use std::path::PathBuf;

use crate::error::CustomError;

#[derive(Debug)]
pub(crate) struct BlogPostPage {
    /// Relative path from the root of the blog post.
    pub(crate) path: PathBuf,

    pub(crate) title: Option<String>,
}

impl BlogPostPage {
    pub(crate) fn new<P: Into<PathBuf>>(
        path: P,
        document: organic::types::Document<'_>,
    ) -> Result<BlogPostPage, CustomError> {
        let path = path.into();
        Ok(BlogPostPage {
            path,
            title: get_title(&document),
        })
    }

    /// Get the output path relative to the post directory.
    pub(crate) fn get_output_path(&self) -> PathBuf {
        let mut ret = self.path.clone();
        ret.set_extension("html");
        ret
    }
}

fn get_title(document: &organic::types::Document<'_>) -> Option<String> {
    organic::types::AstNode::from(document)
        .iter_all_ast_nodes()
        .filter_map(|node| match node {
            organic::types::AstNode::Keyword(kw) if kw.key.eq_ignore_ascii_case("title") => {
                Some(kw)
            }
            _ => None,
        })
        .last()
        .map(|kw| kw.value.to_owned())
}