(*
 * Copyright (c) 2017-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

open! IStd
module F = Format
module MF = MarkupFormatter

type lock = Lock | Unlock | LockedIfTrue | NoEffect

type thread = BackgroundThread | MainThread | MainThreadIfTrue | UnknownThread

let is_thread_utils_type java_pname =
  let pn = Typ.Procname.Java.get_class_name java_pname in
  String.is_suffix ~suffix:"ThreadUtils" pn || String.is_suffix ~suffix:"ThreadUtil" pn


let is_thread_utils_method method_name_str = function
  | Typ.Procname.Java java_pname ->
      is_thread_utils_type java_pname
      && String.equal (Typ.Procname.Java.get_method java_pname) method_name_str
  | _ ->
      false


let get_thread = function
  | Typ.Procname.Java java_pname when is_thread_utils_type java_pname -> (
    match Typ.Procname.Java.get_method java_pname with
    | "assertMainThread" | "assertOnUiThread" | "checkOnMainThread" ->
        MainThread
    | "isMainThread" | "isUiThread" ->
        MainThreadIfTrue
    | "assertOnBackgroundThread" | "assertOnNonUiThread" | "checkOnNonUiThread" ->
        BackgroundThread
    | _ ->
        UnknownThread )
  | _ ->
      UnknownThread


let cpp_lock_types_matcher =
  QualifiedCppName.Match.of_fuzzy_qual_names
    [ "apache::thrift::concurrency::ReadWriteMutex"
    ; "folly::LockedPtr"
    ; "folly::MicroSpinLock"
    ; "folly::RWSpinLock"
    ; "folly::SharedMutex"
      (* NB not impl as in [matcher_lock] as this is just a type, not a call *)
    ; "folly::SpinLock"
    ; "folly::SpinLockGuard"
    ; "std::mutex" ]


let get_lock =
  let is_cpp_lock =
    let matcher_lock =
      QualifiedCppName.Match.of_fuzzy_qual_names
        [ "apache::thrift::concurrency::ReadWriteMutex::acquireRead"
        ; "apache::thrift::concurrency::ReadWriteMutex::acquireWrite"
        ; "folly::MicroSpinLock::lock"
        ; "folly::RWSpinLock::lock"
        ; "folly::RWSpinLock::lock_shared"
        ; "folly::SharedMutexImpl::lockExclusiveImpl"
        ; "folly::SharedMutexImpl::lockSharedImpl"
        ; "folly::SpinLock::lock"
        ; "std::lock"
        ; "std::mutex::lock"
        ; "std::unique_lock::lock" ]
    in
    let matcher_lock_constructor =
      QualifiedCppName.Match.of_fuzzy_qual_names
        [ "folly::LockedPtr::LockedPtr"
        ; "folly::SpinLockGuard::SpinLockGuard"
        ; "std::lock_guard::lock_guard"
        ; "std::unique_lock::unique_lock" ]
    in
    fun pname actuals ->
      QualifiedCppName.Match.match_qualifiers matcher_lock (Typ.Procname.get_qualifiers pname)
      || QualifiedCppName.Match.match_qualifiers matcher_lock_constructor
           (Typ.Procname.get_qualifiers pname)
         (* Passing additional parameter allows to defer the lock *)
         && Int.equal 2 (List.length actuals)
  and is_cpp_unlock =
    let matcher =
      QualifiedCppName.Match.of_fuzzy_qual_names
        [ "apache::thrift::concurrency::ReadWriteMutex::release"
        ; "folly::LockedPtr::~LockedPtr"
        ; "folly::MicroSpinLock::unlock"
        ; "folly::RWSpinLock::unlock"
        ; "folly::RWSpinLock::unlock_shared"
        ; "folly::SharedMutexImpl::unlock"
        ; "folly::SharedMutexImpl::unlock_shared"
        ; "folly::SpinLock::unlock"
        ; "folly::SpinLockGuard::~SpinLockGuard"
        ; "std::lock_guard::~lock_guard"
        ; "std::mutex::unlock"
        ; "std::unique_lock::unlock"
        ; "std::unique_lock::~unique_lock" ]
    in
    fun pname ->
      QualifiedCppName.Match.match_qualifiers matcher (Typ.Procname.get_qualifiers pname)
  and is_cpp_trylock =
    let matcher =
      QualifiedCppName.Match.of_fuzzy_qual_names
        ["folly::SpinLock::try_lock"; "std::unique_lock::owns_lock"; "std::unique_lock::try_lock"]
    in
    fun pname ->
      QualifiedCppName.Match.match_qualifiers matcher (Typ.Procname.get_qualifiers pname)
  in
  fun pname actuals ->
    match pname with
    | Typ.Procname.Java java_pname -> (
        if is_thread_utils_method "assertHoldsLock" (Typ.Procname.Java java_pname) then Lock
        else
          match
            (Typ.Procname.Java.get_class_name java_pname, Typ.Procname.Java.get_method java_pname)
          with
          | ( ( "java.util.concurrent.locks.Lock"
              | "java.util.concurrent.locks.ReentrantLock"
              | "java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock"
              | "java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock" )
            , ("lock" | "lockInterruptibly") ) ->
              Lock
          | ( ( "java.util.concurrent.locks.Lock"
              | "java.util.concurrent.locks.ReentrantLock"
              | "java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock"
              | "java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock" )
            , "unlock" ) ->
              Unlock
          | ( ( "java.util.concurrent.locks.Lock"
              | "java.util.concurrent.locks.ReentrantLock"
              | "java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock"
              | "java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock" )
            , "tryLock" ) ->
              LockedIfTrue
          | ( "com.facebook.buck.util.concurrent.AutoCloseableReadWriteUpdateLock"
            , ("readLock" | "updateLock" | "writeLock") ) ->
              Lock
          | _ ->
              NoEffect )
    | (Typ.Procname.ObjC_Cpp _ | C _) as pname when is_cpp_lock pname actuals ->
        Lock
    | (Typ.Procname.ObjC_Cpp _ | C _) as pname when is_cpp_unlock pname ->
        Unlock
    | (Typ.Procname.ObjC_Cpp _ | C _) as pname when is_cpp_trylock pname ->
        LockedIfTrue
    | pname when Typ.Procname.equal pname BuiltinDecl.__set_locked_attribute ->
        Lock
    | pname when Typ.Procname.equal pname BuiltinDecl.__delete_locked_attribute ->
        Unlock
    | _ ->
        NoEffect


let get_current_class_and_annotated_superclasses is_annot tenv pname =
  match pname with
  | Typ.Procname.Java java_pname ->
      let current_class = Typ.Procname.Java.get_class_type_name java_pname in
      let annotated_classes =
        PatternMatch.find_superclasses_with_attributes is_annot tenv current_class
      in
      Some (current_class, annotated_classes)
  | _ ->
      None


let find_annotated_or_overriden_annotated_method is_annot pname tenv =
  PatternMatch.override_find
    (fun pn ->
      Annotations.pname_has_return_annot pn ~attrs_of_pname:Summary.proc_resolve_attributes
        is_annot )
    tenv pname


let ui_matcher_records =
  let open MethodMatcher in
  let fragment_methods =
    (* sort police: this is in lifecycle order *)
    [ "onAttach"
    ; "onCreate"
    ; "onCreateView"
    ; "onActivityCreated"
    ; "onStart"
    ; "onResume"
    ; "onPause"
    ; "onStop"
    ; "onDestroyView"
    ; "onDestroy"
    ; "onDetach" ]
  in
  (* search_superclasses is true by default in how [default] is treated *)
  [ {default with classname= "android.support.v4.app.Fragment"; methods= fragment_methods}
  ; {default with classname= "android.app.Fragment"; methods= fragment_methods}
  ; {default with classname= "android.content.ContentProvider"; methods= ["onCreate"]}
  ; {default with classname= "android.content.BroadcastReceiver"; methods= ["onReceive"]}
  ; { default with
      classname= "android.app.Service"
    ; methods= ["onBind"; "onCreate"; "onDestroy"; "onStartCommand"] }
  ; { default with
      classname= "android.app.Activity"
    ; methods= ["onCreate"; "onStart"; "onRestart"; "onResume"; "onPause"; "onStop"; "onDestroy"]
    }
  ; { default with
      (* according to Android documentation, *all* methods of the View class run on UI thread, but
       let's be a bit conservative and catch all methods that start with "on".
       https://developer.android.com/reference/android/view/View.html *)
      method_prefix= true
    ; classname= "android.view.View"
    ; methods= ["on"] } ]


let is_ui_method =
  let matchers = List.map ui_matcher_records ~f:MethodMatcher.of_record in
  (* we pass an empty actuals list because all matching is done on class and method name here *)
  fun tenv pname -> MethodMatcher.of_list matchers tenv pname []


let runs_on_ui_thread =
  (* assume that methods annotated with @UiThread, @OnEvent, @OnBind, @OnMount, @OnUnbind,
     @OnUnmount always run on the UI thread *)
  let annotation_matchers =
    [ Annotations.ia_is_mainthread
    ; Annotations.ia_is_ui_thread
    ; Annotations.ia_is_on_bind
    ; Annotations.ia_is_on_event
    ; Annotations.ia_is_on_mount
    ; Annotations.ia_is_on_unbind
    ; Annotations.ia_is_on_unmount ]
  in
  let is_annot annot = List.exists annotation_matchers ~f:(fun m -> m annot) in
  let mono_pname = MF.wrap_monospaced Typ.Procname.pp in
  fun tenv proc_desc ->
    let pname = Procdesc.get_proc_name proc_desc in
    if
      Annotations.pdesc_has_return_annot proc_desc Annotations.ia_is_worker_thread
      || find_annotated_or_overriden_annotated_method Annotations.ia_is_worker_thread pname tenv
         |> Option.is_some
      || get_current_class_and_annotated_superclasses Annotations.ia_is_worker_thread tenv pname
         |> Option.value_map ~default:false ~f:(function _, [] -> false | _ -> true)
    then None
    else if is_ui_method tenv pname then
      Some (F.asprintf "%a is a standard UI-thread method" mono_pname pname)
    else if Annotations.pdesc_has_return_annot proc_desc is_annot then
      Some
        (F.asprintf "%a is annotated %s" mono_pname pname
           (MF.monospaced_to_string Annotations.ui_thread))
    else
      match find_annotated_or_overriden_annotated_method is_annot pname tenv with
      | Some override_pname ->
          Some
            (F.asprintf "class %a overrides %a, which is annotated %s" mono_pname pname mono_pname
               override_pname
               (MF.monospaced_to_string Annotations.ui_thread))
      | None -> (
        match get_current_class_and_annotated_superclasses is_annot tenv pname with
        | Some (current_class, (super_class :: _ as super_classes)) ->
            let middle =
              if List.exists super_classes ~f:(Typ.Name.equal current_class) then ""
              else F.asprintf " extends %a, which" (MF.wrap_monospaced Typ.Name.pp) super_class
            in
            Some
              (F.asprintf "class %s%s is annotated %s"
                 (MF.monospaced_to_string (Typ.Name.name current_class))
                 middle
                 (MF.monospaced_to_string Annotations.ui_thread))
        | _ ->
            None )