import XCTest

@testable import MiaoYan

/// Exercises the pure-string ingestion path of `WikilinkIndex.updateNote`,
/// which does not require `Note`/`Storage` bootstrapping. This is what runs
/// during live editing and is the regression surface most worth covering.
@MainActor
final class WikilinkIndexTests: XCTestCase {

    private var index: WikilinkIndex { WikilinkIndex.shared }

    // XCTestCase's setUp/tearDown across Swift 6.1's strict concurrency
    // are awkward: the sync variants are nonisolated (can't touch the
    // @MainActor index), and `super.setUp()` in the async variants flags
    // XCTestCase as non-Sendable. Sidestep both by cleaning the shared
    // index inline at the start of each test instead.
    private func resetIndex() {
        for title in ["A", "B", "C", "D"] {
            // removeNote on a non-existent title is a no-op, so this is
            // safe even on a fresh index.
            index.removeNote(title: title)
        }
    }

    func testUpdateNoteRecordsOutlinks() {
        resetIndex()
        index.updateNote(title: "A", content: "see [[B]] and [[C]]")

        XCTAssertEqual(Set(index.getOutlinks(for: "A")), Set(["B", "C"]))
    }

    func testBacklinksReverseUpdateNote() {
        resetIndex()
        index.updateNote(title: "A", content: "links to [[B]]")
        index.updateNote(title: "C", content: "also links to [[B]]")

        XCTAssertEqual(Set(index.getBacklinks(for: "B")), Set(["A", "C"]))
    }

    func testUpdateNoteReplacesPreviousOutlinks() {
        resetIndex()
        index.updateNote(title: "A", content: "[[B]]")
        index.updateNote(title: "A", content: "[[C]]")

        XCTAssertEqual(index.getOutlinks(for: "A"), ["C"])
        XCTAssertTrue(index.getBacklinks(for: "B").isEmpty, "stale backlink to B should be cleared")
        XCTAssertEqual(index.getBacklinks(for: "C"), ["A"])
    }

    func testRemoveNoteClearsBothDirections() {
        resetIndex()
        index.updateNote(title: "A", content: "[[B]]")
        index.removeNote(title: "A")

        XCTAssertTrue(index.getOutlinks(for: "A").isEmpty)
        XCTAssertTrue(index.getBacklinks(for: "B").isEmpty)
    }

    func testWhitespaceInsideBracketsIsTrimmed() {
        resetIndex()
        index.updateNote(title: "A", content: "[[  B  ]]")

        XCTAssertEqual(index.getOutlinks(for: "A"), ["B"])
    }

    func testEmptyContentYieldsNoLinks() {
        resetIndex()
        index.updateNote(title: "A", content: "no wikilinks here")

        XCTAssertTrue(index.getOutlinks(for: "A").isEmpty)
    }

    func testMultipleOccurrencesOfSameLinkAreDeduped() {
        resetIndex()
        index.updateNote(title: "A", content: "[[B]] then [[B]] then [[B]]")

        XCTAssertEqual(index.getOutlinks(for: "A"), ["B"])
    }
}