markplus_render 0.1.0

HTML and PDF renderer for the MarkPlus ecosystem (AST → HTML / Typst → PDF)
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249

//    Copyright [2026] [Purnendu Kumar]
//
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0

//! `wasm-bindgen` exports for `markplus_render`.
//!
//! Enabled only when compiled with `--features wasm`.
//!
//! ## JavaScript usage
//!
//! ```js
//! import init, { MarkplusRenderWasm } from "./markplus_render.js";
//!
//! await init();
//!
//! const templates = {
//!   "default/article.html.tera": htmlTemplateStr,
//!   "default/article.typ.tera":  typstTemplateStr,
//! };
//! const renderer = new MarkplusRenderWasm(templates);
//!
//! const html = renderer.render_html(assetJson, "default/article.html.tera");
//! const typ  = renderer.render_typst(assetJson, "default/article.typ.tera");
//! const pdf  = renderer.compile_pdf_from_asset(assetJson, "default/article.typ.tera");
//! ```

use wasm_bindgen::prelude::*;
use serde_json::Value;

use crate::engine::RenderEngine;
use markplus_core::json::SiteAsset;

/// Main wasm entry point for `markplus_render`.
#[wasm_bindgen]
pub struct MarkplusRenderWasm {
    engine: RenderEngine,
}

#[wasm_bindgen]
impl MarkplusRenderWasm {
    /// Construct from a JS object mapping template names to template source strings.
    ///
    /// ```js
    /// const r = new MarkplusRenderWasm({ "default/article.html.tera": "<html>..." });
    /// ```
    #[wasm_bindgen(constructor)]
    pub fn new(templates_js: JsValue) -> Result<MarkplusRenderWasm, JsValue> {
        console_error_panic_hook::set_once();
        let templates: std::collections::HashMap<String, String> =
            serde_wasm_bindgen::from_value(templates_js)?;
        let engine = RenderEngine::builder()
            .build_with_templates(templates)
            .map_err(|e| JsValue::from_str(&e.to_string()))?;
        Ok(MarkplusRenderWasm { engine })
    }

    /// Render HTML from a [`SiteAsset`] JSON object.
    ///
    /// `asset_json` — the full JSON object produced by `markplus_core::parse_document`
    /// (or the JS equivalent from `parse_document_to_json`).
    pub fn render_html(&self, asset_json: JsValue, template_name: &str) -> Result<String, JsValue> {
        let asset = asset_from_js(asset_json)?;
        self.engine
            .render_html(&asset, template_name)
            .map_err(|e| JsValue::from_str(&e.to_string()))
    }

    /// Render a Typst source string from a [`SiteAsset`] JSON object.
    pub fn render_typst(&self, asset_json: JsValue, template_name: &str) -> Result<String, JsValue> {
        let asset = asset_from_js(asset_json)?;
        self.engine
            .render_typst_string(&asset, template_name)
            .map_err(|e| JsValue::from_str(&e.to_string()))
    }

    /// Compile a Typst source string directly into PDF bytes.
    pub fn compile_pdf(&self, typst_src: &str) -> Result<Vec<u8>, JsValue> {
        self.engine
            .compile_pdf(typst_src)
            .map_err(|e| JsValue::from_str(&e.to_string()))
    }

    /// Render Typst source from a [`SiteAsset`] and immediately compile to PDF bytes.
    ///
    /// Combines `render_typst` + `compile_pdf` in one call.
    pub fn compile_pdf_from_asset(
        &self,
        asset_json: JsValue,
        template_name: &str,
    ) -> Result<Vec<u8>, JsValue> {
        let asset = asset_from_js(asset_json)?;
        let typ_src = self.engine
            .render_typst_string(&asset, template_name)
            .map_err(|e| JsValue::from_str(&e.to_string()))?;
        self.engine
            .compile_pdf(&typ_src)
            .map_err(|e| JsValue::from_str(&e.to_string()))
    }

    /// Lightweight HTML rendering without Tera — converts AST nodes to HTML inline.
    ///
    /// Useful when no template is loaded or for fast previews. Does not require
    /// a template to be registered.
    pub fn render_html_simple(&self, asset_json: JsValue) -> Result<String, JsValue> {
        let asset = asset_from_js(asset_json)?;
        Ok(render_ast_simple(&asset))
    }
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

fn asset_from_js(js: JsValue) -> Result<SiteAsset, JsValue> {
    let val: Value = serde_wasm_bindgen::from_value(js)?;
    serde_json::from_value(val).map_err(|e| JsValue::from_str(&e.to_string()))
}

/// Simple non-Tera AST → HTML renderer for lightweight wasm previews.
fn render_ast_simple(asset: &SiteAsset) -> String {
    let mut out = String::new();
    for node in &asset.ast {
        render_node_simple(node, &mut out);
    }
    out
}

fn render_node_simple(node: &Value, out: &mut String) {
    match node["t"].as_str().unwrap_or("") {
        "heading" => {
            let level = node["level"].as_u64().unwrap_or(1).min(6);
            let text = collect_inline_text(node.get("children").and_then(Value::as_array).unwrap_or(&[]));
            out.push_str(&format!("<h{level}>{text}</h{level}>"));
        }
        "paragraph" => {
            let text = collect_inline_text(node.get("children").and_then(Value::as_array).unwrap_or(&[]));
            out.push_str(&format!("<p>{text}</p>"));
        }
        "fenced" => {
            let name = node["name"].as_str().unwrap_or("");
            let raw = escape_html(node["raw"].as_str().unwrap_or(""));
            out.push_str(&format!("<pre><code class=\"language-{name}\">{raw}</code></pre>"));
        }
        "math_block" => {
            let src = escape_html(node["src"].as_str().unwrap_or(""));
            out.push_str(&format!("<p class=\"math-block\">{src}</p>"));
        }
        "blockquote" => {
            out.push_str("<blockquote>");
            if let Some(ch) = node.get("children").and_then(Value::as_array) {
                for child in ch { render_node_simple(child, out); }
            }
            out.push_str("</blockquote>");
        }
        "list" => {
            let ordered = node["ordered"].as_bool().unwrap_or(false);
            let tag = if ordered { "ol" } else { "ul" };
            out.push_str(&format!("<{tag}>"));
            if let Some(items) = node.get("items").and_then(Value::as_array) {
                for item in items {
                    out.push_str("<li>");
                    if let Some(ch) = item.get("children").and_then(Value::as_array) {
                        for c in ch { render_node_simple(c, out); }
                    }
                    out.push_str("</li>");
                }
            }
            out.push_str(&format!("</{tag}>"));
        }
        "table" => {
            out.push_str("<table>");
            if let Some(head) = node.get("headers").and_then(Value::as_array) {
                out.push_str("<thead><tr>");
                for cell in head {
                    let text = collect_inline_text(cell.get("children").and_then(Value::as_array).unwrap_or(&[]));
                    out.push_str(&format!("<th>{text}</th>"));
                }
                out.push_str("</tr></thead>");
            }
            if let Some(rows) = node.get("rows").and_then(Value::as_array) {
                out.push_str("<tbody>");
                for row in rows {
                    out.push_str("<tr>");
                    if let Some(cells) = row.as_array() {
                        for cell in cells {
                            let text = collect_inline_text(cell.get("children").and_then(Value::as_array).unwrap_or(&[]));
                            out.push_str(&format!("<td>{text}</td>"));
                        }
                    }
                    out.push_str("</tr>");
                }
                out.push_str("</tbody>");
            }
            out.push_str("</table>");
        }
        "hr" => out.push_str("<hr>"),
        _ => {}
    }
}

fn collect_inline_text(children: &[Value]) -> String {
    let mut out = String::new();
    for child in children {
        match child["t"].as_str().unwrap_or("") {
            "text"        => out.push_str(&escape_html(child["text"].as_str().unwrap_or(""))),
            "strong"      => {
                let inner = collect_inline_text(child.get("children").and_then(Value::as_array).unwrap_or(&[]));
                out.push_str(&format!("<strong>{inner}</strong>"));
            }
            "em"          => {
                let inner = collect_inline_text(child.get("children").and_then(Value::as_array).unwrap_or(&[]));
                out.push_str(&format!("<em>{inner}</em>"));
            }
            "code"        => out.push_str(&format!("<code>{}</code>", escape_html(child["text"].as_str().unwrap_or("")))),
            "link"        => {
                let href = child["href"].as_str().unwrap_or("#");
                let inner = collect_inline_text(child.get("children").and_then(Value::as_array).unwrap_or(&[]));
                out.push_str(&format!("<a href=\"{href}\">{inner}</a>"));
            }
            "image"       => {
                let src = child["src"].as_str().unwrap_or("");
                let alt = child["alt"].as_str().unwrap_or("");
                out.push_str(&format!("<img src=\"{src}\" alt=\"{alt}\">"));
            }
            "math_inline" => out.push_str(&format!("<span class=\"math-inline\">{}</span>", escape_html(child["src"].as_str().unwrap_or("")))),
            "hard_break"  => out.push_str("<br>"),
            "soft_break"  => out.push(' '),
            "del"         => {
                let inner = collect_inline_text(child.get("children").and_then(Value::as_array).unwrap_or(&[]));
                out.push_str(&format!("<del>{inner}</del>"));
            }
            _ => {
                if let Some(t) = child["text"].as_str() { out.push_str(&escape_html(t)); }
            }
        }
    }
    out
}

fn escape_html(s: &str) -> String {
    s.replace('&', "&amp;")
     .replace('<', "&lt;")
     .replace('>', "&gt;")
     .replace('"', "&quot;")
}