const BARE_MESHDROP_CHUNK_RAW = 12 * 1024

function bareMeshdropName(path) {
  const parts = String(path || '').split('/')
  return parts[parts.length - 1] || 'file.bin'
}

function bareMeshdropChunkB64Limit() {
  const raw = BARE_MESHDROP_CHUNK_RAW
  return Math.ceil((raw * 4) / 3) + 16
}

function bareMeshdropChunkSliceB64(b64, index) {
  const max = bareMeshdropChunkB64Limit()
  const from = index * max
  const to = Math.min(b64.length, from + max)
  return b64.slice(from, to)
}

async function bareMeshdropDbRead(ctx) {
  const p = bareP2pDataFile(ctx, 'meshdrop')
  const cur = await bareP2pReadJson(ctx, p)
  if (cur && typeof cur === 'object') return cur
  return {
    schema: 2,
    outgoing: {},
    incoming: {},
    transfers: {}
  }
}

async function bareMeshdropDbWrite(ctx, db) {
  return bareP2pWriteJson(ctx, bareP2pDataFile(ctx, 'meshdrop'), db)
}

function bareMeshdropEnsureTransfer(db, transferId) {
  if (!db.transfers || typeof db.transfers !== 'object') db.transfers = {}
  if (!db.transfers[transferId]) {
    db.transfers[transferId] = {
      transferId,
      status: 'new',
      chunksTotal: 0,
      chunksReceived: 0,
      updatedAtMs: Date.now()
    }
  }
  return db.transfers[transferId]
}

async function run(ctx, argv) {
  const argv0 = argv[0] || 'meshdrop'
  const parsed = bareP2pParseCommonFlags(argv.slice(1))
  const args = parsed.rest
  const opt = parsed.opt
  if (opt.help || args.length === 0) {
    ctx.console.log(
      bareP2pHelpText(
        argv0,
        'P2P file inbox/outbox over bare-p2p envelopes on chat transport.',
        argv0 +
          ' offer FILE [--to PEER_HINT] | send-next OFFER_ID [MAX_CHUNKS] | inbox [N] | accept OFFER_ID | fetch OFFER_ID [DEST] | status [TRANSFER_ID] | cancel TRANSFER_ID',
        ['offer ./file.bin --to peerHint', 'send-next offer-123 8', 'status --summary'],
        ['swarmtop', 'peerctl']
      )
    )
    if (args.length === 0) ctx.exitCode = 1
    return
  }

  const sub = args[0]
  if (sub === 'offer') {
    const file = args[1]
    if (!file) {
      return bareP2pError(ctx, argv0, 'offer requires FILE', argv0 + ' --help', opt)
    }
    const b = await ctx.vfs.readFile(file)
    if (!b) {
      return bareP2pError(ctx, argv0, 'unable to read ' + file, 'check file path', opt)
    if (opt.dryRun) {
      bareP2pPrint(ctx, { ok: true, dryRun: true, action: 'offer', file, to }, opt)
      return
    }
    }
    const b64 = ctx.b4a.toString(b, 'base64')
    const toIdx = args.indexOf('--to')
    const to = toIdx >= 0 ? String(args[toIdx + 1] || '').trim() : ''
    const offerId = bareP2pId('offer')
    const transferId = bareP2pId('xfer')
    const chunkChars = bareMeshdropChunkB64Limit()
    const chunksTotal = Math.max(1, Math.ceil(b64.length / chunkChars))
    const firstChunk = bareMeshdropChunkSliceB64(b64, 0)
    const db = await bareMeshdropDbRead(ctx)
    if (!db.outgoing || typeof db.outgoing !== 'object') db.outgoing = {}
    db.outgoing[offerId] = {
      offerId,
      transferId,
      file,
      fileName: bareMeshdropName(file),
      byteLength: b.byteLength,
      base64: b64,
      chunkChars,
      chunksTotal,
      sentChunks: firstChunk ? 1 : 0,
      to,
      status: 'offered',
      updatedAtMs: Date.now()
    }
    const tr = bareMeshdropEnsureTransfer(db, transferId)
    tr.role = 'sender'
    tr.offerId = offerId
    tr.status = 'offered'
    tr.chunksTotal = chunksTotal
    tr.chunksReceived = 0
    tr.updatedAtMs = Date.now()
    await bareMeshdropDbWrite(ctx, db)

    if (typeof ctx.bareOsEmitMirrorDriveHint === 'function') {
      ctx.bareOsEmitMirrorDriveHint({
        app: 'meshdrop',
        phase: 'offer',
        offerId,
        transferId,
        fileName: bareMeshdropName(file),
        byteLength: b.byteLength,
        chunksTotal
      })
    }
    const r = bareP2pSend(ctx, 'meshdrop', 'offer', {
      offerId,
      transferId,
      fromPath: file,
      fileName: bareMeshdropName(file),
      byteLength: b.byteLength,
      chunkChars,
      chunksTotal,
      firstChunkB64: firstChunk,
      to
    })
    if (r && r.ok === false) {
      return bareP2pError(ctx, argv0, String(r.reason || 'send failed'), 'swarmdoctor', opt)
    }
    bareP2pPrint(ctx, 'offered ' + file + ' as ' + offerId + ' (' + chunksTotal + ' chunks)', opt)
    bareP2pMaybeNext(ctx, opt, argv0 + ' send-next ' + offerId)
    return
  }

  if (sub === 'send-next') {
    const offerId = String(args[1] || '').trim()
    if (!offerId) {
      return bareP2pError(ctx, argv0, 'send-next requires OFFER_ID', argv0 + ' status', opt)
    }
    const maxChunks = Math.max(
      1,
      Math.min(64, parseInt(args[2] || '8', 10) || 8)
    )
    const db = await bareMeshdropDbRead(ctx)
    const rec = db?.outgoing?.[offerId]
    if (!rec) {
      return bareP2pError(ctx, argv0, 'unknown offer: ' + offerId, argv0 + ' status', opt)
    }
    let sent = 0
    while (sent < maxChunks && rec.sentChunks < rec.chunksTotal) {
      const idx = rec.sentChunks
      const chunk = bareMeshdropChunkSliceB64(rec.base64, idx)
      const r = bareP2pSend(ctx, 'meshdrop', 'chunk', {
        offerId: rec.offerId,
        transferId: rec.transferId,
        index: idx,
        chunksTotal: rec.chunksTotal,
        chunkB64: chunk
      })
      if (r && r.ok === false) break
      rec.sentChunks++
      rec.updatedAtMs = Date.now()
      sent++
    }
    rec.status = rec.sentChunks >= rec.chunksTotal ? 'all-chunks-sent' : 'sending'
    const tr = bareMeshdropEnsureTransfer(db, rec.transferId)
    tr.status = rec.status
    tr.updatedAtMs = rec.updatedAtMs
    await bareMeshdropDbWrite(ctx, db)
    bareP2pSend(ctx, 'meshdrop', 'progress', {
      offerId: rec.offerId,
      transferId: rec.transferId,
      sentChunks: rec.sentChunks,
      chunksTotal: rec.chunksTotal
    })
    bareP2pPrint(ctx, 'sent ' + sent + ' chunk(s), ' + rec.sentChunks + '/' + rec.chunksTotal, opt)
    return
  }

  if (sub === 'inbox') {
    const n = Math.max(1, Math.min(200, parseInt(args[1] || '20', 10) || 20))
    const rows = bareP2pCollectFromHistory(ctx, 'meshdrop', 2000)
    const offers = rows.filter((r) => r.packet?.kind === 'offer').slice(-n)
    for (const row of offers) {
      const p = row.packet?.payload || {}
      const offerId = typeof p.offerId === 'string' ? p.offerId : '?'
      const fileName = typeof p.fileName === 'string' ? p.fileName : '?'
      const bytes = typeof p.byteLength === 'number' ? p.byteLength : 0
      const chunks = typeof p.chunksTotal === 'number' ? p.chunksTotal : '?'
      const from = row.displayName || row.fromPeerKey.slice(0, 10) || 'peer'
      bareP2pPrint(ctx,
        '[' +
          bareP2pFmtClock(row.receivedAtMs) +
          '] ' +
          offerId +
          '  ' +
          fileName +
          '  ' +
          bytes +
          'B  chunks=' +
          String(chunks) +
          '  from=' +
          from
      , opt)
    }
    return
  }

  if (sub === 'accept') {
    const offerId = String(args[1] || '').trim()
    if (!offerId) {
      return bareP2pError(ctx, argv0, 'accept requires OFFER_ID', argv0 + ' inbox', opt)
    }
    const rows = bareP2pCollectFromHistory(ctx, 'meshdrop', 2000)
    const offer = rows.findLast(
      (r) =>
        r.packet?.kind === 'offer' &&
        r.packet.payload &&
        typeof r.packet.payload === 'object' &&
        r.packet.payload.offerId === offerId
    )
    if (!offer) {
      return bareP2pError(ctx, argv0, 'offer not found: ' + offerId, argv0 + ' inbox', opt)
    }
    const p = offer.packet.payload
    const transferId =
      typeof p.transferId === 'string' ? p.transferId : bareP2pId('xfer')
    const fileName =
      typeof p.fileName === 'string' ? p.fileName : offerId + '.received'
    const chunksTotal = typeof p.chunksTotal === 'number' ? p.chunksTotal : 1
    const db = await bareMeshdropDbRead(ctx)
    if (!db.incoming || typeof db.incoming !== 'object') db.incoming = {}
    db.incoming[offerId] = {
      offerId,
      transferId,
      fileName,
      chunksTotal,
      chunks: {},
      acceptedAtMs: Date.now(),
      status: 'accepted'
    }
    if (typeof p.firstChunkB64 === 'string' && p.firstChunkB64) {
      db.incoming[offerId].chunks[0] = p.firstChunkB64
    }
    const tr = bareMeshdropEnsureTransfer(db, transferId)
    tr.role = 'receiver'
    tr.offerId = offerId
    tr.status = 'accepted'
    tr.chunksTotal = chunksTotal
    tr.chunksReceived = Object.keys(db.incoming[offerId].chunks).length
    tr.updatedAtMs = Date.now()
    await bareMeshdropDbWrite(ctx, db)
    bareP2pSend(ctx, 'meshdrop', 'accept', { offerId, transferId })
    bareP2pPrint(ctx, 'accepted ' + offerId + ' (transfer ' + transferId + ')', opt)
    return
  }

  if (sub === 'fetch') {
    const offerId = String(args[1] || '').trim()
    if (!offerId) {
      return bareP2pError(ctx, argv0, 'fetch requires OFFER_ID', argv0 + ' inbox', opt)
    }
    const rows = bareP2pCollectFromHistory(ctx, 'meshdrop', 2000)
    const offer = rows.findLast(
      (r) =>
        r.packet?.kind === 'offer' &&
        r.packet.payload &&
        typeof r.packet.payload === 'object' &&
        r.packet.payload.offerId === offerId
    )
    if (!offer) {
      return bareP2pError(ctx, argv0, 'offer not found: ' + offerId, argv0 + ' inbox', opt)
    }
    const p = offer.packet.payload
    const fileName =
      typeof p.fileName === 'string' ? p.fileName : offerId + '.bin'
    const dest = args[2] || fileName
    const db = await bareMeshdropDbRead(ctx)
    const incoming = db?.incoming?.[offerId]
    if (!incoming) {
      return bareP2pError(ctx, argv0, 'offer not accepted locally', argv0 + ' accept ' + offerId, opt)
    }
    const chunks = incoming.chunks && typeof incoming.chunks === 'object' ? incoming.chunks : {}
    const total = typeof incoming.chunksTotal === 'number' ? incoming.chunksTotal : 0
    const pieces = []
    for (let i = 0; i < total; i++) {
      const part = chunks[i]
      if (typeof part !== 'string' || !part) {
        return bareP2pError(ctx, argv0, 'missing chunk ' + i + '/' + total, argv0 + ' status ' + incoming.transferId, opt)
      }
      pieces.push(part)
    }
    const buf = ctx.b4a.from(pieces.join(''), 'base64')
    await ctx.vfs.writeFile(dest, buf)
    incoming.status = 'saved'
    incoming.savedTo = dest
    incoming.savedAtMs = Date.now()
    const tr = bareMeshdropEnsureTransfer(db, incoming.transferId)
    tr.status = 'saved'
    tr.chunksReceived = total
    tr.updatedAtMs = Date.now()
    await bareMeshdropDbWrite(ctx, db)
    bareP2pSend(ctx, 'meshdrop', 'complete', {
      offerId,
      transferId: incoming.transferId,
      savedTo: dest
    })
    bareP2pPrint(ctx, 'saved ' + offerId + ' -> ' + dest, opt)
    return
  }

  if (sub === 'status') {
    const transferId = String(args[1] || '').trim()
    const db = await bareMeshdropDbRead(ctx)
    const rows = bareP2pCollectFromHistory(ctx, 'meshdrop', 2000)
    for (const row of rows) {
      const kind = row.packet?.kind
      const p = row.packet?.payload
      if (!p || typeof p !== 'object') continue
      const id = typeof p.transferId === 'string' ? p.transferId : ''
      if (transferId && id !== transferId) continue
      if (kind === 'chunk' && typeof p.offerId === 'string' && typeof p.index === 'number') {
        const inRec = db?.incoming?.[p.offerId]
        if (inRec && inRec.status !== 'cancelled' && inRec.status !== 'saved') {
          if (!inRec.chunks || typeof inRec.chunks !== 'object') inRec.chunks = {}
          if (typeof p.chunkB64 === 'string' && !inRec.chunks[p.index]) {
            inRec.chunks[p.index] = p.chunkB64
          }
          const got = Object.keys(inRec.chunks).length
          inRec.status = got >= inRec.chunksTotal ? 'received-all' : 'receiving'
          const tr = bareMeshdropEnsureTransfer(db, inRec.transferId)
          tr.status = inRec.status
          tr.chunksTotal = inRec.chunksTotal
          tr.chunksReceived = got
          tr.updatedAtMs = Date.now()
        }
      }
      if (kind === 'cancel' && id) {
        const tr = bareMeshdropEnsureTransfer(db, id)
        tr.status = 'cancelled'
        tr.updatedAtMs = Date.now()
      }
      if (kind === 'progress' && id) {
        const tr = bareMeshdropEnsureTransfer(db, id)
        if (typeof p.sentChunks === 'number') tr.sentChunks = p.sentChunks
        if (typeof p.chunksTotal === 'number') tr.chunksTotal = p.chunksTotal
        tr.status = 'sending'
        tr.updatedAtMs = Date.now()
      }
      if (kind === 'complete' && id) {
        const tr = bareMeshdropEnsureTransfer(db, id)
        tr.status = 'complete'
        tr.updatedAtMs = Date.now()
      }
    }
    await bareMeshdropDbWrite(ctx, db)
    const items = Object.values(db.transfers || {})
      .filter((x) => !transferId || x.transferId === transferId)
      .sort((a, b) => (b.updatedAtMs || 0) - (a.updatedAtMs || 0))
    if (!items.length) {
      bareP2pPrint(ctx, opt.summary ? { transfers: 0 } : 'no transfers', opt)
      return
    }
    if (opt.summary) {
      bareP2pPrint(
        ctx,
        {
          transfers: items.length,
          active: items.filter((x) => String(x.status || '').includes('send') || String(x.status || '').includes('receiv')).length
        },
        opt
      )
      return
    }
    for (const it of items) {
      bareP2pPrint(
        ctx,
        (it.transferId || '?') +
          ' role=' +
          String(it.role || '?') +
          ' status=' +
          String(it.status || '?') +
          ' chunks=' +
          String(it.chunksReceived || 0) +
          '/' +
          String(it.chunksTotal || 0)
        ,
        opt
      )
    }
    return
  }

  if (sub === 'cancel') {
    const transferId = String(args[1] || '').trim()
    if (!transferId) {
      return bareP2pError(ctx, argv0, 'cancel requires TRANSFER_ID', argv0 + ' status', opt)
    }
    if (!opt.yes) {
      bareP2pPrint(ctx, 'confirmation required: pass --yes to cancel transfer', opt)
      ctx.exitCode = 1
      return
    }
    const db = await bareMeshdropDbRead(ctx)
    const tr = bareMeshdropEnsureTransfer(db, transferId)
    tr.status = 'cancelled'
    tr.updatedAtMs = Date.now()
    await bareMeshdropDbWrite(ctx, db)
    bareP2pSend(ctx, 'meshdrop', 'cancel', { transferId })
    bareP2pPrint(ctx, 'cancelled ' + transferId, opt)
    return
  }

  const sug = bareP2pSuggestSubcommand(sub, ['offer', 'send-next', 'inbox', 'accept', 'fetch', 'status', 'cancel'])
  bareP2pError(ctx, argv0, 'unsupported subcommand' + (sug ? ' (did you mean ' + sug + '?)' : ''), argv0 + ' --help', opt)
}