using System;
using System.Web;
using NewLife.Log;
using XUrlRewrite.Configuration;

namespace XUrlRewrite.Helper
{
    /// <summary>
    /// Url重写辅助工具类
    /// </summary>
    public class RewriteHelper
    {
        private String toTemplateDir;
        private String toPath;
        private String toQuery;
        private String fromPath;
        private String fromQuery;
        private String matchRule;

        /// <summary>
        /// 构造方法
        /// </summary>
        protected RewriteHelper()
        {
        }

        /// <summary>
        /// 创建Url重写辅助工具,主要用于在模板页解析相对于模板的路径
        /// </summary>
        /// <param name="fromPath"></param>
        /// <param name="fromQuery"></param>
        /// <param name="app"></param>
        /// <returns></returns>
        internal static RewriteHelper Create(String fromPath, String fromQuery, string matchRule, HttpApplication app)
        {
            RewriteHelper ret = new RewriteHelper();
            ret.fromPath = fromPath;
            ret.fromQuery = fromQuery;
            ret.matchRule = matchRule;
            ret.Path = app.Request.ApplicationPath.TrimEnd('/') + fromPath;
            ret.AppRelativeCurrentExecutionFilePath = "~" + fromPath;

            ret.QueryString = HttpUtility.ParseQueryString("");
            ret.QueryString.Add(app.Request.QueryString);

            HttpContext.Current.Items[typeof(RewriteHelper).FullName] = ret;
            return ret;
        }

        /// <summary>
        /// 获取当前请求中的RewriteHelper类,如果不存在会返回空白类,即所有涉及路径的操作和普通Page相关的路径操作一致
        /// </summary>
        public static RewriteHelper Current
        {
            get
            {
                RewriteHelper ret = HttpContext.Current.Items[typeof(RewriteHelper).FullName] as RewriteHelper;
                if (null == ret)
                {
                    ret = RewriteHelperEmpty;
                }
                return ret;
            }
        }

        /// <summary>
        /// 设置Url重写的目标地址信息
        /// </summary>
        /// <param name="rTemplateDir"></param>
        /// <param name="rPath"></param>
        /// <param name="rQuery"></param>
        /// <returns></returns>
        internal RewriteHelper RewriteToInfo(String rTemplateDir, String rPath, String rQuery)
        {
            toTemplateDir = rTemplateDir;
            toPath = rPath;
            toQuery = rQuery;
            return this;
        }

        /// <summary>
        /// 输出Url重写跟踪日志
        /// </summary>
        public void TraceLog()
        {
            if (Manager.Debug)
            {
                XTrace.WriteLine("Url重写跟踪 " + ToString());
            }
        }

        /// <summary>
        /// <see cref="System.Web.HttpRequest.Path"/>
        /// </summary>
        public String Path { get; set; }

        /// <summary>
        /// <see cref="System.Web.HttpRequest.FilePath"/>
        /// </summary>
        public String FilePath
        {
            get
            {
                return Path;
            }
        }

        /// <summary>
        /// <see cref="System.Web.HttpRequest.CurrentExecutionFilePath"/>
        /// </summary>
        public String CurrentExecutionFilePath
        {
            get
            {
                return Path;
            }
        }

        /// <summary>
        /// <see cref="System.Web.HttpRequest.AppRelativeCurrentExecutionFilePath"/>
        /// </summary>
        public String AppRelativeCurrentExecutionFilePath { get; set; }

        /// <summary>
        /// <see cref="System.Web.HttpRequest.QueryString"/>
        /// </summary>
        public System.Collections.Specialized.NameValueCollection QueryString { get; set; }

        private String _FormAction;
        /// <summary>
        /// 当前模板页form标签合理的action地址
        /// </summary>
        public String FormAction
        {
            get
            {
                if (null == _FormAction)
                {
                    _FormAction = VirtualPathUtility.GetFileName(fromPath);
                    _FormAction += fromQuery.Length > 0 ? "?" + fromQuery : "";
                }
                return _FormAction;
            }
        }

        /// <summary>
        /// 解析指定的Url,返回相对于域名根路径的Url,即以/开头的路径
        /// </summary>
        /// <param name="url">如果以~/开头表示从模板根路径开始, 如果以/开头将原样返回, 其它路径按照相对于当前模板文件的路径决定</param>
        /// <returns></returns>
        public virtual String ResolveUrl(String url)
        {
            return VirtualPathUtility.ToAbsolute(_ResolveUrl(url));
        }

        /// <summary>
        /// 解析指定的Url,返回相对于当前应用的Url,即以~/开头的路径
        /// </summary>
        /// <param name="url">参见ResolveUrl方法的url参数</param>
        /// <returns></returns>
        public virtual String ResolveUrlAppRelative(String url)
        {
            return VirtualPathUtility.ToAppRelative(_ResolveUrl(url));
        }

        private String _ResolveUrl(String url)
        {
            if (url[0] == '~' && url[1] == '/')
            {
                return VirtualPathUtility.RemoveTrailingSlash(toTemplateDir) + url.Substring(1);
            }
            else if (url[0] == '/')
            {
                return url;
            }
            else
            {
                return VirtualPathUtility.RemoveTrailingSlash(toTemplateDir) + VirtualPathUtility.GetDirectory(toPath) + url;
            }
        }

        /// <summary>
        /// 重写
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            return string.Format("{0} 重写为 {1} 规则:{2}",
                    fromPath + ("?" + fromQuery).TrimEnd('?'),
                    toTemplateDir + toPath + ("?" + (toQuery + "&" + fromQuery).Trim('&')).TrimEnd('?'),
                    matchRule);
        }

        static RewriteHelper RewriteHelperEmpty = new RewriteHelperEmptyWrap();

        /// <summary>
        /// 空重写辅助工具
        /// </summary>
        private class RewriteHelperEmptyWrap : RewriteHelper
        {
            public RewriteHelperEmptyWrap()
            {
                _FormAction = "";
            }

            public override String ResolveUrl(String url)
            {
                if (url[0] == '~' && url[1] == '/')
                {
                    return VirtualPathUtility.ToAbsolute(url);
                }
                return url;
            }

            public override String ResolveUrlAppRelative(String url)
            {
                if (url[0] == '~' && url[1] == '/')
                {
                    return VirtualPathUtility.ToAppRelative(url);
                }
                return url;
            }
        }
    }
}