use std::borrow::Borrow;
use std::collections::HashSet;
use std::hash::Hash;

use dioxus::prelude::*;
use tavern::{Adventurer, Legend, Lore, Tale};

use crate::page::Page;
use crate::server::*;



const AUTHOR_CSS: Asset = asset!("/assets/css/blog_author.css");
const LIST_CSS: Asset = asset!("/assets/css/blog_list.css");
const NAV_CSS: Asset = asset!("/assets/css/blog_nav.css");
const POST_CSS: Asset = asset!("/assets/css/blog_post.css");
const TAG_CSS: Asset = asset!("/assets/css/blog_tag.css");



/// Trait to toggle the presence of a value (like a tag) in a set.
pub trait Togglable
{
   type Item: ?Sized;

   fn toggle(&mut self, item: &Self::Item);
   fn is_toggled(&self, item: &Self::Item) -> bool;
}

impl Togglable for HashSet<String>
{
   type Item = str;


   fn toggle(&mut self, item: &str)
   {
      if self.contains(item)
      {
         self.remove(item);
      }
      else
      {
         self.insert(item.to_owned());
      }
   }

   fn is_toggled(&self, item: &str) -> bool
   {
      self.contains(item)
   }
}



fn convert_tag<S>(text: S) -> (String, String)
   where S: AsRef<str>
{
   if let Some((first, second)) = text.as_ref().split_once('-')
   {
      (first.to_owned(), second.to_owned())
   }
   else
   {
      (text.as_ref().to_owned(), "none".to_owned())
   }
}

fn strip_tag(text: &str) -> &str
{
   if let Some((first, _)) = text.split_once('-')
   {
      first
   }
   else
   {
      text
   }
}



#[component]
pub fn TagItem(tag: String, style: String) -> Element
{
   rsx! {
         li
         {
            class: "tag_item",
            Link
               {
                  class: "{style}",
                  to: Page::Blog { tag: tag.clone() },
                  "{tag}"
               }
   //         a { class: "{style}", "{tag}" }
         }
      }
}

#[component]
pub fn TagList(children: Element) -> Element
{
   rsx! {
      document::Link { rel: "stylesheet", href: TAG_CSS }

      h5
      {
         class: "blog_tag_style",
         ul
         {
            class: "tag_list",
            {children}
         }
      }
   }
}


#[component]
pub fn BlogAuthor() -> Element
{
   rsx! {
      document::Link { rel: "stylesheet", href: AUTHOR_CSS }

      section
      {
         class: "blog_author_style",

      }
   }
}


#[component]
pub fn BlogItem(title: String, slug: String, author: String, summary: String,
                tags: Vec<String>)
                -> Element
{
   let tags: Vec<(String, String)> =
      tags.iter().map(|t| convert_tag(t)).collect();

   rsx! {
      li
      {
         class: "blog_item",
         Link
         {
            to: Page::Post { slug: slug },
            h1 { "{title}" }
         }
         TagList
         {
            for (tag, style) in tags
            {
               TagItem
               {
                  tag: tag.clone(),
                  style: style.clone()
               }
            }
         }
         h4 { "Author: {author}" }
         p { "{summary}" }
      }
   }
}


#[component]
pub fn BlogList(tags: Signal<HashSet<String>>, children: Element) -> Element
{
   let list = use_server_future(move || {
      let categories = tags().iter().cloned().collect();

      async move { get_blog_list(categories).await }
   })?;

   // The tale depends on the post future resolving.
   let mut summaries: Signal<Option<Vec<Lore>>> = use_signal(|| None);
   use_context_provider(|| summaries);

   use_effect(move || {
      if let Some(Ok(data)) = &*list.read()
      {
         summaries.set(Some(data.clone()));
      }
   });

   rsx! {
      document::Link { rel: "stylesheet", href: LIST_CSS }

      section
      {
         class: "blog_list_style",
         ul
         {
            class: "blog_list",

      match &*list.read()
      {
         Some(Ok(lores)) =>
         {
            rsx!
            {
               for lore in lores
               {
                  BlogItem
                  {
                     title: lore.title.clone(),
                     slug: lore.slug.clone(),
                     author: lore.author.clone(),
                     summary: lore.summary.clone(),
                     tags: lore.tags.clone()
                  }
               }
            }
         }

         Some(Err(e)) =>
         {
            rsx!
            {
               p { "Unable to show post header." }
               p { "{e}" }
            }
         }

         None =>
         {
            rsx!
            {
               p { "Loading..." }
            }
         }
      }

            {children}
         }
      }
   }
}

#[component]
pub fn TagSelector(toggled_tags: Signal<HashSet<String>>) -> Element
{
   let mut categories = use_signal(|| Vec::<String>::new());

   let tags = use_server_future(move || async move { get_tags().await })?;

   use_effect(move ||
   {
      if let Some(Ok(ref tags_vec)) = *tags.read()
      {
         categories.set(tags_vec.clone());
      }
   });

   rsx!
   {
      document::Link { rel: "stylesheet", href: NAV_CSS }

      section
      {
         class: "blog_nav_style",
         div
         {
            class: "tag_style",
            h2 { "Categories" }
            ul
            {
               class: "tag_list",

               if categories.read().is_empty()
               {
                  p { "Loading..." }
               }
               else
               {
                  for tag in categories.read().iter().cloned()
                  {
                     li
                     {
                        class: "tag_item",
                        span
                        {
                           class: if toggled_tags.read().is_toggled(&tag)
                           { "tag selected" }

                           else
                           { "tag" },

                           onclick: move |_|
                           { toggled_tags.write().toggle(&tag); },

                           "{strip_tag(&tag)}"
                        }
                     }
                  }
               }
            }
         }
      }
   }
}

#[component]
pub fn PostHeaderAuthor(adventurer: Signal<Option<Adventurer>>) -> Element
{
   rsx! {
      match adventurer()
      {
         Some(author) =>
         {
            rsx!
            {
               h4
               {
                  "Author: ",
                  a { href: "{author.legend.profile}", "{author.name} @{author.handle}" }
               }
            }
         }

         None =>
         {
            rsx! { h4 { "Author: Unknown" } }
         }
      }
   }
}

#[component]
pub fn PostHeader(tale: Signal<Option<Tale>>,
                  adventurer: Signal<Option<Adventurer>>) -> Element
{
   let converted_tags = use_memo(move || {
      tale().as_ref()
            .map(|t| {
               t.lore
                .tags
                .iter()
                .map(|tag| convert_tag(tag))
                .collect::<Vec<_>>()
            })
            .unwrap_or_default()
   });

   rsx! {
      match tale()
      {
         Some(tale) =>
         {
            rsx!
            {
               h1 { {tale.lore.title} }
               TagList
               {
                  for (tag, style) in converted_tags().iter()
                  {
                     TagItem
                     {
                        tag: tag.clone(),
                        style: style.clone()
                     }
                  }
               }
            }
         }

         None =>
         {
            rsx! { p { "Loading post header..." } }
         }
      }

      match adventurer()
      {
         Some(_) =>
         {
            rsx! { PostHeaderAuthor { adventurer: adventurer } }
         }

         None =>
         {
            rsx! { p { "Loading author..." } }
         }
      }
   }
}

#[component]
pub fn BlogPost(slug: Signal<String>, children: Element) -> Element
{
   // The tale depends on the post future resolving.
   let mut tale: Signal<Option<Tale>> = use_signal(|| None);
   let mut adventurer = use_signal(|| None);

   // Run a once off server fetch of the unchanging blog data.
   let post = use_server_future(move ||
   {
      // Make this reactive so that as the page changes it should rerun this.
      let url_slug = slug();

      async move { get_blog_post(url_slug).await }
   })?;

   let author = use_server_future(move || {
      let handle = match tale()
      {
         Some(data) => data.lore.author,

         None => "unknown_author_handle".to_string()
      };

      async move { get_author(handle).await }
   })?;

   use_effect(move || {
      if let Some(Ok(data)) = &*post.read()
      {
         tale.set(Some(data.clone()));
      }
   });

   use_effect(move || {
      if let Some(Ok(data)) = &*author.read()
      {
         adventurer.set(Some(data.clone()));
      }
   });


   rsx! {
      document::Link { rel: "stylesheet", href: POST_CSS }

      article
      {
         class: "blog_post_style",

         match &*post.read()
         {
            Some(Ok(post)) =>
            {
               rsx!
               {
                  PostHeader
                  {
                     tale: tale,
                     adventurer: adventurer
                  }

                  //Story {}

                  div { dangerous_inner_html: "{post.story}" }

                  //Author {}
               }
            }

            Some(Err(e)) =>
            {
               rsx!
               {
                  p { "Unable to load desired post: {slug.read()}" }
                  p { "{e}" }
               }
            }

            None =>
            {
               rsx!
               {
                  p { "Loading..." }
               }
            }
         }

         {children}
      }
   }
}

#[component]
pub fn TagNav() -> Element
{
   let tags = use_server_future(move || async move { get_tags().await })?;

   rsx!
   {
      document::Link { rel: "stylesheet", href: NAV_CSS }

      section
      {
         class: "blog_nav_style",
         div
         {
            class: "tag_style",
            h2 { "Categories" }
            ul
            {
               class: "tag_list",
               match &*tags.read()
               {
                  Some(Ok(categories)) =>
                  {
                     rsx!
                     {
                        for tag in categories
                        {
                           li
                           {
                              class: "tag_item",
                              a { href: "/blog/{strip_tag(tag)}", "{strip_tag(tag)}" }
                           }
                        }
                     }
                  }

                  Some(Err(e)) =>
                  {
                     rsx!
                     {
                        p { "Unable to show desired post." }
                        p { "{e}" }
                     }
                  }

                  None =>
                  {
                     rsx!
                     {
                        p { "Loading..." }
                     }
                  }
               }
            }
         }
      }
   }
}