// Author: Orlys
// Github: https://github.com/Orlys

namespace Yuuna.Contracts.Modules
{
    using System;
    using System.Collections.Immutable;
    using System.Reflection;
    using System.Runtime.Loader;
    using Yuuna.Contracts.Optimization;
    using Yuuna.Contracts.Patterns;
    using Yuuna.Contracts.Semantics;
    using Yuuna.Contracts.TextSegmention;

    /// <summary>
    /// 模組狀態。
    /// </summary>
    public enum ModuleStatus
    {
        /// <summary>
        /// 未初始化。
        /// </summary>
        Uninitialized,
        /// <summary>
        /// 初始化失敗。
        /// </summary>
        FailToInitialize,
        /// <summary>
        /// 初始化完成。
        /// </summary>
        Initialized,
    }

    internal interface IModule
    {
        IPatternSet Patterns { get; }
    }

    public abstract class ModuleBase  
    { 

        protected virtual string ModuleName { get; }

        private readonly PatternFactory _patternfactory;
        
        internal IPatternSet  Patterns => this._patternfactory;

        public ModuleBase()
        {
            this._patternfactory = new PatternFactory(this);
            this.ModuleName = this.GetType().Name;
            this.Status = ModuleStatus.Uninitialized;
        }

        /// <summary>
        /// 模組名稱。
        /// </summary>
        public string Name
        {
            get
            {
                var t = this.GetType();
                var getMethod = t.GetProperty(nameof(this.ModuleName),  (BindingFlags)52).GetGetMethod(true);
                if (!getMethod.GetBaseDefinition().Equals(getMethod))
                {
                    try
                    {
                        var test = this.ModuleName;
                        if (!string.IsNullOrWhiteSpace(test))
                        {
                            return test;
                        }
                    }
                    catch
                    {
                    }
                    return t.Name;
                }
                else
                    return this.ModuleName;
            }
        }

        /// <summary>
        /// 表示模組是否已初始化。
        /// </summary>
        public ModuleStatus Status { get; private set; }

        /// <summary>
        /// 初始化模組
        /// </summary>
        /// <param name="textSegmenter">分詞器</param>
        /// <param name="groupManager">群組管理</param>
        internal void Initialize(ITextSegmenter textSegmenter, IGroupManager groupManager)
        {
            if (this.Status.Equals(ModuleStatus.Uninitialized))
            {
                try
                {
                    this.BuildPatterns(groupManager, this._patternfactory);
                    textSegmenter.Load(groupManager);
                    this.Status = ModuleStatus.Initialized;
                    this.AfterInitialize();
                }
                catch //(Exception e)
                {
                    this.Status = ModuleStatus.FailToInitialize;
                }
            }
        }


        /// <summary>
        /// 在初始化後引發。
        /// </summary>
        protected virtual void AfterInitialize()
        {
        }

        /// <summary>
        /// 建立模式規則。
        /// </summary>
        /// <param name="g"></param>
        /// <param name="p"></param>
        protected abstract void BuildPatterns(IGroupManager g, IPatternBuilder p);
    }
}