let usage =
  {|coollang toolchain

사용법:
  coolc check <file.cool>...   타입/effect/capability 검사 (import를 따라 모듈 그래프 전체)
  coolc iface <file.cool>      interface 표면과 해시 출력
  coolc run <file.cool>        typed IR 인터프리터로 실행
  coolc tokens <file.cool>     토큰 덤프 (렉서 디버깅)
  coolc ast <file.cool>        구문 트리 덤프 (파서 디버깅)
  coolc deps <file.cool>       외부 참조 목록 (모듈의 의존 표면)
  coolc version                버전 출력
|}

let report_errors errors =
  List.iter (fun e -> prerr_endline (Coollang.Driver.string_of_error e)) errors;
  1

let report = function Ok () -> 0 | Error errors -> report_errors errors

let dump_tokens file =
  match Coollang.Driver.tokens file with
  | Error errors -> report_errors errors
  | Ok tokens ->
      List.iter (fun t -> print_endline (Coollang.Token.show t)) tokens;
      0

let dump_ast file =
  match Coollang.Driver.ast file with
  | Error errors -> report_errors errors
  | Ok m ->
      List.iter
        (fun it -> print_endline (Coollang.Ast.show_item it))
        m.Coollang.Ast.items;
      0

(* import를 따라 모듈 그래프를 로드하고 전부 검사한다. root는 첫 파일의 디렉터리다. *)
let check_graph files =
  match files with
  | [] ->
      prerr_endline "검사할 파일이 없습니다";
      2
  | first :: _ ->
      let st = Coollang.Session.create ~root:(Filename.dirname first) () in
      List.iter (fun f -> Coollang.Session.load st f) files;
      let errors = Coollang.Session.errors st in
      List.iter
        (fun e -> prerr_endline (Coollang.Session.string_of_error e))
        errors;
      if errors = [] then 0 else 1

let dump_iface file =
  let st = Coollang.Session.create ~root:(Filename.dirname file) () in
  Coollang.Session.load st file;
  match Coollang.Session.find st file with
  | None -> 1
  | Some e ->
      Printf.printf "hash %s\n" e.iface.Coollang.Iface.hash;
      List.iter
        (fun it -> print_endline (Coollang.Ast.show_item it))
        e.iface.Coollang.Iface.items;
      0

let dump_deps file =
  match Coollang.Driver.resolve file with
  | Error errors -> report_errors errors
  | Ok info ->
      List.iter
        (fun (name, (p : Coollang.Token.pos)) ->
          Printf.printf "%d:%d %s\n" p.line p.col name)
        info.Coollang.Resolve.externals;
      0

let () =
  let argv = Array.to_list Sys.argv in
  let code =
    match List.tl argv with
    | "check" :: files -> check_graph files
    | [ "iface"; file ] -> dump_iface file
    | [ "run"; file ] -> report (Coollang.Driver.run file)
    | [ "tokens"; file ] -> dump_tokens file
    | [ "ast"; file ] -> dump_ast file
    | [ "deps"; file ] -> dump_deps file
    | [ "version" ] ->
        print_endline Coollang.Version.string;
        0
    | [] | [ "help" ] | [ "--help" ] | [ "-h" ] ->
        print_string usage;
        0
    | cmd :: _ ->
        Printf.eprintf "알 수 없는 명령: %s\n\n%s" cmd usage;
        2
  in
  exit code