new Argument((char)0, longName));
        public ArgumentContainer Add(char shortName, string longName) => Add(new Argument(shortName, longName));
        public ArgumentContainer Add(char shortName, string longName, string defaultValue) => Add(new Argument(shortName, longName, defaultValue));
        public ArgumentContainer Add(int shortName, string longName, string defaultValue) => Add(new Argument((char)shortName, longName, defaultValue));

        public string[] Parse(IEnumerable<string> args)
        {
            List<string> unusedArguments = new List<string>();
            
            Queue<string> q = new Queue<string>(args);
            while (q.Count > 0)
            {
                string currentOption = q.Dequeue();

                if (currentOption[0].Equals('-'))
                {
                    if (currentOption[1].Equals('-'))
                    {
                        String aname = currentOption.Substring(2);

                        if (aname.Equals("change-static"))
                        {
                            string typeName = q.Dequeue();
                            string fieldName = q.Dequeue();
                            string value = q.Dequeue();
                            ChangeStatic(typeName, fieldName, value);
                        }
                        else if (Contains(aname))
                        {
                            IArgument argument = this[aname];
                            argument.Value = argument.HasArgument ? q.Dequeue() : "";
                        } else
                        {
                            unusedArguments.Add("--" + aname);
                        }
                    }
                    else
                    {
                        foreach (char option in currentOption.Substring(1))
                        {
                            IArgument argument = this[option];
                            argument.Value = argument.HasArgument ? q.Dequeue() : "";
                        }
                    }
                }
                else
                {
                    unusedArguments.Add(currentOption);
                }
            }

            return unusedArguments.ToArray();
        }
        public void Parse(ref string[] args) => args = Parse(args);

        public static string[] ApplyArguments<T>(string[] arguments)
        {
            ArgumentContainer argumentContainer = new ArgumentContainer();
            argumentContainer.AddStaticOptions(typeof(T));
            return argumentContainer.Parse(arguments);
        }
        public static void ApplyArguments<T>(ref string[] arguments)
        {
            arguments = ApplyArguments<T>(arguments);
        }

        public static string[] ApplyArguments<T>(T instance,string[] arguments)
        {
            ArgumentContainer argumentContainer = new ArgumentContainer();
            argumentContainer.AddOptions(instance);
            return argumentContainer.Parse(arguments);
        }
        public static void ApplyArguments<T>(T instance,ref string[] arguments)
        {
            arguments = ApplyArguments(instance, arguments);
        }

        public ArgumentContainer AddStaticOptions(Type type)
        {
            foreach (FieldInfo fieldInfo in type.GetFields(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
            {
                if (fieldInfo.GetCustomAttribute<StaticArgumentAttribute>() != null)
                    Add(new FieldArgument(fieldInfo, fieldInfo.GetCustomAttribute<StaticArgumentAttribute>()));
            }
            foreach (PropertyInfo propertyInfo in type.GetProperties(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
            {
                if (propertyInfo.GetCustomAttribute<StaticArgumentAttribute>() != null)
                    Add(new PropertyArgument(propertyInfo, propertyInfo.GetCustomAttribute<StaticArgumentAttribute>()));
            }

            return this;
        }
        public ArgumentContainer AddOptions<T>(T instance)
        {
            foreach (FieldInfo fieldInfo in typeof(T).GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public))
            {
                if (fieldInfo.GetCustomAttribute<StaticArgumentAttribute>() != null)
                    Add(new FieldArgument(instance, fieldInfo));
            }
            foreach (PropertyInfo propertyInfo in typeof(T).GetProperties(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public))
            {
                if (propertyInfo.GetCustomAttribute<StaticArgumentAttribute>() != null)
                    Add(new PropertyArgument(instance, propertyInfo));
            }

            return this;
        }

        public ArgumentContainer AddStaticOptions<T>() => AddStaticOptions(typeof(T));
        
        
        public void ChangeStatic(string typeName,string fieldname,string value)
        {
            Type type = Type.GetType(typeName);
            FieldInfo fieldInfo = type.GetField(fieldname, BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);

            object castValue = Convert.ChangeType(value, fieldInfo.FieldType);
            fieldInfo.SetValue(null,castValue);
        }
    }
}