import gleam/dynamic.{type Dynamic}
import gleam/dynamic/decode
import gleam/erlang/atom.{type Atom}
import gleam/erlang/process.{type Selector}
import gleam/list
import gleam/result

pub type Socket

pub type SocketReason {
  Closed
  Timeout
  Badarg
  Terminated
  Eaddrinuse
  Eaddrnotavail
  Eafnosupport
  Ealready
  Econnaborted
  Econnrefused
  Econnreset
  Edestaddrreq
  Ehostdown
  Ehostunreach
  Einprogress
  Eisconn
  Emsgsize
  Enetdown
  Enetunreach
  Enopkg
  Enoprotoopt
  Enotconn
  Enotty
  Enotsock
  Eproto
  Eprotonosupport
  Eprototype
  Esocktnosupport
  Etimedout
  Ewouldblock
  Exbadport
  Exbadseq
}

pub type TcpOption =
  #(Atom, Dynamic)

pub type ReceiveMode {
  Count(Int)
  Once
  Pull
  All
}

pub type PacketType {
  Binary
  List
}

pub type Options {
  Receive(ReceiveMode)
  PacketsOf(PacketType)
  SendTimeout(Int)
  SendTimeoutClose(Bool)
  Reuseaddr(Bool)
  Nodelay(Bool)
  Cacerts(Dynamic)
  CustomizeHostnameCheck(Dynamic)
}

pub const default_options = [
  PacketsOf(Binary),
  SendTimeout(30_000),
  SendTimeoutClose(True),
  Reuseaddr(True),
  Nodelay(True),
]

@external(erlang, "gleam@function", "identity")
fn from(value: a) -> Dynamic

pub fn convert_options(options: List(Options)) -> List(TcpOption) {
  let active = atom.create("active")
  list.map(options, fn(opt) {
    case opt {
      Receive(Count(count)) -> #(active, dynamic.int(count))
      Receive(Once) -> #(active, from(atom.create("once")))
      Receive(Pull) -> #(active, dynamic.bool(False))
      Receive(All) -> #(active, dynamic.bool(True))
      PacketsOf(Binary) -> #(atom.create("mode"), from(Binary))
      PacketsOf(List) -> #(atom.create("mode"), from(List))
      Cacerts(data) -> #(atom.create("cacerts"), data)
      Nodelay(bool) -> #(atom.create("nodelay"), dynamic.bool(bool))
      Reuseaddr(bool) -> #(atom.create("reuseaddr"), dynamic.bool(bool))
      SendTimeout(int) -> #(atom.create("send_timeout"), dynamic.int(int))
      SendTimeoutClose(bool) -> #(
        atom.create("send_timeout_close"),
        dynamic.bool(bool),
      )
      CustomizeHostnameCheck(funcs) -> #(
        atom.create("customize_hostname_check"),
        funcs,
      )
    }
  })
}

pub type Shutdown {
  Read
  Write
  ReadWrite
}

pub type SocketMessage {
  Data(BitArray)
  Err(SocketReason)
}

type ErlangSocketMessage {
  Ssl
  SslClosed
  SslError
  Tcp
  TcpClosed
  TcpError
}

pub fn selector() -> Selector(Result(SocketMessage, List(decode.DecodeError))) {
  process.new_selector()
  |> process.select_record(Tcp, 2, fn(data) {
    {
      use msg <- decode.field(2, decode.bit_array)
      decode.success(Data(msg))
    }
    |> decode.run(data, _)
  })
  |> process.select_record(Ssl, 2, fn(data) {
    {
      use msg <- decode.field(2, decode.bit_array)
      decode.success(Data(msg))
    }
    |> decode.run(data, _)
  })
  |> process.select_record(SslClosed, 1, fn(_socket) { Ok(Err(Closed)) })
  |> process.select_record(TcpClosed, 1, fn(_socket) { Ok(Err(Closed)) })
  |> process.select_record(TcpError, 2, fn(data) {
    {
      use reason <- decode.field(2, atom.decoder())
      let socket_message =
        parse_known_socket_reason(reason)
        |> result.map(Err)
        |> result.map(decode.success)
        |> result.map_error(fn(_data) {
          decode.failure(Err(Badarg), "SocketReason")
        })
      case socket_message {
        Ok(message) -> message
        Error(message) -> message
      }
    }
    |> decode.run(data, _)
  })
  |> process.select_record(SslError, 2, fn(data) {
    {
      use reason <- decode.field(2, atom.decoder())
      let socket_message =
        parse_known_socket_reason(reason)
        |> result.map(Err)
        |> result.map(decode.success)
        |> result.map_error(fn(_data) {
          decode.failure(Err(Badarg), "SocketReason")
        })
      case socket_message {
        Ok(message) -> message
        Error(message) -> message
      }
    }
    |> decode.run(data, _)
  })
}

@external(erlang, "public_key", "cacerts_get")
pub fn get_certs() -> Dynamic

@external(erlang, "stratus_ffi", "custom_sni_matcher")
pub fn get_custom_matcher() -> Options

@external(erlang, "stratus_ffi", "parse_known_socket_reason")
fn parse_known_socket_reason(reason: Atom) -> Result(SocketReason, Dynamic)