From 767fb66c035f72a30cb99e1223630db6fa97abbf Mon Sep 17 00:00:00 2001
From: sgoudham <sgoudham@gmail.com>
Date: Fri, 29 Apr 2022 04:41:40 +0100
Subject: [PATCH] Create proper skeleton

---
 src/bin/mdbook-template.rs |  64 ++++++++++++++++++++++
 src/lib.rs                 | 106 ++++++++++++++++++++++++++++++++++---
 2 files changed, 164 insertions(+), 6 deletions(-)
 create mode 100644 src/bin/mdbook-template.rs

diff --git a/src/bin/mdbook-template.rs b/src/bin/mdbook-template.rs
new file mode 100644
index 0000000..48314ac
--- /dev/null
+++ b/src/bin/mdbook-template.rs
@@ -0,0 +1,64 @@
+use std::{io, process};
+
+use clap::{Arg, ArgMatches, Command};
+use mdbook::errors::Error;
+use mdbook::preprocess::{CmdPreprocessor, Preprocessor};
+use semver::{Version, VersionReq};
+
+use mdbook_template::Template;
+
+fn main() {
+    let matches = make_app().get_matches();
+
+    let preprocessor = Template::new();
+
+    if let Some(sub_args) = matches.subcommand_matches("supports") {
+        handle_supports(&preprocessor, sub_args);
+    } else if let Err(e) = handle_preprocessing(&preprocessor) {
+        eprintln!("{}", e);
+        process::exit(1);
+    }
+}
+
+pub fn make_app() -> Command<'static> {
+    Command::new("mdbook-template")
+        .about("A mdbook preprocessor that allows the re-usability of template files with variable arguments")
+        .subcommand(
+        Command::new("supports")
+            .arg(Arg::new("renderer").required(true))
+            .about("Check whether a renderer is supported by this preprocessor"),
+    )
+}
+
+fn handle_preprocessing(pre: &dyn Preprocessor) -> Result<(), Error> {
+    let (ctx, book) = CmdPreprocessor::parse_input(io::stdin())?;
+
+    let book_version = Version::parse(&ctx.mdbook_version)?;
+    let version_req = VersionReq::parse(mdbook::MDBOOK_VERSION)?;
+
+    if !version_req.matches(&book_version) {
+        eprintln!(
+            "Warning: The {} plugin was built against version {} of mdbook, \
+             but we're being called from version {}",
+            pre.name(),
+            mdbook::MDBOOK_VERSION,
+            ctx.mdbook_version
+        );
+    }
+
+    let processed_book = pre.run(&ctx, book)?;
+    serde_json::to_writer(io::stdout(), &processed_book)?;
+
+    Ok(())
+}
+
+fn handle_supports(pre: &dyn Preprocessor, sub_args: &ArgMatches) -> ! {
+    let renderer = sub_args.value_of("renderer").expect("Required argument");
+    let supported = pre.supports_renderer(renderer);
+
+    if supported {
+        process::exit(0);
+    } else {
+        process::exit(1);
+    }
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 1b4a90c..bfd1f89 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,8 +1,102 @@
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        let result = 2 + 2;
-        assert_eq!(result, 4);
+use fancy_regex::{CaptureMatches, Captures, Regex};
+use lazy_static::lazy_static;
+use log::info;
+use mdbook::book::Book;
+use mdbook::errors::Result;
+use mdbook::preprocess::{Preprocessor, PreprocessorContext};
+use mdbook::BookItem;
+use toml::Value;
+
+lazy_static! {
+    static ref ARGS: Regex = Regex::new(r"(?<=\s|\A)([^\s=]+)=(.*?)(?=(?:\s[^\s=]+=|$))").unwrap();
+    static ref WHOLE_TEMPLATE: Regex = Regex::new(r"\\\{\{\#.*\}\}|\{\{\s*\#([a-zA-Z0-9_]+)\s+([a-zA-Z0-9_.-/]+)\s*([^}]+)\}\}").unwrap();
+    // static ref RE: Regex = Regex::new(r"\\\{\{\#.*\}\}|\{\{\s*\#([a-zA-Z0-9_]+)\s+([a-zA-Z0-9-_.]+)\s*((?<=\s|\A)([^\s=]+)=(.*?)(?=(?:\s[^\s=]+=|$)))*\}\}").unwrap();
+}
+
+#[derive(Default)]
+pub struct Template;
+
+impl Template {
+    pub fn new() -> Self {
+        Template
+    }
+}
+
+impl Preprocessor for Template {
+    fn name(&self) -> &str {
+        "template"
     }
+
+    fn run(&self, ctx: &PreprocessorContext, mut book: Book) -> Result<Book> {
+        /*
+        TODO - 29/04/2022
+         Store All Files in Key/Value Pairs
+         Start iterating through each chapter in the book
+            1. Get template string
+            2. Remove }} at the end of template string
+            3. Store template string arguments in Key/Value Pairs
+            4. Get the template and dynamically find/replace
+            5. Set the chapter content to the new one
+         Return the book to mdbook
+         */
+
+        env_logger::init_from_env(env_logger::Env::default().default_filter_or("info"));
+
+        if let Some(config) = ctx.config.get_preprocessor(self.name()) {
+            let default = Value::String(String::from("templates/"));
+            let template_dir = config.get("templates-dir").unwrap_or(&default);
+            info!("Reading from directory {}", template_dir);
+        }
+
+        book.for_each_mut(|book_item| {
+            if let BookItem::Chapter(ref mut chapter) = book_item {
+                chapter.content = String::from("All content is now replaced");
+            }
+        });
+
+        Ok(book)
+    }
+
+    fn supports_renderer(&self, renderer: &str) -> bool {
+        renderer == "html"
+    }
+}
+
+#[derive(PartialEq, Debug, Clone)]
+pub struct Link<'a> {
+    start_index: usize,
+    end_index: usize,
+    pub link_text: &'a str,
+}
+
+impl<'a> Link<'a> {
+    fn from_capture(cap: Captures<'a>) -> Option<Link<'a>> {
+        cap.get(0).map(|mat| Link {
+            start_index: mat.start(),
+            end_index: mat.end(),
+            link_text: mat.as_str(),
+        })
+    }
+}
+
+pub struct LinkIter<'a>(CaptureMatches<'a, 'a>);
+
+impl<'a> Iterator for LinkIter<'a> {
+    type Item = Link<'a>;
+    fn next(&mut self) -> Option<Link<'a>> {
+        for cap in &mut self.0 {
+            if let Some(inc) = Link::from_capture(cap.unwrap()) {
+                return Some(inc);
+            }
+        }
+        None
+    }
+}
+
+pub fn extract_template_links(contents: &str) -> LinkIter<'_> {
+    LinkIter(WHOLE_TEMPLATE.captures_iter(contents))
 }
+
+pub fn extract_template_arguments(contents: &str) -> LinkIter<'_> {
+    LinkIter(ARGS.captures_iter(contents))
+}
\ No newline at end of file