init

src/lib.rs

@@ -0,0 +1,125 @@
+use epub::doc::{EpubDoc, NavPoint};
+use html2md::parse_html;
+use std::collections::HashMap;
+use std::fs;
+use std::io::{Read, Seek};
+use std::path::{Path, PathBuf};
+
+pub fn convert_epub_to_mdbook(
+    epub_path: impl AsRef<Path>,
+    output_dir: Option<impl AsRef<Path>>,
+) -> anyhow::Result<()> {
+    let book_name = epub_path.as_ref().with_extension("");
+    let book_name = book_name.file_name().unwrap().to_str().unwrap();
+    let pwd = PathBuf::from(".");
+    let output_dir = match output_dir {
+        Some(output_dir) => output_dir.as_ref().join(book_name),
+        None => pwd.join(book_name),
+    };
+
+    fs::create_dir_all(output_dir.join("src"))?;
+
+    let mut doc = EpubDoc::new(&epub_path)?;
+    let title = if let Some(title) = doc.metadata.get("title") {
+        title.first().unwrap_or(&book_name.to_string()).clone()
+    } else {
+        book_name.to_string()
+    };
+    let creator = doc.metadata.get("creator").and_then(|v| v.first().cloned());
+
+    let (toc, html_files) = toc_to_md(&doc, &title)?;
+    fs::write(output_dir.join("src/SUMMARY.md"), toc)?;
+
+    extract_chapters_and_resources(&mut doc, &output_dir, &html_files)?;
+    write_book_toml(&output_dir, &title, creator)?;
+    Ok(())
+}
+
+pub fn nav_point_to_md(
+    nav: &NavPoint,
+    indent: usize,
+    html_files: &HashMap<PathBuf, PathBuf>,
+) -> Option<String> {
+    let file = html_files.get(&nav.content)?;
+    let mut md = format!(
+        "{}- [{}]({})\n",
+        "  ".repeat(indent),
+        nav.label,
+        file.to_str()?
+    );
+    for child in &nav.children {
+        if let Some(child_md) = nav_point_to_md(child, indent + 1, html_files) {
+            md.push_str(&child_md);
+        }
+    }
+    Some(md)
+}
+
+pub fn toc_to_md<R: Read + Seek>(
+    doc: &EpubDoc<R>,
+    title: &str,
+) -> anyhow::Result<(String, HashMap<PathBuf, PathBuf>)> {
+    let toc = doc.toc.clone();
+
+    let mut markdown = format!("# {}\n\n", title);
+    let html_files = doc
+        .resources
+        .iter()
+        .filter(|(_, (_, mime))| mime == "application/xhtml+xml")
+        .map(|(_, (path, _))| (path.clone(), path.with_extension("md")))
+        .collect::<HashMap<PathBuf, PathBuf>>();
+    for nav in toc {
+        if let Some(md) = nav_point_to_md(&nav, 0, &html_files) {
+            markdown.push_str(&md);
+        }
+    }
+    Ok((markdown, html_files))
+}
+
+pub fn extract_chapters_and_resources<R: Read + Seek>(
+    doc: &mut EpubDoc<R>,
+    output_dir: impl AsRef<Path>,
+    html_files: &HashMap<PathBuf, PathBuf>,
+) -> anyhow::Result<()> {
+    let output_dir = output_dir.as_ref();
+    let src_dir = output_dir.join("src");
+
+    for (_, (path, _)) in doc.resources.clone().into_iter() {
+        let content = match doc.get_resource_by_path(&path) {
+            Some(content) => content,
+            None => continue,
+        };
+
+        if let Some(path) = html_files.get(&path) {
+            let target_path = src_dir.join(path);
+            if let Some(parent) = target_path.parent() {
+                fs::create_dir_all(parent)?;
+            }
+            let html = String::from_utf8(content)?;
+            let markdown = parse_html(&html);
+            fs::write(target_path, markdown)?;
+        } else {
+            let target_path = src_dir.join(&path);
+            if let Some(parent) = target_path.parent() {
+                fs::create_dir_all(parent)?;
+            }
+            fs::write(target_path, content)?;
+        }
+    }
+    Ok(())
+}
+
+pub fn write_book_toml(
+    output_dir: impl AsRef<Path>,
+    title: &str,
+    creator: Option<String>,
+) -> anyhow::Result<()> {
+    let output_dir = output_dir.as_ref();
+    let creator = match creator {
+        Some(creator) => format!("author = \"{creator}\"\n"),
+        None => "".to_string(),
+    };
+    let toml_content = format!("[book]\ntitle = \"{title}\"\n{creator}",);
+    fs::write(output_dir.join("book.toml"), toml_content)?;
+    Ok(())
+}