use crate::cohost_account::CohostAccount;
use crate::cohost_posts::*;
use crate::ARGS;
use rss::Channel;

pub fn channel_for_posts_page(
    project_name: impl AsRef<str>,
    project: CohostAccount,
    mut page: CohostPostsPage,
    originals_only: bool,
) -> Channel {
    let project_name = project_name.as_ref().clone();
    let mut builder = rss::ChannelBuilder::default();
    builder
        .title(format!(
            "{} Cohost Posts{}",
            project.display_name,
            if originals_only { "" } else { " and Shares" }
        ))
        .description(project.description)
        .generator(Some(format!(
            "{} {}",
            env!("CARGO_CRATE_NAME"),
            env!("CARGO_PKG_VERSION")
        )))
        .link(format!("https://cohost.org/{}", project_name,));

    page.items.sort_by_key(|item| item.published_at);
    let mut items = Vec::with_capacity(page.number_items);
    for item in page.items {
        let mut item_builder = rss::ItemBuilder::default();
        let mut categories: Vec<rss::Category> = Vec::with_capacity(item.tags.len());
        for tag in item.tags.iter().cloned() {
            categories.push(rss::Category {
                name: tag,
                domain: Some("https://cohost.org".into()),
            });
        }
        item_builder
            .link(item.url.clone())
            .title(item.headline)
            .author(item.poster.handle)
            .guid(Some(rss::Guid {
                value: item.url.clone(),
                permalink: true,
            }))
            .categories(categories)
            .pub_date(item.published_at.to_rfc2822())
            .source(Some(rss::Source {
                title: Some(format!("{} Cohost Posts", project.display_name)),
                url: format!("https://{}/feed/{}.rss", ARGS.domain, project_name),
            }));

        let mut body_text = String::new();

        if let Some(shared_post_id) = item.transparent_share_of_post_id {
            if originals_only {
                continue;
            }
            body_text.push_str(&format!(
                "(share of post {} without any commentary)\n\n---\n\n",
                shared_post_id
            ));
        } else if item.share_tree.len() == 1 {
            body_text.push_str("(in reply to another post)\n\n---\n\n")
        } else if item.share_tree.len() > 1 {
            body_text.push_str(&format!(
                "(in reply to {} other posts)\n\n---\n\n",
                item.share_tree.len()
            ));
        }

        if item.cws.is_empty() {
            body_text.push_str(&item.plain_body);
        } else {
            body_text.push_str("Sensitive post, body text omitted. Content warnings:");
            for cw in item.cws {
                body_text.push_str(&format!(" {},", cw));
            }
            body_text.pop(); // Remove trailing comma
            body_text.push_str("\n\n---\n\n")
        };

        if !item.tags.is_empty() {
            body_text.push_str("\n\n Post tagged:");
            for tag in item.tags {
                body_text.push_str(&format!(" #{},", tag));
            }
            body_text.pop(); // Remove trailing comma
        }

        use pulldown_cmark::Options;
        let options = Options::ENABLE_FOOTNOTES
            & Options::ENABLE_STRIKETHROUGH
            & Options::ENABLE_TABLES
            & Options::ENABLE_TASKLISTS;
        let parser = pulldown_cmark::Parser::new_ext(&body_text, options);
        let mut html_output = String::new();
        pulldown_cmark::html::push_html(&mut html_output, parser);
        item_builder.content(html_output);

        for attachment in item.blocks.into_iter().filter_map(|block| block.attachment) {
            use mime_guess::from_path as guess_mime_from_path;
            use rss::EnclosureBuilder;
            let enclosure = EnclosureBuilder::default()
                .mime_type(
                    guess_mime_from_path(&attachment.file_url)
                        .first_or_octet_stream()
                        .to_string(),
                )
                .url(attachment.file_url)
                .build();
            item_builder.enclosure(enclosure);
        }

        items.push(item_builder.build());
    }

    builder.items(items);

    builder.build()
}