import { describe, expect, test } from 'bun:test'

const sliceAnsi = (await import('../sliceAnsi')).default
const ESC = '\x1b'

describe('sliceAnsi', () => {
  test('plain text slice identical to String.slice', () => {
    expect(sliceAnsi('hello world', 0, 5)).toBe('hello')
    expect(sliceAnsi('hello world', 6)).toBe('world')
  })

  test('slice entire string', () => {
    expect(sliceAnsi('abc', 0)).toBe('abc')
  })

  test('empty slice (start === end)', () => {
    expect(sliceAnsi('abc', 2, 2)).toBe('')
  })

  test('preserves ANSI color codes within slice', () => {
    const input = '\x1b[31mred\x1b[0m normal'
    const result = sliceAnsi(input, 0, 3)
    expect(result).toContain('\x1b[31m')
    expect(result).toContain('red')
  })

  test('closes opened ANSI styles at slice end', () => {
    const input = '\x1b[31mhello world\x1b[0m'
    const result = sliceAnsi(input, 0, 5)
    expect(result).toContain('\x1b[31m')
    expect(result).toContain('hello')
    // undoAnsiCodes uses specific close codes (e.g. \x1b[39m for foreground)
    expect(result).toMatch(new RegExp(`${ESC}\\[\\d+m`))
    // The result should start with open code and end with a close code
    const withoutText = result.replace('hello', '')
    // Should have at least one open and one close code
    expect(withoutText.length).toBeGreaterThan(0)
  })

  test('slice starting mid-ANSI skips codes before start', () => {
    const input = '\x1b[31mhello\x1b[0m \x1b[32mworld\x1b[0m'
    const result = sliceAnsi(input, 6, 11)
    expect(result).toContain('world')
    expect(result).toContain('\x1b[32m')
    expect(result).not.toContain('\x1b[31m')
  })

  test('slice of plain text from middle', () => {
    expect(sliceAnsi('abcdefgh', 2, 5)).toBe('cde')
  })

  test('slice past end of string returns everything', () => {
    expect(sliceAnsi('abc', 0, 100)).toBe('abc')
  })

  test('slice starting at end returns empty', () => {
    expect(sliceAnsi('abc', 3)).toBe('')
  })

  test('handles empty string', () => {
    expect(sliceAnsi('', 0, 5)).toBe('')
  })

  test('multiple ANSI codes nested', () => {
    const input = '\x1b[1m\x1b[31mbold red\x1b[0m\x1b[0m'
    const result = sliceAnsi(input, 0, 4)
    expect(result).toContain('bold')
    // Both styles should be opened and then closed
    expect(result).toContain('\x1b[1m')
    expect(result).toContain('\x1b[31m')
  })

  test('slice with no end parameter returns to end of string', () => {
    expect(sliceAnsi('hello world', 6)).toBe('world')
  })

  test('ANSI codes at boundaries are handled correctly', () => {
    const input = 'a\x1b[31mb\x1b[0mc'
    // "abc" visually, position: a=0, b=1, c=2
    const result = sliceAnsi(input, 1, 2)
    // undoAnsiCodes uses \x1b[39m for foreground reset, not \x1b[0m
    expect(result).toContain('b')
    expect(result).toContain('\x1b[31m')
    expect(result).toMatch(new RegExp(`${ESC}\\[\\d+m.*${ESC}\\[\\d+m`)) // open + close codes
  })
})