feat(web/converse): Import repository

Imports the converse forum software I wrote a few years ago. I want to
clean this up a bit and try using Hotwire with it.

Note: The original repository was AGPL-3.0 licensed. I'm the copyright
holder and have relicensed it to GPL-3.0 in the commit that is being
merged.

Imported from: https://github.com/tazjin/converse

git-subtree-dir: web/converse
git-subtree-mainline: 386afdc794
git-subtree-split: 09168021e7
Change-Id: Ia8b587db5174ef5b3c52910d3d027199150c58e0

web/converse/src/render.rs

@@ -0,0 +1,265 @@
+// Copyright (C) 2018-2021 Vincent Ambo <tazjin@tvl.su>
+//
+// This file is part of Converse.
+//
+// This program is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see
+// <https://www.gnu.org/licenses/>.
+
+//! This module defines a rendering actor used for processing Converse
+//! data into whatever format is needed by the templates and rendering
+//! them.
+
+use actix::prelude::*;
+use askama::Template;
+use errors::*;
+use std::fmt;
+use md5;
+use models::*;
+use chrono::prelude::{DateTime, Utc};
+use comrak::{ComrakOptions, markdown_to_html};
+
+pub struct Renderer {
+    pub comrak: ComrakOptions,
+}
+
+impl Actor for Renderer {
+    type Context = actix::Context<Self>;
+}
+
+/// Represents a data formatted for human consumption
+#[derive(Debug)]
+struct FormattedDate(DateTime<Utc>);
+
+impl fmt::Display for FormattedDate {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.0.format("%a %d %B %Y, %R"))
+    }
+}
+
+/// Message used to render the index page.
+pub struct IndexPage {
+    pub threads: Vec<ThreadIndex>,
+}
+message!(IndexPage, Result<String>);
+
+#[derive(Debug)]
+struct IndexThread {
+    id: i32,
+    title: String,
+    sticky: bool,
+    closed: bool,
+    posted: FormattedDate,
+    author_name: String,
+    post_author: String,
+}
+
+#[derive(Template)]
+#[template(path = "index.html")]
+struct IndexPageTemplate {
+    threads: Vec<IndexThread>,
+}
+
+impl Handler<IndexPage> for Renderer {
+    type Result = Result<String>;
+
+    fn handle(&mut self, msg: IndexPage, _: &mut Self::Context) -> Self::Result {
+        let threads: Vec<IndexThread> = msg.threads
+            .into_iter()
+            .map(|thread| IndexThread {
+                id: thread.thread_id,
+                title: thread.title, // escape_html(&thread.title),
+                sticky: thread.sticky,
+                closed: thread.closed,
+                posted: FormattedDate(thread.posted),
+                author_name: thread.thread_author,
+                post_author: thread.post_author,
+            })
+            .collect();
+
+        let tpl = IndexPageTemplate {
+            threads
+        };
+
+        tpl.render().map_err(|e| e.into())
+    }
+}
+
+/// Message used to render a thread.
+pub struct ThreadPage {
+    pub current_user: i32,
+    pub thread: Thread,
+    pub posts: Vec<SimplePost>,
+}
+message!(ThreadPage, Result<String>);
+
+// "Renderable" structures with data transformations applied.
+#[derive(Debug)]
+struct RenderablePost {
+    id: i32,
+    body: String,
+    posted: FormattedDate,
+    author_name: String,
+    author_gravatar: String,
+    editable: bool,
+}
+
+/// This structure represents the transformed thread data with
+/// Markdown rendering and other changes applied.
+#[derive(Template)]
+#[template(path = "thread.html")]
+struct RenderableThreadPage {
+    id: i32,
+    title: String,
+    closed: bool,
+    posts: Vec<RenderablePost>,
+}
+
+/// Helper function for computing Gravatar links.
+fn md5_hex(input: &[u8]) -> String {
+    format!("{:x}", md5::compute(input))
+}
+
+fn prepare_thread(comrak: &ComrakOptions, page: ThreadPage) -> RenderableThreadPage {
+    let user = page.current_user;
+
+    let posts = page.posts.into_iter().map(|post| {
+        let editable = user != 1 && post.user_id == user;
+
+        RenderablePost {
+            id: post.id,
+            body: markdown_to_html(&post.body, comrak),
+            posted: FormattedDate(post.posted),
+            author_name: post.author_name.clone(),
+            author_gravatar: md5_hex(post.author_email.as_bytes()),
+            editable,
+        }
+    }).collect();
+
+    RenderableThreadPage {
+        posts,
+        closed: page.thread.closed,
+        id: page.thread.id,
+        title: page.thread.title,
+    }
+}
+
+impl Handler<ThreadPage> for Renderer {
+    type Result = Result<String>;
+
+    fn handle(&mut self, msg: ThreadPage, _: &mut Self::Context) -> Self::Result {
+        let renderable = prepare_thread(&self.comrak, msg);
+        renderable.render().map_err(|e| e.into())
+    }
+}
+
+/// The different types of editing modes supported by the editing
+/// template:
+#[derive(Debug, PartialEq)]
+pub enum EditingMode {
+    NewThread,
+    PostReply,
+    EditPost,
+}
+
+impl Default for EditingMode {
+    fn default() -> EditingMode { EditingMode::NewThread }
+}
+
+/// This is the template used for rendering the new thread, edit post
+/// and reply to thread forms.
+#[derive(Template, Default)]
+#[template(path = "post.html")]
+pub struct FormTemplate {
+    /// Which editing mode is to be used by the template?
+    pub mode: EditingMode,
+
+    /// Potential alerts to display to the user (e.g. input validation
+    /// results)
+    pub alerts: Vec<&'static str>,
+
+    /// Either the title to be used in the subject field or the title
+    /// of the thread the user is responding to.
+    pub title: Option<String>,
+
+    /// Body of the post being edited, if present.
+    pub post: Option<String>,
+
+    /// ID of the thread being replied to or the post being edited.
+    pub id: Option<i32>,
+}
+
+/// Message used to render new thread page.
+///
+/// It can optionally contain a vector of warnings to display to the
+/// user in alert boxes, such as input validation errors.
+#[derive(Default)]
+pub struct NewThreadPage {
+    pub alerts: Vec<&'static str>,
+    pub title: Option<String>,
+    pub post: Option<String>,
+}
+message!(NewThreadPage, Result<String>);
+
+impl Handler<NewThreadPage> for Renderer {
+    type Result = Result<String>;
+
+    fn handle(&mut self, msg: NewThreadPage, _: &mut Self::Context) -> Self::Result {
+        let ctx = FormTemplate {
+            alerts: msg.alerts,
+            title: msg.title,
+            post: msg.post,
+            ..Default::default()
+        };
+        ctx.render().map_err(|e| e.into())
+    }
+}
+
+/// Message used to render post editing page.
+pub struct EditPostPage {
+    pub id: i32,
+    pub post: String,
+}
+message!(EditPostPage, Result<String>);
+
+impl Handler<EditPostPage> for Renderer {
+    type Result = Result<String>;
+
+    fn handle(&mut self, msg: EditPostPage, _: &mut Self::Context) -> Self::Result {
+        let ctx = FormTemplate {
+            mode: EditingMode::EditPost,
+            id: Some(msg.id),
+            post: Some(msg.post),
+            ..Default::default()
+        };
+
+        ctx.render().map_err(|e| e.into())
+    }
+}
+
+/// Message used to render search results
+#[derive(Template)]
+#[template(path = "search.html")]
+pub struct SearchResultPage {
+    pub query: String,
+    pub results: Vec<SearchResult>,
+}
+message!(SearchResultPage, Result<String>);
+
+impl Handler<SearchResultPage> for Renderer {
+    type Result = Result<String>;
+
+    fn handle(&mut self, msg: SearchResultPage, _: &mut Self::Context) -> Self::Result {
+        msg.render().map_err(|e| e.into())
+    }
+}