(* This file is part of the Catala compiler, a specification language for tax
   and social benefits computation rules. Copyright (C) 2020 Inria,
   contributors: Denis Merigoux <denis.merigoux@inria.fr>, Emile Rolley
   <emile.rolley@tuta.io>

   Licensed under the Apache License, Version 2.0 (the "License"); you may not
   use this file except in compliance with the License. You may obtain a copy of
   the License at

   http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   License for the specific language governing permissions and limitations under
   the License. *)

module Cli = Utils.Cli
module File = Utils.File
module Errors = Utils.Errors
module Pos = Utils.Pos

(** Associates a {!type: Cli.backend_lang} with its string represtation. *)
let languages = ["en", Cli.En; "fr", Cli.Fr; "pl", Cli.Pl]

(** Associates a file extension with its corresponding {!type: Cli.backend_lang}
    string representation. *)
let extensions = [".catala_fr", "fr"; ".catala_en", "en"; ".catala_pl", "pl"]

(** Entry function for the executable. Returns a negative number in case of
    error. Usage: [driver source_file options]*)
let driver source_file (options : Cli.options) : int =
  try
    List.iter
      (fun d ->
        match Sys.is_directory d with
        | true -> Plugin.load_dir d
        | false -> ()
        | exception Sys_error _ -> ())
      options.plugins_dirs;
    Cli.set_option_globals options;
    Cli.debug_print "Reading files...";
    let filename = ref "" in
    (match source_file with
    | Pos.FileName f -> filename := f
    | Contents c -> Cli.contents := c);
    (match options.max_prec_digits with
    | None -> ()
    | Some i -> Cli.max_prec_digits := i);
    let l =
      match options.language with
      | Some l -> l
      | None -> (
        (* Try to infer the language from the intput file extension. *)
        let ext = Filename.extension !filename in
        if ext = "" then
          Errors.raise_error
            "No file extension found for the file '%s'. (Try to add one or to \
             specify the -l flag)"
            !filename;
        try List.assoc ext extensions with Not_found -> ext)
    in
    let language =
      try List.assoc l languages
      with Not_found ->
        Errors.raise_error
          "The selected language (%s) is not supported by Catala" l
    in
    Cli.locale_lang := language;
    let backend = options.backend in
    let backend =
      match Cli.backend_option_of_string backend with
      | #Cli.backend_option_builtin as backend -> backend
      | `Plugin s -> (
        try `Plugin (Plugin.find s)
        with Not_found ->
          Errors.raise_error
            "The selected backend (%s) is not supported by Catala" backend)
    in
    let prgm =
      Surface.Parser_driver.parse_top_level_file source_file language
    in
    let prgm = Surface.Fill_positions.fill_pos_with_legislative_info prgm in
    (match backend with
    | `Makefile ->
      let backend_extensions_list = [".tex"] in
      let source_file =
        match source_file with
        | FileName f -> f
        | Contents _ ->
          Errors.raise_error
            "The Makefile backend does not work if the input is not a file"
      in
      let output_file =
        match options.output_file with
        | Some f -> f
        | None -> Filename.remove_extension source_file ^ ".d"
      in
      Cli.debug_print "Writing list of dependencies to %s..." output_file;
      File.with_out_channel output_file @@ fun oc ->
      Printf.fprintf oc "%s:\\\n%s\n%s:"
        (String.concat "\\\n"
           (output_file
           :: List.map
                (fun ext -> Filename.remove_extension source_file ^ ext)
                backend_extensions_list))
        (String.concat "\\\n" prgm.program_source_files)
        (String.concat "\\\n" prgm.program_source_files)
    | (`Latex | `Html) as backend ->
      let source_file =
        match source_file with
        | FileName f -> f
        | Contents _ ->
          Errors.raise_error
            "The literate programming backends do not work if the input is not \
             a file"
      in
      Cli.debug_print "Weaving literate program into %s"
        (match backend with `Latex -> "LaTeX" | `Html -> "HTML");
      let output_file =
        match options.output_file with
        | Some f -> f
        | None -> (
          Filename.remove_extension source_file
          ^ match backend with `Latex -> ".tex" | `Html -> ".html")
      in
      File.with_formatter_of_file output_file (fun fmt ->
          let weave_output =
            match backend with
            | `Latex ->
              Literate.Latex.ast_to_latex language
                ~print_only_law:options.print_only_law
            | `Html ->
              Literate.Html.ast_to_html language
                ~print_only_law:options.print_only_law
          in
          Cli.debug_print "Writing to %s" output_file;
          if options.wrap_weaved_output then
            match backend with
            | `Latex ->
              Literate.Latex.wrap_latex prgm.Surface.Ast.program_source_files
                language fmt (fun fmt -> weave_output fmt prgm)
            | `Html ->
              Literate.Html.wrap_html prgm.Surface.Ast.program_source_files
                language fmt (fun fmt -> weave_output fmt prgm)
          else weave_output fmt prgm)
    | ( `Interpret | `Typecheck | `OCaml | `Python | `Scalc | `Lcalc | `Dcalc
      | `Scopelang | `Proof | `Plugin _ ) as backend -> (
      Cli.debug_print "Name resolution...";
      let ctxt = Surface.Name_resolution.form_context prgm in
      let scope_uid =
        match options.ex_scope, backend with
        | None, `Interpret ->
          Errors.raise_error "No scope was provided for execution."
        | None, _ ->
          snd
            (try Desugared.Ast.IdentMap.choose ctxt.scope_idmap
             with Not_found ->
               Errors.raise_error "There isn't any scope inside the program.")
        | Some name, _ -> (
          match Desugared.Ast.IdentMap.find_opt name ctxt.scope_idmap with
          | None ->
            Errors.raise_error "There is no scope \"%s\" inside the program."
              name
          | Some uid -> uid)
      in
      Cli.debug_print "Desugaring...";
      let prgm = Surface.Desugaring.desugar_program ctxt prgm in
      Cli.debug_print "Collecting rules...";
      let prgm = Desugared.Desugared_to_scope.translate_program prgm in
      match backend with
      | `Scopelang ->
        File.with_formatter_of_opt_file options.output_file @@ fun fmt ->
        if Option.is_some options.ex_scope then
          Format.fprintf fmt "%a\n"
            (Scopelang.Print.format_scope ~debug:options.debug)
            ( scope_uid,
              Scopelang.Ast.ScopeMap.find scope_uid prgm.program_scopes )
        else
          Format.fprintf fmt "%a\n"
            (Scopelang.Print.format_program ~debug:options.debug)
            prgm
      | ( `Interpret | `Typecheck | `OCaml | `Python | `Scalc | `Lcalc | `Dcalc
        | `Proof | `Plugin _ ) as backend -> (
        Cli.debug_print "Translating to default calculus...";
        let prgm, type_ordering =
          Scopelang.Scope_to_dcalc.translate_program prgm
        in
        let prgm =
          if options.optimize then begin
            Cli.debug_print "Optimizing default calculus...";
            Dcalc.Optimizations.optimize_program prgm
          end
          else prgm
        in
        let prgrm_dcalc_expr =
          Bindlib.unbox (Dcalc.Ast.build_whole_program_expr prgm scope_uid)
        in
        match backend with
        | `Dcalc ->
          File.with_formatter_of_opt_file options.output_file @@ fun fmt ->
          if Option.is_some options.ex_scope then
            Format.fprintf fmt "%a\n"
              (Dcalc.Print.format_scope ~debug:options.debug prgm.decl_ctx)
              ( scope_uid,
                Option.get
                  (Dcalc.Ast.fold_left_scope_defs ~init:None
                     ~f:(fun acc scope_def _ ->
                       if
                         Dcalc.Ast.ScopeName.compare scope_def.scope_name
                           scope_uid
                         = 0
                       then Some scope_def.scope_body
                       else acc)
                     prgm.scopes) )
          else
            Format.fprintf fmt "%a\n"
              (Dcalc.Print.format_expr prgm.decl_ctx)
              prgrm_dcalc_expr
        | ( `Interpret | `Typecheck | `OCaml | `Python | `Scalc | `Lcalc
          | `Proof | `Plugin _ ) as backend -> (
          Cli.debug_print "Typechecking...";
          let _typ = Dcalc.Typing.infer_type prgm.decl_ctx prgrm_dcalc_expr in
          (* Cli.debug_print (Format.asprintf "Typechecking results :@\n%a"
             (Dcalc.Print.format_typ prgm.decl_ctx) typ); *)
          match backend with
          | `Typecheck ->
            (* That's it! *)
            Cli.result_print "Typechecking successful!"
          | `Proof ->
            let vcs =
              Verification.Conditions.generate_verification_conditions prgm
                (match options.ex_scope with
                | None -> None
                | Some _ -> Some scope_uid)
            in

            Verification.Solver.solve_vc prgm.decl_ctx vcs
          | `Interpret ->
            Cli.debug_print "Starting interpretation...";
            let results =
              Dcalc.Interpreter.interpret_program prgm.decl_ctx prgrm_dcalc_expr
            in
            let out_regex = Re.Pcre.regexp "\\_out$" in
            let results =
              List.map
                (fun ((v1, v1_pos), e1) ->
                  let v1 =
                    Re.Pcre.substitute ~rex:out_regex ~subst:(fun _ -> "") v1
                  in
                  (v1, v1_pos), e1)
                results
            in
            let results =
              List.sort
                (fun ((v1, _), _) ((v2, _), _) -> String.compare v1 v2)
                results
            in
            Cli.debug_print "End of interpretation";
            Cli.result_print "Computation successful!%s"
              (if List.length results > 0 then " Results:" else "");
            List.iter
              (fun ((var, _), result) ->
                Cli.result_format "@[<hov 2>%s@ =@ %a@]" var
                  (Dcalc.Print.format_expr ~debug:options.debug prgm.decl_ctx)
                  result)
              results
          | (`OCaml | `Python | `Lcalc | `Scalc | `Plugin _) as backend -> (
            Cli.debug_print "Compiling program into lambda calculus...";
            let prgm =
              if options.avoid_exceptions then
                Lcalc.Compile_without_exceptions.translate_program prgm
              else Lcalc.Compile_with_exceptions.translate_program prgm
            in
            let prgm =
              if options.optimize then begin
                Cli.debug_print "Optimizing lambda calculus...";
                Lcalc.Optimizations.optimize_program prgm
              end
              else prgm
            in
            let prgm =
              if options.closure_conversion then (
                Cli.debug_print "Performing closure conversion...";
                let prgm = Lcalc.Closure_conversion.closure_conversion prgm in
                let prgm = Bindlib.unbox prgm in
                prgm)
              else prgm
            in
            match backend with
            | `Lcalc ->
              File.with_formatter_of_opt_file options.output_file @@ fun fmt ->
              if Option.is_some options.ex_scope then
                Format.fprintf fmt "%a\n"
                  (Lcalc.Print.format_scope ~debug:options.debug prgm.decl_ctx)
                  ( scope_uid,
                    Option.get
                      (Dcalc.Ast.fold_left_scope_defs ~init:None
                         ~f:(fun acc scope_def _ ->
                           if
                             Dcalc.Ast.ScopeName.compare scope_def.scope_name
                               scope_uid
                             = 0
                           then Some scope_def.scope_body
                           else acc)
                         prgm.scopes) )
              else
                ignore
                  (Dcalc.Ast.fold_left_scope_defs ~init:0
                     ~f:(fun i scope_def _ ->
                       Format.fprintf fmt "%s%a"
                         (if i = 0 then "" else "\n")
                         (Lcalc.Print.format_scope prgm.decl_ctx)
                         (scope_uid, scope_def.scope_body);
                       i + 1)
                     prgm.scopes)
            | (`OCaml | `Python | `Scalc | `Plugin _) as backend -> (
              let source_file =
                match source_file with
                | FileName f -> f
                | Contents _ ->
                  Errors.raise_error
                    "This backend does not work if the input is not a file"
              in
              let new_output_file (extension : string) : string =
                match options.output_file with
                | Some f -> f
                | None -> Filename.remove_extension source_file ^ extension
              in
              match backend with
              | `OCaml ->
                let output_file = new_output_file ".ml" in
                File.with_out_channel output_file @@ fun oc ->
                let fmt = Format.formatter_of_out_channel oc in
                Cli.debug_print "Compiling program into OCaml...";
                Cli.debug_print "Writing to %s..." output_file;
                Lcalc.To_ocaml.format_program fmt prgm type_ordering
              | `Plugin (Plugin.Lcalc p) ->
                let output_file = new_output_file p.Plugin.extension in
                Cli.debug_print "Compiling program through backend \"%s\"..."
                  p.Plugin.name;
                Cli.debug_print "Writing to %s..." output_file;
                p.Plugin.apply output_file prgm type_ordering
              | (`Python | `Scalc | `Plugin (Plugin.Scalc _)) as backend -> (
                let prgm = Scalc.Compile_from_lambda.translate_program prgm in
                match backend with
                | `Scalc ->
                  File.with_formatter_of_opt_file options.output_file
                  @@ fun fmt ->
                  if Option.is_some options.ex_scope then
                    Format.fprintf fmt "%a\n"
                      (Scalc.Print.format_scope ~debug:options.debug
                         prgm.decl_ctx)
                      (List.find
                         (fun body ->
                           body.Scalc.Ast.scope_body_name = scope_uid)
                         prgm.scopes)
                  else
                    Format.fprintf fmt "%a\n"
                      (Format.pp_print_list
                         ~pp_sep:(fun fmt () -> Format.fprintf fmt "\n\n")
                         (fun fmt scope ->
                           (Scalc.Print.format_scope prgm.decl_ctx) fmt scope))
                      prgm.scopes
                | `Python ->
                  let output_file = new_output_file ".py" in
                  Cli.debug_print "Compiling program into Python...";
                  Cli.debug_print "Writing to %s..." output_file;
                  File.with_out_channel output_file @@ fun oc ->
                  let fmt = Format.formatter_of_out_channel oc in
                  Scalc.To_python.format_program fmt prgm type_ordering
                | `Plugin (Plugin.Lcalc _) -> assert false
                | `Plugin (Plugin.Scalc p) ->
                  let output_file = new_output_file p.Plugin.extension in
                  Cli.debug_print "Compiling program through backend \"%s\"..."
                    p.Plugin.name;
                  Cli.debug_print "Writing to %s..." output_file;
                  p.Plugin.apply output_file prgm type_ordering)))))));
    0
  with
  | Errors.StructuredError (msg, pos) ->
    Cli.error_print "%s" (Errors.print_structured_error msg pos);
    -1
  | Sys_error msg ->
    Cli.error_print "System error: %s" msg;
    -1

let main () =
  let return_code =
    Cmdliner.Cmd.eval'
      (Cmdliner.Cmd.v Cli.info (Cli.catala_t (fun f -> driver (FileName f))))
  in
  exit return_code

(* Export module PluginAPI, hide parent module Plugin *)
module Plugin = Plugin.PluginAPI