when not isMainModule:
  {.error: "this module is not a library, import blobsets instead".}

import std/asyncdispatch, std/nre, std/os, std/strutils, std/tables, std/parseopt, std/streams, std/rdstdin, std/random
import cbor
import ./blobsets, ./blobsets/filestores,
  ./blobsets/httpservers, ./blobsets/httpstores

import os, strutils
when defined(readLine):
  import rdstdin, linenoise

proc openStore(): BlobStore =
  const key = "BLOB_STORE_URL"
  var url = os.getEnv key
  if url == "":
    url = "/tmp/blobs"
    #quit(key & " not set in environment")
  if url.startsWith "http://":
    newHttpStore(url)
  else:
    newFileStore(url)

proc serverMain(): Future[void] =
  let
    store = newFileStore("/tmp/blobs")
    server = newHttpStoreServer(store)
  server.serve((Port)8080)

proc dumpMain() =
  var args = newSeq[string]()
  for kind, key, val in getopt():
    if kind == cmdArgument:
      args.add key
  if args.len > 1:
    let store = openStore()
    for i in 1..args.high:
      try:
        for chunk in store.dumpBlob(args[i].toBlobId):
          write(stdout, chunk)
      except:
        writeLine(stderr, "failed to dump '", args[i], "', ", getCurrentExceptionMsg())
        quit(-1)

proc insertPath(store: BlobStore; bs: BlobSet; kind: PathComponent; path: string): BlobSet =
  result = bs
  try:
    case kind
    of pcFile, pcLinkToFile:
      var path = normalizedPath path
      let (id, size) = waitFor store.ingestFile(path)
      path.removePrefix(getCurrentDir())
      path.removePrefix("/")
      result = waitfor insert(store, result, path, id, size)
      writeLine(stdout, id, align($size, 11), " ", path)
    of pcDir, pcLinkToDir:
      for kind, subPath in path.walkDir:
        result = store.insertPath(result, kind, subPath)
  except:
    let e = getCurrentException()
    writeLine(stderr, "failed to ingest '", path, "', ", e.msg)

proc ingestMain() {.async.} =
  var args = newSeq[string]()
  for kind, key, val in getopt():
    if kind == cmdArgument:
      args.add key
  if args.len > 1:
    var set = newBlobSet()
    let store = openStore()
    for i in 1..args.high:
      let path = normalizedPath args[i]
      set = store.insertPath(set, path.getFileInfo.kind, path)
    let final = await store.commit(set)
    writeLine(stdout, final.setId.toHex)

func isShortHash(id: BlobId): bool =
  var r: byte
  for i in countup(16, id.data.high):
    r = r or id.data[i]
  r == 0

proc checkMain() {.async.} =
  randomize()
  var args = newSeq[string]()
  for kind, key, val in getopt():
    if kind == cmdArgument:
      args.add key
  if args.len > 1:
    let store = openStore()
    for i in 1..args.high:
      try:
        var bs = await store.load(args[i].toBlobId)
        let stream = newMemberStream()
        asyncCheck stream.streamMembers(store, bs)
        var m: tuple[key: Key; id: BlobId; size: BiggestInt]
        while true:
          let (valid, m) = await stream.read()
          if not valid: break
          if m.id.isShortHash:
            echo m.key, " has a short hash - ", m.id
            bs = await remove(store, bs, m.key)
            echo "removed ", m.key
          #close(store.openBlobStream(id, size, dataBlob))
        echo "commit repaired set"
        bs = await commit(store, bs)
        writeLine(stdout, "recovered set is ", bs.setId.toHex)
      except:
        writeLine(stderr, "failed to check '", args[i], "', ", getCurrentExceptionMsg())
        quit(-1)

proc replicateMain() {.async.} =
  randomize()
  var
    args = newSeq[string]()
    rng = initRand(rand(int.high))
  for kind, key, val in getopt():
    if kind == cmdArgument:
      args.add key
  if args.len > 3:
    let
      src = openStore()
      dst = newHttpStore(args[1])
    for i in 2..args.high:
      try:
        let
          srcId = args[i].toBlobId
          srcSet = await src.load(srcId)
        var dstSet = newBlobSet()
        let stream = newMemberStream()
        asyncCheck stream.streamMembers(src, srcSet)
        var m: tuple[key: Key; id: BlobId; size: BiggestInt]
        while true:
          let (valid, m) = await stream.read()
          if not valid: break
          let
            readStream = src.openBlobStream(m.id, m.size, dataBlob)
            ingestStream = dst.openIngestStream(m.size, dataBlob)
          var buf: array[0x16000, byte]
          while true:
            let n = await readStream.read(addr buf, buf.len)
            if n == 0: break
            await ingestStream.ingest(addr buf, n)
          close readStream
          let (otherId, otherSize) = await ingestStream.finish()
          if otherId != m.id or otherSize != m.size:
            writeLine(stderr, "replication mismatch ",
              m.id, ":", m.size, " replicated to ",
              otherId, ":", otherSize)
            quit -1
          dstSet = await insert(dst, dstSet, m.key, m.id, m.size)
        let
          newSet = await commit(dst, dstSet)
          dstId = newSet.setId
        doAssert(dstId == srcId, "set mismatch after replication")
      except:
        writeLine(stderr, "failed to replicate '", args[i], "', ", getCurrentExceptionMsg())
        quit -1

type
  EvalError = object of CatchableError

  Env = ref EnvObj

  AtomKind = enum
    atomBlob
    atomSet
    atomPath
    atomString
    atomKey
    atomNum
    atomSymbol
    atomError

  Atom = object
    case kind: AtomKind
    of atomBlob:
      blob: BlobId
      size: BiggestInt
    of atomSet:
      bs: BlobSet
    of atomPath:
      path: string
      name: string
    of atomString:
      str: string
    of atomKey:
      key: Key
    of atomNum:
      num: BiggestInt
    of atomSymbol:
      sym: string
    of atomError:
      err: string

  Func = proc(env: Env; arg: NodeObj): NodeRef

  NodeKind = enum
    nodeError
    nodeList
    nodeAtom
    nodeFunc

  NodeRef = ref NodeObj
    ## NodeRef is used to chain nodes into lists.
  NodeObj = object
    ## NodeObj is used to mutate nodes without side-effects.
    case kind: NodeKind
    of nodeList:
      headRef, tailRef: NodeRef
    of nodeAtom:
      atom: Atom
    of nodeFunc:
      fun: Func
      name: string
    of nodeError:
      errMsg: string
      errNode: NodeRef
    nextRef: NodeRef

  EnvObj = object
    store: BlobStore
    bindings: Table[string, NodeObj]
    blobs: Table[string, tuple[id: BlobId, size: BiggestInt]]
    sets: Table[string, BlobSet]

proc print(a: Atom; s: Stream)
proc print(ast: NodeRef; s: Stream)

proc newAtom(id: BlobId, size: BiggestInt): Atom =
  Atom(kind: atomBlob, blob: id, size: size)

proc newAtom(bs: BlobSet): Atom =
  Atom(kind: atomSet, bs: bs)

proc newAtomError(msg: string): Atom =
  Atom(kind: atomError, err: msg)

proc newAtomPath(s: string): Atom =
  try:
    let path = expandFilename s
    Atom(kind: atomPath, path: path, name: extractFilename(s))
  except OSError:
    newAtomError("invalid path '$1'" % s)

proc newAtomString(s: string): Atom =
  Atom(kind: atomString, str: s)

proc newAtom(k: Key): Atom =
  Atom(kind: atomKey, key: k)

proc newAtom(i: Natural): Atom =
  Atom(kind: atomNum, num: i)

proc newNodeError(msg: string; n: NodeObj): NodeRef =
  var p = new NodeRef
  p[] = n
  NodeRef(kind: nodeError, errMsg: msg, errNode: p)

proc newNode(a: Atom): NodeRef =
  NodeRef(kind: nodeAtom, atom: a)

proc newNodeList(): NodeRef =
  NodeRef(kind: nodeList)

proc next(n: NodeObj | NodeRef): NodeObj =
  ## Return a copy of list element that follows Node n.
  assert(not n.nextRef.isNil, "next element is nil")
  result = n.nextRef[]

proc head(list: NodeObj | NodeRef): NodeObj =
  ## Return the start element of a list Node.
  list.headRef[]

proc `next=`(n, p: NodeRef) =
  ## Return a copy of list element that follows Node n.
  assert(n.nextRef.isNil, "append to node that is not at the end of a list")
  n.nextRef = p

iterator list(n: NodeObj): NodeObj =
  ## Iterate over members of a list node.
  var n = n.headRef
  while not n.isNil:
    yield n[]
    n = n.nextRef

iterator walk(n: NodeObj): NodeObj =
  ## Walk down the singly linked list starting from a member node.
  var n = n
  while not n.nextRef.isNil:
    yield n
    n = n.nextRef[]
  yield n

proc append(list, n: NodeRef) =
  ## Append a node to the end of a list node.
  if list.headRef.isNil:
    list.headRef = n
    list.tailRef = n
  else:
    list.tailRef.next = n
    while not list.tailRef.nextRef.isNil:
      assert(list.tailRef != list.tailRef.nextRef)
      list.tailRef = list.tailRef.nextRef

proc append(list: NodeRef; n: NodeObj) =
  let p = new NodeRef
  p[] = n
  list.append p

template returnError(n: NodeObj) =
    if n.atom.kind == atomError:
      return n.atom.newNode

proc getBlob(env: Env; path: string): tuple[id: BlobId, size: BiggestInt] =
  result = env.blobs.getOrDefault(path)
  if result.size == 0:
    result = waitFor env.store.ingestFile(path)
    if result.size != 0:
      env.blobs[path] = result

proc getSet(env: Env; path: string): BlobSet=
  result = env.sets.getOrDefault(path)
  if result.isNil:
    result = newBlobSet()
    result = env.store.insertPath(result, path.getFileInfo.kind, path)
    if not result.isEmpty:
      env.sets[path] = result

type
  Tokens = seq[string]

  Reader = ref object
    buffer: string
    tokens: Tokens
    pos: int

proc newReader(): Reader =
  Reader(buffer: "", tokens: newSeq[string]())

proc next(r: Reader): string =
  assert(r.pos < r.tokens.len, $r.tokens)
  result = r.tokens[r.pos]
  inc r.pos

proc peek(r: Reader): string =
  assert(r.pos < r.tokens.len, $r.tokens)
  r.tokens[r.pos]

proc print(a: Atom; s: Stream) =
  case a.kind
  of atomPath:
    s.write a.path
  of atomBlob:
    s.write $a.blob
    s.write '|'
    s.write $a.size
  of atomSet:
    case a.bs.kind
    of coldNode:
      s.write $a.bs.setId
    else:
      s.write "«set»"
  of atomString:
    s.write '"'
    s.write a.str
    s.write '"'
  #[
  of atomData:
    let fut = newFutureStream[string]()
    asyncCheck env.store.fileStream(a.fileCid, fut)
    while true:
      let (valid, chunk) = fut.read()
      if not valid: break
      f.write chunk
    ]#
  of atomKey:
    s.write $a.key
  of atomNum:
    s.write $a.num
  of atomSymbol:
    s.write a.sym
  of atomError:
    s.write "«"
    s.write a.err
    s.write "»"

proc print(ast: NodeObj; s: Stream) =
  case ast.kind:
  of nodeAtom:
    ast.atom.print(s)
  of nodeList:
    s.write "\n("
    for n in ast.list:
      s.write " "
      n.print(s)
    s.write " )"
  of nodeFunc:
    s.write "#<procedure "
    s.write ast.name
    s.write ">"
  of nodeError:
    s.write "«"
    s.write ast.errMsg
    s.write ": "
    ast.errNode.print s
    s.write "»"

proc print(ast: NodeRef; s: Stream) =
  if ast.isNil:
    s.write "«nil»"
  else:
    ast[].print s

proc readAtom(r: Reader): Atom =
  let token = r.next
  block:
    if token[token.low] == '"':
      if token[token.high] != '"':
        newAtomError("invalid string '$1'" % token)
      else:
        newAtomString(token[1..token.len-2])
    elif token.contains DirSep:
      # TODO: memoize this, store a table of paths to atoms
      newAtomPath token
    elif token.len in { blobHexLen, blobVisualLen }:
      Atom(kind: atomSet, bs: newBlobSet(token.toSetId))
    else:
      Atom(kind: atomSymbol, sym: token.normalize)
  #except:
   # newAtomError(getCurrentExceptionMsg())

proc readForm(r: Reader): NodeRef

proc readList(r: Reader): NodeRef =
  result = newNodeList()
  while true:
    if (r.pos == r.tokens.len):
      return nil
    let p = r.peek
    case p[p.high]
    of ')':
      discard r.next
      break
    else:
      result.append r.readForm

proc readForm(r: Reader): NodeRef =
  case r.peek[0]
  of '(':
    discard r.next
    r.readList
  else:
    r.readAtom.newNode

proc tokenizer(s: string): Tokens =
  # TODO: this sucks
  let tokens = s.findAll(re"""[\s,]*(~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])*"|;.*|[^\s\[\]{}('"`,;)]*)""")
  result = newSeqOfCap[string] tokens.len
  for s in tokens:
    let t = s.strip(leading = true, trailing = false).strip(leading = false, trailing = true)
    if t.len > 0:
      result.add t

proc read(r: Reader; line: string): NodeRef =
  r.pos = 0
  if r.buffer.len > 0:
    r.buffer.add " "
    r.buffer.add line
    r.tokens = r.buffer.tokenizer
  else:
    r.tokens = line.tokenizer
  result = r.readForm
  if result.isNil:
    r.buffer = line
  else:
    r.buffer.setLen 0

proc assertArgCount(args: NodeObj; len: int) =
  var arg = args
  for _ in 2..len:
    doAssert(not arg.nextRef.isNil)
    arg = arg.next
  doAssert(arg.nextRef.isNil)

##
# Builtin functions
#

proc applyFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 2)
  let
    fn = args
    ln = fn.next
  fn.fun(env, ln.head)

proc cborFunc(env: Env; arg: NodeObj): NodeRef =
  assertArgCount(arg, 1)
  newNode(newAtomString($toCbor(arg.atom.bs)))

proc commitFunc(env: Env; arg: NodeObj): NodeRef =
  assertArgCount(arg, 1)
  let cold = waitFor commit(env.store, arg.atom.bs)
  cold.newAtom.newNode

#[
proc copyFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 3)
  let
    x = args
    y = x.next
    z = y.next
  var root = newFsRoot()
  let dir = env.getUnixfs x.atom.cid
  for name, node in dir.items:
    root.add(name, node)
  root.add(z.atom.str, dir[y.atom.str])
  let cid = env.store.putDag(root.toCbor)
  cid.newAtom.newNode
]#

proc consFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 2)
  result = newNodeList()
  let
    car = args
    cdr = args.next
  result.append car
  result.append cdr.head

proc defineFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 2)
  let
    symN = args
    val = args.next
  env.bindings[symN.atom.sym] = val
  new result
  result[] = val

proc globFunc(env: Env; args: NodeObj): NodeRef =
  result = newNodeList()
  for n in args.walk:
    let a = n.atom
    case a.kind
    of atomPath:
      result.append n
    of atomString:
      for match in walkPattern a.str:
        result.append match.newAtomPath.newNode
    else:
      result = newNodeError("invalid glob argument", n)

proc hexFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 1)
  let a = args.atom
  case a.kind
  of atomBlob:
    a.blob.toHex.newAtomString.newNode
  of atomSet:
    case a.bs.kind
    of hotNode:
      let cold = waitFor commit(env.store, a.bs)
      cold.setId.toHex.newAtomString.newNode
    of coldNode:
      a.bs.setId.toHex.newAtomString.newNode
    of leafNode:
      a.bs.blob.toHex.newAtomString.newNode
  else:
    newNodeError("cannot convert to hex", args)

proc keyFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 1)
  let k = args.atom.str.toKey
  k.newAtom.newNode

proc ingestFunc(env: Env; args: NodeObj): NodeRef =
  var bs: BlobSet
  for n in args.walk:
    if bs.isNil:
      bs = env.getSet(n.atom.path)
    else:
      bs = env.store.union(bs, env.getSet(n.atom.path))
  result = bs.newAtom.newNode

proc insertFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 3)
  let
    trie = args.atom.bs
    blob = args.next.atom
    name = args.next.next.atom.str
  let newBs = waitFor env.store.insert(trie, name, blob.blob, blob.size)
  doAssert(not newBs.isNil)
  newNode(newAtom(newBs))

proc blobFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 1)
  let (id, size) = env.getBlob args.atom.path
  newNode(newAtom(id, size))

proc listFunc(env: Env; args: NodeObj): NodeRef =
  ## Standard Lisp 'list' function.
  result = newNodeList()
  new result.headRef
  result.headRef[] = args
  result.tailRef = result.headRef
  while not result.tailRef.nextRef.isNil:
    result.tailRef = result.tailRef.nextRef

proc loadFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 1)
  let bs = waitFor env.store.load(args.atom.bs.setId)
  bs.newAtom.newNode

proc mapFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 2)
  result = newNodeList()
  let f = args.fun
  for v in args.next.list:
    result.append f(env, v)

#[
proc mergeFunc(env: Env; args: NodeObj): NodeRef =
  var root = newFsRoot()
  for n in args.walk:
    let
      a = n.atom
      dir = env.getUnixfs a.cid
    for name, node in dir.items:
      root.add(name, node)
  let cid = env.store.putDag(root.toCbor)
  cid.newAtom.newNode
]#

proc pathFunc(env: Env; arg: NodeObj): NodeRef =
  result = arg.atom.str.newAtomPath.newNode

proc randomFunc(env: Env; arg: NodeObj): NodeRef =
  assertArgCount(arg, 1)
  var rng = initRand(rand(int.high))
  let bs = arg.atom.bs
  var random: NodeRef
  env.store.randomApply(bs, rng) do (id: BlobId; size: BiggestInt):
    random = newNode(newAtom(id, size))
  if random.isNil: newNodeList()
  else: random

proc removeFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 2)
  let
    bs = args.atom.bs
    name = args.next.atom.str
  newNode(newAtom(waitFor env.store.remove(bs, name)))

proc searchFunc(env: Env; args: NodeObj): NodeRef =
  assertArgCount(args, 2)
  var found: NodeRef
  let
    bs = args.atom.bs
    name = args.next.atom.str
  apply(env.store, bs, name) do (id: BlobId; size: BiggestInt):
    found = newNode(newAtom(id, size))
  if found.isNil:
    result = newNodeList()
  else:
    result = found

proc unionFunc(env: Env; args: NodeObj): NodeRef =
  var bs: BlobSet
  for n in args.walk:
    if bs.isNil:
      bs = n.atom.bs
    else:
      bs = env.store.union(bs, n.atom.bs)
  result = bs.newAtom.newNode

##
# Environment
#

proc bindEnv(env: Env; name: string; fun: Func) =
  assert(not env.bindings.contains name)
  env.bindings[name] = NodeObj(kind: nodeFunc, fun: fun, name: name)

proc newEnv(store: BlobStore): Env =
  result = Env(
    store: store,
    bindings: initTable[string, NodeObj](),
    blobs: initTable[string, tuple[id: BlobId, size: BiggestInt]](),
    sets: initTable[string, BlobSet]())
  result.bindEnv "apply", applyFunc
  result.bindEnv "blob", blobFunc
  result.bindEnv "cbor", cborFunc
  result.bindEnv "commit", commitFunc
  result.bindEnv "cons", consFunc
  #result.bindEnv "copy", copyFunc
  result.bindEnv "define", defineFunc
  result.bindEnv "glob", globFunc
  result.bindEnv "hex", hexFunc
  result.bindEnv "ingest", ingestFunc
  result.bindEnv "insert", insertFunc
  result.bindEnv "key", keyFunc
  result.bindEnv "load", loadFunc
  result.bindEnv "list", listFunc
  result.bindEnv "map", mapFunc
  #result.bindEnv "merge", mergeFunc
  result.bindEnv "path", pathFunc
  result.bindEnv "random", randomFunc
  result.bindEnv "remove", removeFunc
  result.bindEnv "search", searchFunc
  result.bindEnv "union", unionFunc

proc eval(ast: NodeRef; env: Env): NodeRef

proc eval_ast(ast: NodeRef; env: Env): NodeRef =
  result = ast
  case ast.kind
  of nodeList:
    result = newNodeList()
    while not ast.headRef.isNil:
      # cut out the head of the list and evaluate
      let n = ast.headRef
      ast.headRef = n.nextRef
      n.nextRef = nil
      let x = n.eval(env)
      result.append x
  of nodeAtom:
    if ast.atom.kind == atomSymbol:
      if env.bindings.contains ast.atom.sym:
        result = new NodeRef
        result[] = env.bindings[ast.atom.sym]
  else: discard

proc eval(ast: NodeRef; env: Env): NodeRef =
  var input = ast[]
  try:
    if ast.kind == nodeList:
      if ast.headRef == nil:
        newNodeList()
      else:
        let
          ast = eval_ast(ast, env)
          head = ast.headRef
        if head.kind == nodeFunc:
          if not head.nextRef.isNil:
            input = head.next
            head.fun(env, input)
          else:
            input = NodeObj(kind: nodeList)
            head.fun(env, input)
        else:
          input = head[]
          newNodeError("not a function", input)
    else:
      eval_ast(ast, env)
  except EvalError:
    newNodeError(getCurrentExceptionMsg(), input)
  except FieldError:
    newNodeError("invalid argument", input)
  except OSError:
    newNodeError(getCurrentExceptionMsg(), input)

proc readLineSimple(prompt: string; line: var TaintedString): bool =
  stdin.readLine(line)

#[
when defined(genode):
  proc openStore(): BlobStore =
    result = newDagfsClient("repl")
else:
  proc openStore(): BlobStore =
    var host = ""
    for kind, key, value in getopt():
      if kind == cmdShortOption:
        if key == "h":
          if host != "":
            quit "only a single store path argument is accepted"
          host = value
    if host == "": host = "127.0.0.1"
    try: result = newTcpClient(host)
    except:
          quit("failed to connect to store at $1 ($2)" % [host, getCurrentExceptionMsg()])
]#

proc emptyMain() =
  let
    store = openStore()
    bs = waitFor store.commit(newBlobSet())
  echo bs.setId.toHex

proc replMain() =
  randomize()
  var scripted: bool
  for kind, key, value in getopt():
    if kind == cmdShortOption and key == "s":
      scripted = true
  let
    #store = openStore()
    store = openStore()
    env = newEnv(store)
    outStream = stdout.newFileStream
    readLine = if scripted: readLineSimple else: readLineFromStdin
  var
    reader = newReader()
    line = newStringOfCap 128
  while readLine("> ", line):
    if line.len > 0:
      let ast = reader.read(line)
      if not ast.isNil:
        ast.eval(env).print(outStream)
        outStream.write "\n"
        flush outStream

const Prompt = ">>> "

proc getLine(prompt: string): string =
  # Using line editing
  when defined(readLine):
    result = readLineFromStdin(prompt)
  else:
    # Primitive fallback
    stdout.write(prompt)
    result = stdin.readline()

when isMainModule:
  var cmd = ""
  for kind, key, val in getopt():
    if kind == cmdArgument:
      cmd = key
      break
  case normalize(cmd)
  of "": quit("no subcommand specified")
  of "empty": emptyMain()
  of "repl": replMain()
  of "dump": dumpMain()
  of "ingest": waitFor ingestMain()
  of "server": waitFor serverMain()
  of "check": waitFor checkMain()
  of "replicate": waitFor replicateMain()
  else: quit("no such subcommand " & cmd)