import { test } from '@japa/runner'
import { crc32 } from 'node:zlib'
import { decodeRar4Name, parseRarHeaders, rarFormat, storedEntryData, walkRar, type RarEntry, type VolumeReader } from '#lib/rar/index'
import { crc32Hex } from '#lib/yenc/index'

/** Entries without the extraction fields, for comparing listings. */
const listing = (entries: RarEntry[]) => entries.map(({ stored, dataOffset, ...rest }) => rest)

// --- RAR 4 builders -----------------------------------------------------------

const RAR4 = Buffer.from([0x52, 0x61, 0x72, 0x21, 0x1a, 0x07, 0x00])

function rar4Block(type: number, flags: number, body: Buffer) {
  const header = Buffer.alloc(7)
  header.writeUInt8(type, 2)
  header.writeUInt16LE(flags, 3)
  header.writeUInt16LE(7 + body.length, 5)
  const block = Buffer.concat([header, body])
  block.writeUInt16LE(crc32(block.subarray(2)) & 0xffff, 0)
  return block
}

function rar4Main(flags: number) {
  return rar4Block(0x73, flags, Buffer.alloc(6))
}

function rar4File(name: Buffer, opts: { flags?: number; packed: number; unpacked: number; method?: number }) {
  const body = Buffer.alloc(25)
  body.writeUInt8(opts.method ?? 0x33, 18)
  body.writeUInt32LE(opts.packed, 0)
  body.writeUInt32LE(opts.unpacked, 4)
  body.writeUInt16LE(name.length, 19)
  // LONG_BLOCK (0x8000) is always set on file headers.
  return Buffer.concat([rar4Block(0x74, 0x8000 | (opts.flags ?? 0), Buffer.concat([body, name])), Buffer.alloc(opts.packed)])
}

// --- RAR 5 builders -----------------------------------------------------------

const RAR5 = Buffer.from([0x52, 0x61, 0x72, 0x21, 0x1a, 0x07, 0x01, 0x00])

function vint(value: number) {
  const bytes: number[] = []
  do {
    let byte = value % 128
    value = Math.floor(value / 128)
    if (value > 0) byte |= 0x80
    bytes.push(byte)
  } while (value > 0)
  return Buffer.from(bytes)
}

function rar5Block(type: number, headerFlags: number, fields: Buffer, opts: { extra?: Buffer; data?: number } = {}) {
  let flags = headerFlags
  const parts = [vint(type)]
  const sizes: Buffer[] = []
  if (opts.extra) {
    flags |= 0x0001
    sizes.push(vint(opts.extra.length))
  }
  if (opts.data !== undefined) {
    flags |= 0x0002
    sizes.push(vint(opts.data))
  }
  const header = Buffer.concat([...parts, vint(flags), ...sizes, fields, opts.extra ?? Buffer.alloc(0)])
  const sized = Buffer.concat([vint(header.length), header])
  const crc = Buffer.alloc(4)
  crc.writeUInt32LE(crc32(sized) >>> 0)
  return Buffer.concat([crc, sized, Buffer.alloc(opts.data ?? 0)])
}

function rar5File(name: string, size: number, opts: { packed: number; headerFlags?: number; encrypted?: boolean; dir?: boolean }) {
  const nameBuf = Buffer.from(name, 'utf8')
  const fields = Buffer.concat([
    vint(opts.dir ? 0x0001 : 0), // file flags
    vint(size),
    vint(0x20), // attributes
    vint(0), // compression info
    vint(0), // host OS
    vint(nameBuf.length),
    nameBuf,
  ])
  // Encryption record: size, type 1, then its data (dummy here).
  const extra = opts.encrypted ? Buffer.concat([vint(3), vint(0x01), Buffer.from([0, 0])]) : undefined
  return rar5Block(2, opts.headerFlags ?? 0, fields, { extra, data: opts.packed })
}

test.group('rar / RAR 4', () => {
  test('lists files of a first volume, including 64-bit sizes and flags', ({ assert }) => {
    const data = Buffer.concat([
      RAR4,
      rar4Main(0x0001 | 0x0100), // volume, first volume
      rar4File(Buffer.from('Some.Movie.2024/movie.mkv'), { packed: 10, unpacked: 5_000_000, flags: 0x0002 }),
    ])
    assert.equal(rarFormat(data), 'rar4')
    const info = parseRarHeaders(data)!
    assert.include(info, { format: 'rar4', volume: true, firstVolume: true, headersEncrypted: false, truncated: true })
    assert.deepEqual(listing(info.entries), [
      { name: 'Some.Movie.2024/movie.mkv', size: 5_000_000, packedSize: 10, directory: false, encrypted: false, splitBefore: false, splitAfter: true },
    ])
  })

  test('detects password-protected files and encrypted headers', ({ assert }) => {
    const files = parseRarHeaders(
      Buffer.concat([RAR4, rar4Main(0), rar4File(Buffer.from('secret.bin'), { packed: 4, unpacked: 4, flags: 0x0004 })])
    )!
    assert.isTrue(files.entries[0].encrypted)
    const headers = parseRarHeaders(Buffer.concat([RAR4, rar4Main(0x0080)]))!
    assert.isTrue(headers.headersEncrypted)
    assert.lengthOf(headers.entries, 0)
  })

  test('copies out stored entries, not compressed ones', ({ assert }) => {
    const data = Buffer.concat([
      RAR4,
      rar4Main(0),
      rar4File(Buffer.from('a.nzb'), { packed: 5, unpacked: 5, method: 0x30 }),
      rar4File(Buffer.from('b.nzb'), { packed: 5, unpacked: 9 }),
    ])
    const [stored, packed] = parseRarHeaders(data)!.entries
    data.write('<nzb>', stored.dataOffset)
    assert.equal(storedEntryData(data, stored)?.toString(), '<nzb>')
    assert.isFalse(packed.stored)
    assert.isNull(storedEntryData(data, packed))
  })

  test('stops at a header with a bad CRC', ({ assert }) => {
    const good = rar4File(Buffer.from('a.bin'), { packed: 1, unpacked: 1 })
    const bad = rar4File(Buffer.from('b.bin'), { packed: 1, unpacked: 1 })
    bad[10] ^= 0xff
    const info = parseRarHeaders(Buffer.concat([RAR4, rar4Main(0), good, bad]))!
    assert.deepEqual(info.entries.map((e) => e.name), ['a.bin'])
  })

  test('decodes compressed Unicode names', ({ assert }) => {
    // "é.txt": ASCII fallback "?.txt", then highByte 0, flags 0b01_00_00_00 (é via high byte,
    // then 3 plain bytes), followed by one more flag byte for the last byte.
    const ascii = Buffer.from('?.txt', 'latin1')
    const encoded = Buffer.from([0x00, 0b01000000, 0xe9, 0x2e, 0x74, 0x78, 0b00000000, 0x74])
    assert.equal(decodeRar4Name(Buffer.concat([ascii, Buffer.from([0]), encoded])), 'é.txt')
    assert.equal(decodeRar4Name(Buffer.from('plain.txt')), 'plain.txt')
  })
})

test.group('rar / RAR 5', () => {
  test('lists files and reads volume flags', ({ assert }) => {
    const data = Buffer.concat([
      RAR5,
      rar5Block(1, 0, vint(0x0001)), // main: volume, no volume number → first volume
      rar5File('Release/track01.flac', 30_000_000, { packed: 20, headerFlags: 0x0010 }),
    ])
    assert.equal(rarFormat(data), 'rar5')
    const info = parseRarHeaders(data)!
    assert.include(info, { format: 'rar5', volume: true, firstVolume: true, headersEncrypted: false })
    assert.deepEqual(listing(info.entries), [
      { name: 'Release/track01.flac', size: 30_000_000, packedSize: 20, directory: false, encrypted: false, splitBefore: false, splitAfter: true },
    ])
  })

  test('a later volume carries a volume number', ({ assert }) => {
    const info = parseRarHeaders(Buffer.concat([RAR5, rar5Block(1, 0, Buffer.concat([vint(0x0003), vint(4)]))]))!
    assert.isFalse(info.firstVolume)
  })

  test('detects encrypted files and encrypted headers', ({ assert }) => {
    const files = parseRarHeaders(Buffer.concat([RAR5, rar5Block(1, 0, vint(0)), rar5File('x.mkv', 1, { packed: 1, encrypted: true })]))!
    assert.isTrue(files.entries[0].encrypted)
    const headers = parseRarHeaders(Buffer.concat([RAR5, rar5Block(4, 0, Buffer.alloc(3))]))!
    assert.isTrue(headers.headersEncrypted)
  })

  test('marks the listing complete at the end-of-archive header', ({ assert }) => {
    const info = parseRarHeaders(Buffer.concat([RAR5, rar5Block(1, 0, vint(0)), rar5File('a', 1, { packed: 1 }), rar5Block(5, 0, vint(0))]))!
    assert.isFalse(info.truncated)
    assert.lengthOf(info.entries, 1)
  })

  test('copies out entries stored without compression', ({ assert }) => {
    const data = Buffer.concat([RAR5, rar5Block(1, 0, vint(0)), rar5File('a.nzb', 5, { packed: 5 }), rar5Block(5, 0, vint(0))])
    const entry = parseRarHeaders(data)!.entries[0]
    assert.isTrue(entry.stored)
    data.write('<nzb>', entry.dataOffset)
    assert.equal(storedEntryData(data, entry)?.toString(), '<nzb>')
    assert.isNull(storedEntryData(data.subarray(0, entry.dataOffset + 2), entry))
    assert.isNull(storedEntryData(data, { ...entry, encrypted: true }))
  })

  test('returns null for other data', ({ assert }) => {
    assert.isNull(parseRarHeaders(Buffer.from('PAR2\0PKT', 'latin1')))
  })
})

test.group('rar / release naming from contents', () => {
  const info = (names: string[]) =>
    ({ format: 'rar5', volume: false, firstVolume: true, solid: false, headersEncrypted: false, truncated: true,
       entries: names.map((name) => ({ name, size: 1, packedSize: 1, directory: false, encrypted: false, splitBefore: false, splitAfter: false })) }) as any

  test('uses the shared top-level directory when it looks like a release name', async ({ assert }) => {
    const { releaseNameFromContents } = await import('#services/ArchiveService')
    assert.equal(
      releaseNameFromContents(info(['GLDY_LX_-_Pretty_Girl_Rage_EP-WEB-2026-DIM/00-a.jpg', 'GLDY_LX_-_Pretty_Girl_Rage_EP-WEB-2026-DIM/01-b.flac'])),
      'GLDY_LX_-_Pretty_Girl_Rage_EP-WEB-2026-DIM'
    )
    // No directory: the largest readable entry names the release.
    assert.equal(
      releaseNameFromContents(info(['Joker.Folie.a.Deux.2024.2160p.HMAX.WEB-DL.MULTi.DDP5.1.Atmos.H.265.nzb'])),
      'Joker.Folie.a.Deux.2024.2160p.HMAX.WEB-DL.MULTi.DDP5.1.Atmos.H.265'
    )
    assert.isUndefined(releaseNameFromContents(info(['movie.mkv'])))
    assert.isUndefined(releaseNameFromContents(info(['Xq8r2KdLm3Zw91PqA7.mkv'])))
    assert.isUndefined(releaseNameFromContents(info(['a/x', 'b/y'])))
    assert.isUndefined(releaseNameFromContents(info(['Xq8r2KdLm3Zw91Pq/x.mkv'])))
  })

  test('recognises obfuscated names', async ({ assert }) => {
    const { looksRandom } = await import('#services/ArchiveService')
    assert.isTrue(looksRandom('CGBWgdhlSCAOAW62gLWRRM'))
    assert.isTrue(looksRandom('0220e975b1417f96b77dc64410e10ebc'))
    assert.isFalse(looksRandom('Plus.and.Minus.S01E06.1080p'))
    assert.isFalse(looksRandom('1790546808_nicovideo_jp_watch_sm26679715'))
  })
})

test.group('rar / looksRandom capitals', () => {
  test('long letter-only tokens with many capitals are random', async ({ assert }) => {
    const { looksRandom } = await import('#services/ArchiveService')
    assert.isTrue(looksRandom('RmISakytFwXSCEzjVEpaKk'))
    assert.isTrue(looksRandom('326678d1d07ef12a.bin'))
    assert.isFalse(looksRandom('Some.Show.S01E01'))
    assert.isFalse(looksRandom('TheQuickBrownFoxJumps'))
  })
})

// --- Archive walks (D40) --------------------------------------------------------

/** Volumes split into segments of `segmentSize` bytes; counts the segments read. */
function memoryReader(volumes: Buffer[], segmentSize: number) {
  const read = new Set<string>()
  const reader: VolumeReader & { segments: Set<string> } = {
    segments: read,
    volumes: volumes.length,
    size: (v) => volumes[v].length,
    async read(v, offset, more) {
      const index = Math.floor(offset / segmentSize)
      if (offset >= volumes[v].length) return null
      read.add(`${v}:${index}`)
      if (more) read.add(`${v}:${index + 1}`)
      return volumes[v].subarray(offset, (index + (more ? 2 : 1)) * segmentSize)
    },
  }
  return reader
}

function rar5Set() {
  const main = (n: number) => rar5Block(1, 0, n === 0 ? vint(0x0001) : Buffer.concat([vint(0x0003), vint(n)]))
  const end = rar5Block(5, 0, vint(0x0001))
  const SPLIT_BEFORE = 0x0008
  const SPLIT_AFTER = 0x0010
  return [
    Buffer.concat([RAR5, main(0), rar5File('Book/01.mp3', 3000, { packed: 3000 }), rar5File('Book/02.mp3', 7000, { packed: 5000, headerFlags: SPLIT_AFTER }), end]),
    Buffer.concat([
      RAR5,
      main(1),
      rar5File('Book/02.mp3', 7000, { packed: 2000, headerFlags: SPLIT_BEFORE }),
      rar5File('Book/03.mp3', 1000, { packed: 1000 }),
      rar5File('Book/04.mp3', 4500, { packed: 4000, headerFlags: SPLIT_AFTER }),
      end,
    ]),
    Buffer.concat([RAR5, main(2), rar5File('Book/04.mp3', 4500, { packed: 500, headerFlags: SPLIT_BEFORE }), rar5File('Book/05.mp3', 100, { packed: 100 }), rar5Block(5, 0, vint(0))]),
  ]
}

test.group('rar / archive walks', () => {
  test('lists every entry of a RAR5 set, reading a segment per header', async ({ assert }) => {
    // 700-byte segments: headers get cut off by segment ends.
    const reader = memoryReader(rar5Set(), 700)
    const walk = await walkRar(reader)
    assert.isTrue(walk.complete)
    assert.equal(walk.format, 'rar5')
    assert.deepEqual(walk.entries.map((e) => e.name), ['Book/01.mp3', 'Book/02.mp3', 'Book/03.mp3', 'Book/04.mp3', 'Book/05.mp3'])
    assert.equal(walk.entries[1].size, 7000)
    const total = rar5Set().reduce((sum, v) => sum + Math.ceil(v.length / 700), 0)
    assert.isBelow(reader.segments.size, total / 2)
  })

  test('lists a RAR4 set across volumes', async ({ assert }) => {
    const end = rar4Block(0x7b, 0, Buffer.alloc(0))
    const volumes = [
      Buffer.concat([RAR4, rar4Main(0x0001 | 0x0100), rar4File(Buffer.from('a.flac'), { packed: 900, unpacked: 900 }), rar4File(Buffer.from('b.flac'), { packed: 2000, unpacked: 2500, flags: 0x0002 }), end]),
      Buffer.concat([RAR4, rar4Main(0x0001), rar4File(Buffer.from('b.flac'), { packed: 500, unpacked: 2500, flags: 0x0001 }), rar4File(Buffer.from('c.flac'), { packed: 10, unpacked: 10 }), end]),
    ]
    const walk = await walkRar(memoryReader(volumes, 512))
    assert.isTrue(walk.complete)
    assert.deepEqual(walk.entries.map((e) => e.name), ['a.flac', 'b.flac', 'c.flac'])
  })

  test('stops at a missing segment or a broken header, keeping what it found', async ({ assert }) => {
    const set = rar5Set()
    const missing = memoryReader(set, 700)
    const read = missing.read.bind(missing)
    missing.read = async (v, offset, more) => (v === 1 ? null : read(v, offset, more))
    const partial = await walkRar(missing)
    assert.equal(partial.stopped, 'unreadable')
    assert.deepEqual(partial.entries.map((e) => e.name), ['Book/01.mp3', 'Book/02.mp3'])

    const broken = rar5Set()
    // The header of 03.mp3 in volume 2, after 02.mp3's continuation and its data.
    const at = broken[1].indexOf(Buffer.from('Book/03.mp3')) - 4
    broken[1][at] ^= 0xff
    const invalid = await walkRar(memoryReader(broken, 700))
    assert.equal(invalid.stopped, 'invalid')
    assert.lengthOf(invalid.entries, 2)
  })

  test('finds segments from their yEnc offsets', async ({ assert }) => {
    const { SegmentReader } = await import('#services/ArchiveWalkService')
    const set = rar5Set()
    const size = 700
    const articles = new Map<string, Buffer>()
    const files = set.map((volume, v) => {
      const segments = []
      for (let i = 0; i * size < volume.length; i++) {
        const id = `v${v}s${i}@test`
        articles.set(id, yencArticle(`x.part${v + 1}.rar`, volume, i, size))
        segments.push({ number: i + 1, id, size: 0 })
      }
      return { id: v + 1, segments }
    })
    const reader = new SegmentReader(files, 100, async (id) => articles.get(id)!)
    const walk = await walkRar(reader)
    assert.isTrue(walk.complete)
    assert.lengthOf(walk.entries, 5)
    assert.isBelow(reader.fetched, articles.size / 2)

    const capped = new SegmentReader(files, 3, async (id) => articles.get(id)!)
    const stopped = await walkRar(capped)
    assert.equal(stopped.stopped, 'unreadable')
    assert.equal(capped.fetched, 3)
  })
})

/** One yEnc article of `file`: part `index` of `size` bytes. */
function yencArticle(name: string, file: Buffer, index: number, size: number) {
  const data = file.subarray(index * size, (index + 1) * size)
  const total = Math.ceil(file.length / size)
  const out: number[] = []
  for (const byte of data) {
    const c = (byte + 42) & 0xff
    // Escape the critical characters, and '.' and whitespace so no line needs dot-stuffing.
    if ([0x00, 0x0a, 0x0d, 0x3d, 0x2e, 0x09, 0x20].includes(c)) out.push(0x3d, (c + 64) & 0xff)
    else out.push(c)
  }
  const lines: string[] = []
  const encoded = Buffer.from(out)
  for (let i = 0; i < encoded.length; i += 128) {
    let end = Math.min(encoded.length, i + 128)
    if (encoded[end - 1] === 0x3d && end < encoded.length) end++
    lines.push(encoded.subarray(i, end).toString('latin1'))
    i = end - 128
  }
  const head = `=ybegin part=${index + 1} total=${total} line=128 size=${file.length} name=${name}\r\n=ypart begin=${index * size + 1} end=${index * size + data.length}\r\n`
  const tail = `\r\n=yend size=${data.length} part=${index + 1} pcrc32=${crc32Hex(data)}\r\n`
  return Buffer.from(head + lines.join('\r\n') + tail, 'latin1')
}