import { describe, expect, test } from 'bun:test'
import { blobLines } from '../main/reviews/store/anchors'
import { clampLines, lineCount, viewText } from './lines'

const samples = ['', '\n', 'a', 'a\n', 'a\nb', 'a\nb\n', 'a\n\n', '\n\n', 'a\r\nb\r\n', 'a\nb\n\n\n']

describe('lineCount', () => {
  test('agrees with the store', () => {
    for (const s of samples) expect([s, lineCount(s)]).toEqual([s, blobLines(Buffer.from(s)).length])
  })
})

describe('viewText', () => {
  test('drops only the line break ending the last line', () => {
    expect(viewText('a\nb\n')).toBe('a\nb')
    expect(viewText('a\nb')).toBe('a\nb')
    expect(viewText('a\r\nb\r\n')).toBe('a\r\nb')
    expect(viewText('a\n\n')).toBe('a\n')
    expect(viewText('\n')).toBe('')
  })

  test('leaves an editor as many lines as the store counts, keeping every position', () => {
    // An editor's line count: line breaks + 1 (CRLF is one break).
    const editorLines = (s: string) => s.split(/\r?\n/).length
    for (const s of samples) {
      const v = viewText(s)
      expect(s.startsWith(v)).toBe(true)
      if (s) expect([s, editorLines(v)]).toEqual([s, lineCount(s)])
    }
  })
})

describe('clampLines', () => {
  test('cuts a range to the lines there are', () => {
    expect(clampLines([2, 3], 5)).toEqual([2, 3])
    expect(clampLines([4, 6], 5)).toEqual([4, 5])
    expect(clampLines([0, 1], 5)).toEqual([1, 1])
    expect(clampLines([6, 6], 5)).toBeNull()
    expect(clampLines([1, 1], 0)).toBeNull()
  })
})