use super::backends::{custom, plain, syntect};
use crate::file_info::{CodeBackend, PreviewSpec};
use ratatui::text::Line;
pub(crate) fn render_code_preview<F>(
spec: PreviewSpec,
text: &str,
line_numbers: bool,
line_limit: usize,
canceled: &F,
) -> Vec<Line<'static>>
where
F: Fn() -> bool,
{
match spec.code_backend {
CodeBackend::Plain => {
plain::render_plain_code_preview(text, line_numbers, line_limit, canceled)
}
CodeBackend::Custom(kind) => {
custom::render_custom_code_preview(kind, text, line_numbers, line_limit, canceled)
}
CodeBackend::Syntect => {
render_syntect_with_fallback(spec, text, line_numbers, line_limit, canceled)
}
}
}
fn render_syntect_with_fallback<F>(
spec: PreviewSpec,
text: &str,
line_numbers: bool,
line_limit: usize,
canceled: &F,
) -> Vec<Line<'static>>
where
F: Fn() -> bool,
{
let Some(code_syntax) = spec.code_syntax else {
return plain::render_plain_code_preview(text, line_numbers, line_limit, canceled);
};
if !syntect::is_enabled(code_syntax) {
return plain::render_plain_code_preview(text, line_numbers, line_limit, canceled);
}
syntect::render_syntect_code_preview(code_syntax, text, line_numbers, line_limit, canceled)
.unwrap_or_else(|_| {
plain::render_plain_code_preview(text, line_numbers, line_limit, canceled)
})
}
#[cfg(test)]
mod tests {
use super::*;
use crate::file_info::{CodeBackend, CustomCodeKind, PreviewKind, PreviewSpec};
use ratatui::text::Line;
use std::cell::Cell;
fn line_text(line: &Line<'_>) -> String {
line.spans
.iter()
.map(|span| span.content.as_ref())
.collect::<String>()
}
fn line_texts(lines: &[Line<'_>]) -> Vec<String> {
lines.iter().map(line_text).collect()
}
#[test]
fn enabled_javascript_preview_specs_use_syntect() {
let preview = render_code_preview(
PreviewSpec::code("javascript", CodeBackend::Syntect, None),
"const value = 1;\n",
true,
20,
&|| false,
);
let expected = syntect::render_syntect_code_preview(
"javascript",
"const value = 1;\n",
true,
20,
&|| false,
)
.expect("javascript should render through syntect");
assert_eq!(preview, expected);
}
#[test]
fn enabled_typescript_family_uses_syntect_aliases() {
let preview = render_code_preview(
PreviewSpec::code("tsx", CodeBackend::Syntect, None),
"export function App() { return <div>Hello</div>; }\n",
true,
20,
&|| false,
);
let expected = syntect::render_syntect_code_preview(
"tsx",
"export function App() { return <div>Hello</div>; }\n",
true,
20,
&|| false,
)
.expect("tsx should render through syntect");
assert_eq!(preview, expected);
}
#[test]
fn enabled_generic_source_preview_specs_use_syntect() {
for (code_syntax, text) in [
("rust", "fn main() {}\n"),
("go", "package main\nfunc main() {}\n"),
("c", "#include <stdio.h>\nint main(void) { return 0; }\n"),
(
"cpp",
"#include <iostream>\nint main() { std::cout << \"hi\"; }\n",
),
(
"cs",
"public class Greeter { public string Greet(string name) => name; }\n",
),
(
"java",
"class Main {\n public static void main(String[] args) {}\n}\n",
),
(
"dart",
"class Greeter { String greet(String name) => name; }\n",
),
(
"zig",
"const std = @import(\"std\");\npub fn main() void {}\n",
),
("php", "<?php echo \"hi\";\n"),
(
"swift",
"struct Greeter { func greet(name: String) -> String { name } }\n",
),
(
"kotlin",
"class Greeter { fun greet(name: String): String = name }\n",
),
(
"elixir",
"defmodule Greeter do\n def greet(name), do: \"hi #{name}\"\nend\n",
),
(
"powershell",
"function Invoke-Greeting([string]$Name) { Write-Host \"Hello $Name\" }\n",
),
("python", "class Greeter:\n pass\n"),
("ruby", "class Greeter\nend\n"),
("lua", "local name = \"elio\"\n"),
("make", "build:\n\tcc main.c\n"),
("bash", "export PATH=\"$HOME/bin:$PATH\"\n"),
("html", "<div class=\"app\">elio</div>\n"),
("xml", "<layout id=\"main\" />\n"),
("css", ".app { color: #fff; }\n"),
("scss", "$fg: #fff;\n.button { color: $fg; }\n"),
("sass", "$fg: #fff\n.button\n color: $fg\n"),
("less", "@fg: #fff;\n.button { color: @fg; }\n"),
(
"nix",
"{ description = \"elio\"; outputs = { self }: { packages.default = self; }; }\n",
),
(
"cmake",
"cmake_minimum_required(VERSION 3.28)\nproject(elio)\n",
),
(
"qml",
"import QtQuick\nItem {\n property bool active: true\n onActiveChanged: console.log(\"changed\")\n}\n",
),
] {
let preview = render_code_preview(
PreviewSpec::code(code_syntax, CodeBackend::Syntect, None),
text,
true,
20,
&|| false,
);
let expected =
syntect::render_syntect_code_preview(code_syntax, text, true, 20, &|| false)
.expect("{code_syntax} should render through syntect");
assert_eq!(preview, expected, "expected {code_syntax} to use syntect");
}
}
#[test]
fn syntect_renderer_returns_error_for_unknown_syntax() {
assert!(
syntect::render_syntect_code_preview(
"totally-unknown-syntax",
"hello\n",
true,
20,
&|| false,
)
.is_err()
);
}
#[test]
fn unsupported_syntect_specs_still_fall_back_to_plain_rendering() {
let preview = render_code_preview(
PreviewSpec::code("totally-unknown-syntax", CodeBackend::Syntect, None),
"still plain\n",
true,
20,
&|| false,
);
let expected = plain::render_plain_code_preview("still plain\n", true, 20, &|| false);
assert_eq!(preview, expected);
}
#[test]
fn custom_preview_specs_use_custom_backend() {
let preview = render_code_preview(
PreviewSpec::code("jsonc", CodeBackend::Custom(CustomCodeKind::Jsonc), None),
"{\n // comment\n}\n",
true,
20,
&|| false,
);
let expected = crate::preview::code::custom::render_custom_code_preview(
CustomCodeKind::Jsonc,
"{\n // comment\n}\n",
true,
20,
&|| false,
);
assert_eq!(preview, expected);
}
#[test]
fn unknown_syntect_preview_specs_fall_back_to_plain_text() {
let text = "first()\nsecond()\n";
let preview = render_code_preview(
PreviewSpec::code("totally-unknown-syntax", CodeBackend::Syntect, None),
text,
true,
20,
&|| false,
);
let expected = plain::render_plain_code_preview(text, true, 20, &|| false);
assert_eq!(preview, expected);
assert_eq!(
line_texts(&preview),
vec![" 1 first()".to_string(), " 2 second()".to_string()]
);
}
#[test]
fn missing_syntect_code_syntax_falls_back_to_plain_text() {
let text = "plain text\nstill visible\n";
let preview = render_code_preview(
PreviewSpec {
kind: PreviewKind::Source,
language_hint: Some("unknown"),
code_syntax: None,
code_backend: CodeBackend::Syntect,
structured_format: None,
document_format: None,
},
text,
true,
20,
&|| false,
);
let expected = plain::render_plain_code_preview(text, true, 20, &|| false);
assert_eq!(preview, expected);
}
#[test]
fn golden_code_previews_keep_expected_text_layout_across_backends() {
let syntect_preview = render_code_preview(
PreviewSpec::code("rust", CodeBackend::Syntect, None),
"fn main() {\n println!(\"hi\");\n}\n",
true,
20,
&|| false,
);
assert_eq!(
line_texts(&syntect_preview),
vec![
" 1 fn main() {".to_string(),
" 2 println!(\"hi\");".to_string(),
" 3 }".to_string(),
]
);
let custom_preview = render_code_preview(
PreviewSpec::code("jsonc", CodeBackend::Custom(CustomCodeKind::Jsonc), None),
"{\n // keep me\n \"name\": \"elio\"\n}\n",
true,
20,
&|| false,
);
assert_eq!(
line_texts(&custom_preview),
vec![
" 1 {".to_string(),
" 2 // keep me".to_string(),
" 3 \"name\": \"elio\"".to_string(),
" 4 }".to_string(),
]
);
}
#[test]
fn renderer_respects_line_limit_before_backend_dispatch() {
let syntect_preview = render_code_preview(
PreviewSpec::code("rust", CodeBackend::Syntect, None),
"fn one() {}\nfn two() {}\nfn three() {}\n",
true,
2,
&|| false,
);
assert_eq!(
line_texts(&syntect_preview),
vec![" 1 fn one() {}".to_string(), " 2 fn two() {}".to_string()]
);
let custom_preview = render_code_preview(
PreviewSpec::code("jsonc", CodeBackend::Custom(CustomCodeKind::Jsonc), None),
"{\n // first\n // second\n}\n",
true,
2,
&|| false,
);
assert_eq!(
line_texts(&custom_preview),
vec![" 1 {".to_string(), " 2 // first".to_string()]
);
}
#[test]
fn renderer_stops_on_cancellation_without_empty_placeholder() {
let calls = Cell::new(0usize);
let preview = render_code_preview(
PreviewSpec::code("rust", CodeBackend::Syntect, None),
"fn first() {}\nfn second() {}\nfn third() {}\n",
true,
20,
&|| {
let current = calls.get();
calls.set(current + 1);
current >= 1
},
);
assert_eq!(line_texts(&preview), vec![" 1 fn first() {}".to_string()]);
let canceled_immediately = render_code_preview(
PreviewSpec::code("rust", CodeBackend::Syntect, None),
"fn hidden() {}\n",
true,
20,
&|| true,
);
assert!(canceled_immediately.is_empty());
}
}