(*
 * Copyright (c) 2016-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 L = Logging

let already_imported_files = ref []

let rec parse_import_file import_file channel =
  if List.mem ~equal:String.equal !already_imported_files import_file then
    L.(die ExternalError) "Cyclic imports: file '%s' was already imported." import_file
  else
    match CTLParserHelper.parse_al_file import_file channel with
    | Some
        { import_files= imports
        ; global_macros= curr_file_macros
        ; global_paths= curr_file_paths
        ; checkers= _ } ->
        already_imported_files := import_file :: !already_imported_files ;
        collect_all_macros_and_paths ~from_file:import_file imports curr_file_macros
          curr_file_paths
    | None ->
        L.(debug Linters Medium) "No macros or paths found.@\n" ;
        ([], [])


and collect_all_macros_and_paths ~from_file imports curr_file_macros curr_file_paths =
  L.(debug Linters Medium) "#### Start parsing import macros #####@\n" ;
  let import_macros, import_paths = parse_imports ~from_file imports in
  L.(debug Linters Medium) "#### Add global macros to import macros #####@\n" ;
  let macros = List.append import_macros curr_file_macros in
  let paths = List.append import_paths curr_file_paths in
  (macros, paths)


(** Parse import files with macro definitions, and return a list of LET clauses *)
and parse_imports ~from_file imports_files =
  let source_dir = Filename.dirname from_file in
  let resolve_import fimport =
    if Filename.is_relative fimport then source_dir ^/ fimport else fimport |> Filename.realpath
  in
  let parse_one_import_file fimport0 (macros, paths) =
    let fimport = resolve_import fimport0 in
    L.(debug Linters Medium) "  Loading import macros from file %s@\n" fimport ;
    let in_channel = In_channel.create fimport in
    let parsed_macros, parsed_paths = parse_import_file fimport in_channel in
    In_channel.close in_channel ;
    let macros = List.append parsed_macros macros in
    let paths = List.append parsed_paths paths in
    (macros, paths)
  in
  List.fold_right ~f:parse_one_import_file ~init:([], []) imports_files


let parse_ctl_file linters_def_file channel : CFrontend_errors.linter list =
  match CTLParserHelper.parse_al_file linters_def_file channel with
  | Some
      { import_files= imports
      ; global_macros= curr_file_macros
      ; global_paths= curr_file_paths
      ; checkers= parsed_checkers } ->
      already_imported_files := [linters_def_file] ;
      let macros, paths =
        collect_all_macros_and_paths ~from_file:linters_def_file imports curr_file_macros
          curr_file_paths
      in
      let macros_map = CFrontend_errors.build_macros_map macros in
      let paths_map = CFrontend_errors.build_paths_map paths in
      L.(debug Linters Medium) "#### Start Expanding checkers #####@\n" ;
      let exp_checkers = CFrontend_errors.expand_checkers macros_map paths_map parsed_checkers in
      L.(debug Linters Medium) "#### Checkers Expanded #####@\n" ;
      if Config.debug_mode then List.iter ~f:CTL.print_checker exp_checkers ;
      CFrontend_errors.create_parsed_linters linters_def_file exp_checkers
  | None ->
      L.(debug Linters Medium) "No linters found.@\n" ;
      []


(** Parse the files with linters definitions, and return a list of linters *)
let parse_ctl_files linters_def_files : CFrontend_errors.linter list =
  let collect_parsed_linters linters_def_file linters =
    L.(debug Linters Medium) "Loading linters rules from %s@\n" linters_def_file ;
    let in_channel = In_channel.create linters_def_file in
    let parsed_linters = parse_ctl_file linters_def_file in_channel in
    In_channel.close in_channel ;
    List.append parsed_linters linters
  in
  List.fold_right ~f:collect_parsed_linters ~init:[] linters_def_files


let rec get_responds_to_selector stmt =
  let open Clang_ast_t in
  let responToSelectorMethods = ["respondsToSelector:"; "instancesRespondToSelector:"] in
  match stmt with
  | ObjCMessageExpr (_, [_; ObjCSelectorExpr (_, _, _, method_name)], _, mdi)
  | ObjCMessageExpr (_, [ObjCSelectorExpr (_, _, _, method_name)], _, mdi)
    when List.mem ~equal:String.equal responToSelectorMethods mdi.Clang_ast_t.omei_selector ->
      [method_name]
  | BinaryOperator (_, [stmt1; stmt2], _, bo_info)
    when PolyVariantEqual.( = ) bo_info.Clang_ast_t.boi_kind `LAnd ->
      List.append (get_responds_to_selector stmt1) (get_responds_to_selector stmt2)
  | ImplicitCastExpr (_, [stmt], _, _)
  | ParenExpr (_, [stmt], _)
  | ExprWithCleanups (_, [stmt], _, _) ->
      get_responds_to_selector stmt
  | _ ->
      []


let rec is_core_foundation_version_number stmt =
  let open Clang_ast_t in
  match stmt with
  | DeclRefExpr (_, _, _, decl_ref_info) -> (
    match decl_ref_info.drti_decl_ref with
    | Some decl_ref_info ->
        let name_info, _, _ = CAst_utils.get_info_from_decl_ref decl_ref_info in
        String.equal name_info.ni_name "kCFCoreFoundationVersionNumber"
    | None ->
        false )
  | ImplicitCastExpr (_, [stmt], _, _) ->
      is_core_foundation_version_number stmt
  | _ ->
      false


let rec current_os_version_constant stmt =
  let open Clang_ast_t in
  match stmt with
  | FloatingLiteral (_, _, _, number) ->
      CiOSVersionNumbers.version_of number
  | IntegerLiteral (_, _, _, info) ->
      CiOSVersionNumbers.version_of info.ili_value
  | ImplicitCastExpr (_, [stmt], _, _) ->
      current_os_version_constant stmt
  | _ ->
      None


let rec get_current_os_version stmt =
  let open Clang_ast_t in
  match stmt with
  | BinaryOperator (_, [stmt1; stmt2], _, bo_info)
    when PolyVariantEqual.( = ) bo_info.Clang_ast_t.boi_kind `GE
         && is_core_foundation_version_number stmt1 ->
      Option.to_list (current_os_version_constant stmt2)
  | BinaryOperator (_, [stmt1; stmt2], _, bo_info)
    when PolyVariantEqual.( = ) bo_info.Clang_ast_t.boi_kind `LE
         && is_core_foundation_version_number stmt2 ->
      Option.to_list (current_os_version_constant stmt1)
  | BinaryOperator (_, [stmt1; stmt2], _, bo_info)
    when PolyVariantEqual.( = ) bo_info.Clang_ast_t.boi_kind `LAnd ->
      List.append (get_current_os_version stmt1) (get_current_os_version stmt2)
  | ImplicitCastExpr (_, [stmt], _, _)
  | ParenExpr (_, [stmt], _)
  | ExprWithCleanups (_, [stmt], _, _) ->
      get_current_os_version stmt
  | _ ->
      []


let rec get_ios_available_version stmt =
  let open Clang_ast_t in
  match stmt with
  | ObjCAvailabilityCheckExpr (_, _, _, oacei) ->
      oacei.oacei_version
  | ImplicitCastExpr (_, [stmt], _, _)
  | ParenExpr (_, [stmt], _)
  | ExprWithCleanups (_, [stmt], _, _) ->
      get_ios_available_version stmt
  | _ ->
      None


let compute_if_context (context : CLintersContext.context) stmt =
  let selector = get_responds_to_selector stmt in
  let receiver_class_method_call =
    match
      (CPredicates.get_selector (Stmt stmt), CPredicates.receiver_class_method_call (Stmt stmt))
    with
    | Some selector, Some receiver when String.equal selector "class" ->
        Option.to_list (CPredicates.declaration_name receiver)
    | _ ->
        []
  in
  let os_version = get_current_os_version stmt in
  let ios_available_version_opt = Option.to_list (get_ios_available_version stmt) in
  let os_version = List.append ios_available_version_opt os_version in
  let within_responds_to_selector_block, within_available_class_block, ios_version_guard =
    match context.if_context with
    | Some if_context ->
        let within_responds_to_selector_block =
          List.append selector if_context.within_responds_to_selector_block
        in
        let within_available_class_block =
          List.append receiver_class_method_call if_context.within_available_class_block
        in
        let ios_version_guard = List.append os_version if_context.ios_version_guard in
        (within_responds_to_selector_block, within_available_class_block, ios_version_guard)
    | None ->
        (selector, receiver_class_method_call, os_version)
  in
  Some
    ( {within_responds_to_selector_block; within_available_class_block; ios_version_guard}
      : CLintersContext.if_context )


let get_method_body_opt decl =
  let open Clang_ast_t in
  match decl with
  | FunctionDecl (_, _, _, fdi)
  | CXXMethodDecl (_, _, _, fdi, _)
  | CXXConstructorDecl (_, _, _, fdi, _)
  | CXXConversionDecl (_, _, _, fdi, _)
  | CXXDestructorDecl (_, _, _, fdi, _) ->
      fdi.Clang_ast_t.fdi_body
  | ObjCMethodDecl (_, _, mdi) ->
      mdi.Clang_ast_t.omdi_body
  | BlockDecl (_, block_decl_info) ->
      block_decl_info.Clang_ast_t.bdi_body
  | _ ->
      Logging.die InternalError "Should only be called with method, but got %s"
        (Clang_ast_proj.get_decl_kind_string decl)


let call_tableaux linters cxt an map_active =
  if CFrontend_config.tableaux_evaluation then Tableaux.build_valuation linters an cxt map_active


let rec do_frontend_checks_stmt linters (context : CLintersContext.context)
    (map_act : Tableaux.context_linter_map) stmt =
  let open Clang_ast_t in
  let an = Ctl_parser_types.Stmt stmt in
  (*L.(debug Linters Medium)
    "@\n >>>>>>Visit node %i <<<<<@\n" (Ctl_parser_types.ast_node_pointer an) ; *)
  let do_all_checks_on_stmts context map_active stmt =
    ( match stmt with
    | DeclStmt (_, _, decl_list) ->
        List.iter ~f:(do_frontend_checks_decl linters context map_active) decl_list
    | BlockExpr (_, _, _, decl) ->
        List.iter ~f:(do_frontend_checks_decl linters context map_active) [decl]
    | _ ->
        () ) ;
    do_frontend_checks_stmt linters context map_active stmt
  in
  CFrontend_errors.invoke_set_of_checkers_on_node linters context an ;
  (* The map should be visited when we enter the node before visiting children *)
  let map_active = Tableaux.update_linter_context_map linters an map_act in
  let stmt_context_list =
    match stmt with
    | ObjCAtSynchronizedStmt (_, stmt_list) ->
        [({context with CLintersContext.in_synchronized_block= true}, stmt_list)]
    | OpaqueValueExpr (_, lstmt, _, opaque_value_expr_info) -> (
      match opaque_value_expr_info.Clang_ast_t.ovei_source_expr with
      | Some stmt ->
          [(context, lstmt @ [stmt])]
      | _ ->
          [(context, lstmt)] )
    | IfStmt (_, [stmt1; stmt2; cond_stmt; inside_if_stmt; inside_else_stmt]) ->
        let inside_if_stmt_context =
          {context with CLintersContext.if_context= compute_if_context context cond_stmt}
        in
        (* distinguish between then and else branch as they need different context *)
        [ (context, [stmt1; stmt2; cond_stmt; inside_else_stmt])
        ; (inside_if_stmt_context, [inside_if_stmt]) ]
    | ForStmt (_, stmt1 :: stmts) ->
        let inside_for_stmt_decl_context =
          {context with CLintersContext.in_for_loop_declaration= true}
        in
        [(context, stmts); (inside_for_stmt_decl_context, [stmt1])]
    | _ ->
        [(context, snd (Clang_ast_proj.get_stmt_tuple stmt))]
  in
  if CFrontend_config.tableaux_evaluation then
    (* Unlike in the standard algorithm, nodes reachable via transitions
       PointerToDecl are not visited
       during the evaluation of the formula. So we need to visit
       them diring the general visit of the tree. *)
    do_frontend_checks_via_transition linters context map_active an CTL.PointerToDecl ;
  List.iter
    ~f:(fun (cxt, stmts) ->
      List.iter ~f:(do_all_checks_on_stmts cxt map_active) stmts ;
      call_tableaux linters cxt an map_active )
    stmt_context_list


(* Visit nodes via a transition *)
and do_frontend_checks_via_transition linters context map_active an trans =
  let succs = CTL.next_state_via_transition an trans in
  List.iter
    ~f:(fun an' ->
      (*L.(debug Linters Medium)
        "@\n---- Going from %i to %i via transition %a ---- @\n"
        (Ctl_parser_types.ast_node_pointer an) (Ctl_parser_types.ast_node_pointer an')
        CTL.Debug.pp_transition (Some trans) ;*)
      match an' with
      | Ctl_parser_types.Decl d ->
          do_frontend_checks_decl linters context map_active d
      | Ctl_parser_types.Stmt st ->
          do_frontend_checks_stmt linters context map_active st )
    succs


and do_frontend_checks_decl linters (context : CLintersContext.context)
    (map_act : Tableaux.context_linter_map) decl =
  let open Clang_ast_t in
  if CAst_utils.is_implicit_decl decl then () (* do not analyze implicit declarations *)
  else
    let an = Ctl_parser_types.Decl decl in
    (* The map should be visited when we enter the node before visiting children *)
    let map_active = Tableaux.update_linter_context_map linters an map_act in
    match decl with
    | FunctionDecl _
    | CXXMethodDecl _
    | CXXConstructorDecl _
    | CXXConversionDecl _
    | CXXDestructorDecl _
    | BlockDecl _
    | ObjCMethodDecl _ ->
        let context' = CLintersContext.update_current_method context decl in
        CFrontend_errors.invoke_set_of_checkers_on_node linters context' an ;
        (* We need to visit explicitly nodes reachable via Parameters transitions
      because they won't be visited during the evaluation of the formula *)
        do_frontend_checks_via_transition linters context' map_active an CTL.Parameters ;
        ( match get_method_body_opt decl with
        | Some stmt ->
            do_frontend_checks_stmt linters context' map_active stmt
        | None ->
            () ) ;
        call_tableaux linters context' an map_active
    | ObjCImplementationDecl (_, _, decls, _, _) | ObjCInterfaceDecl (_, _, decls, _, _) ->
        CFrontend_errors.invoke_set_of_checkers_on_node linters context an ;
        let context' = {context with current_objc_class= Some decl} in
        List.iter ~f:(do_frontend_checks_decl linters context' map_active) decls ;
        call_tableaux linters context' an map_active
    | ObjCCategoryImplDecl (_, _, decls, _, _) | ObjCCategoryDecl (_, _, decls, _, _) ->
        CFrontend_errors.invoke_set_of_checkers_on_node linters context an ;
        let context' = {context with current_objc_category= Some decl} in
        List.iter ~f:(do_frontend_checks_decl linters context' map_active) decls ;
        call_tableaux linters context' an map_active
    | ObjCProtocolDecl (_, _, decls, _, _) ->
        CFrontend_errors.invoke_set_of_checkers_on_node linters context an ;
        let context' = {context with current_objc_protocol= Some decl} in
        List.iter ~f:(do_frontend_checks_decl linters context' map_active) decls ;
        call_tableaux linters context' an map_active
    | _ ->
        CFrontend_errors.invoke_set_of_checkers_on_node linters context an ;
        ( match Clang_ast_proj.get_decl_context_tuple decl with
        | Some (decls, _) ->
            List.iter ~f:(do_frontend_checks_decl linters context map_active) decls
        | None ->
            () ) ;
        call_tableaux linters context an map_active


let context_with_ck_set context decl_list =
  let is_ck =
    context.CLintersContext.is_ck_translation_unit || ComponentKit.contains_ck_impl decl_list
  in
  if is_ck then {context with CLintersContext.is_ck_translation_unit= true} else context


let find_linters_files () =
  List.concat_map
    ~f:(fun folder -> Utils.find_files ~path:folder ~extension:".al")
    Config.linters_def_folder


let linters_files =
  List.dedup_and_sort ~compare:String.compare (find_linters_files () @ Config.linters_def_file)


let do_frontend_checks (trans_unit_ctx : CFrontend_config.translation_unit_context) ast =
  CFrontend_errors.issue_log := IssueLog.empty ;
  L.(debug Capture Quiet)
    "Loading the following linters files: %a@\n"
    (Pp.comma_seq Format.pp_print_string)
    linters_files ;
  CTL.create_ctl_evaluation_tracker trans_unit_ctx.source_file ;
  let parsed_linters =
    let parsed_linters = parse_ctl_files linters_files in
    CFrontend_errors.filter_parsed_linters parsed_linters trans_unit_ctx.source_file
  in
  let source_file = trans_unit_ctx.CFrontend_config.source_file in
  L.(debug Linters Medium)
    "Start linting file %a with rules: @\n%a@\n" SourceFile.pp source_file
    CFrontend_errors.pp_linters parsed_linters ;
  if Config.print_active_checkers then
    L.progress "Linting file %a, active linters: @\n%a@\n" SourceFile.pp source_file
      CFrontend_errors.pp_linters parsed_linters ;
  Tableaux.init_global_nodes_valuation () ;
  match ast with
  | Clang_ast_t.TranslationUnitDecl (_, decl_list, _, _) ->
      let context = context_with_ck_set (CLintersContext.empty trans_unit_ctx) decl_list in
      let allowed_decls = List.filter ~f:(Tableaux.is_decl_allowed context) decl_list in
      (* We analyze the top level and then all the allowed declarations *)
      let active_map : Tableaux.context_linter_map = Tableaux.init_active_map parsed_linters in
      CFrontend_errors.invoke_set_of_checkers_on_node parsed_linters context
        (Ctl_parser_types.Decl ast) ;
      List.iter ~f:(do_frontend_checks_decl parsed_linters context active_map) allowed_decls ;
      IssueLog.store !CFrontend_errors.issue_log ~dir:Config.lint_issues_dir_name ~file:source_file ;
      L.(debug Linters Medium) "End linting file %a@\n" SourceFile.pp source_file ;
      CTL.save_dotty_when_in_debug_mode trans_unit_ctx.CFrontend_config.source_file
      (*if CFrontend_config.tableaux_evaluation then (
        Tableaux.print_table_size () ;
        Tableaux.print_global_valuation_map ()) *)
  | _ (* NOTE: Assumes that an AST always starts with a TranslationUnitDecl *) ->
      assert false
