+use crate::compositor::{self, Component, RenderContext};

+

+#[cfg(feature = "term")]

+use tui::text::{Span, Spans, Text};

+

+use std::sync::Arc;

+

+use pulldown_cmark::{CodeBlockKind, Event, HeadingLevel, Options, Parser, Tag};

+

+use crate::{

+ graphics::{Margin, Rect, Style},

+ Theme,

+};

+use helix_core::{

+ syntax::{self, HighlightEvent, Syntax},

+ Rope,

+};

+

+#[cfg(feature = "term")]

+fn styled_multiline_text<'a>(text: String, style: Style) -> Text<'a> {

+ let spans: Vec<_> = text

+ .lines()

+ .map(|line| Span::styled(line.to_string(), style))

+ .map(Spans::from)

+ .collect();

+ Text::from(spans)

+}

+

+#[cfg(feature = "term")]

+pub fn highlighted_code_block<'a>(

+ text: String,

+ language: &str,

+ theme: Option<&Theme>,

+ config_loader: Arc<syntax::Loader>,

+ additional_highlight_spans: Option<Vec<(usize, std::ops::Range<usize>)>>,

+) -> Text<'a> {

+ let mut spans = Vec::new();

+ let mut lines = Vec::new();

+

+ let get_theme = |key: &str| -> Style { theme.map(|t| t.get(key)).unwrap_or_default() };

+ let text_style = get_theme(Markdown::TEXT_STYLE);

+ let code_style = get_theme(Markdown::BLOCK_STYLE);

+

+ let theme = match theme {

+ Some(t) => t,

+ None => return styled_multiline_text(text, code_style),

+ };

+

+ let rope = Rope::from(text.as_ref());

+ let syntax = config_loader

+ .language_configuration_for_injection_string(language)

+ .and_then(|config| config.highlight_config(theme.scopes()))

+ .map(|config| Syntax::new(&rope, config, Arc::clone(&config_loader)));

+

+ let syntax = match syntax {

+ Some(s) => s,

+ None => return styled_multiline_text(text, code_style),

+ };

+

+ let highlight_iter = syntax

+ .highlight_iter(rope.slice(..), None, None)

+ .map(|e| e.unwrap());

+ let highlight_iter: Box<dyn Iterator<Item = HighlightEvent>> =

+ if let Some(spans) = additional_highlight_spans {

+ Box::new(helix_core::syntax::merge(highlight_iter, spans))

+ } else {

+ Box::new(highlight_iter)

+ };

+

+ let mut highlights = Vec::new();

+ for event in highlight_iter {

+ match event {

+ HighlightEvent::HighlightStart(span) => {

+ highlights.push(span);

+ }

+ HighlightEvent::HighlightEnd => {

+ highlights.pop();

+ }

+ HighlightEvent::Source { start, end } => {

+ let style = highlights

+ .iter()

+ .fold(text_style, |acc, span| acc.patch(theme.highlight(span.0)));

+

+ let mut slice = &text[start..end];

+ // TODO: do we need to handle all unicode line endings

+ // here, or is just '\n' okay?

+ while let Some(end) = slice.find('\n') {

+ // emit span up to newline

+ let text = &slice[..end];

+ let text = text.replace('\t', " "); // replace tabs

+ let span = Span::styled(text, style);

+ spans.push(span);

+

+ // truncate slice to after newline

+ slice = &slice[end + 1..];

+

+ // make a new line

+ let spans = std::mem::take(&mut spans);

+ lines.push(Spans::from(spans));

+ }

+

+ // if there's anything left, emit it too

+ if !slice.is_empty() {

+ let span = Span::styled(slice.replace('\t', " "), style);

+ spans.push(span);

+ }

+ }

+ }

+ }

+

+ if !spans.is_empty() {

+ let spans = std::mem::take(&mut spans);

+ lines.push(Spans::from(spans));

+ }

+

+ Text::from(lines)

+}

+

+pub struct Markdown {

+ contents: String,

+

+ config_loader: Arc<syntax::Loader>,

+}

+

+// TODO: pre-render and self reference via Pin

+// better yet, just use Tendril + subtendril for references

+

+impl Markdown {

+ const TEXT_STYLE: &'static str = "ui.text";

+ const BLOCK_STYLE: &'static str = "markup.raw.inline";

+ const HEADING_STYLES: [&'static str; 6] = [

+ "markup.heading.1",

+ "markup.heading.2",

+ "markup.heading.3",

+ "markup.heading.4",

+ "markup.heading.5",

+ "markup.heading.6",

+ ];

+

+ pub fn new(contents: String, config_loader: Arc<syntax::Loader>) -> Self {

+ Self {

+ contents,

+ config_loader,

+ }

+ }

+

+ #[cfg(not(feature = "term"))]

+ fn parse(&self, theme: Option<&Theme>) -> () {}

+

+ #[cfg(feature = "term")]

+ fn parse(&self, theme: Option<&Theme>) -> tui::text::Text<'_> {

+ // // also 2021-03-04T16:33:58.553 helix_lsp::transport [INFO] <- {"contents":{"kind":"markdown","value":"\n```rust\ncore::num\n```\n\n```rust\npub const fn saturating_sub(self, rhs:Self) ->Self\n```\n\n---\n\n```rust\n```"},"range":{"end":{"character":61,"line":101},"start":{"character":47,"line":101}}}

+ // let text = "\n```rust\ncore::iter::traits::iterator::Iterator\n```\n\n```rust\nfn collect<B: FromIterator<Self::Item>>(self) -> B\nwhere\n Self: Sized,\n```\n\n---\n\nTransforms an iterator into a collection.\n\n`collect()` can take anything iterable, and turn it into a relevant\ncollection. This is one of the more powerful methods in the standard\nlibrary, used in a variety of contexts.\n\nThe most basic pattern in which `collect()` is used is to turn one\ncollection into another. You take a collection, call [`iter`](https://doc.rust-lang.org/nightly/core/iter/traits/iterator/trait.Iterator.html) on it,\ndo a bunch of transformations, and then `collect()` at the end.\n\n`collect()` can also create instances of types that are not typical\ncollections. For example, a [`String`](https://doc.rust-lang.org/nightly/core/iter/std/string/struct.String.html) can be built from [`char`](type@char)s,\nand an iterator of [`Result<T, E>`](https://doc.rust-lang.org/nightly/core/result/enum.Result.html) items can be collected\ninto `Result<Collection<T>, E>`. See the examples below for more.\n\nBecause `collect()` is so general, it can cause problems with type\ninference. As such, `collect()` is one of the few times you'll see\nthe syntax affectionately known as the 'turbofish': `::<>`. This\nhelps the inference algorithm understand specifically which collection\nyou're trying to collect into.\n\n# Examples\n\nBasic usage:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled: Vec<i32> = a.iter()\n .map(|&x| x * 2)\n .collect();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nNote that we needed the `: Vec<i32>` on the left-hand side. This is because\nwe could collect into, for example, a [`VecDeque<T>`](https://doc.rust-lang.org/nightly/core/iter/std/collections/struct.VecDeque.html) instead:\n\n```rust\nuse std::collections::VecDeque;\n\nlet a = [1, 2, 3];\n\nlet doubled: VecDeque<i32> = a.iter().map(|&x| x * 2).collect();\n\nassert_eq!(2, doubled[0]);\nassert_eq!(4, doubled[1]);\nassert_eq!(6, doubled[2]);\n```\n\nUsing the 'turbofish' instead of annotating `doubled`:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled = a.iter().map(|x| x * 2).collect::<Vec<i32>>();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nBecause `collect()` only cares about what you're collecting into, you can\nstill use a partial type hint, `_`, with the turbofish:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled = a.iter().map(|x| x * 2).collect::<Vec<_>>();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nUsing `collect()` to make a [`String`](https://doc.rust-lang.org/nightly/core/iter/std/string/struct.String.html):\n\n```rust\nlet chars = ['g', 'd', 'k', 'k', 'n'];\n\nlet hello: String = chars.iter()\n .map(|&x| x as u8)\n .map(|x| (x + 1) as char)\n .collect();\n\nassert_eq!(\"hello\", hello);\n```\n\nIf you have a list of [`Result<T, E>`](https://doc.rust-lang.org/nightly/core/result/enum.Result.html)s, you can use `collect()` to\nsee if any of them failed:\n\n```rust\nlet results = [Ok(1), Err(\"nope\"), Ok(3), Err(\"bad\")];\n\nlet result: Result<Vec<_>, &str> = results.iter().cloned().collect();\n\n// gives us the first error\nassert_eq!(Err(\"nope\"), result);\n\nlet results = [Ok(1), Ok(3)];\n\nlet result: Result<Vec<_>, &str> = results.iter().cloned().collect();\n\n// gives us the list of answers\nassert_eq!(Ok(vec![1, 3]), result);\n```";

+

+ let mut options = Options::empty();

+ options.insert(Options::ENABLE_STRIKETHROUGH);

+ let parser = Parser::new_ext(&self.contents, options);

+

+ // TODO: if possible, render links as terminal hyperlinks: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

+ let mut tags = Vec::new();

+ let mut spans = Vec::new();

+ let mut lines = Vec::new();

+

+ let get_theme = |key: &str| -> Style { theme.map(|t| t.get(key)).unwrap_or_default() };

+ let text_style = get_theme(Self::TEXT_STYLE);

+ let code_style = get_theme(Self::BLOCK_STYLE);

+ let heading_styles: Vec<Style> = Self::HEADING_STYLES

+ .iter()

+ .map(|key| get_theme(key))

+ .collect();

+

+ let mut list_stack = Vec::new();

+

+ for event in parser {

+ match event {

+ Event::Start(Tag::List(list)) => list_stack.push(list),

+ Event::End(Tag::List(_)) => {

+ list_stack.pop();

+ }

+ Event::Start(Tag::Item) => {

+ tags.push(Tag::Item);

+ spans.push(Span::from("- "));

+ }

+ Event::Start(tag) => {

+ tags.push(tag);

+ }

+ Event::End(tag) => {

+ tags.pop();

+ match tag {

+ Tag::Heading(_, _, _)

+ | Tag::Paragraph

+ | Tag::CodeBlock(CodeBlockKind::Fenced(_))

+ | Tag::Item => {

+ // whenever code block or paragraph closes, new line

+ let spans = std::mem::take(&mut spans);

+ if !spans.is_empty() {

+ lines.push(Spans::from(spans));

+ }

+ lines.push(Spans::default());

+ }

+ _ => (),

+ }

+ }

+ Event::Text(text) => {

+ // TODO: temp workaround

+ if let Some(Tag::CodeBlock(CodeBlockKind::Fenced(language))) = tags.last() {

+ let tui_text = highlighted_code_block(

+ text.to_string(),

+ language,

+ theme,

+ Arc::clone(&self.config_loader),

+ None,

+ );

+ lines.extend(tui_text.lines.into_iter());

+ } else {

+ let style = if let Some(Tag::Heading(level, ..)) = tags.last() {

+ match level {

+ HeadingLevel::H1 => heading_styles[0],

+ HeadingLevel::H2 => heading_styles[1],

+ HeadingLevel::H3 => heading_styles[2],

+ HeadingLevel::H4 => heading_styles[3],

+ HeadingLevel::H5 => heading_styles[4],

+ HeadingLevel::H6 => heading_styles[5],

+ }

+ } else {

+ text_style

+ };

+ spans.push(Span::styled(text, style));

+ }

+ }

+ Event::Code(text) | Event::Html(text) => {

+ spans.push(Span::styled(text, code_style));

+ }

+ Event::SoftBreak | Event::HardBreak => {

+ // let spans = std::mem::replace(&mut spans, Vec::new());

+ // lines.push(Spans::from(spans));

+ spans.push(Span::raw(" "));

+ }

+ Event::Rule => {

+ lines.push(Spans::from(Span::styled("---", code_style)));

+ lines.push(Spans::default());

+ }

+ // TaskListMarker(bool) true if checked

+ _ => {

+ log::warn!("unhandled markdown event {:?}", event);

+ }

+ }

+ // build up a vec of Paragraph tui widgets

+ }

+

+ if !spans.is_empty() {

+ lines.push(Spans::from(spans));

+ }

+

+ // if last line is empty, remove it

+ if let Some(line) = lines.last() {

+ if line.0.is_empty() {

+ lines.pop();

+ }

+ }

+

+ Text::from(lines)

+ }

+}

+

+#[cfg(feature = "term")]

+impl compositor::term::Render for Markdown {

+ fn render(&mut self, area: Rect, cx: &mut RenderContext<'_>) {

+ use tui::widgets::{Paragraph, Widget, Wrap};

+

+ let text = self.parse(Some(&cx.editor.theme));

+

+ let par = Paragraph::new(text)

+ .wrap(Wrap { trim: false })

+ .scroll((cx.scroll.unwrap_or_default() as u16, 0));

+

+ let margin = Margin {

+ vertical: 1,

+ horizontal: 1,

+ };

+ par.render(area.inner(&margin), cx.surface);

+ }

+}

+

+#[cfg(feature = "ui")]

+impl compositor::ui::Render for Markdown {}

+

+impl Component for Markdown {

+ #[cfg(not(feature = "term"))]

+ fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {

+ None

+ }

+

+ #[cfg(feature = "term")]

+ fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {

+ let padding = 2;

+ if padding >= viewport.1 || padding >= viewport.0 {

+ return None;

+ }

+ let contents = self.parse(None);

+

+ // TODO: account for tab width

+ let max_text_width = (viewport.0 - padding).min(120);

+ let (width, height) = crate::ui::text::required_size(&contents, max_text_width);

+

+ Some((width + padding, height + padding))

+ }

+}