import { describe, expect, it, vi } from 'vitest'
import {
  encodePairingOffer,
  decodePairingOffer,
  parsePairingCode,
  type PairingOffer
} from './pairing'
import { PAIRING_INPUT_MAX_CHARACTERS } from './mobile-pairing-protocol-limits'

describe('pairing offer', () => {
  const offer: PairingOffer = {
    v: 2,
    endpoint: 'ws://192.168.1.10:6768',
    deviceToken: 'abcdef1234567890abcdef1234567890abcdef1234567890',
    publicKeyB64: 'dGVzdC1wdWJsaWMta2V5LWJhc2U2NC1lbmNvZGVk'
  }

  it('encode then decode round-trips correctly', () => {
    const url = encodePairingOffer(offer)
    expect(url).toMatch(/^orca:\/\/pair\?code=/)

    const decoded = decodePairingOffer(url)
    expect(decoded).toEqual(offer)
  })

  it('decodes in browser runtimes without Buffer', () => {
    const url = encodePairingOffer(offer)
    const nodeBuffer = Buffer
    let decoded: PairingOffer | null = null
    try {
      vi.stubGlobal('Buffer', undefined)
      decoded = decodePairingOffer(url)
    } finally {
      vi.stubGlobal('Buffer', nodeBuffer)
    }
    expect(decoded).toEqual(offer)
  })

  it('preserves partial padding consistently across Node and browser runtimes', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!
    expect(code.length % 4).toBe(2)
    const malformedCode = `${code}=`
    const nodeDecoded = parsePairingCode(malformedCode)
    const nodeBuffer = Buffer
    let browserDecoded: PairingOffer | null = null
    try {
      vi.stubGlobal('Buffer', undefined)
      browserDecoded = parsePairingCode(malformedCode)
    } finally {
      vi.stubGlobal('Buffer', nodeBuffer)
    }

    expect({ nodeDecoded, browserDecoded }).toEqual({
      nodeDecoded: offer,
      browserDecoded: offer
    })
  })

  it('preserves non-zero pad bits consistently across Node and browser runtimes', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!
    expect(code.length % 4).toBe(2)
    const alias = `${code.slice(0, -1)}${base64Alias(code.at(-1)!)}`
    const nodeDecoded = parsePairingCode(alias)
    const nodeBuffer = Buffer
    let browserDecoded: PairingOffer | null = null
    try {
      vi.stubGlobal('Buffer', undefined)
      browserDecoded = parsePairingCode(alias)
    } finally {
      vi.stubGlobal('Buffer', nodeBuffer)
    }

    expect({ nodeDecoded, browserDecoded }).toEqual({
      nodeDecoded: offer,
      browserDecoded: offer
    })
  })

  it('accepts canonical base64 padding', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!
    expect(code.length % 4).toBe(2)

    expect(parsePairingCode(`${code}==`)).toEqual(offer)
  })

  it('preserves optional device scope metadata', () => {
    const scopedOffer: PairingOffer = { ...offer, scope: 'mobile' }
    expect(decodePairingOffer(encodePairingOffer(scopedOffer))).toEqual(scopedOffer)
  })

  it('round-trips a TLS reverse-proxy endpoint with an explicit port and path', () => {
    const proxiedOffer = {
      ...offer,
      endpoint: 'wss://proxy.example:443/orca/runtime'
    }

    expect(decodePairingOffer(encodePairingOffer(proxiedOffer))).toEqual(proxiedOffer)
  })

  it('encoded URL uses base64url (no +, /, or = characters)', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!
    expect(code).not.toMatch(/[+/=]/)
  })

  it('rejects URLs with wrong scheme', () => {
    expect(() => decodePairingOffer('https://example.com#abc')).toThrow('Invalid pairing URL')
  })

  it('rejects orca URLs outside the exact pairing route', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!

    expect(parsePairingCode(`orca://pairing?code=${code}`)).toBeNull()
    expect(parsePairingCode(`orca://pair-extra?code=${code}`)).toBeNull()
    expect(() => decodePairingOffer(`orca://pairing?code=${code}`)).toThrow('Invalid pairing URL')
  })

  it('rejects URLs without a pairing code', () => {
    expect(() => decodePairingOffer('orca://pair')).toThrow('Invalid pairing URL')
  })

  it('decodes legacy hash URLs', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!
    expect(decodePairingOffer(`orca://pair#${code}`)).toEqual(offer)
  })

  it('rejects oversized whole URLs before parsing', () => {
    const url = encodePairingOffer(offer)
    const oversizedUrl = `${url}&ignored=${'A'.repeat(PAIRING_INPUT_MAX_CHARACTERS)}`

    expect(() => decodePairingOffer(oversizedUrl)).toThrow(
      'Invalid pairing URL: pairing code exceeds safe size'
    )
  })

  it('rejects payloads with missing fields', () => {
    const partial = { v: 2, endpoint: 'ws://host:1234' }
    const base64 = Buffer.from(JSON.stringify(partial)).toString('base64')
    expect(() => decodePairingOffer(`orca://pair#${base64}`)).toThrow()
  })

  it('rejects payloads with wrong version', () => {
    const wrong = { ...offer, v: 1 }
    const base64 = Buffer.from(JSON.stringify(wrong)).toString('base64')
    expect(() => decodePairingOffer(`orca://pair#${base64}`)).toThrow()
  })

  it('rejects payloads with missing publicKeyB64', () => {
    const wrong = { v: 2, endpoint: 'ws://host:1234', deviceToken: 'tok' }
    const base64 = Buffer.from(JSON.stringify(wrong)).toString('base64')
    expect(() => decodePairingOffer(`orca://pair#${base64}`)).toThrow()
  })
})

describe('parsePairingCode', () => {
  const offer: PairingOffer = {
    v: 2,
    endpoint: 'ws://192.168.1.10:6768',
    deviceToken: 'token-abc',
    publicKeyB64: 'pubkey-xyz'
  }

  it('parses a full orca://pair# URL', () => {
    const url = encodePairingOffer(offer)
    expect(parsePairingCode(url)).toEqual(offer)
  })

  it('parses a bare base64url payload (without scheme prefix)', () => {
    const url = encodePairingOffer(offer)
    const base64url = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!
    expect(parsePairingCode(base64url)).toEqual(offer)
  })

  it('tolerates surrounding whitespace from clipboard', () => {
    const url = encodePairingOffer(offer)
    expect(parsePairingCode(`  ${url}\n`)).toEqual(offer)
  })

  it('rejects oversized whole raw input before trimming', () => {
    const url = encodePairingOffer(offer)
    const code = new URLSearchParams(url.slice(url.indexOf('?') + 1)).get('code')!

    expect(parsePairingCode(`${code}${' '.repeat(PAIRING_INPUT_MAX_CHARACTERS)}`)).toBeNull()
  })

  it('returns null for empty input', () => {
    expect(parsePairingCode('')).toBeNull()
    expect(parsePairingCode('   ')).toBeNull()
  })

  it('returns null for garbage input', () => {
    expect(parsePairingCode('not a pairing code')).toBeNull()
    expect(parsePairingCode('https://example.com')).toBeNull()
  })

  it('returns null for valid base64 of unrelated JSON', () => {
    const bogus = Buffer.from(JSON.stringify({ hello: 'world' })).toString('base64')
    expect(parsePairingCode(bogus)).toBeNull()
  })
})

function base64Alias(character: string): string {
  const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_'
  return alphabet[alphabet.indexOf(character) + 1]!
}