use gpui::SharedString;
use nostr::prelude::*;

/// Parsed NIP-34 repository announcement (plain data, ready for the UI).
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Announcement {
    /// Repository ID (`d` tag).
    pub id: String,
    /// Author of the announcement event.
    pub owner: PublicKey,
    /// When the announcement was published (for latest-wins resolution).
    pub created_at: Timestamp,
    pub name: Option<SharedString>,
    pub description: Option<SharedString>,
    /// Webpage URLs for browsing.
    pub web: Vec<Url>,
    /// URLs for `git clone`.
    pub clone: Vec<Url>,
    /// Relays the repository monitors for patches and issues.
    pub relays: Vec<RelayUrl>,
    /// Earliest unique commit ID (`r` tag with `euc` marker).
    pub euc: Option<String>,
    /// Other recognized maintainers.
    pub maintainers: Vec<PublicKey>,
    /// Hashtags labelling the repository (`t` tags).
    pub hashtags: Vec<String>,
}

/// Subject of a NIP-34 issue or pull request event: the `subject` tag,
/// falling back to the first non-empty line of the content.
pub fn activity_subject(event: &Event) -> SharedString {
    let subject = event
        .tags
        .iter()
        .find_map(|tag| match Nip34Tag::parse(tag.as_slice()) {
            Ok(Nip34Tag::Subject(subject)) => Some(subject),
            _ => None,
        });

    subject
        .map(SharedString::from)
        .or_else(|| {
            event
                .content
                .lines()
                .map(str::trim)
                .find(|line| !line.is_empty())
                .map(SharedString::from)
        })
        .unwrap_or(SharedString::from("Untitled"))
}

impl Announcement {
    /// Parse a kind `30617` event. Returns `None` if the kind is wrong or the `d` tag is missing.
    pub fn from_event(event: &Event) -> Option<Self> {
        if event.kind != Kind::GitRepoAnnouncement {
            return None;
        }

        let id = event.tags.identifier()?;

        let mut hashtags: Vec<String> = Vec::new();
        hashtags.extend(event.tags.hashtags().map(|t| t.to_string()));

        let mut name: Option<SharedString> = None;
        let mut description: Option<SharedString> = None;
        let mut web: Vec<Url> = Vec::new();
        let mut clone: Vec<Url> = Vec::new();
        let mut relays: Vec<RelayUrl> = Vec::new();
        let mut euc: Option<String> = None;
        let mut maintainers: Vec<PublicKey> = Vec::new();

        for tag in event.tags.iter() {
            match Nip34Tag::parse(tag.as_slice()) {
                Ok(Nip34Tag::Name(value)) => name = Some(value.into()),
                Ok(Nip34Tag::Description(value)) => description = Some(value.into()),
                Ok(Nip34Tag::Web(urls)) => web.extend(urls),
                Ok(Nip34Tag::Clone(urls)) => clone.extend(urls),
                Ok(Nip34Tag::Relays(urls)) => relays.extend(urls),
                Ok(Nip34Tag::EarliestUniqueCommitId(commit)) => euc = Some(commit.to_string()),
                Ok(Nip34Tag::Maintainers(keys)) => maintainers.extend(keys),
                _ => {}
            }
        }

        Some(Self {
            owner: event.pubkey,
            created_at: event.created_at,
            id,
            name,
            description,
            web,
            clone,
            relays,
            euc,
            maintainers,
            hashtags,
        })
    }

    /// The repository address of this announcement.
    pub fn addr(&self) -> crate::RepoAddr {
        crate::repo_addr(self.owner, self.id.clone())
    }

    /// The description of the repository, or a default if none is provided.
    pub fn description(&self) -> SharedString {
        self.description
            .clone()
            .unwrap_or(SharedString::from("No description"))
    }
}

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

    const MAINTAINER_HEX: &str = "68d81165918100b7da43fc28f7d1fc12554466e1115886b9e7bb326f65ec4272";

    fn keys() -> Keys {
        Keys::new(
            SecretKey::from_hex("0000000000000000000000000000000000000000000000000000000000000001")
                .expect("valid secret key"),
        )
    }

    /// Build a signed kind `30617` event from raw tag values.
    fn announcement_event(tags: &[&[&str]]) -> Event {
        let tags: Vec<Tag> = tags
            .iter()
            .map(|t| Tag::parse(t.to_vec()).expect("valid tag"))
            .collect();

        EventBuilder::new(Kind::GitRepoAnnouncement, "")
            .tags(tags)
            .finalize(&keys())
            .expect("signed event")
    }

    #[test]
    fn parses_full_announcement() {
        let event = announcement_event(&[
            &["d", "my-repo"],
            &["name", "My Repo"],
            &["description", "A test repository"],
            &["web", "https://example.com/repo"],
            &["clone", "https://example.com/repo.git"],
            &["relays", "wss://relay.example.com"],
            &["r", "aa231c4c6a5777dc89b42207b499891a344add5c", "euc"],
            &["maintainers", MAINTAINER_HEX],
            &["t", "rust"],
            &["t", "nostr"],
        ]);

        let announcement = Announcement::from_event(&event).expect("parses");

        assert_eq!(announcement.owner, keys().public_key());
        assert_eq!(announcement.id, "my-repo");
        assert_eq!(announcement.name.as_deref(), Some("My Repo"));
        assert_eq!(
            announcement.description.as_deref(),
            Some("A test repository")
        );
        assert_eq!(
            announcement.web,
            vec![Url::parse("https://example.com/repo").unwrap()]
        );
        assert_eq!(
            announcement.clone,
            vec![Url::parse("https://example.com/repo.git").unwrap()]
        );
        assert_eq!(
            announcement.relays,
            vec![RelayUrl::parse("wss://relay.example.com").unwrap()]
        );
        assert_eq!(
            announcement.euc.as_deref(),
            Some("aa231c4c6a5777dc89b42207b499891a344add5c")
        );
        assert_eq!(
            announcement.maintainers,
            vec![PublicKey::from_hex(MAINTAINER_HEX).expect("valid pubkey")]
        );
        assert_eq!(announcement.hashtags, vec!["rust", "nostr"]);
    }

    #[test]
    fn requires_d_tag() {
        let event = announcement_event(&[&["name", "No id"]]);

        assert!(Announcement::from_event(&event).is_none());
    }

    #[test]
    fn ignores_other_kinds() {
        let event = EventBuilder::new(Kind::GitIssue, "")
            .finalize(&keys())
            .expect("signed event");

        assert!(Announcement::from_event(&event).is_none());
    }

    #[test]
    fn drops_malformed_values() {
        let event = announcement_event(&[
            &["d", "my-repo"],
            &["clone", "not a url"],
            &["relays", "wss://good.example.com"],
            &["maintainers", "not-a-pubkey"],
        ]);

        let announcement = Announcement::from_event(&event).expect("parses");

        // An invalid URL keeps the whole clone tag from being parsed.
        assert!(announcement.clone.is_empty());
        assert_eq!(
            announcement.relays,
            vec![RelayUrl::parse("wss://good.example.com").unwrap()]
        );
        assert!(announcement.maintainers.is_empty());
    }

    #[test]
    fn ignores_unknown_tags() {
        let event = announcement_event(&[&["d", "my-repo"], &["t", "label"], &["subject", "n/a"]]);

        let announcement = Announcement::from_event(&event).expect("parses");

        assert_eq!(announcement.id, "my-repo");
        assert!(announcement.name.is_none());
        assert!(announcement.web.is_empty());
    }
}