import { describe, it, expect } from 'vitest'
import { extractCodeBlocks } from '../../src/repl/code-blocks.js'

describe('extractCodeBlocks', () => {
  it('returns empty array for empty string', () => {
    expect(extractCodeBlocks('')).toEqual([])
  })

  it('returns empty array for null/falsy input', () => {
    expect(extractCodeBlocks(null as unknown as string)).toEqual([])
  })

  it('returns empty array when no fences present', () => {
    expect(extractCodeBlocks('Just some plain text, no code here.')).toEqual([])
  })

  it('extracts a single fenced block without language', () => {
    const md = '```\nhello world\n```'
    const result = extractCodeBlocks(md)
    expect(result).toHaveLength(1)
    expect(result[0].lang).toBeNull()
    expect(result[0].code).toBe('hello world')
  })

  it('extracts a block with a language tag', () => {
    const md = '```typescript\nconst x = 1\n```'
    const result = extractCodeBlocks(md)
    expect(result).toHaveLength(1)
    expect(result[0].lang).toBe('typescript')
    expect(result[0].code).toBe('const x = 1')
  })

  it('extracts multiple fenced blocks', () => {
    const md = '```bash\necho hi\n```\nsome text\n```python\nprint("hello")\n```'
    const result = extractCodeBlocks(md)
    expect(result).toHaveLength(2)
    expect(result[0].lang).toBe('bash')
    expect(result[0].code).toBe('echo hi')
    expect(result[1].lang).toBe('python')
    expect(result[1].code).toBe('print("hello")')
  })

  it('trims single trailing newline from code', () => {
    const md = '```js\nconsole.log(1)\n```'
    expect(extractCodeBlocks(md)[0].code).toBe('console.log(1)')
  })

  it('preserves intentional blank lines inside code', () => {
    const md = '```\nline1\n\nline3\n```'
    expect(extractCodeBlocks(md)[0].code).toBe('line1\n\nline3')
  })

  it('ignores empty fenced blocks (no content)', () => {
    const md = '```\n```'
    expect(extractCodeBlocks(md)).toEqual([])
  })

  it('handles language with spaces in the tag (trims it)', () => {
    const md = '```  js  \nconsole.log()\n```'
    const result = extractCodeBlocks(md)
    expect(result[0].lang).toBe('js')
  })

  it('handles language-only whitespace tag → null lang', () => {
    const md = '```   \ncode here\n```'
    const result = extractCodeBlocks(md)
    expect(result[0].lang).toBeNull()
  })

  it('extracts multi-line code block correctly', () => {
    const code = 'function foo() {\n  return 42\n}'
    const md = '```typescript\n' + code + '\n```'
    expect(extractCodeBlocks(md)[0].code).toBe(code)
  })
})