//! Allow users to add summary comments in Issues & Pull Requests.
//!
//! Users can make a new summary entry by commenting the following:
//!
//! ```md
//! @rustbot note summary-title
//! ```
//!
//! If this is the first summary entry, rustbot will amend the original post (the top-level comment) to add a "Notes" section. The section should **not** be edited by hand.
//!
//! ```md
//! <!-- TRIAGEBOT_SUMMARY_START -->
//!
//! ### Summary Notes
//!
//! - ["summary-title" by @username](link-to-comment)
//!
//! Generated by triagebot, see [help](https://github.com/rust-lang/triagebot/wiki/Note) for how to add more
//! <!-- TRIAGEBOT_SUMMARY_END -->
//! ```
//!
//! If this is *not* the first summary entry, rustbot will simply append the new entry to the existing notes section:
//!
//! ```md
//! <!-- TRIAGEBOT_SUMMARY_START -->
//!
//! ### Summary Notes
//!
//! - ["first-note" by @username](link-to-comment)
//! - ["second-note" by @username](link-to-comment)
//! - ["summary-title" by @username](link-to-comment)
//!
//! <!-- TRIAGEBOT_SUMMARY_END -->
//! ```
//!

use crate::{config::NoteConfig, github::Event, handlers::Context, interactions::EditIssueBody};
use parser::command::note::NoteCommand;
use tracing as log;

#[derive(Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
struct NoteDataEntry {
    title: String,
    comment_url: String,
    author: String,
}

impl NoteDataEntry {
    pub fn to_markdown(&self) -> String {
        format!(
            "\n- [\"{title}\" by @{author}]({comment_url})",
            title = self.title,
            author = self.author,
            comment_url = self.comment_url
        )
    }
}

#[derive(Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize, Default)]
struct NoteData {
    entries: Vec<NoteDataEntry>,
}

impl NoteData {
    pub fn remove(&mut self, title: &str) -> () {
        let idx = self.entries.iter().position(|x| x.title == title).unwrap();
        log::debug!(
            "Removing element {:#?} from index {}",
            self.entries[idx],
            idx
        );
        self.entries.remove(idx);
    }
    pub fn to_markdown(&self) -> String {
        if self.entries.is_empty() {
            return String::new();
        }
        let mut text = String::from("\n### Summary Notes\n");
        for entry in &self.entries {
            text.push_str(&entry.to_markdown());
        }
        text.push_str("\n\nGenerated by triagebot, see [help](https://github.com/rust-lang/triagebot/wiki/Note) for how to add more");
        text
    }
}

pub(super) async fn handle_command(
    ctx: &Context,
    _config: &NoteConfig,
    event: &Event,
    cmd: NoteCommand,
) -> anyhow::Result<()> {
    let issue = event.issue().unwrap();
    let e = EditIssueBody::new(&issue, "SUMMARY");

    let mut current: NoteData = e.current_data().unwrap_or_default();

    let comment_url = String::from(event.html_url().unwrap());
    let author = event.user().login.to_owned();

    match &cmd {
        NoteCommand::Summary { title } => {
            let new_entry = NoteDataEntry {
                title: title.to_owned(),
                comment_url,
                author,
            };

            log::debug!("New Note Entry: {:#?}", new_entry);
            current.entries.push(new_entry);
        }
        NoteCommand::Remove { title } => {
            current.remove(title);
        }
    }

    let new_markdown = current.to_markdown();
    log::debug!("New MD: {:#?}", new_markdown);

    e.apply(&ctx.github, new_markdown, current).await?;

    Ok(())
}