using System;
using System.Globalization;
using Umbraco.Core;
using Umbraco.Core.Models;
using UmbracoSettings = Umbraco.Core.Configuration.UmbracoSettings;
using Umbraco.Web.Configuration;
using umbraco;
using umbraco.cms.businesslogic.web;

namespace Umbraco.Web.Routing
{
	/// <summary>
	/// Represents a request for one specified Umbraco IPublishedContent to be rendered
	/// by one specified template, using one specified Culture and RenderingEngine.
	/// </summary>
	public class PublishedContentRequest
	{
	    private bool _readonly;

		/// <summary>
		/// Triggers once the published content request has been prepared, but before it is processed.
		/// </summary>
		/// <remarks>When the event triggers, preparation is done ie domain, culture, document, template,
		/// rendering engine, etc. have been setup. It is then possible to change anything, before
		/// the request is actually processed and rendered by Umbraco.</remarks>
		public static event EventHandler<EventArgs> Prepared;

		// the engine that does all the processing
		// because in order to keep things clean and separated,
		// the content request is just a data holder
		private readonly PublishedContentRequestEngine _engine;

		/// <summary>
		/// Initializes a new instance of the <see cref="PublishedContentRequest"/> class with a specific Uri and routing context.
		/// </summary>
		/// <param name="uri">The request <c>Uri</c>.</param>
		/// <param name="routingContext">A routing context.</param>
		internal PublishedContentRequest(Uri uri, RoutingContext routingContext)
		{
			if (uri == null) throw new ArgumentNullException("uri");
			if (routingContext == null) throw new ArgumentNullException("routingContext");

			Uri = uri;
			RoutingContext = routingContext;

			_engine = new PublishedContentRequestEngine(this);

            RenderingEngine = RenderingEngine.Unknown;
		}

		/// <summary>
		/// Gets the engine associated to the request.
		/// </summary>
		internal PublishedContentRequestEngine Engine { get { return _engine; } }

		/// <summary>
		/// Prepares the request.
		/// </summary>
		internal void Prepare()
		{
			_engine.PrepareRequest();
		}

		/// <summary>
		/// Updates the request when there is no template to render the content.
		/// </summary>
		internal void UpdateOnMissingTemplate()
		{
            var __readonly = _readonly;
		    _readonly = false;
			_engine.UpdateRequestOnMissingTemplate();
		    _readonly = __readonly;
		}

		/// <summary>
		/// Triggers the Prepared event.
		/// </summary>
		internal void OnPrepared()
		{
			if (Prepared != null)
				Prepared(this, EventArgs.Empty);

		    if (!HasPublishedContent)
                Is404 = true; // safety

		    _readonly = true;
		}

		/// <summary>
		/// Gets or sets the cleaned up Uri used for routing.
		/// </summary>
		/// <remarks>The cleaned up Uri has no virtual directory, no trailing slash, no .aspx extension, etc.</remarks>
		public Uri Uri { get; private set; }

        private void EnsureWriteable()
        {
            if (_readonly)
                throw new InvalidOperationException("Cannot modify a PublishedContentRequest once it is read-only.");
        }

		#region PublishedContent

		/// <summary>
		/// The requested IPublishedContent, if any, else <c>null</c>.
		/// </summary>
		private IPublishedContent _publishedContent;

		/// <summary>
		/// The initial requested IPublishedContent, if any, else <c>null</c>.
		/// </summary>
		/// <remarks>The initial requested content is the content that was found by the finders,
		/// before anything such as 404, redirect... took place.</remarks>
		private IPublishedContent _initialPublishedContent;

		/// <summary>
		/// Gets or sets the requested content.
		/// </summary>
		/// <remarks>Setting the requested content clears <c>Template</c>.</remarks>
		public IPublishedContent PublishedContent
		{			
			get { return _publishedContent; }
			set
			{
                EnsureWriteable();
				_publishedContent = value;
                IsInternalRedirectPublishedContent = false;
				TemplateModel = null;
			}
		}

		/// <summary>
        /// Sets the requested content, following an internal redirect.
        /// </summary>
        /// <param name="content">The requested content.</param>
        /// <remarks>Depending on <c>UmbracoSettings.InternalRedirectPreservesTemplate</c>, will
        /// preserve or reset the template, if any.</remarks>
        public void SetInternalRedirectPublishedContent(IPublishedContent content)
        {
            EnsureWriteable();

            // unless a template has been set already by the finder,
            // template should be null at that point. 

            // IsInternalRedirect if IsInitial, or already IsInternalRedirect
            var isInternalRedirect = IsInitialPublishedContent || IsInternalRedirectPublishedContent;

            // redirecting to self
            if (content.Id == PublishedContent.Id) // neither can be null
            {
                // no need to set PublishedContent, we're done
                IsInternalRedirectPublishedContent = isInternalRedirect;
                return;
            }

            // else

            // save
            var template = _template;
            var renderingEngine = RenderingEngine;

            // set published content - this resets the template, and sets IsInternalRedirect to false
            PublishedContent = content;
		    IsInternalRedirectPublishedContent = isInternalRedirect;

            // must restore the template if it's an internal redirect & the config option is set
            if (isInternalRedirect && UmbracoSettings.For<WebRouting>().InternalRedirectPreservesTemplate)
            {
                // restore
                _template = template;
                RenderingEngine = renderingEngine;
            }
        }

        /// <summary>
		/// Gets the initial requested content.
		/// </summary>
		/// <remarks>The initial requested content is the content that was found by the finders,
		/// before anything such as 404, redirect... took place.</remarks>
		public IPublishedContent InitialPublishedContent { get { return _initialPublishedContent; } }

		/// <summary>
		/// Gets value indicating whether the current published content is the initial one.
		/// </summary>
		public bool IsInitialPublishedContent 
		{
			get
			{
			    return _initialPublishedContent != null && _initialPublishedContent == _publishedContent;
			}
		}

        /// <summary>
        /// Indicates that the current PublishedContent is the initial one.
        /// </summary>
        public void SetIsInitialPublishedContent()
        {
            EnsureWriteable();

            // note: it can very well be null if the initial content was not found
            _initialPublishedContent = _publishedContent;
            IsInternalRedirectPublishedContent = false;
        }

        /// <summary>
        /// Gets or sets a value indicating whether the current published content has been obtained
        /// from the initial published content following internal redirections exclusively.
        /// </summary>
        /// <remarks>Used by PublishedContentRequestEngine.FindTemplate() to figure out whether to
        /// apply the internal redirect or not, when content is not the initial content.</remarks>
        public bool IsInternalRedirectPublishedContent { get; private set; }

        /// <summary>
        /// Gets a value indicating whether the content request has a content.
        /// </summary>
        public bool HasPublishedContent
        {
            get { return PublishedContent != null; }
        }

		#endregion

		#region Template

        /// <summary>
        /// The template model, if any, else <c>null</c>.
        /// </summary>
        private ITemplate _template;

	    /// <summary>
        /// Gets or sets the template model to use to display the requested content.
        /// </summary>
        internal ITemplate TemplateModel 
        {
            get
            {
                return _template;
            }

            set
            {
                _template = value;
                RenderingEngine = RenderingEngine.Unknown; // reset

                if (_template != null)
                    RenderingEngine = _engine.FindTemplateRenderingEngine(_template.Alias);
            }
        }

        /// <summary>
        /// Gets the alias of the template to use to display the requested content.
        /// </summary>
        public string TemplateAlias
        {
            get 
            { 
                return _template == null ? null : _template.Alias; 
            }
        }

        /// <summary>
        /// Tries to set the template to use to display the requested content.
        /// </summary>
        /// <param name="alias">The alias of the template.</param>
        /// <returns>A value indicating whether a valid template with the specified alias was found.</returns>
        /// <remarks>
        /// <para>Successfully setting the template does refresh <c>RenderingEngine</c>.</para>
        /// <para>If setting the template fails, then the previous template (if any) remains in place.</para>
        /// </remarks>
        public bool TrySetTemplate(string alias)
        {
            EnsureWriteable();

            if (string.IsNullOrWhiteSpace(alias))
            {
                TemplateModel = null;
                return true;
            }

            // NOTE - can we stil get it with whitespaces in it due to old legacy bugs?
            alias = alias.Replace(" ", "");

            var model = ApplicationContext.Current.Services.FileService.GetTemplate(alias);
            if (model == null)
                return false;

            TemplateModel = model;                    
            return true;
        }

        /// <summary>
        /// Sets the template to use to display the requested content.
        /// </summary>
        /// <param name="template">The template.</param>
        /// <remarks>Setting the template does refresh <c>RenderingEngine</c>.</remarks>
        public void SetTemplate(ITemplate template)
        {
            EnsureWriteable();
            TemplateModel = template;
        }

        /// <summary>
        /// Gets a value indicating whether the content request has a template.
        /// </summary>
        public bool HasTemplate
        {
            get { return _template != null; }
        }

		#endregion

		#region Domain and Culture

		/// <summary>
        /// Gets or sets the content request's domain.
        /// </summary>
        public Domain Domain { get; internal set; }

		/// <summary>
		/// Gets or sets the content request's domain Uri.
		/// </summary>
		/// <remarks>The <c>Domain</c> may contain "example.com" whereas the <c>Uri</c> will be fully qualified eg "http://example.com/".</remarks>
		public Uri DomainUri { get; internal set; }

		/// <summary>
		/// Gets a value indicating whether the content request has a domain.
		/// </summary>
		public bool HasDomain
		{
			get { return Domain != null; }
		}

	    private CultureInfo _culture;

	    /// <summary>
	    /// Gets or sets the content request's culture.
	    /// </summary>
	    public CultureInfo Culture
	    {
            get { return _culture; }
            set
            {
                EnsureWriteable();
                _culture = value;
            }
	    }

		// note: do we want to have an ordered list of alternate cultures,
        // to allow for fallbacks when doing dictionnary lookup and such?

		#endregion

		#region Rendering

		/// <summary>
		/// Gets or sets whether the rendering engine is MVC or WebForms.
		/// </summary>
		public RenderingEngine RenderingEngine { get; internal set; }

		#endregion

		/// <summary>
		/// Gets or sets the current RoutingContext.
		/// </summary>
		public RoutingContext RoutingContext { get; private set; }

		/// <summary>
		/// The "umbraco page" object.
		/// </summary>
		private page _umbracoPage;

		/// <summary>
		/// Gets or sets the "umbraco page" object.
		/// </summary>
		/// <remarks>
		/// This value is only used for legacy/webforms code.
		/// </remarks>
		internal page UmbracoPage
		{
			get
			{
				if (_umbracoPage == null)
					throw new InvalidOperationException("The umbraco page object is only available once Finalize()");

				return _umbracoPage;
			}
			set { _umbracoPage = value; }
		}

		#region Status

		/// <summary>
        /// Gets or sets a value indicating whether the requested content could not be found.
        /// </summary>
		/// <remarks>This is set in the <c>PublishedContentRequestBuilder</c>.</remarks>
        public bool Is404 { get; internal set; }

        /// <summary>
        /// Indicates that the requested content could not be found.
        /// </summary>
        /// <remarks>This is for public access, in custom content finders or <c>Prepared</c> event handlers,
        /// where we want to allow developers to indicate a request is 404 but not to cancel it.</remarks>
        public void SetIs404()
        {
            EnsureWriteable();
            Is404 = true;
        }

        /// <summary>
        /// Gets a value indicating whether the content request triggers a redirect (permanent or not).
        /// </summary>
        public bool IsRedirect { get { return !string.IsNullOrWhiteSpace(RedirectUrl); } }

        /// <summary>
        /// Gets or sets a value indicating whether the redirect is permanent.
        /// </summary>
        public bool IsRedirectPermanent { get; private set; }

        /// <summary>
        /// Gets or sets the url to redirect to, when the content request triggers a redirect.
        /// </summary>
        public string RedirectUrl { get; private set; }

        /// <summary>
        /// Indicates that the content request should trigger a redirect (302).
        /// </summary>
        /// <param name="url">The url to redirect to.</param>
        /// <remarks>Does not actually perform a redirect, only registers that the response should
        /// redirect. Redirect will or will not take place in due time.</remarks>
        public void SetRedirect(string url)
        {
            EnsureWriteable();
            RedirectUrl = url;
            IsRedirectPermanent = false;
        }

        /// <summary>
        /// Indicates that the content request should trigger a permanent redirect (301).
        /// </summary>
        /// <param name="url">The url to redirect to.</param>
        /// <remarks>Does not actually perform a redirect, only registers that the response should
        /// redirect. Redirect will or will not take place in due time.</remarks>
        public void SetRedirectPermanent(string url)
        {
            EnsureWriteable();
            RedirectUrl = url;
            IsRedirectPermanent = true;
        }

        /// <summary>
        /// Indicates that the content requet should trigger a redirect, with a specified status code.
        /// </summary>
        /// <param name="url">The url to redirect to.</param>
        /// <param name="status">The status code (300-308).</param>
        /// <remarks>Does not actually perform a redirect, only registers that the response should
        /// redirect. Redirect will or will not take place in due time.</remarks>
        public void SetRedirect(string url, int status)
        {
            EnsureWriteable();

            if (status < 300 || status > 308)
                throw new ArgumentOutOfRangeException("status", "Valid redirection status codes 300-308.");

            RedirectUrl = url;
            IsRedirectPermanent = (status == 301 || status == 308);
            if (status != 301 && status != 302) // default redirect statuses
                ResponseStatusCode = status;
        }

        /// <summary>
        /// Gets or sets the content request http response status code.
        /// </summary>
        /// <remarks>Does not actually set the http response status code, only registers that the response
        /// should use the specified code. The code will or will not be used, in due time.</remarks>
        public int ResponseStatusCode { get; private set; }

        /// <summary>
        /// Gets or sets the content request http response status description.
        /// </summary>
        /// <remarks>Does not actually set the http response status description, only registers that the response
        /// should use the specified description. The description will or will not be used, in due time.</remarks>
        public string ResponseStatusDescription { get; private set; }

        /// <summary>
        /// Sets the http response status code, along with an optional associated description.
        /// </summary>
        /// <param name="code">The http status code.</param>
        /// <param name="description">The description.</param>
        /// <remarks>Does not actually set the http response status code and description, only registers that
        /// the response should use the specified code and description. The code and description will or will
        /// not be used, in due time.</remarks>
        public void SetResponseStatus(int code, string description = null)
        {
            EnsureWriteable();

            // .Status is deprecated
            // .SubStatusCode is IIS 7+ internal, ignore
            ResponseStatusCode = code;
            ResponseStatusDescription = description;
        }
		
        #endregion		
    }
}