import Testing

@testable import NorgKeyboardToolbar

struct LineScannerTests {

  @Test func lineStartFindsBeginningOfCurrentLine() {
    let chars = Array("first\nsecond")
    // Cursor inside "second" (offset 9 -> the 'o').
    #expect(LineScanner.lineStart(in: chars, at: 9) == 6)
  }

  @Test func lineStartAtBufferStartIsZero() {
    let chars = Array("hello")
    #expect(LineScanner.lineStart(in: chars, at: 3) == 0)
  }

  @Test func lineStartJustAfterNewlineIsTheNewLine() {
    let chars = Array("a\nb")
    // Offset 2 sits at 'b', whose line starts right after the newline.
    #expect(LineScanner.lineStart(in: chars, at: 2) == 2)
  }

  @Test func lineEndFindsNextNewline() {
    let chars = Array("first\nsecond")
    #expect(LineScanner.lineEnd(in: chars, at: 2) == 5)
  }

  @Test func lineEndAtLastLineIsBufferCount() {
    let chars = Array("first\nsecond")
    #expect(LineScanner.lineEnd(in: chars, at: 8) == chars.count)
  }

  @Test func lineEndOnNewlineStaysPut() {
    let chars = Array("a\nb")
    // Offset 1 is the newline itself.
    #expect(LineScanner.lineEnd(in: chars, at: 1) == 1)
  }

  @Test func handlesEmptyBuffer() {
    let chars: [Character] = []
    #expect(LineScanner.lineStart(in: chars, at: 0) == 0)
    #expect(LineScanner.lineEnd(in: chars, at: 0) == 0)
  }
}