tedi 0.16.1

//! Marker types for issue file format.
//!
//! Markers are HTML comments or special syntax that encode metadata in issue files.
//! This module provides decoding and encoding for all marker types, ensuring
//! consistent handling of whitespace and formatting.

use std::fmt;

use crate::{Header, IssueIdentity, IssueLink};

/// Issue identity marker - encodes how an issue relates to GitHub.
///
/// Formats:
/// - Linked: `<!-- @user url -->`
/// - Pending: `<!-- pending -->` or no marker (default)
/// - Virtual: `<!-- virtual -->`
#[derive(Clone, Debug, PartialEq)]
pub enum IssueMarker {
	/// Linked to GitHub: `<!-- @user url -->` or `<!-- url -->` (user unknown)
	Linked { user: Option<String>, link: IssueLink },
	/// Pending creation on GitHub (will be created on first sync)
	Pending,
	/// Virtual (local-only, never syncs to GitHub)
	Virtual,
}

impl IssueMarker {
	/// Decode an issue marker from HTML comment inner content.
	/// Returns `Pending` for empty/unrecognized content (default).
	pub fn decode(inner: &str) -> Self {
		let s = inner.trim();

		// Empty or explicit pending
		if s.is_empty() || s == "pending" {
			return Self::Pending;
		}

		// Legacy: `local:` also means pending
		if s.starts_with("local:") {
			return Self::Pending;
		}

		// Virtual
		if s == "virtual" || s.starts_with("virtual:") {
			return Self::Virtual;
		}

		// Linked format: `@user url` or just `url`
		if let Some(rest) = s.strip_prefix('@')
			&& let Some(space_idx) = rest.find(' ')
		{
			let user = rest[..space_idx].to_string();
			let url = rest[space_idx + 1..].trim();
			if let Some(link) = IssueLink::parse(url) {
				return Self::Linked { user: Some(user), link };
			}
		}

		// Try bare URL (no user prefix)
		if let Some(link) = IssueLink::parse(s) {
			return Self::Linked { user: None, link };
		}

		// Default to pending for unrecognized
		Self::Pending
	}

	/// Parse an issue marker from the end of a string, returning the marker and remaining content.
	///
	/// Recognizes:
	/// - `<!-- @user url -->` (linked)
	/// - `<!-- pending -->` or `<!-- -->` (pending)
	/// - `<!-- virtual -->` (virtual)
	/// - `<!--sub ... -->` (legacy sub prefix, stripped)
	/// - `!n` shorthand for pending (case insensitive)
	///
	/// Returns `None` if no valid marker is found at the end.
	pub fn parse_from_end(s: &str) -> Option<(Self, &str)> {
		let trimmed = s.trim_end();

		// Shorthand: `!n` or `!N` for pending
		if trimmed.ends_with("!n") || trimmed.ends_with("!N") {
			let rest = trimmed[..trimmed.len() - 2].trim_end();
			return Some((Self::Pending, rest));
		}

		// HTML comment: `<!-- ... -->`
		if let Some(marker_end) = trimmed.rfind("-->")
			&& let Some(marker_start) = trimmed[..marker_end].rfind("<!--")
		{
			let inner = trimmed[marker_start + 4..marker_end].trim();
			// Strip legacy `sub ` prefix if present
			let inner = match inner.strip_prefix("sub ") {
				Some(stripped) => {
					tracing::warn!("legacy `<!--sub ...-->` marker detected; use `<!-- ... -->` instead");
					stripped
				}
				None => inner,
			};
			let marker = Self::decode(inner);
			let rest = trimmed[..marker_start].trim_end();
			return Some((marker, rest));
		}

		None
	}

	/// Check if a string ends with a valid issue marker.
	pub fn is_at_end(s: &str) -> bool {
		Self::parse_from_end(s).is_some()
	}

	/// Encode the issue marker to HTML comment inner content.
	pub fn encode(&self) -> String {
		match self {
			Self::Linked { user: Some(user), link } => format!("@{user} {}", link.as_str()),
			Self::Linked { user: None, link } => link.as_str().to_string(),
			Self::Pending => "pending".to_string(),
			Self::Virtual => "virtual".to_string(),
		}
	}

	/// Get the selector for this marker.
	/// For linked issues, returns GitId. For pending/virtual, returns Title.
	pub fn selector(&self, title: &str) -> super::IssueSelector {
		match self {
			Self::Linked { link, .. } => super::IssueSelector::GitId(link.number()),
			Self::Pending | Self::Virtual => super::IssueSelector::title(title),
		}
	}
}

impl fmt::Display for IssueMarker {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "<!-- {} -->", self.encode())
	}
}

impl From<&IssueIdentity> for IssueMarker {
	fn from(identity: &IssueIdentity) -> Self {
		if let Some(meta) = identity.as_linked() {
			IssueMarker::Linked {
				user: meta.user.clone(),
				link: meta.link().clone(),
			}
		} else if identity.is_virtual {
			IssueMarker::Virtual
		} else {
			IssueMarker::Pending
		}
	}
}

/// A marker that can appear in issue files.
/// All markers normalize whitespace on decode and encode with consistent spacing.
#[derive(Clone, Debug, PartialEq)]
pub enum Marker {
	/// Issue identity marker
	Issue(IssueMarker),
	/// Comment marker: `<!-- @user url#issuecomment-123 -->`
	Comment { user: String, url: String, id: u64 },
	/// New comment marker: `<!-- new comment -->`
	NewComment,
	/// Blockers section marker: `# Blockers`
	/// Uses the Header type for encoding/decoding.
	/// Legacy format (`<!-- blockers -->`) is still decoded but encodes to Header format.
	BlockersSection(Header),
	/// Omitted start marker: `<!--omitted {{{always-->` (vim fold start)
	OmittedStart,
	/// Omitted end marker: `<!--,}}}-->` (vim fold end)
	OmittedEnd,
}

impl Marker {
	/// Decode a marker from a string.
	/// For BlockersSection, the entire line (after trimming) must match.
	/// For other markers, decodes the HTML comment content.
	/// Returns None if the string doesn't contain a recognized marker.
	pub fn decode(s: &str) -> Option<Self> {
		let trimmed = s.trim();

		// Shorthand: `!c` or `!C` for new comment
		if trimmed.eq_ignore_ascii_case("!c") {
			return Some(Marker::NewComment);
		}

		// Shorthand: `!b` or `!B` for blockers section
		if trimmed.eq_ignore_ascii_case("!b") {
			return Some(Marker::BlockersSection(Header::new(1, "Blockers")));
		}

		// Check for header-based blockers marker using the Header type: `# Blockers`
		if let Some(header) = Header::decode(trimmed) {
			let content_lower = header.content.to_ascii_lowercase();
			let content_trimmed = content_lower.trim_end_matches(':');
			if content_trimmed == "blockers" || content_trimmed == "blocker" {
				return Some(Marker::BlockersSection(header));
			}
		}

		// Check for HTML comment markers
		if !trimmed.starts_with("<!--") || !trimmed.ends_with("-->") {
			return None;
		}

		// Extract inner content, normalizing whitespace
		let inner = trimmed.strip_prefix("<!--")?.strip_suffix("-->")?.trim();
		let lower = inner.to_ascii_lowercase();

		// Blockers (legacy HTML comment) - entire comment must be just "blockers"
		// Decodes to Header format for consistency
		if lower == "blockers" || lower == "blocker" {
			return Some(Marker::BlockersSection(Header::new(1, "Blockers")));
		}

		// New comment
		if lower == "new comment" {
			return Some(Marker::NewComment);
		}

		// Omitted vim fold markers
		if lower.starts_with("omitted") && lower.contains("{{{") {
			return Some(Marker::OmittedStart);
		}
		if lower.starts_with(",}}}") || lower == ",}}}" {
			return Some(Marker::OmittedEnd);
		}

		// Comment marker (contains #issuecomment-)
		if inner.contains("#issuecomment-") {
			// Must have @user prefix
			if let Some(rest) = inner.strip_prefix('@')
				&& let Some(space_idx) = rest.find(' ')
			{
				let user = rest[..space_idx].to_string();
				let url = rest[space_idx + 1..].trim();
				let id = url.split("#issuecomment-").nth(1).and_then(|s| {
					let digits: String = s.chars().take_while(|c| c.is_ascii_digit()).collect();
					digits.parse().ok()
				})?;
				return Some(Marker::Comment { user, url: url.to_string(), id });
			}
			return None;
		}

		// Issue marker (delegate to IssueMarker::decode)
		Some(Marker::Issue(IssueMarker::decode(inner)))
	}

	/// Encode the marker to a string with consistent formatting.
	pub fn encode(&self) -> String {
		match self {
			Marker::Issue(issue) => issue.to_string(),
			Marker::Comment { user, url, .. } => format!("<!-- @{user} {url} -->"),
			Marker::NewComment => "<!-- new comment -->".to_string(),
			Marker::BlockersSection(header) => header.encode(),
			Marker::OmittedStart => "<!--omitted {{{always-->".to_string(),
			Marker::OmittedEnd => "<!--,}}}-->".to_string(),
		}
	}
}

impl fmt::Display for Marker {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "{}", self.encode())
	}
}

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

	#[test]
	fn test_issue_marker_decode_linked() {
		let marker = IssueMarker::decode("@owner https://github.com/owner/repo/issues/123");
		assert!(matches!(marker, IssueMarker::Linked { user: Some(ref user), ref link } if user == "owner" && link.number() == 123));
	}

	#[test]
	fn test_issue_marker_decode_pending() {
		assert_eq!(IssueMarker::decode(""), IssueMarker::Pending);
		assert_eq!(IssueMarker::decode("pending"), IssueMarker::Pending);
		assert_eq!(IssueMarker::decode("local:"), IssueMarker::Pending);
		assert_eq!(IssueMarker::decode("local:anything"), IssueMarker::Pending);
		assert_eq!(IssueMarker::decode("unrecognized stuff"), IssueMarker::Pending);
	}

	#[test]
	fn test_issue_marker_decode_virtual() {
		assert_eq!(IssueMarker::decode("virtual"), IssueMarker::Virtual);
		assert_eq!(IssueMarker::decode("virtual:"), IssueMarker::Virtual);
	}

	#[test]
	fn test_issue_marker_encode() {
		assert_eq!(IssueMarker::Pending.encode(), "pending");
		assert_eq!(IssueMarker::Virtual.encode(), "virtual");

		let link = IssueLink::parse("https://github.com/owner/repo/issues/123").unwrap();
		let linked = IssueMarker::Linked {
			user: Some("owner".to_string()),
			link,
		};
		assert_eq!(linked.encode(), "@owner https://github.com/owner/repo/issues/123");
	}

	#[test]
	fn test_issue_marker_roundtrip() {
		let link = IssueLink::parse("https://github.com/owner/repo/issues/123").unwrap();
		let markers = vec![
			IssueMarker::Pending,
			IssueMarker::Virtual,
			IssueMarker::Linked {
				user: Some("owner".to_string()),
				link,
			},
		];

		for marker in markers {
			let encoded = marker.encode();
			let decoded = IssueMarker::decode(&encoded);
			assert_eq!(marker, decoded, "Roundtrip failed for {marker:?}");
		}
	}

	#[test]
	fn test_decode_issue_marker_via_marker() {
		// Linked
		let m = Marker::decode("<!-- @owner https://github.com/owner/repo/issues/123 -->");
		assert!(matches!(m, Some(Marker::Issue(IssueMarker::Linked { .. }))));

		// Pending (explicit)
		let m = Marker::decode("<!-- pending -->");
		assert!(matches!(m, Some(Marker::Issue(IssueMarker::Pending))));

		// Virtual
		let m = Marker::decode("<!-- virtual -->");
		assert!(matches!(m, Some(Marker::Issue(IssueMarker::Virtual))));

		// Legacy local:
		let m = Marker::decode("<!-- local: -->");
		assert!(matches!(m, Some(Marker::Issue(IssueMarker::Pending))));
	}

	#[test]
	fn test_decode_comment() {
		let m = Marker::decode("<!-- @owner https://github.com/owner/repo/issues/123#issuecomment-456 -->");
		assert!(matches!(m, Some(Marker::Comment { user, id, .. }) if user == "owner" && id == 456));
	}

	#[test]
	fn test_decode_blockers_section() {
		fn is_blockers_section(marker: Option<Marker>) -> bool {
			matches!(marker, Some(Marker::BlockersSection(_)))
		}

		// Markdown header (preferred)
		assert!(is_blockers_section(Marker::decode("# Blockers")));
		assert!(is_blockers_section(Marker::decode("## Blockers")));
		assert!(is_blockers_section(Marker::decode("### Blockers:")));
		// With leading/trailing whitespace
		assert!(is_blockers_section(Marker::decode("  # Blockers  ")));
		// Legacy HTML comment (converts to Header)
		assert!(is_blockers_section(Marker::decode("<!--blockers-->")));
		assert!(is_blockers_section(Marker::decode("<!-- blockers -->")));
		assert!(is_blockers_section(Marker::decode("<!--blocker-->")));

		// Shorthand
		assert!(is_blockers_section(Marker::decode("!b")));
		assert!(is_blockers_section(Marker::decode("!B")));
		assert!(is_blockers_section(Marker::decode("  !b  ")));

		// Should NOT match if there's other content on the line
		assert!(!is_blockers_section(Marker::decode("# Blockers and more")));
		assert!(!is_blockers_section(Marker::decode("Some text # Blockers")));

		// Test that Header content and level are preserved
		if let Some(Marker::BlockersSection(header)) = Marker::decode("## Blockers") {
			assert_eq!(header.level, 2);
			assert_eq!(header.content, "Blockers");
		} else {
			panic!("Expected BlockersSection with Header");
		}
	}

	#[test]
	fn test_decode_new_comment() {
		assert_eq!(Marker::decode("<!--new comment-->"), Some(Marker::NewComment));
		assert_eq!(Marker::decode("<!-- new comment -->"), Some(Marker::NewComment));
		// Shorthand
		assert_eq!(Marker::decode("!c"), Some(Marker::NewComment));
		assert_eq!(Marker::decode("!C"), Some(Marker::NewComment));
		assert_eq!(Marker::decode("  !c  "), Some(Marker::NewComment));
	}

	#[test]
	fn test_decode_omitted() {
		assert_eq!(Marker::decode("<!--omitted {{{always-->"), Some(Marker::OmittedStart));
		assert_eq!(Marker::decode("<!-- omitted {{{always -->"), Some(Marker::OmittedStart));
		assert_eq!(Marker::decode("<!--,}}}-->"), Some(Marker::OmittedEnd));
	}

	#[test]
	fn test_encode() {
		assert_eq!(Marker::Issue(IssueMarker::Pending).encode(), "<!-- pending -->");
		assert_eq!(Marker::Issue(IssueMarker::Virtual).encode(), "<!-- virtual -->");
		assert_eq!(Marker::BlockersSection(Header::new(1, "Blockers")).encode(), "# Blockers");
		assert_eq!(Marker::BlockersSection(Header::new(2, "Blockers")).encode(), "## Blockers");
		assert_eq!(Marker::NewComment.encode(), "<!-- new comment -->");
		assert_eq!(Marker::OmittedStart.encode(), "<!--omitted {{{always-->");
		assert_eq!(Marker::OmittedEnd.encode(), "<!--,}}}-->");
	}

	#[test]
	fn test_roundtrip() {
		let link = IssueLink::parse("https://github.com/owner/repo/issues/123").unwrap();
		let markers = vec![
			Marker::Issue(IssueMarker::Pending),
			Marker::Issue(IssueMarker::Virtual),
			Marker::Issue(IssueMarker::Linked {
				user: Some("owner".to_string()),
				link: link.clone(),
			}),
			Marker::Comment {
				user: "owner".to_string(),
				url: "https://github.com/owner/repo/issues/123#issuecomment-456".to_string(),
				id: 456,
			},
			Marker::NewComment,
			Marker::OmittedStart,
			Marker::OmittedEnd,
		];

		for marker in markers {
			let encoded = marker.encode();
			let decoded = Marker::decode(&encoded).unwrap_or_else(|| panic!("Failed to decode: {encoded}"));
			assert_eq!(marker, decoded, "Roundtrip failed for {marker:?}");
		}
	}

	#[test]
	fn test_issue_marker_parse_from_end() {
		// Shorthand !n
		let (marker, title) = IssueMarker::parse_from_end("My title !n").unwrap();
		assert_eq!(marker, IssueMarker::Pending);
		assert_eq!(title, "My title");

		let (marker, title) = IssueMarker::parse_from_end("My title !N").unwrap();
		assert_eq!(marker, IssueMarker::Pending);
		assert_eq!(title, "My title");

		// HTML comment markers
		let (marker, title) = IssueMarker::parse_from_end("My title <!-- pending -->").unwrap();
		assert_eq!(marker, IssueMarker::Pending);
		assert_eq!(title, "My title");

		let (marker, title) = IssueMarker::parse_from_end("My title <!-- virtual -->").unwrap();
		assert_eq!(marker, IssueMarker::Virtual);
		assert_eq!(title, "My title");

		let (marker, title) = IssueMarker::parse_from_end("My title <!-- @owner https://github.com/owner/repo/issues/123 -->").unwrap();
		assert!(matches!(marker, IssueMarker::Linked { user: Some(ref user), .. } if user == "owner"));
		assert_eq!(title, "My title");

		// Legacy sub prefix
		let (marker, title) = IssueMarker::parse_from_end("My title <!--sub @owner https://github.com/owner/repo/issues/123 -->").unwrap();
		assert!(matches!(marker, IssueMarker::Linked { user: Some(ref user), .. } if user == "owner"));
		assert_eq!(title, "My title");

		// No marker
		assert!(IssueMarker::parse_from_end("My title").is_none());
		assert!(IssueMarker::parse_from_end("My title with - [ ] checkbox").is_none());
	}
}