import { describe, it, expect } from 'vitest'
import { generateTotp, totpRemainingSeconds, base32Decode, extractSecret, validateTotpSecret } from '../../../src/lib/crypto/totp.js'

// RFC 6238 test vectors (Appendix B, SHA-1) use the ASCII secret
// "12345678901234567890" whose base32 is GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ.
const RFC_SECRET = 'GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ'

describe('base32Decode', () => {
  it('decodes the RFC secret to the expected ASCII bytes', () => {
    const bytes = base32Decode(RFC_SECRET)
    expect(String.fromCharCode(...bytes)).toBe('12345678901234567890')
  })

  it('ignores whitespace and padding', () => {
    expect(base32Decode('JBSWY3DP EHPK3PXP').length).toBe(10)
    expect(base32Decode('JBSWY3DPEHPK3PXP==').length).toBe(10)
  })

  it('throws on invalid characters', () => {
    // '0','1','8','9' are not valid base32
    expect(() => base32Decode('ABC0')).toThrow(/Invalid base32/)
  })
})

describe('extractSecret', () => {
  it('passes through a bare base32 secret (normalized)', () => {
    expect(extractSecret('jbs-wy3dpehpk3pxp')).toBe('JBSWY3DPEHPK3PXP')
  })

  it('pulls the secret out of an otpauth:// URI', () => {
    expect(extractSecret('otpauth://totp/Example:alice?secret=JBSWY3DPEHPK3PXP&issuer=Example'))
      .toBe('JBSWY3DPEHPK3PXP')
  })

  it('returns empty string for empty input', () => {
    expect(extractSecret('')).toBe('')
    expect(extractSecret('   ')).toBe('')
  })
})

describe('generateTotp (RFC 6238 vectors)', () => {
  it('matches the RFC 6238 SHA-1 vectors at 6 digits', async () => {
    const vectors = [
      [59, '287082'],
      [1111111109, '081804'],
      [1111111111, '050471'],
      [1234567890, '005924'],
      [2000000000, '279037'],
      [20000000000, '353130'],
    ]
    for (const [t, expected] of vectors) {
      await expect(generateTotp(RFC_SECRET, { timestamp: t })).resolves.toBe(expected)
    }
  })

  it('supports custom digit counts', async () => {
    // 8-digit vector at t=59 is 94287082
    await expect(generateTotp(RFC_SECRET, { timestamp: 59, digits: 8 })).resolves.toBe('94287082')
  })

  it('rejects an empty/invalid secret', async () => {
    await expect(generateTotp('')).rejects.toThrow(/empty or invalid/)
    await expect(generateTotp('!!!!')).rejects.toThrow()
  })

  it('changes over time', async () => {
    const a = await generateTotp(RFC_SECRET, { timestamp: 30 })
    const b = await generateTotp(RFC_SECRET, { timestamp: 90 })
    // 30 and 90 map to counters 1 and 3 — codes differ.
    expect(a).not.toBe(b)
  })
})

describe('validateTotpSecret', () => {
  const GOOD = 'JBSWY3DPEHPK3PXP' // valid 10-byte base32 secret

  it('accepts a blank secret (optional)', () => {
    expect(validateTotpSecret('').valid).toBe(true)
    expect(validateTotpSecret('   ').valid).toBe(true)
  })

  it('accepts a valid bare base32 secret', () => {
    expect(validateTotpSecret(GOOD).valid).toBe(true)
  })

  it('accepts hyphen-grouped base32 and otpauth:// URIs', () => {
    expect(validateTotpSecret('JBSW-Y3DP-EHPK-3PXP').valid).toBe(true)
    expect(validateTotpSecret(`otpauth://totp/Example:alice?secret=${GOOD}&issuer=Example`).valid).toBe(true)
  })

  it('rejects invalid base32 characters', () => {
    const r = validateTotpSecret('ABC9012345678901')
    expect(r.valid).toBe(false)
    expect(r.error).toMatch(/Invalid TOTP secret/)
  })

  it('rejects a secret that is too short', () => {
    const r = validateTotpSecret('ABCDEF') // 4 decoded bytes < minBytes
    expect(r.valid).toBe(false)
    expect(r.error).toMatch(/too short/)
  })

  it('rejects an otpauth:// URI with no secret parameter', () => {
    const r = validateTotpSecret('otpauth://totp/x?issuer=y')
    expect(r.valid).toBe(false)
  })
})

describe('totpRemainingSeconds', () => {
  it('returns period for exact boundary', () => {
    expect(totpRemainingSeconds({ timestamp: 0, period: 30 })).toBe(30)
  })
  it('counts down within a period', () => {
    expect(totpRemainingSeconds({ timestamp: 5, period: 30 })).toBe(25)
    expect(totpRemainingSeconds({ timestamp: 29, period: 30 })).toBe(1)
  })
})