use glob::glob;
use rake::{Rake, StopWords};
use serde::{Deserialize, Serialize};
use serde_yml;
use std::fs;

#[derive(Debug, Serialize, Deserialize)]
struct MetaData {
    categories: Vec<String>,
    date: String,
    tags: Vec<String>,
    title: String,
    keywords: Option<Vec<String>>, // Optional field to append keywords
}

pub fn parse(directory_path: &str) -> Result<(), Box<dyn std::error::Error>> {
    let stop_words = StopWords::from_file("static/stoplist.txt")?;
    let rake = Rake::new(stop_words);

    for entry in glob(format!("{}/**/*.md", directory_path).as_str())? {
        let path = entry?;
        let contents = fs::read_to_string(path.clone())?;

        // remove leading ---
        let contents = contents.lines().skip(1).collect::<Vec<&str>>().join("\n");

        // Split the Markdown content from the metadata
        if let Some(split_index) = contents.find("---\n\n") {
            let (front_matter, content) = contents.split_at(split_index);

            let mut metadata: MetaData = serde_yml::from_str(front_matter)?;

            // Extract keywords using RAKE
            let keywords = rake.run(content);

            // Append keywords to metadata
            metadata.keywords = Some(keywords.iter().map(|kw| kw.keyword.to_string()).collect());

            // Serialize the metadata back to YAML and write to the file
            let new_front_matter = serde_yml::to_string(&metadata)?;
            // add back leading ---
            let new_front_matter = format!("---\n\n{}", new_front_matter);

            let new_contents = format!("{}\n\n{}", new_front_matter, content);
            fs::write(path, new_contents)?;
        }
    }

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_parse() {
        let directory_path = "static";
        let result = parse(directory_path);
        assert!(result.is_ok());
    }
}