/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Simon Hudon
-/

prelude
import Init.Core
import Init.Data.UInt
import Init.Data.ToString.Basic
import Init.Data.String.Basic

/-
Imitate the structure of IOErrorType in Haskell:
https://hackage.haskell.org/package/base-4.12.0.0/docs/System-IO-Error.html#t:IOErrorType
-/
inductive IO.Error where
  | alreadyExists (filename : Option String) (osCode : UInt32) (details : String) -- EEXIST, EINPROGRESS, EISCONN
  | otherError (osCode : UInt32) (details : String)    -- EFAULT, default
  | resourceBusy (osCode : UInt32) (details : String)
      -- EADDRINUSE, EBUSY, EDEADLK, ETXTBSY
  | resourceVanished (osCode : UInt32) (details : String)
      -- ECONNRESET, EIDRM, ENETDOWN, ENETRESET,
      -- ENOLINK, EPIPE
  | unsupportedOperation (osCode : UInt32) (details : String)
      -- EADDRNOTAVAIL, EAFNOSUPPORT, ENODEV, ENOPROTOOPT
      -- ENOSYS, EOPNOTSUPP, ERANGE, ESPIPE, EXDEV
  | hardwareFault (osCode : UInt32) (details : String)          -- EIO
  | unsatisfiedConstraints (osCode : UInt32) (details : String) -- ENOTEMPTY
  | illegalOperation (osCode : UInt32) (details : String)       -- ENOTTY
  | protocolError (osCode : UInt32) (details : String)
      -- EPROTO, EPROTONOSUPPORT, EPROTOTYPE
  | timeExpired (osCode : UInt32) (details : String)
      -- ETIME, ETIMEDOUT

  | interrupted (filename : String) (osCode : UInt32) (details : String)       -- EINTR
  | noFileOrDirectory (filename : String) (osCode : UInt32) (details : String) -- ENOENT
  | invalidArgument (filename : Option String) (osCode : UInt32) (details : String)
      -- ELOOP, ENAMETOOLONG, EDESTADDRREQ, EILSEQ, EINVAL, EDOM, EBADF
      -- ENOEXEC, ENOSTR, ENOTCONN, ENOTSOCK
  | permissionDenied (filename : Option String) (osCode : UInt32) (details : String)
      -- EACCES, EROFS, ECONNABORTED, EFBIG, EPERM
  | resourceExhausted (filename : Option String) (osCode : UInt32) (details : String)
      -- EMFILE, ENFILE, ENOSPC, E2BIG, EAGAIN, EMLINK:
      -- EMSGSIZE, ENOBUFS, ENOLCK, ENOMEM, ENOSR:
  | inappropriateType (filename : Option String) (osCode : UInt32) (details : String)
      -- EISDIR, EBADMSG, ENOTDIR:
  | noSuchThing (filename : Option String) (osCode : UInt32) (details : String)
      -- ENXIO, EHOSTUNREACH, ENETUNREACH, ECHILD, ECONNREFUSED,
      -- ENODATA, ENOMSG, ESRCH

  | unexpectedEof
  | userError (msg : String)
  deriving Inhabited

@[export lean_mk_io_user_error]
def IO.userError (s : String) : IO.Error :=
  IO.Error.userError s

instance : Coe String IO.Error := ⟨IO.userError⟩

namespace IO.Error

@[export lean_mk_io_error_already_exists_file]
def mkAlreadyExistsFile : String → UInt32 → String → IO.Error :=
  alreadyExists ∘ some

@[export lean_mk_io_error_eof]
def mkEofError : Unit → IO.Error := fun _ =>
  unexpectedEof

@[export lean_mk_io_error_inappropriate_type_file]
def mkInappropriateTypeFile : String → UInt32 → String → IO.Error :=
  inappropriateType ∘ some

@[export lean_mk_io_error_interrupted]
def mkInterrupted : String → UInt32 → String → IO.Error :=
  interrupted

@[export lean_mk_io_error_invalid_argument_file]
def mkInvalidArgumentFile : String → UInt32 → String → IO.Error :=
  invalidArgument ∘ some

@[export lean_mk_io_error_no_file_or_directory]
def mkNoFileOrDirectory : String → UInt32 → String → IO.Error :=
  noFileOrDirectory

@[export lean_mk_io_error_no_such_thing_file]
def mkNoSuchThingFile : String → UInt32 → String → IO.Error :=
  noSuchThing ∘ some

@[export lean_mk_io_error_permission_denied_file]
def mkPermissionDeniedFile : String → UInt32 → String → IO.Error :=
  permissionDenied ∘ some

@[export lean_mk_io_error_resource_exhausted_file]
def mkResourceExhaustedFile : String → UInt32 → String → IO.Error :=
  resourceExhausted ∘ some

@[export lean_mk_io_error_unsupported_operation]
def mkUnsupportedOperation : UInt32 → String → IO.Error :=
  unsupportedOperation

@[export lean_mk_io_error_resource_exhausted]
def mkResourceExhausted : UInt32 → String → IO.Error :=
  resourceExhausted none

@[export lean_mk_io_error_already_exists]
def mkAlreadyExists : UInt32 → String → IO.Error :=
  alreadyExists none

@[export lean_mk_io_error_inappropriate_type]
def mkInappropriateType : UInt32 → String → IO.Error :=
  inappropriateType none

@[export lean_mk_io_error_no_such_thing]
def mkNoSuchThing : UInt32 → String → IO.Error :=
  noSuchThing none

@[export lean_mk_io_error_resource_vanished]
def mkResourceVanished : UInt32 → String → IO.Error :=
  resourceVanished

@[export lean_mk_io_error_resource_busy]
def mkResourceBusy : UInt32 → String → IO.Error :=
  resourceBusy

@[export lean_mk_io_error_invalid_argument]
def mkInvalidArgument : UInt32 → String → IO.Error :=
  invalidArgument none

@[export lean_mk_io_error_other_error]
def mkOtherError : UInt32 → String → IO.Error :=
  otherError

@[export lean_mk_io_error_permission_denied]
def mkPermissionDenied : UInt32 → String → IO.Error :=
  permissionDenied none

@[export lean_mk_io_error_hardware_fault]
def mkHardwareFault : UInt32 → String → IO.Error :=
  hardwareFault

@[export lean_mk_io_error_unsatisfied_constraints]
def mkUnsatisfiedConstraints : UInt32 → String → IO.Error :=
  unsatisfiedConstraints

@[export lean_mk_io_error_illegal_operation]
def mkIllegalOperation : UInt32 → String → IO.Error :=
  illegalOperation

@[export lean_mk_io_error_protocol_error]
def mkProtocolError : UInt32 → String → IO.Error :=
  protocolError

@[export lean_mk_io_error_time_expired]
def mkTimeExpired : UInt32 → String → IO.Error :=
  timeExpired

private def downCaseFirst (s : String) : String := s.modify 0 Char.toLower

def fopenErrorToString (gist fn : String) (code : UInt32) : Option String → String
  | some details => downCaseFirst gist ++ " (error code: " ++ toString code ++ ", " ++ downCaseFirst details ++ ")\n  file: " ++ fn
  | none => downCaseFirst gist ++ " (error code: " ++ toString code ++ ")\n  file: " ++ fn

def otherErrorToString (gist : String) (code : UInt32) : Option String → String
  | some details => downCaseFirst gist ++ " (error code: " ++ toString code ++ ", " ++ downCaseFirst details ++ ")"
  | none => downCaseFirst gist ++ " (error code: " ++ toString code ++ ")"

@[export lean_io_error_to_string]
def toString : IO.Error → String
  | unexpectedEof                            => "end of file"
  | inappropriateType (some fn) code details => fopenErrorToString "inappropriate type" fn code details
  | inappropriateType none code details      => otherErrorToString "inappropriate type" code details
  | interrupted fn code details              => fopenErrorToString "interrupted system call" fn code details
  | invalidArgument (some fn) code details   => fopenErrorToString "invalid argument" fn code details
  | invalidArgument none code details        => otherErrorToString "invalid argument" code details
  | noFileOrDirectory fn code _              => fopenErrorToString "no such file or directory" fn code none
  | noSuchThing (some fn) code details       => fopenErrorToString "no such thing" fn code details
  | noSuchThing none code details            => otherErrorToString "no such thing" code details
  | permissionDenied (some fn) code details  => fopenErrorToString details fn code none
  | permissionDenied none code details       => otherErrorToString details code none
  | resourceExhausted (some fn) code details => fopenErrorToString "resource exhausted" fn code details
  | resourceExhausted none code details      => otherErrorToString "resource exhausted" code details
  | alreadyExists none code details          => otherErrorToString "already exists" code details
  | alreadyExists (some fn) code details     => fopenErrorToString "already exists" fn code details
  | otherError code details                  => otherErrorToString details code none
  | resourceBusy code details                => otherErrorToString "resource busy" code details
  | resourceVanished code details            => otherErrorToString "resource vanished" code details
  | hardwareFault code _                     => otherErrorToString "hardware fault" code none
  | illegalOperation code details            => otherErrorToString "illegal operation" code details
  | protocolError code details               => otherErrorToString "protocol error" code details
  | timeExpired code details                 => otherErrorToString "time expired" code details
  | unsatisfiedConstraints code _            => otherErrorToString "directory not empty" code none
  | unsupportedOperation code details        => otherErrorToString "unsupported operation" code details
  | userError msg                            => msg

instance : ToString IO.Error := ⟨ IO.Error.toString ⟩

end IO.Error